The Serenity of Big Volcanoes: Recovery Running around Kilauea

The greater part of the vast floor of the desert under us was as black as ink, and apparently smooth and level; but over a mile square of it was ringed and streaked and striped with a thousand branching streams of liquid and gorgeously brilliant fire! It looked like a colossal railroad map of the State of Massachusetts done in chain lightning on a midnight sky. Imagine it – imagine a coal-black sky shivered into a tangled network of angry fire! Mark Twain, on his visit to Kilauea in June, 1866.

Halemaumau

Halemaumau – a crater within a crater. Halemaumau is a crater within the large summit crater of Kilauea, and has been active with lava lakes rising and falling in the last 2 years. This photo is from about a mile away and 1,500 feet above Halemaumau. The smoke is one of the main reasons the crater trail is closed. Click on any photo for full sized view.

Few things are more inspiring to a geoscientist, and disappointing to the average visitor, than the volcanoes of the Big Island of Hawaii.  In the last three quarters of a million years volcanic activity has built one of the largest mountains on Earth; in geologic terms this is almost a quantum time unit! Hawaii has 5 volcanic centers (and a sixth is waiting to emerge above sea level southeast of the island) which built a land mass with a surface area of over 4000 sq miles above sea level and has two summits topping 13,600 feet (Mauna Loa at 13,680′ and Mauna Kea at 13,800′ above sea level).  However, the average person that visits the Big Island is disappointed because these giants don’t have the crags and steep elevation gradients of stratvolcanoes like Mt. Rainier or Mt. St. Helens. True to their name, Hawaiian shield volcanoes the are shaped like the overturned shallow bowl shields of ancient Roman warriors.

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First glimpse of Hawaii on a flight from the mainland. On the left is the summit of Mauna Kea, and in the distance is Mauna Loa. The distance between the coastline in the picture and the summit of Mauna Kea is only 20 miles – making for spectacular prominence! But, alas, for most this view does not captivate.

These gentle giants are formed by thousands of eruptions that pour out basaltic lava that has the viscosity of hot syrup – and when it cools it leaves a simple layered stack of black rock.  Rarely are Hawaiian eruptions violent – no towering clouds of hot ash reaching 50,000′ above the surface of the Earth, or decapitating the tops of mountains like the 1980 eruption of Mt. St. Helens.  We like our geology violent…hence, the oft repeated comments at Volcanoes National Park, “is this all there is?  where is the lava?” When Mark Twain visited kilauea in 1866 he professed to being very disappointed.  He eventually warmed to the volcano, but was surprised at its “bland character”.

However, to the geoscientist, the enormity of Hawaii is spellbinding.  So much melted rock gives witness to the dynamics of a young and hot planet.  This is one of the wonders of the world that is so much bigger than mankind.  I have to frequently travel to Oahu for business, and I was able to stitch together a brief vacation on the Big Island which is coincident with the recovery period after running the Antelope Canyon Ultra.  There is no better way to experience geology than to run along the rocks;  recovery means sore legs (and in my case very tender feet), so the runs have to be short and slow (even slower than usual).  I planned a couple of short runs around Kilauea and long naps next to the wonderful beaches of the Kona Coast.  Running rejuvenated my body, but Kilauea soothed my soul.

Geologic map of the State of Hawai'i [Plate 8: Geologic map of the island of Hawai'i [scale 1:250,000]]

Geologic Map of the Big Island (scale 1:250,000).  The colors are largely related to age since all the rocks are pretty damn similar – basalt.  From the north (top of the map) the volcanoes are Kohala, Mauna Kea, Hualalai, Mauna Loa and Kilauea (all the red colored units).

Kilauea – Erupting since 1983!

The geology map of Hawaii resembles the tee-shirts seen at a Grateful Dead concert.  Colorful and vaguely psychedelic, the map is mostly stripes delineating lava flows.  The figure above shows the slow and steady march of the volcanoes to the south and east.  Kohala is now extinct, and Mauna Kea’s last eruption was more than 4500 years ago.  This volcanic trend, extending to all the Hawaiian Islands and the Emperor Seamount Chain located to the northwest, was one of the most mysterious geologic observations, and awaited the paradigm of plate tectonics for an explanation.  In 1963 J. Tuzo Wilson proposed that a “hot spot” caused all these volcanic islands – this hot spot was an upwelling of very hot mantle material  that melted through the cold oceanic plate (the Pacific Plate) as it moved to the northwest.  Imagine a blow torch beneath a piece of slowing moving tar paper.  The torch will melt the tar and leave a linear scar depicting the direction of motion of the tar paper.  Although Wilson’s hot spot model was a huge intellectual leap forward during the formative days of plate tectonics, it is now considered to be a gross simplification of a very complex process.  No matter, the theory does capture the fact that huge amounts of molten rock have reached the surface and built the Hawaiian Islands – and provides insight that Hawaii will continue to grow for millions of years into the future, with land masses emerging to the southeast of today’s Big Island (a far more benign process than what the Chinese are doing in the Spratly Islands….).

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The summit of Mauna Loa from the crater of Kilauea. The passing of the guard – Kilauea is now the most active volcano in the world, and sits some 9000 feet between the summit of Mauna Loa.

Kilauea is now the center of volcanic activity on Hawaii.  Eruptions might still occur on Mauna Loa (likely), Hualalai (plausible) and Mauna Kea (probably not), but Kilauea is spewing out basalt at prodigious rate, and in a few hundred thousand years will have a summit about 13,000 feet.  I first visited Kilauea in 1984 as a relatively new faculty member on a boondoggle (field trips are one of the main reasons scientists choose “geology” as a profession).  My visit corresponded with the one year anniversary of the an eruption on Kilauea – an eruption that has continued to today!

halemaumaufromdistance

Peering into Kilauea Crater from smoking cliffs. The view is disconcerting – below the grassy lip of the crater there is a 1500′ drop and then a nearly flat parking lot like layer of basalt. In the distance is a second crater, Halemaumau, which presently has a lave lake 300’below its crater lip.

On that first visit I got to hike through the Kilauea Crater, and right up to Halemuamau.  The 1983 eruption was producing lava several miles to the southeast of the crater, and there was little activity to indicate molten rock was ascending from some 60 km beneath the surface and collecting in shallower magma chambers.  Once the lava erupted it flows down the slopes of Kilauea into the sea. The focus of volcanic activity then was along what is called the southeastern rift zone; there were occasional fountains of lava out of a crater called Pu`u `Ō`ō, but it was not visible from the Kilauea Crater.

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Eruptions near Kilauea crater. Although only a few of the eruptions of Kilauea surface in the crater, there are numerous flows that constantly remake the landscape. Recovery Trail Runs were in Kilauea Iki, a path along Chain of Craters Road, and Keanakakoi Crater.

I have visited Kilauea many times since 1984, mostly because my wife had a post doctoral stint (1992-1994) with the USGS and worked on the geodetics of Kilauea.  Although it is common to think of Kilauea as a shield volcano, therefore, like its older brothers Mauna Loa and Mauna Kea, it is in fact very different at this stage of its development.  The magma being erupted from Kilauea most closely resembles the magma erupted from Mauna Kea.  So despite appearances – and being located high on the flank of Mauna Loa – Kilauea is the southwestern extension of Mauna Kea.

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A tectonic map of Kilauea. There are three important features: the summit crater, the southwest rift and the east rift zone. As Kilauea builds on the slope of Mauna Loa the weight of eruptive lava flows “pull away” from the summit and slide towards the sea opening up the rift zones.

Every time Kilauea erupts and lava pours out, it travels down hill towards the Pacific ocean.  As the lava cools it places a load on the Mauna Loa slope; this load eventually is too much for the slope to support and a wedge is “torn” away.  This wedge is defined by the summit crater, southwest rift zone, and east rift zone.  This “tearing” is really the odd shaped pie piece sliding downhill.  The tearing opens up creates other pathways for the magma stored beneath Kilauea to erupt on to the surface.  Until Kilauea grows tall enough to minimize the elevation head of Mauna Loa the rift zones will continue to have eruptions.

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Picture a lava flows exposed on the Chain of Craters Road. This is actually a tilted stack of basalt sheets. I took this picture on the Chain of Craters run.

This means that the volcano is not growing in a simple way – it builds, slips, and starts a new cycle of building that could be anywhere along the rift zones or the summit.  What is remarkable about the present eruption is that every part of the volcano has been active at one time or another; it started in east rift zone 10 miles from the summit and over a five year period 1 cubic mile of lava poured out.  In the 1990s the Pu`u `Ō`ō crater collapsed and numerous other new, smaller craters located northwest of Pu`u `Ō`ō opened up. Eventually, the volcanic center returned to Pu`u `Ō`ō, and by 2005 another couple of cubic miles of lava had flowed forth. In 2011 the volcanic activity shifted to the Kilauea Crater and southwestern rift zone, and on April 24, 2015, lava overflowed  Halema’uma’u crater within Kilauea.  It was this event that ultimately led to the closing of the trails and hiking near Kilauea.

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Volume of lava erupted from Kilauea in the last 200 years. The strong uptick in volcano growth on the right hand side of the chart is due to the present ongoing eruption.

It is difficult to fathom the rapid nature of the changes on Kilauea.  For a geoscientist it is like watching a movie at 100 times normal viewing speed.  The rocks may all look the same – black basalt – but face of the volcano is changing a rate that is similar to the changes in my own face (sags here and there, some age spots, and teeth falling out).  Running on rocks younger than me – way younger in some cases – is a unique experience!

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Running on the floor of Kilauea Iki. The basalt beneath my feet is from the 1959 eruption. Ever so slowly, trees are trying to reclaim the landscape.

Running on Rock Younger than Me

When I first envisioned this mini-vacation on the Big Island I thought I would try the ultimate volcano trail run — up to the summit of Mauna Loa from a trail head located near Kilauea.  The run starts at 6,000′ and over 19 miles climbs 7,500′ with traverses of rough lava flows interspersed with clumps of forest.  However, a 38 mile round trip — unsupported — was a total pipe dream.  Especially after running a 55 km ultra only days before arriving in Hawaii.  My next plan was to run through Kilauea Crater and recreate the hikes I experienced on my first visit. However, the plan was foiled when I found that the crater was off limits since the Halemaumau lava lake rose, and there was a significant increase in SO2 emissions (a very toxic gas!).  This meant that I was on to plan C, the best idea anyway.  I spent 2 days on 3 runs of modest distance (4-8 miles), and just enjoyed the rocks.

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The trail across Kilauea Iki. The view is approximately 1 mile to the southern rim.  A pathway can be made out streaking across the center of the frame.

The first run was down and across a crater located just southeast of Kilauea Crater, Kilauea Iki (see the map above – it is the green colored crater).  The trail is well maintained but rocky and challenging for a run.  Over a mile the path way drops 600 feet from the trail head to the Iki floor.  The Iki floor is a smooth surface, occasionally interrupted by fissures and blowouts. The age of the floor is easy to calculate – it is the 1959 eruption!  The rock is 3 years younger than me.  The race across the crater floor is easy and relatively fast (although fast is a relative term). The run from south to north in the crater took about 14 minutes – but then there is a long climb back up towards the rim.  The climb up is through thick vegetation – Iki is located right between the wet and dry side of Hawaii, and mists are a constant running companion.  The total trip is 4.5 miles; but the rain and mist meant that we had the crater nearly to our selves!

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One of the many bizarre basalt structures in the 1974 flow. The hole in the lower left of the figure is where the lava surrounded a tree – it eventually burned the tree away leaving a tunnel behind, and a lava clump to mark the former timber stand.

The next day I completed two other runs along the east rift zone (or more accurately, along the Chain of Craters Road).  The trails here wander from small crater to small crater.  Any crater older than about 30 years is being reclaimed by the vegetation.  The landscape is eery and strange.  Long sheets of basalt, but occasionally these sheets are covered with mounds – it sort of looks like volcanic acne.  These mounds are monuments to former stands of tall trees.  As the lava flowed downhill the trees impeded the progress, some lava chilled and became solid around the burning tree trucks.  These chilled regions built up mounds – and today the mounds have perfect holes throughout where tree trucks where eventually burned away.  The figure above is one of these basalt pimples, and you can see the round “tube” of a former trunk in the lower left of the photo.  The most impressive flow on the run was from an eruption in 1974 (the same year I graduated from high school).  The lava is remarkable smooth, and easy running.  However, once you step off the flow it is extremely difficult running.  The total distance covered was just under 8 miles.  The run ends near a truly spectacular view of the ocean across a series of high cliffs, known as Pali.

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Looking down towards the sea – 4 miles away, and a 2000′ drop. There are a series of steep cliffs, known as the Pali, that mark the breaking and sliding away of the stack of lava flows.

The Pali are fault scraps cutting across the lava flows – these scarps are the weak zones that fail once the load of basalt becomes too large.

faults

Fault map of the southeastern side of Hawaii. The faults represent breakaway regions sliding the load created by the basalt towards the deep ocean. Each of the faults has a significant scar – a large cliff known as “pali” in Hawaiian.

Running down the scarps is easy work except the views are run-stopping.  This trail run is all on the dry side of Hawaii, so no pesky trees to obscure the view.  I was a graduate student at Caltech when seismologist began to model the seismograms from exotic sources, and the 1975 Hawaii earthquake, with an epicenter within the Pali, proved to have a source mechanism that it is consistent with a large landslide.  The 1975 event is the largest Hawaiian earthquake (or, more precisely, landslide induced earthquake), and had a magnitude of 7.2 and caused a 12 m high local tsunami.

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The edge of Hawaii – although the flows and pali continue far out to sea.  The total elevation of Mauna Loa, as measured from the sea floor, is about 56,000 ft.  Nearly twice the height of Everest, but no high camp or oxygen is required to summit.

At the ocean my runs end – sort of trivial in terms of distance, but perfect therapy for recovery from an ultra run.  Actually, the real recovery was to my soul.  Immersed in the geologic equivalent to a black hole, all the trials and tribulations of the last 2 months seem like back ground noise.  Relaxed.

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Sunset on the Kona Coast. Waves framing a sun disappearing behind Maui off in the distance.

 

Hot Spots and Glaciers: Running from the North American Plate to the Eurasian Plate

Beneath all the wealth of detail in a geological map lies an elegant, orderly simplicity — J. Tuzo WilsonScottish Canadian geophysicist that laid much of the framework for modern Plate Tectonics.

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Sunrise in the Hengladir Valley, near Hengill Volcano, Iceland. Running with Michelle and looking at a boiling hot spring. Elísabet Margeirsdóttir photograph. Click on any figure to make it full sized.

4.5 billion years is a long time — even for a geoscientist.  The age of the Earth is known with remarkable precision (the error in age is less that +/- 1 percent), thanks to radiometric dating of Earth and Moon igneous rocks and meteorites from other parts of the solar system.  The Earth has been an evolving planet for about one third of the existence of the universe; despite this “old age”, the planet is a dynamic and HOT planet.  The heat flow from the Earth’s interior is a little less than 50 terawatts, which drives the constant reshaping of the surface — raising mountains, erupting volcanoes and causing earthquakes.  The source of this geothermal energy is fairly well understood, and is due to the decay of radioactive elements and primordial heat (the heat left over from the original formation of the planet).  However, how the heat is transferred from the Earth’s interior to the surface is less well understood.  The details of the heat transfer matters — it is the driver of plate tectonics.

In the early part of the 19th Century Charles Lyell, a great British geologist, proposed that the Earth had to be at least 300 million years old based on the slow rates of geologic processes.  This ancient age for the planet not only infuriated the religious order of the day, but it annoyed the growing global physics community because it was based on speculation and logic arguments instead of models and calculations.  Lord Kelvin expressed this contempt simply: “When you measure what you are speaking about and express it in numbers, you know something about it, but when you cannot express it in numbers your knowledge about is of a meagre and unsatisfactory kind.”  Kelvin went on to calculate the age of the Earth assuming cooling through conduction, and arrived at an age of between 20 and 90 million years.  I used to assign this problem as homework in my course on mathematical methods in geophysics.  The calculation is straightforward and stunningly incorrect.  Kelvin’s calculation had almost nothing to do with the Earth’s heat flow – it had the wrong heat transport model by ignoring convention and did not account for continuing heat production through radioactive decay.  In 1919 Arthur Holmes — another great British geologist — suggested that the high temperatures in the Earth’s interior meant that rocks could “flow” in convection, and mass movement was the primary mechanism for moving heat from the deep interior to the surface.

Arthur-Holmes-convection-02

Arthur Holmes used his idea of convection in the mantle of the Earth to propose a mechanism to drive plate tectonics in 1928. It took another 30 years before the Earth science community began to understand it as the unifying theory in geology.

It took another 30 years before a later generation of geophysicists took Holmes ideas and connected them with observations of ocean bathymetry, volcanic chemistry, and the geography of earthquakes to understand Plate Tectonics.  However, there were some still some very odd observations that defied explanation with the plate tectonics paradigm.  One of these was the idea of “hot spots” – large volcanic complexes that seemed to be located totally independent of plate tectonics.  J. Tuzo Wilson — a Canadian geophysicist — showed that Hawaii was a long chain of volcanic islands that could be explained as a “hot spot” that melted the overlying plate as it passed by on its path determined by the driving forces of plate tectonics.  The nature of these hot spots was a subject to great debate (during my graduate school career it was the regular topic of daily coffee discussions), with most scientists believing that they were thin columns of hot mantle that came from depths near the Earth’s core.  Today, the concept of “thin” plumes is largely rejected in favor of broad convection plumes.

There is one place on Earth where a hot spot and a mid-ocean ridge coexist – Iceland.  This is a truly strange and marvelous place.  The hotspot has created an island about 1/3 the size of New Mexico; the center of the island is constantly being pulled apart as the mid-Atlantic ridge grows and the North America plate moves away from Eurasia at a rate of about 2 cm per year.

geologicmap.iceland

Geologic Map of Iceland. The “pink” zones show the recent volcanic activity that includes both the spreading center that travels across iceland through the Reykjavik Peninsula in the southeast to Husavik in the north as well as the center of the hotspot.

I have always wanted to visit Iceland and see with my own eyes the most impressive expression of the Earth’s heat engine.  The physical location of Iceland — centered about 66 degrees north latitude — adds an extra wrinkle to the heat.  The climate demands snow and ice…the geology demands volcanoes and lava flows.  Finally the opportunity arrived to visit Iceland arose, and I planned to run from North America to Eurasia, and from glaciers to geysers.

adventuremap

Map of southwest Iceland, and the locations of our various runs, treks and geology visits.

Running in the Rift

I planned a late September trip to Iceland, and arranged to see the geology the only way it is meant to be seen — underfoot.  I had the fantasy of the ultimate trail run; running from one major tectonic plate to another.  The mid-Atlantic ridge comes ashore in Iceland along the Reykjavik Peninsula (see the geologic map above), and the splits the island from north-to-south. The plate boundary is not a single, simple fault.  It is more diffuse;  however, geodetic measures clearly delineate that it is possible to run from North America to Eurasia with a  good geology map.

About 25 miles east of Reykjavik sits Hengill Volcano.  Modest by volcanic measures, Hengill is a row of craters aligned along a NNE trend, and has erupted material that now covers about 100 km2.  The last eruption was about 2000 year before the present, but today is a major source of geothermal electrical production. The climb up the volcano offers wonderful views even though its maximum elevation is only 2200 ft.

We (my wife and I) planned a run from the west side of Hengill, up towards the summit craters, and then down Reykjadalur Valley, which is also known as the Smokey Valley due to its large number of fumaroles.  We used a running tour guide from Arctic Running (Elísabet Margeirsdóttir) to lead us over the 10.5 miles of very varied terrain.

michelleandterryuphill1

Running on the flank of Hengill Volcano.  This rocky hills are called “borgs”.

After a brief climb up the flank of Hengill, the run is across a moonscape of cinders and volcanic bombs and cobbles.  The run is challenging because of the surprises in footing, but is mostly slow paced because there is so much to see.  After about 6 miles the trail crosses a pass that allows a view 40 km to the north.

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Smackdab in the middle of the Mid-Atlantic Rift – North America to the left of the photo, Eurasia to the right. In the distance is the large lake Þingvallavatn, which is in the rift valley (usually marked on maps for the culture center Thingvellir).

In the distance is Þingvallavatn, the largest lake in Iceland.  This lake is located within the rift valley separating the plates.  On another day we visited the lake and the numerous basalt flows and dozens of grabens.

Thingvellir

Þingvallavatn and the rift valley. There are numerous fissures in the basalt that are expressions of dozens of pull-apart grabbens. These grabens are an markers of the plate boundaries. However, despite the advertisements that you can “stand on both plates”, the boundary is more diffuse – probably 2-5 miles across. The view is to the southeast, and on the horizon is Volcano Hengill, source of the previous pictures.

Þingvallavatn is partially within Þingvallir National Park, which is quite popular with the tourists.  The original Icelandic Parliament was established here in 930 (about 60 years after Norsemen arrived on the Island), and remained here until the beginning of the 19th Century.  Despite the crowds, a short hike will allow one to explore the geology in relative solitude.

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Another graben at Þingvallavatn. The sides of the grabben form the channel for a river.

The trail run turns to the south from the pass on the flanks of Hengill and enters Reykjadalur.  Every hillside is alive with fumaroles – the mountains are literally smoking. At about mile 8 the warm waters of the all the springs drain into a modest river which runs along a short plain.  The river here is famous for bathing, and indeed we stopped and soaked a bit before running on to the end of the trail.  The water in the various natural pools is about 100 degrees – a warm bath.

terryrunning5

Running down hard scoria into Reykjadalur – The Smokey Valley.

The final part of the run has a challenge that is unlike any I have faced.  There are two spots that have warning signs advising hikers not to breath in the milky clouds coming from some of the springs.  The warning talks of health hazards – and it clearly related to the release of H2S.

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A special hazard of running the lower Smokey Valley – clouds of steam that are rich is H2S. Signs warn to hold your breath….really.

At the first of the these warning I attempted to hold my breath, but clearly I was not running fast enough, and had to take a deep gulp of air right in the middle of the cloud.  The rotten egg smell is enough to cause one to knell over, but the total exposure is pretty limited.

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Kerið crater — just beyond the completion of the Smokey Valley trail run. A 3000 year old scoria crater filled with water.

A short distance beyond the end of the trail run is a series of “cinder cones” that have erupted in the last few hundred years.  The best preserved of these is Kerið crater, which is filled with a deep blue lake.  The contrast in colors – the red of the scoria and the blue of the lake make for a striking geologic panorama.

startuptoThorsmork

Glacier on mountains mean flowing water everywhere. Starting up the the washout plains to Thorsmork, and one of the scenic waterfalls.

Trekking Across a Volcanic Complex

A short jog across the plate boundaries serves only as a reminder that the geology of Iceland is immense!  The Hengill area is dominated by the dynamics of the spreading center.  Further to the east are a series of very large volcanic complexes – not really volcanoes, but a series of vents and craters that have a strong fingerprint of the deeper mantle chemistry indicative of the Iceland hotspot.

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Glacial outwash on the road to Thorsmörk. On the horizon is another volcano, Tindfjallajokull.

Only a few 10s of miles east of Hengill sits the most famous Iceland volcano, Hekla. Hekla is a stratavolcano that is about 4900 ft in elevation, and has had 20 significant eruptions since the first occupation of Iceland.  There are numerous deposits in Ireland and Scotland of tephra from Hekla eruptions.  A large eruption conjured a vision of hell, and a monk wrote: “The renowned fiery cauldron of Sicily which men call Hell’s chimney … that cauldron is affirmed to be like a small furnace compared to this enormous inferno”.  Hekla is one of only two Icelandic words that made it into common English language.  “Heck” is a shortened version of Hekla, and “what the heck” literally means “what the hell”.

800px-Hekla_(A._Ortelius)_Detail_from_map_of_Iceland_1585

Abraham Ortelius’ 1585 map of Iceland showing Hekla in eruption. The text translates as “The Hekla, perpetually condemned to storms and snow, vomits stones under terrible noise”.

A few miles southeast of Helka is one of the treasures of Iceland, Thorsmörk (Thor’s Valley).  This valley is bounded by glaciers to the north and south (Tindfjallajokull and Eyjafjallajökull respectively), and blocked by a third major glacier, Myrdalsjokull in the east.  I planned to hike between the Eyjafjallajökull and Myrdalsjokull glaciers (adding the word glacier is redundant since jokull means glacier, but Icelandic words are very difficult!) through a pass known as Fimmvörðuháls.  The second part of my jog across Iceland was trek on the edges of the hotspot.

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The beginning of the trek – Thorsmörk, looking up at the glaciers of Myrdalsjokull and across the wide plain of a flood basin and the river Krossa.  The Myrdalsjokull glacier sits atop the Katla volcanic complex – one of the largest in Iceland.

We hired a ride to the Thorsmörk, and hoped for about 35 km of walking. Along the way we visited one of the small valley glaciers that connects to Eyjafjallajökull, Gigjokull. Eyjafjalla erupted in 2010, and caused significant ice melting that caused Gigjokull to surge, and released a great outwash of debris destroying the jökulurð (terminal moraine).

EFLA

Gigjokull glacier;  The toe is about 50 m across.

A few miles beyond Gigjokull we begin our trek climbing along the flanks of Eyjafjalla.  The soft volcanic tephras and modestly welded tuffs are deeply eroded by the constant rainfall.  The trek is up and down, intermixed with stunning views.

trekingonMyrdalsjokull

On the trail, looking up at Myrdalsjokull. The elevation on the trail is 1600 feet, and glacier line is 2200 feet. Scenic hike, but the volcanic terrain has been eroded with endless canyons, so lots of climbing and descending.

The last climb of the day is up a hill called Rettarfell.  Coming down the trail there is a view across the Krossa river.  The fall colors are tremendous – delicate red flows intermixed with yellow grasses offset the harsh black and gray volcanic rumble. In the picture below the end of journey is in sight – a hut across the river in the center of the photograph.

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Descending off the flank of Eyjafjalla into the hut for the evening. Fall colors are spectacular.

The first day has been perfect weather wise, and the trekking was quite enjoyable. However, the weather forecast for the next day is ominous.

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Descending into the valley for the end of day one.

One of the most challenging aspects of the trek is actually crossing the Krossa. The river is braided with many strands, and the main sections have channels flowing several feet deep.  In the hut there is a “book of shame” that documents all the jeeps that attempted to cross the river only to become mired, and then flooded.  Various hiking clubs in Iceland have built portable bridges that can be wheeled from one location to another as the river changes its course.  From high up on the ridges at Rettarfell I can see the bridges, but they look like they are just stuck out randomly on the flood plain – we joke that Iceland, like American, has its bridges to no where.  Fortunately, the bridges are in the right spot and traveling across to the hut for the evening is uneventful.

Trekcabin

Early in the morning of day 2 in Thorsmörk – a short night because we waited for a meager northern lights.

The hut is comfortable – and a light sleeping bag on a foam mattress is more like probation than a life sentence in prison.  Although the clouds began to come in around 10 pm, we held out hope that the total darkness of the remote area would reward us with a glimpse of the northern lights.  Indeed, as predicted by the Iceland Aurora Watch, the lights appeared at 10:30.  However, they were quite weak and fleeting.  The was a chance that they would reappear at midnight, but all we got for that wait was sleep deprivation.  On the other hand, the night sky was filled with stars I seldom get to see, and the Milky Way splashed across the horizon like a haphazard paint stroke.

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First morning’s light. Clouds moving in, but barely indicated the steady rain to follow.

The plan for the second day was a 22 km trek with a descent along the Skógá River, ending with a spectacular water fall, Skógafoss (foss means “falls” in Icelandic, so Skogafoss waterfall is also a wonderful redundancy!).  However, by 10 am the rain was falling in buckets, and the wind had gusts in which it was impossible to remain upright. We shortened the hike – but covered distances along the trail on both sides of the pass.  By 2pm it was clear that this trek would mostly be noted for the fact that we did not drown.

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Skógafoss falls, along the Skógá River, draining both Eyjafjallajökull and Myrdalsjokull.  The drop across the basalt cliff is about 60 m, and produces a persistent mist.  This mist is famous for strong rainbows…however, there are no rainbows in the driving rain.

The end of the trek comes with the realization that Michelle’s rain gear is no longer certified…everything leaked.

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End of the trek – and the 20 year old quality raincoat that can now be best used as a sponge.

After the trek we made a short trip to Reynisfjara, which is famous for its black sand beaches.  The beaches are indeed beautiful, but it is interesting that if you say “black sand beach” to an Icelander they will reply – all our beaches are black sand, and there are too many miles to count.

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Black sand beaches of Reynisfjara. The “sand” is actually pebbles of basalt.

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A close up of the “black sand”. The image is about 2 feet across. I tried running on the beach, and it was quite difficult!

The purpose of the trek was to visit the glaciers and volcanics of the hotspot.  Although the scenery was amazing, it was difficult to see uniqueness in the volcanics; it is clear that the stratavolcanoes are broad and much larger than the modest structures along the extension of the Reykjavik Ridge.  However, the changes in rock type is subtle – at least to the eye.

Dotting the i – Visiting Geysir and Langjokull

No visit to the volcanoes of southwest Iceland would be complete without a journey to Geysir and then on to the second largest Icelandic glacier, Langjökull (strictly speaking, Langjökull is an “icecap” – meaning it flows in all directions from its summit). This particular journey is not amenable to running (or trekking), so we hired a driver.

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The pool of hot water over The Great Geysir in the Haukadalur Valley. The valley sits in a structural embayment within a rhyolite dome, and the meteoric waters that fall on the dome descend through cracks and are heated by a shallow magma body. The Great Geysir no longer erupts, but that probably is a temporary condition.

The Haukadalur Valley is about 50 km northeast of Þingvallavatn.  There are a half dozen large, boiling hot springs in an area roughly the size of two football fields. Presently there is only one of these that erupts with regularity – Strokkur – which has a periodicity of about 8 minutes.  The Great Geysir was the first boiling fountain described in literature, and was adopted into the English language as “geyser”. In the past the Great Geysir had eruptions that reached 170 m in height.  The plumbing of the system of hot springs appears to be highly influenced/connected to the occurrence of earthquakes in the area.  Moderate sized quakes appear to turn on and off the eruptive cycles of the various springs.

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Crystal clear water in a boiling hot spring. Looking down this conduit one can see approximately 2 m (or so the sign says). Although the water is crystal clear, every few minutes a cluster of bubbles ascend releasing pungent H2S gas.

Haukadalur Valley suffers from inevitable comparisons with Yellowstone and Old Faithful.  The modest sized region is thick with tourists – but most of these are loaded and unloaded in large buses that follow a loop called the “Golden Circle”.  We did not spend much time at Geysir, but it was on the way to Langjökull so the stop is worthwhile.  The massive glacier Langjökull is visible from Haukadalur, and frames a horizon as an imposing block of snow and ice.

Langjokullglacier

Langjökull – a massive ice cap glacier. The glacier has a volume of ice that is approximately 200 km3. Late in the season – like the 3rd week in Sept — the lower reaches of the glacier is covered with black mounds that resemble giant ant mounds.

Langjökull covers a highlands that is actually two active volcanic systems.  The glacier is about 50 km long in the north-south direction and 20 km wide (east-west); at its  thickest the ice is 580 m.  The large size of the glacier makes it easily seen from space (see the location map at the top of the blog section on the Hengill run).  Unfortunately, the glacier is in rapid retreat.  Using 1990 as a baseline, Langjökull has lost 15% of its ariel extent, and models project it will disappear by the middle of next century.

glacierriver2

A large moulin – vertical hole or shaft in the glacier that serves as a plumbing system within the ice mass. Our line of snow mobiles are in the upper left for scale.

We toured the glacier via snowmobile.  As advertised, driving the snowmobiles was no more difficult than driving a bicycle.  I ride my bike a lot, so my thought was “this will be really easy”.  Well, Michelle and I sharing a snowmobile means that we had to coordinate our leans with every sharp turn.  Our coordination was not world class.  However, the tour allowed us to see the scale of the glacier, and certainly observe the obvious signs of ice retreat.

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A spot of color in the volcanic highlands. The fall season gives texture to the otherwise monotonous gray of volcanic rubble.

The journey to, and away from Langjökull is a winding dirt road through barren volcanic badlands.  However, late in the fall the sparse vegetation is alive with bright color.  There is something majestic about survival of these plants even in the most hostile environments.

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The most famous water fall in Iceland – Gullfoss.

The drive back to Reykjavik follows the Hvítá river for a short distance.  Along this route the river tumbles over a 3 step staircase creating a beautiful waterfall.  Gullfoss, like Geysir, is on the tour bus route for the Golden Circle so the area is always crowed with camera clickers (okay, I was also a camera clicker).

Hotspots require more time

The geology of Iceland is wonderful – and although the southwestern portion of the island is relatively compact, it is clear that a series of runs and treks hardly do justice to the remarkable tectonic processes that are going on here.  The evidence of volcanism is everywhere, but strangely mysterious in that it is also hidden.  The forces of water, ice and erosion are also everywhere.  Nothing about the landscape of the island seems permanent; wait a hundred years, and eruptions and floods will change the view shed.  It is clear that a real visit to Iceland requires far more than a few days…but it is a great place to run!

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Urridafoss falls – the largest VOLUME waterfall in Iceland, and totally off the beaten track.  Waterfalls here a ubiquitous, and perhaps a bigger signature of the geology than even the volcanoes.

The World’s Greatest Mineral Rush: Uranium Minerals of the Colorado Plateau

My experiments proved that the radiation of uranium compounds … is an atomic property of the element of uranium. Its intensity is proportional to the quantity of uranium contained in the compound, and depends neither on conditions of chemical combination, nor on external circumstances, such as light or temperature — Marie Skłodowska Curie, Polish/French scientist who won 2 Nobel Prizes;  her doctorate thesis was the first to show that radiation came from an atom, not from environmental conditions.

When rock blooms yellow and Geiger counters rattle - uranium! From a National Geographic Society publication, 1953

When rock blooms yellow and Geiger counters rattle – uranium! From a National Geographic Society publication, 1953. Click on any figure for a larger version.

The theme of the 2015 Denver Gem and Mineral show is “Minerals of the American Southwest”. The theme evokes images of colorful copper minerals from Arizona, gold and silver from Colorado, red beryl and champagne topaz from Utah, and perfect fluorites from Bingham, New Mexico. The four states have a rich mining heritage with boom towns, barons, and villains. The influence of the American Southwest on the modern mineral collecting hobby is also outsized – from personalities of famous collectors and mineral dealers to mega mineral shows, perhaps no geographic region is more influential. The southwest was also the site of the greatest mineral rush in history, but is largely unremembered – the great uranium rush of the 1950s.

My father and I visited many of the uranium mines – mostly the abandoned ones in Utah – in the early 1970s, and I collected a boat load of  “yellow smears”.  I learned how to read the x-ray diffraction films from studying samples I prepared for identification.  I was cautioned to store these treasures in the barn rather than my bedroom because of issues with radon or radioactive decay.  I never really built a systematic collection, and my specimens were eventually disposed of for environmental reasons, but I was fascinated by the story of the uranium minerals.  In 1974, I read Edward Abbey’s book Desert Solitaireand was deeply affectedly by his descriptions of the joy of  isolation and the beauty of the canyon country and mountains around Moab. I also saw in this book the tremendous loss that we experience when we destroy wilderness.  I was asked to talk at the 2015 Denver show on minerals of the southwest, and it was assumed I would wax on and on about the silver minerals…but I decided to revisit uranium!

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Small crystal clusters of carnotite, largest cluster is 0.7 mm across. San Juan Co., Utah

The launch of the Manhattan Project in 1939 suddenly made uranium a valuable commodity, but established mines were few globally; in the US only a few mines in western Colorado were producing any uranium (mainly as a byproduct of vanadium mining). Leslie Grooves, director of the Manhattan Project secretly purchased the entire stockpile of  Vanadium Corporation of America, which was stored at Uravan, Colorado – but that was only 800 tons of ore. Once the war was over the US had less than 100 pounds of enriched uranium (U235), and development of domestic uranium mining became a government priority. The newly minted Atomic Energy Commission announced remarkable incentives for new uranium discoveries: a price of $3.50 per pound of uranium oxide, and a $10,000 bonus paid on the delivery of 20 tones of ore that assayed 20 percent uranium oxide. By the early 1950s there were more prospectors looking for uranium on the Colorado Plateau than ever mined gold in the history of California – in fact, there were 30 uranium “rushers” for every 1 ’49 rusher to the Sierra Nevada.

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Hundred’s of articles appeared in the early 1950s publicized the “rush” for uranium. Many of these articles were funded by the AEC and suppliers of geiger counters.

The AEC incentives worked — by the mid-1950s there were about 800 major uranium ore producers on the Colorado Plateau, and ore production was doubling every 18 months.  The rush made more millionaires than the great Colorado silver rushes of the 1870s or the Arizona copper rushes of the 1880s.  Moab, Utah was dubbed the “Uranium capital of the World”, and had 20 millionaires for every 250 citizens.  The AEC cancelled the bonus for uranium production in the early 1970s, and eventually the mining industry declined to a subsistence level.  However, the rush to the Colorado Plateau had a huge impact – from 1949 to 1971 the mines produced about 400 million tons of ore that yielded 200,000 tons metric tons of uranium metal.

Coincident with the great uranium rush, mineral hobbyist clubs and minerals shows exploded – the American Federation of Mineralogical Societies (AFMS) was founded in 1947.  Although it is a stretch to directly connect the great uranium rush with the rise of mineral collecting as a hobby, it is obvious that the heavy promotion of uranium prospecting peaked the interest of many Americans, and rock hounding entered a golden age.  Many collectors purchased or collected uranium minerals from the Plateau, and these prizes sat in places of honor in the collector’s cabinets.  However, as the hazards of uranium mining became understood in the 1970s, collectors began to dispose many of their specimens.  Today, it is almost impossible to find a fine Colorado Plateau uranium mineral specimen – and the heritage of an amazing American event has faded from the public memory.

uraniummines

Map showing the location of uranium mines in the US. The data is from a EPA data base, and does not show the size of the mine. However, the density of the mines is a good indication of the richness of the deposits.

A Brief History of the Colorado Plateau Uranium

The history of uranium on the Colorado Plateau begins a half century before the Great Rush when prospectors were looking for the more valuable commodities of radium and vanadium.   Settlers in the Paradox Basin in southwest Colorado knew of a yellow, powdery material found in sandstones before 1880; it is likely that Ute and Navajo Indians collected this same material as a pigment for hundreds of years. By the late 1890s various prospectors had collected a few hundred pounds of the material, but did not know what it was, nor could they find a market. In 1881 Tom Talbert discovered the same yellow material in Montrose County, and eventually this material found its way to Gordon Kimball in Ouray. Kimball sent samples to Frenchman Charles Poulot (residing in Denver) in 1898, who determined it contained both uranium and vanadium. Poulot gave the material to M. M. C. Friedel and E. Cumenge (of Cumengite fame) who determined an approximate formula: K2(UO2)2(VO4)2·1-3H2O  Also in the samples were significant amounts of radium – which is a decay product of U238.  This coincided with Curie’s discovery of the element radium, and she began to purchase carnotite from Colorado for research.  Radium became the vanguard material for worldwide research on radioactivity, and a number of mines were staked along the Colorado Plateau.

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Colorado radium played a very significant roll in the lab of Madame Curie, and was essential to define the unit of radioactivity, the Curie.

Aside from staking claims, nothing of substance happened in carnotite mining until 1910 when a new medical market for radium developed — it appeared to have a dramatic effect on certain cancerous tumors — and southwestern Colorado became a major supplier.  However, the outbreak of WWI completely quashed the demand. As the demand for radium dried up, the demand for vanadium increased rapidly. It was discovered early in the 20th century that adding a small amount of vanadium increased the strength of steel. In 1905 Henry Ford was introduced to a vanadium rich steel, and was so impressed with its characteristics, he used it in the chassis of his Model-T.  By the end of WWI the carnotite mining shifted from the focus on recovering radium to vanadium, and by 1922 radium recovery ceased all together.  Although the demand for vanadium was cyclic, by about 1935 it had become an important enough metal that Vanadium Corporation of America purchased most of the former carnotite mines, and founded the town of Uravan (contraction of uranium and vanadium).

carnotite.early

Location of the carnotite deposits mined for radium and then vanadium before WWII. From Chenoweth, 1981.

After 1936 there was a steady increase in prospecting and development of properties along the Utah-Colorado border targeted the Morrison Formation (Jurassic age), in particular, a fluvial sandstone/mudstone unit called the Salt Wash Member.  With the outbreak of WWII steel became essential; vanadium was declared a strategic metal, and more than 600,000 tons of vanadium ore with a 2% grade was produced.

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Mine and mills at Uravan, ca 1935

The modern era of uranium exploration and mining on the Colorado Plateau began when the Atomic Energy Commission was established by the Atomic Energy Act of 1946.  All  functions of the Manhattan Project, including the acquisition of uranium, were transferred to the ACE at mid-night, December 31, 1946. The AEC set up a procurement shop in Grand Junction, Colorado and begin devising schemes for securing uranium. At the time there were only 15 mines operating on the Colorado Plateau, and uranium was still considered a lesser product than vanadium. The AEC was the only buyer of uranium, and thus, set a price they thought would incentivize production; it soon became apparent that the AEC also had to be involved in the milling of ore, and provided bonuses for uranium oxide concentrations. The very first procurement contract was signed with Vanadium Corporation of American on May 28, 1947. The AEC demanded a rapid expansion of exploration and mining efforts, and provided assistance by undertaking geologic surveys and providing free assay services.

Between 1948 and 1956 the AEC and the USGS tasked several hundred geologists to scourer the Colorado Plateau and make their maps and drilling core results freely available to prospectors. The AEC also built more than a thousand miles of roads across the plateau to promote access to the most remote regions. Prospectors and weekend treasure hunters flocked to Utah and Colorado, and later to New Mexico and Arizona.  Some of these prospectors struck it rich, and lived life higher than the biggest copper or silver baron of the 19th century.  One of these “lucky” prospectors was Charlie Steen.

For two years Steen roamed the area around Moab, Utah and “barely” subsisted with his family in a trailer and tar paper shack. Using his experience in the oil industry, he was certain the uranium would collect in anticlines – sort of like an oil trap – and he drilled haphazardly. On July 6, 1952, Steen drilled into an incredibly rich deposit of “pitchblende” (uraninite) at 200 feet depth, and over the next year developed the Mi Vida mine. The fact that the ore was uraninite – not carnotite-  in a rock type previously not shown to carry uranium, and at a depth that similarly unexpected, caught the government geologists by surprise. Steen became a multi-millionaire, and his find electrified the country – and greatly accelerated the rush to the plateau!

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Charlie Steen underground with his son at the Mi Vida Mine, ca 1955

Geologists began to understand the nature of the Colorado Plateau uranium deposits in the late 1950s. Garrels and Larsen (1959) published USGS professional paer 320, Geochemistry and Mineralogy of the Colorado Plateau Uranium Ores, and it became clear that hydrology was the most important factor in localizing the uranium in vast  columns of sedimentary rock.

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Uranium deposits on the Colorado Plateau in 1959 with a size of more than 1000 tons.

Uranium is found in more than a dozen sedimentary strata on the plateau but the Morrison formation of late Jurassic age and Chinle of Triassic age account for 95% of the produced uranium. The Morrison was formed from the erosional sediments derived from a highlands called the Elko that existed along what today is the Utah-Nevada border. These sediments were deposited in floodplains, river channels and swamps, not unlike the Mississippi delta today. The Chinle is dominated by eolian (wind-driven dunes) deposits with smaller river channels cut during intervals of more precipitation. The uranium appears to have mobilized by ground water; dissolving and moving sparsely concentrated uranium and precipitating and concentrating that uranium when structural or chemical boundaries are encountered. The deposition of the uranium occurred millions of years after the deposit of the sedimentary rocks — perhaps 100 million years later.  The deposition is most signifiant where the sediments contained trapped organic materials – logs in river channels or organic ooze in swamps. In fact, there are many examples of petrified logs that have been completely replaced by uraninite or coffinite.

The real key to the Colorado Plateau deposits is the long term stability of the sediment column.  This stability has allowed dilute solutions to build these diffuse deposits.  This is not the best environment to grow beautiful crystals, but small variations in chemistry has allowed for a wide range of uranium minerals.  Through 2010 the Colorado Plateau has produced more than 600,000 tons of uranium oxide – and today contains 15% of the worldwide uranium reserve.

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High purity uranium “biscuit”. Uranium metal is not known in nature.

Colorado Plateau Uranium Minerals

The mineralogy of uranium is a fascinating and complex topic – the nearly ubiquitous presence off U in the environment, its large atomic radius, strong affinity for oxygen (lithophile), and high solubility in certain valence states leads to large number of secondary uranium minerals. The lithophile nature of U also means that 4.5 billion years of Earth evolution has concentrated the element in the crust; the statistic abundance of U in the crust is 2.7 ppm, as compared to 0.075 pm for silver and .004 ppm for gold. In other words, there are 675 atoms of uranium for every atom of gold in crustal rocks!

Figure1_OriginEarth

Relative abundance of elements from cosmology, normalized to the abundance of Si. Note that uranium, as expected with its large Z, is much rarer than lighter elements. It is a few orders of magnitude less common than gold. However, uranium is strongly lithophilic, and has been concentrated in the Earth’s crust to the point that it is more common on the surface than either gold or silver.

The fact that uranium has been so strongly enriched in the crust is also one of the reasons it is so ubiquitous – traces can be found in every rock type, soils and water. Uranium is a “5f electron” element, which controls much of the way it behaves in the environment. 5f refers to the electron configuration, or the distribution of electrons about the atom; uranium is an electron donor and has four different valence states depending on environmental conditions. Two of these states, U4+ and U6+, are stable in geologic environments. In igneous environments the +4 valence state prevails, and uranium is one of the last elements to form minerals in a magmatic or hydrothermal fluid. By far, the most common mineral to form in igneous environments is uraninite (UO2).  However, once that uraninite is exposed to a humid and oxidizing environment the surface of the uraninite undergoes oxidation and the U4+ → U6+; the higher valence state is incompatible with the uraninite structure, and the uraninite decomposes, releasing the U6+, which rapidly binds with two oxygen atoms to form the uranyl ion [UO2]2+

The uranyl ion has a linear structure, with very strong bonding between the uranium and oxygen, and it is highly soluble in ground water.  This high solubility leads to extraordinary mobility of uranium, and a key contributor to Colorado Plateau deposits.  The uranium mined today in Grants or Paradox Basin did not originate anywhere near those locations; it likely was deposited in minor uraninite deposits during the billions of years of mountain building in what has become the North American Plate.  Decomposed, oxidize, and transported through great distances, the uranium was concentrated when subtle encounters with ground water chemistry changes.

changingvalence

Paragenetic sequence of uranium minerals — from primary uraninite with a +4 valence to hundreds of uranium minerals with a +6 valence (from Plasil, 2014).

The mineralogy of U6+ is very diverse because of the uranyl ion; it has a linear, dumbbell shaped structure that cannot be easily substituted by other high valence cations. The uranyl ion will most commonly attach to tetrahedral anion groups; SO4, PO4, AsO4, SiO4. Any charge balance is then accommodated by other cations. The figure above is a generalization of the paragenes of uranium minerals; at the top is the primary oxides and moving down the chart shows the minerals that form as uranyl migrates away from the primary source. Typically uranyl carbonates form first, and vanadates – like carnotite – form far from the original source and after many generations of mineral growth and decomposition.

There are about 160 different uranium minerals known, and 61 have been reported as coming from the Colorado Plateau, and 12 have the Plateau as their type locality (there are dozen uranium minerals yet to be characterized for the Plateau deposits).  The names are mostly unfamiliar to collectors – things like Becquerelite Ca(UO2)6O4(OH)6 · 8H2O,  Schrockingerite, NaCa3(UO2)(CO3)3(SO4)F · 10H2O and Rabbittite, Ca3Mg3(UO2)2(CO3)6(OH)4 · 18H2O.  They have colors that span the rainbow, although bright yellows and deep greens are favored.  Those minerals that contain the uranyl ion all fluoresce (although U4+ minerals do not), and differences in hydration – and loss of water with alteration – changes the fluorescence. Unfortunately, the sedimentary deposits of the Plateau do not lend themselves to environments in which large, distinct crystals grow.  Below is a gallery of some of the more important uranium speciemens:

Carnotite K2(UO2)2(VO4)2 · 3H2O

Carnotite.HappyJack(BYU)

Carnotite, Happy Jack MIne, Utah. BYU collection.

carnotite.monumentvalley.arizona

Carnotite crystals, to 2 mm. Monument Valley, Arizona. Stephan Wolfsried photograph and specimen.

Coffinite U(SiO4)1-x(OH)4

coffinite.1

Coffinite, Mount Taylor deposit, Ambrosia Lake area, Grants District, McKinley Co., New Mexico. Field of view is 3cm.

Uraninite UO2

uraninite.bigindiandistrict.sanjuanco.utah

Uraninite, Big Indian District, San Juan Co., Utah.

Tyuyamunite Ca(UO2)2(VO4)2 · 5-8H2O

Tyuyamunite.paradoxvalley

Tyuyamunite, Paradox Valley, Montrose Co., Colorado. Dave Bunk collection, Jesse La Plante photograph.

Zippeite K3(UO2)4(SO4)2O3(OH) · 3H2O

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Zippeite, Big Gypsum Valley, San Miguel Co., Colorado. Dave Bunk collection, Jesse La Plante photograph.

Unknown Uranium Carbonate

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Slick Rock, San Miguel Co., Colorado. Dave Bunk collection, Jesse La Plante photograph.

The uranium minerals were intimately associated with vanadium minerals – often these carried some amount of the uranyl complex.  The Colorado Plateau vanadium minerals are as unique as their uranium counterparts, and often even more colorful and unusual.  A few are featured below:

Schrockingerite NaCa3(UO2)(CO3)3(SO4)F · 10H2O

schrockingerite.monogrammesa

Schrockingerite, Monogram Mesa, Montrose Co., Colorado. Dave Bunk collection, Jesse La Plante photograph.

Metamunirite NaVO3

metamunirite.burromine.slickrock.sanmiguel

Metamunirite, Burro Mine, Slick Rock, San Miguel Co., Colorado. Dave Bunk collection, Jesse La Plante photograph.

Metahewettite CaV6O16 · 3H2O

metahewetite.hummermine.uravan

Metahewettite, Hummer Mine, Uravan, Montrose Co., Colorado. Dave Bunk collection, Jesse La Plante photograph.

Pascoite Ca3(V10O28) · 17H2O

pascoite.biggypsumvalley.sanmiguelco

Pascoite, Big Gypsum Valley, San Miguel Co., Colorado. Dave Bunk collection, Jesse La Plante photograph.

Metarossite Ca(V2O6) · 2H2O

metarossite.arrowheadclaim.sanmiguelco

Metarossite, Arrowhead Claim, San Miguel Co., Colorado. Dave Bunk collection, Jesse La Plante photograph.

Hewettite CaV6O16 · 9H2O

hewettite.hummermine.uravan

Hewettite, Hummer Mine, Uravan, Montrose Co., Colorado. Dave Bunk collection, Jesse La Plate photograph.

Paradise Lost

The Great Uranium rush was over by the early 1960s.  Many lone prospectors roamed some of the most desolate and beautiful country in the world in search of radioactive treasure.  Uranium mining in the 1960s was controlled by large corporations, and huge open pit mines like Jackpile east of Grants, New Mexico supplied tons of uranium.  By 1971 the government had more uranium than it could possibly use, and cancelled the incentives.  By 1980 the world market drove the prices for the silver-colored metal to prices that shut down even the largest producers.  Today the prices occasionally spike, leading to much discussion about reviving mining on the Colorado Plateau.  However, the heavy environmental toll has a very dark legacy.  It is unlikely that there will ever be another uranium mine in the Triassic and Jurassic sandstones that make the plateau look like the landscape of Mars.

San Juan Solstice 50M; A most beautiful run cut way too short

“Joy to you, we’ve won”, the final words uttered by Philippides upon running from Marathon to Athens to announce the victory over the Persians, circa 490 BC.  Philippides was a professional day-long runner delivering urgent messages.  He is an inspiration for ultra runners — he ran first to Sparta to plea for help (240 km over two days), and then ran the 40 km from Marathon to Athens before expiring.

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Top of Handies Peak, San Juan Mountains, early June, 2009. The view is to the southeast, and you can see above timberline for 35 miles.

Calderas, collapse, karats, and cannibals, oh my!  The tiny town of Lake City in southwestern Colorado is the home to a magnificent mountain ultra, the San Juan Solstice 50 miler (SJS50).  Lake City is the epicenter of unbelievably beautiful high mountains, amazing geology, mineral and mining history, and only a few miles from the most infamous episode of cannibalism in the old wild west.  In my opinion the San Juan Mountains are the most beautiful in the world, and the mining history has drawn me to the range for 50 years; the opportunity to run a long race through the mountains I have known was something incredibly special that I just had to do (even if I was only marginally qualified for the extreme course!).

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Michelle Hall, my wife, on her first 14er Handies Peak. Over her shoulder Uncompahgre and Wetterhorn (more 14ers) are visible. Handies is a couple of miles southwest of the SJS50 course.

I first visited the San Juans with my father on a mineral collecting expedition in the early 1960s.  Although I have no real memory of that adventure, I know that it was the first of more than 50 trips we would take before I left home for college.  I visited every mining camp, large and small, across the San Juans looking for mineral treasure.  I found silver, gold, rhodochrosite, great quartz crystals, galena, hubnerite, and artifacts galore. But mostly, I found a place that inspired and thrilled me, and connected with my soul.  The San Juans are no longer a “hidden gem”; they are visited by more than 150,000 people every year.  Telluride has become a major ski resort and playground of the rich.  There are dozens of companies that provide jeep tours to some of the most remote and rugged corners of the range, and sometimes in the summer there are more than 500 ATVs ferrying people to vistas they could barely imagine before they got to the San Juans.  However, despite its growing popularity, the San Juans are still a wilderness, and there are ample opportunities for solitude and reflection — along with climbing, camping, running, and yes, even mineral collecting.

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Collecting minerals. My grandson’s first mineral collecting trip was to TomBoy located in the San Juans above Telluride. He was 2 and half years old, and found lots of rocks…and a taste of the world’s most beautiful mountain range.

The San Juans are where I took my then-to-become wife on our first “very serious” date.  Once she camped above timberline, and pounded on rocks looking for silver, and had to purify water before breakfast, we knew that we were right for each other.  She saw Cement Creek, Cinnamon and Stoney Pass and the ghost town of Animas Forks before she met my parents.  Years later we returned for a celebration of an anniversary and she climbed her first 14er, Handies Peak.  Later my son would also climb his first 14er there, and it transformed him into a “mountain man”.

Lake City is on the north-central flank of the San Juans, and is less well known than the “big three” mining towns that brought much fame to the area:  Silverton, Ouray, and Telluride.  However, Lake City is just as historic, and is only a few miles – as the crow flies – from 5 peaks that top 14,000 feet. The San Juan Solstice 50 started as the Lake City 50 miler back in 1995.  The terrain is spectacular, but also poses challenges for snow pack and summer lightning storms – much of the course is above timberline. In the early part of last decade the race assumed its modern name, and the goal of running close to the solstice became a mantra.  The SJS50 is extremely popular, and requires runners to qualify and signup for a lottery for the 250 available spots.  The lottery and wait list adds drama to the hopeful runners, but the real challenge is waiting to see if the snow pack cooperates with the third week in June.  In 2015 it was touch and go – an amazing wet late spring kept the high country under a thick white blanket.  Snows finally began to melt in mid-June – and boy did they melt, sending roaring runoff down the drainages.  This set the stage for a true adventure – a 50 mile run with more than 12,800 feet elevation gain and loss, a low point of about 8,700 ft elevation, and an average elevation of approximately 11,000 ft, snow fields, and 9 stream crossing with churning melt waters.  What could possibly go wrong?

Well, it turns out lots can go wrong – flat tires on 4WD roads, warning for missing 25 mile/hour speed limits, and most unfortunately, a bad trip on a downhill run that ends a race early.  However,  the SJS50 is now a life challenge for me.

fromUlay

Artifacts from the Ute and Ulay mines, located just beyond Alpine Gulch. In the early part of the 20th Century there was a major struggle between newly formed unions and mine management that played out across the mining camps of the Southwest. Pictured are two union ribbons and a ceremonial “sliver slug” stamped “Ulay” (the slug is about 2 inches across). These artifacts are from the collection of a close friend, Dave Bunk. The history of the Lake City is really about the miners and mines – and what is left today are these wonderful artifacts. Jesse LaPlante photograph.

There’s gold in them thar hills (with a shout out to Mark Twain)

I have written several articles on the San Juans – some for technical journals, and some for more popular literature.  Recently, Gloria Staebler and Lithographie published a monogramThe San Juan Triangle of Colorado; Mountains of Minerals that captures the spirit of the geology and the wonderful minerals.  From my writing in the monogram I attempt to tell the tale of the 8th wonder of the world.

san-juan-triangle-co_2

Lithographie monographie on the San Juans (http://www.lithographie.org/bookshop/the_san_juan_triangle.htm)

The San Juan Mountains are a spectacular range of towering and rugged peaks that cover an area larger than the entire state of Vermont –  25,000 sq km of alpine bliss in southwestern Colorado. The range stretches from Creede in the northeast to Durango in the southwest; the San Juans are home to 14 peaks over 14,000 feet in elevation and  hundreds of peaks that top 12,000 feet.  The topography is extraordinarily steep, and much of the range is above timberline.  The imposing landscape was shaped by some of the most violent volcanic eruptions known in geologic history.  Between 35 and 26 million years ago huge volcanic centers rose and collapsed and erupted 10s of thousands of cubic km of rhyolitic and andesitic tuffs.  The scared landscape that remained was full of factures and faults that would later localize the magmatic fluids that deposited the ore bodies of some of Colorado’s richest mining districts:  Creede, Summitville, Silverton, Ouray, Telluride, Rico, and of course, Lake City.

allthecalderas

The volcanic centers of the San Juans. The western-most center is a series of calderas that formed over a 5 million year period nearly 28 million years ago. The initials “LC” denotes the Lake City Caldera, home of the SJS50.

The extraordinary episode of volcanism that created the San Juan Mountains began at the end of the Eocene (a geologic epoch 56-34 million years ago).  More than 30 centers of volcanism formed through out southern Colorado and northern New Mexico in what is known as the Mid-Tertiary Ignimbrite Flare-Up.  These volcanoes probably looked like stratavolcanos that form above subduction zones (eg, Mount Rainier and Mount Fuji) but they produced far more voluminous eruptions.  Initially, the eruptions produced andesites and explosive ash falls, but starting about 30 million years ago huge sheets of pyroclastic flows were erupted.  The pyroclastic flows are welded tuffs known as ignimbrites. These flows are unparalleled in size; within the San Juans there are at least 22 flows that are larger than 100 cubic kilometers.  The only way to explain these flows is to assume nearly continuous eruptions for dozens of years.  The eruptive centers ultimately collapse forming large calderas. The largest eruption known in the geologic record occurred in the San Juan Mountains at the La Garita Caldera north of Creede (denoted as LG in the figure above).   La Garita produced the Fish Canyon eruption 28 million years ago; the Fish Canyon Tuff was voluminous – more than 5000 cubic kilometers!  The Fish Canyon tuff could fill Lake Michigan!  Equally remarkable, after La Garita erupted the Fish Canyon tuff, the volcanic system continued to be active for 1.5 million years producing at least 7 other major eruptions.

The reason for the Mid-Tertiary Ignimbrite Flare-Up is a subject of geologic debate, but most geologists believe that the volcanism is related to the tectonics along the west coast of North America.  The Laramide Orogeny, which resulted in the uplift of much of the Rocky Mountains along an arc from Canada to New Mexico, is thought to be related to the subduction of the Farallon oceanic plate beneath North America.  The Farallon plate was quite young geologically, and thus buoyant.  This likely resulted in a shallow angle of subduction, which caused an uplift of the entire western US.  About 35 million years ago the last bit of the Farallon plate was subducted resulting in a major re-ordering of plate tectonics on the western edge of the North America.  Without subduction, the Farallon plate began to simply sink through the mantle in a process that is known as “slab roll-back”. This allowed very hot mantle to melt large regions of the lower most crust, and created the magma sources for the ignimbrites.  The eruptions of ignimbrites lead to the collapse of the huge calderas throughout the San Juans and developed a structural fabric that would localize much younger volcanic activity, which would give rise to rich mineral districts.

LakeCityCaldera

The Lake City Caldera (from Bove et al., 2001). The high peaks between Henson Creek, which passes through Lake City, and the Lake Fork of the Gunnison River are all volcanic centers that erupted about 22.5 million years before the present.  Collapse of the volcanic center produced an elliptical depression – about 1/2 the diameter of the Valles Grande Caldera near Los Alamos.

In the area defined by the San Juan Triangle (Telluride-Ouray-Silverton, and over to Lake City) there are four collapsed calderas; the Uncompahgre, San Juan, Silverton, and Lake City.  The first three were formed during a time period of 29 to 27 million years ago.  The Lake City caldera was the last to form, at the end of the ignimbrite flare up, 22.5 million years ago.  The geologic record within the San Juan Triangle is complex and difficult to interpret due to the superposition of the calderas and their structural manifestations. The Uncompahgre and San Juan calderas are the oldest; they were active at the same time, and collapsed simultaneously with the eruption of a very large ignimbrite sheet.   The ring faults associated with the Uncompahgre and San Juan calderas form an oblong structure that is about 45 km by 15 km, trending southwest-northeast. The formation of the Lake City Caldera was the last gasp of the Mid-Tertiary Ignimbrite flare up.  The rich ore deposits in the San Juan Triangle were emplaced 5 to 15 m.y. after the calderas formed. This mineralization is classified as epithermal and is associated with minor episodes of magmatic activity.   The base metal deposits contain mainly galena, sphalerite, and chalcopyrite while the precious metal deposits are mainly native gold.  Silver occurs in a suite of exotic minerals that includes tetrahedrite/tennantite, proustite, and pyrargyrite.  Gangue minerals include quartz (most common), calcite, pyrite, pyroxmangite, rhodochrosite, fluorite, and barite.

CapitolCityminerals

Minerals from “Mr. Mesler’s Mine”, which was located in Capitol City, and short distance beyond Alpine Gulch on Henson Creek (about 9 miles from Lake City). From Dave Bunk’s collection (Jesse LaPlante photograph).

There were hints of the great mineral wealth of the San Juans in the earliest expeditions exploring the western US.  In 1848, John Fremont led a privately funded expedition into Colorado to scout a route for an intra-continental rail route along the 38th Parallel. The expedition was a disaster due to an exceptionally cold winter, but an unnamed member of Freemont’s party discovered gold nuggets and flakes near present day Lake City. The exact location of the discovery is not known, but it was probably the Lake Fork of the Gunnison River, and may well have been related to the future Golden Fleece mine, which would become Lake City’s most famous mine 30 years later.  This is the first documented discovery of gold in the state of Colorado, although it was largely ignored.

In 1859 gold was discovered along the Front Range, west of present day Denver. This coincided with the decline of gold mining along the Sierra Nevada of California and created a rush of prospectors to Colorado. This became known as the Pike’s Peak Gold Rush, although the gold discoveries had nothing to do with the famous 14er. The huge influx of prospectors far outstripped the easily won gold in the Denver area, and prospectors fanned out to other parts of the Rockies. In the late summer of 1860 Charles Baker led a party of gold seekers to the San Juans. Baker entered the San Juans along the Lake Fork of the Gunnison River – he walked along part of the course of the SJS50! His party eventually passed over Cinnamon Pass, and discovered gold along the Animas River near Silverton.  There was no putting the genie back in the bottle – mining became the heart beat of the San Juans for a century.  The early years were extremely difficult;  the San Juans were actually part of land the US government had agreed was owned by the Ute Indians, the area was so remote that it was nearly impossible to supply and provision, and the mining season was short and harsh due to the alpine environment.  In 1873 the Brunot Agreement opened the land to mining (the Utes in return received $25,000 annually in royalty, and the right to hunt), and  soon toll roads and narrow gage trains began to “civilize” the area.

1911mapofGF

Early cross-section of the Golden Fleece Mine.The upper reaches of the mine assayed at 125 oz of gold and 1250 oz of silver per ton.

The first major mineral discovery near Lake City occurred on August 27, 1871 Henry Henson discovered a rich silver deposit – to be called the Ute-Ulay – along a stream about 3.5 miles from the present location of Lake City. Later this stream would be named Henson Creek (the SJS50 follows Henson Creek for the first 2.5 miles of the course). Once the Brunot Agreement was signed, Henson returned and developed the Ute-Ulay mine, which was a major silver and lead producer (but few mineral specimens exist today – a pity).  This development attracted entrepreneurs of every type; one of these was Enos Hotchkiss who came to build a toll road but instead discovered gold above Lake San Cristobal, a couple of mines south of Lake City.  Hotchkiss did not find much gold at first – in fact his claim was largely based on the obvious color of the rock – anyone with a sprinkling of geologic knowledge just has to gaze up Red Mountain and see the beautiful color of an oxidized cap, and know that there is gold in them thar hills. However, the claim was enough to commit to prospecting, and Lake City was founded on this promise. Eventually the Hotchkiss claim was renamed the Golden Fleece Mine, and became one of Colorado’s most famous.  The early years of the Golden Fleece relied on telluride ores, and there are reports of individual mining carts assaying 50,000 dollars of bullion.  I have been underground at various adits associated with the Golden Fleece looking for rumored veins of hessite, one of my favorite minerals. Alas, like most old San Juan mines, the conditions are deplorable, and one is actually just lucky to get out alive.

goldenfleecestock

Stock certificate from the Golden Fleece mining and milling company dated 1896. Although the Golden Fleece produced silver, and thus was impacted by the 1893 silver crash, the steady production of gold helped the property make it through the “silver crisis”. Dave Bunk collection.

The news of the Golden Fleece started a “Lake City” rush. By 1880 there were dozens of mines in Carson (along the SJS50 course), Argentum and Capitol City.  The population of Lake City swelled to 2500, and the boom times were full steam.  However, silver soon ran into the buzz saw of politics.  The rich deposits of the San Juans began to push the price for silver bullion down, and western mining barons demanded action.  In 1890 Congress passed the Sherman Silver Purchase Act, which required the US government to purchase $4.5 million dollars worth of silver every month.  This proved to be as unpopular among the Republicans of the day as the Affordable Health Care act today, and was repelled in 1893 – and the price of silver plummeted.  In a few week period the price dropped from $1.50 per oz to 63 cents.  At the time, Colorado produced about 2/3 of all the silver in the country; within 2 years more than 1/2 the silver mines in Colorado – including those near Lake City – were shuttered.  Although the mining industry would eventually recover, the heyday had passed.  Today there is some mining in the Lake City area – for example the Golden Wonder Mine located at the head of Deadman’s Gulch – but mostly there is history of an incredible tough breed of pioneer that has long passed.

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Rhodochrosite, Champion Mine, Dave Bunk collection.  The Champion Mine is located near Cinnamon Pass – the road over Cinnamon Pass was built by Enos Hotchkiss. Jesse LaPlante photograph.

In 1911 Irving et. al published Geology and Ore Deposits near Lake City, Colorado.  In the text is a haunting statement: “Secondary enrichment…led to the formation of the rich bonanzas of ruby silver found here and throughout …”  Oh, to find a pyrargyrite or proustite from Lake City! I have not in 50 years, so I suppose I am happy to run the San Juan Solstice instead.

googleLC

Google Earth Image of various points along the SJS50. The course starts in Lake City and head west on Henson Creek, then south up, way up, Alpine Gulch. The course turns towards Redcloud Peak, a 14er, but before arriving there descends into the Lake Fork valley. After crossing the valley the course climbs steeply up to the continental divide, and has 15 miles above timberline.

50 Miles, a clock ticking, and then a trip

Lake City is a small town, and every resident seems to be involved in the race.  The Lake City of my youth was a decaying frontier mining town; like nearly all Colorado mountain mining communities it has been gentrified and is now a destination for outdoor enthusiasts of all sorts. Gentrification came decades later than to Aspen or Telluride, so it is still has the rustic flavor of the early part of the 20th Century.  But make no mistake, expensive vacation homes and a very fine French Chef are now part of the Lake City landscape.  The SJS50 checkin is most of the day before the race – lots of hard core trail runners from all around are wandering the small town park that serves as the start and finish to the race.  It does not take insightful self awareness to immediately recognize that I am not really “like” most of the runners.  However, that is not why I run, and I am truly excited to be in the San Juans.

The final checkin for race begins at 4 am on Saturday, June 27.  I put my drop bags into the piles for a couple of the aid stations, and begin to get nervous.  Visiting various parts of the course the day before I know that it will be wet and muddy, so I have a couple of extra pairs of shoes, lots of socks, and of course, my special energy supplies tucked into my drop bags that proudly displace my name and bib number.  In ultras your bib number is aways assigned alphabetically, so my bag is pretty easy to find (although not as easy to find as my friend Dave Zerkle from Los Alamos….).  At 4:55 a soft bull horn announces that the race will start in 5 minutes.  I hustle into position, but it seems strange to me that runners are still milling around the park or standing in line at the port-a-potties.  Suddenly I hear, with no warning, a growled “GO”, and people are off running.  There are also runners running from the port-a-potties.  I realize that 13 or 14 hours running will not rely on a punctual start.

startinginthedark

The glint of reflective tape and headlamps at 5 am start of the San Juan Solstice. A bit of a chaotic beginning, but a perfect morning.

The first 2.6 miles of the race are up a gravel road along Henson Creek.  There is not much chit-chat, and the sounds I hear are the crunch of 500 feet on the road gravel and mixed with the turbulent roar of Henson Creek bringing snow melt down from the high country.  Dave Zerkle and I settle into a very agreeable pace of a little better than 11 minutes per mile (the specter of 50 miles looms large).  When we arrive at Alpine Gulch we start the real race.  Although we have climbed 500 feet thus far, in the next 6.5 miles we have nearly 4000 feet elevation gain.  The sun is still an hour from lighting the narrow canyon, but there is enough glow to switch off the headlamps.  The creek in Alpine Gulch is churning, but the water is much lower than just a week before. At mile 3.75 we come to the first of 7 (or 8, 9, or 10, but who is counting) crossings of the creek.  The crossing has a rope for assistance, and a number of volunteers to offer advice.  The runners stack up waiting for their chance to jump into the frigid waters…the first step is a doozy, although the water is only a bit above my knees.  Cold, but I am surprised how good it feels!

river.crossing

The first river crossing along Alpine Gulch. This photo was taken the day before the race, scouting the various segments. The picture does not give a great sense of the water depth, but it is about 2.5 feet here. At some of the higher crossing the water is definitely crotch level.

The course criss crosses the gulch many times, and at each water entry there are volunteers and a rope.  Some crossing are more challenging than others, but every time the runners emerge with soaked shoes, socks and compression sleeves.  I really enjoy the crossings, except they continually bunch the runners.  Dave Zerkle and I are trying to maintain a 20 minutes per mile or better (the average grade on most of the climb is 17%).  For the most part, the running dynamics are such that we can pass the slower runners, and get passed by the occasional faster runner (probably the people that were in the port-a-pottie when the race started).  However, around mile 6 I become quite impatient with the “group-pace” and ask to semi-sprint past a dozen runners.  It is hard work, but rewarded with open trail. A downside is that I lost Zerkle.  The first aid station is located at a small saddle at mile 7.6.  The cutoff time for this station is 7:45 am – in other words, 2hr45min from the start.  Sounds easy, but the climb is tough.  I planned on arriving at 7 am, and I am 6 minutes early.  I feel fantastic, and have visions of a sub-13 hr race.

redmountain

View of the south side of Red Mountain from Aid Station #1. The red color that is usually so distinctive is muted in the early morning sun. However, on the ascent up the gulch there are many old mines and the cabins of prospectors past.

Although the aid station is at a saddle, the climbing continues.  I am still moving well, not really tired, and hypnotized by the scenery.  I feel like I am home.  Shortly before summitting at the high point of the first part of the course I catch up to another runner from Los Alamos, Sarah Thien.  She has been battling an injury, and is not her usual rapid self.  We do get to chat a bit, and both marvel that the mountains surrounding us.

terryontop

The first climb is nearly over – a pass on the shoulder of an unnamed 13,600 foot peak visible over my left shoulder. The day is spectacular! In the distance I can see Handies and Sunshine Peaks.

Once on the divide I know that the course is going to descend nearly 3500 feet in the next six miles.  All those hard earned feet and inches of elevation gained are soon to be lost, and gravity wins again.  I always have a difficult time shifting gears from climbing to running downhill.  I suppose it is the stiffness of age, but my hips always have to be convinced that it is okay to have strides longer than 10 inches.  After a mile or so I am beginning to hit a stride of 11:30 minutes per mile;  I had hope for 10 minutes per mile, but I am ahead of schedule never the less!

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Sarah Thien running across the divide. The view is towards the west, and the high peaks of Uncompahgre and Wetterhorn can be seen in the distance.

There are a number of snow crossing, but the elite runners have post holed a pathway.  The snow is soft and wet — and slippery – but mostly enjoyable.  At mile 10.5 the snow is behind me, and the steep descent begins.  I am excited and begin to try and sprint.  Disaster strikes at mile 11 – I trip.  I am on a steep trail section and tumble head-long downhill. I land hard on my artificial knee and my right forearm.  The trail is rutted, and I am facedown, feet above my head, unable to get up.  I realize this is bad, but I hope that it is a typical trail run trip where the blood is always worse than the damage.  My dignity is challenged as I try and right myself – a woman runs past as I am still down and asks “did you fall?”  Oh, if only I could have actually answered that question with a response it deserved!

I get up, and start downhill knowing that the Williams Aid Station is only 4.5 miles ahead.  I can’t really run, but I am moving.  Lots of runners now pass me, reminding me that hubris is a nasty sin. I am worried about my knee – being an artificial joint I imagine some horrific breakage.  Hardly likely, but a concern nevertheless. My right foot (below my artificial knee) is totally numb.  Every step feels like I am swinging a club attached to my knee.  Before the fall I was on pace to arrive at the Williams Aid Station at 9:05 am.  Instead I arrive at 9:32.  I check in, and then very reluctantly, drop the race.

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After clean up – once the blood and grim is removed, it does not look so bad. Well, at least the knee. Unfortunately, the day is done.

The medical staff help clean up the wounds, and I get bandaged up.  My wife is at the aid station, and provides the sad sag-wagon ride back to Lake City.  After only finishing 16 miles I am quite depressed.  I look up on the ride in and see two parts of the course I very much looked forward to: Slumgullion and Vickers.

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Michelle standing at the Slumgullion pass point of interest. Over her head is the scarp of the repeated Earthflows.

The Slumgullion Earthflow is one of the most interesting and odd geologic features on the entire run. In the 1870s this strange tongue of yellow chalky debris was identified as a landslide off Mesa Seco (the map below shows the geography of the slide).  It was later recognized that the Slumgullion was not “a landslide” but a series of large scale debris flows that have been active for hundreds of years.  About 1200 years ago the competent rocks on the top of Mesa Seco began to slide down towards the river valley because the underlying rocks, which are heavily altered ignimbrites from the Lake City Caldera complex, were exposed and rapidly eroded.  The first flow damned the river and formed a prototype Lake San Cristobal.  Eventually the river cut through this old debris flow and drained the lake, only to see two other episodes of mass wasting, one 700 years ago, and most recently, 300 years ago (and this flow is still active). The distance from the head of the flow – the scarp on the cliffs of Mesa Seco – to the toe is about 7 km, and 170 million cubic meters of material are contained within the scarp.

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The Slumgullon – a large landslide due to the collapse of steep cliffs of decomposing volcanic tuff.

There is a section of the slide that remains active.  At one time it was a standard geology student training exercise to measure downward movement with seasonal surveys.  Today the movement is measured with SAR (synthetic aperture radar).  The image below is from a pair of NASA overflights, and is colored to show the motion over a one week period in 2011.  The red/purple colors show the most rapid motion, about 4 inches per week.

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SAR image of the Slumgullion Earthflow. The slide is outlined in red, and the colors are constructed from the fringes of the differences between two radar images. The slide a few hundred meters above the SJS50 crossing is slowly moving downhill.

Although the Slumgullion slide is strange, it pales in weirdness to the last section of the course – the climb up Mesa Seco.  The SJS50 course is very close to the Alferd (sometimes written Alfred) Packer cannibalism site – in fact we are probably running on the very ground that Packer’s victims camped on at back in 1874. Packer – with no real experience, but a gift for tall tales – guided 5 men to the area in February (the middle of winter!) to look for gold.  It seems they were prospecting very close to the future Golden Wonder Mine (it is in Deadman Gulch, named for the Packer victims), but they became snow bound and quickly ran out of supplies.  There are many versions of what happened next, but it is clear that Alferd killed and ate his companions to survive.  For this reason I believe that the final aid station, named “Vicker’s” for the nearby ranch should actually be called Packer, and there should be bacon there…. I ponder what it must have been like to be in the San Juans 140 years ago.  I often think I was born 100 years too late, and could have been a naturalist.  Then I recall the amusing tale of the Hinsdale County Judge that presided over the trial of Packer and sentenced him to be hanged (the sentence was eventually overturned because Alferd ate his victims while Colorado was still a territory, and cannibalism was not a crime in the territory….really!); was reputed to have said: “Stand up yah voracious man-eatin’ sonofabitch…. When yah came to Hinsdale County, there was siven dimmycrats. But you, yah et five of ’em, goddam yah….Packer, you Republican cannibal, I would sintince ya ta hell but the statutes forbid it.”  Ah politics, they have not changed in 140 years.

After I get cleaned up and rebandaged, I go to the finish line and wait for all my friends to finish.  As the first runners come in I am struck how most look very different than runners after a 50K race.  Here they are far more tired, looking thankful for the finish instead of happy.  Nearly every runner I know tells a tale of how difficult the conditions were this year and how hard, very hard, the run was.  I think of Philippides who’s legend inspires ultra runners — giving it all, raising their arms in victory as they cross the finish line, and crumpling to the ground in exhaustion.  I suspect even Philippides would find the SJS50 challenging.

theend

A butterfly at Alpine Gulch. Simple beauty everywhere.

My morning after the race I have come to grips with my race-interupted.  I have decided that this is something I can not leave undone. I will return in 2016 – in fact, it will be the focus of all my training for the next year.  I also wonder how I can make the San Juans my home.

The Riff of the Rio Grande Rift: Running in the Pecos Wilderness and up Santa Fe Baldy

Both the man of science and the man of action live always at the edge of mystery, surrounded by it – J. Robert Oppenheimer, who was appointed the Director of Los Alamos Laboratory in November 1942.

stormoverSangre.post

View of a late spring storm over the Sangre de Cristo mountains viewed from Los Alamos (photo by Jim Stein, Los Alamos photographer extraordinaire, May 26, 2015). The peak in the center-left is Santa Fe Baldy (elevation 12,632 feet).

The town of Los Alamos sits high above the Rio Grande River on the Pajarito Plateau.  The location of the town will always be associated with the Jemez Mountains and the spectacular Valles Caldera; however, the view from the town is always to the east, across the Rio Grande Rift, and towards the Sangre de Cristo Mountains.  The Sangre are the southern most range of mountains that are part of the Rockies, and the view from Los Alamos is dominated by a series of rugged high peaks – Truchas, Jicarita, Sante Fe Baldy Peaks all top 12,500′ – these rocky spires guard the Pecos Wilderness, one of the Jewels of unspoiled New Mexico.

The creation myth of the Los Alamos often casts J. Robert Oppenheimer as selecting the isolated and rugged Pajarito Plateau for the project Y laboratory because of a connection with the Los Alamos Ranch School, a boy’s college prep school. However, that is incorrect – indeed, Oppenheimer recommended and lobbied for a laboratory in New Mexico because of his affection for the area.  But that attachment was with the area that would become the Pecos Wilderness Area.  In 1922 Oppenheimer and his brother Frank visited the Pecos Valley and loved it – so much so, that the brothers first rented, and eventually bought, a ranch along the Pecos River which they named “Perro Caliente” (the legend is that when Oppenheimer found the land for sale he shouted “hot dog”, and the name seemed logical for the new ranch).  When General Groves and Oppenheimer visited New Mexico to locate project Y the preferred site was near Jemez Springs.  However, Oppenheimer convinced Groves that the high cliffs would make the scientists claustrophobic, and thus, unproductive.  The next site visited was the Los Alamos Ranch School, and Oppenheimer beamed with joy at the view towards the Sangre de Cristo mountains, and exclaimed that the scientists would be inspired by the vast vista.  Of course, to the is day, the scientists — at least this one — remain inspired by the magnificent mountains.

attheranch

J. Robert Oppenheimer and E.O. Lawrence at the Oppenheimer Ranch along the Pecos River in the Sangre de Cristo Mountains. Oppenheimer often rode a horse from his ranch up to Lake Katherine just below Santa Fe Baldy.

The high mountain peaks of the Sangre are accessible by a number of trails that are only 35 miles from Los Alamos.  These trails allow great entry into the high country for trail running (and hiking!); several of the trailheads are located at the Santa Fe Ski Basin, and are gateways to runs of 20, 30, and even 50+ miles at elevations that never drop below 10,000′. This is a perfect training ground for the ultras like the San Juan Solstice 50 Miler (June 27, only 2 weeks away) — so off went about 10 runners from Los Alamos and Santa Fe on June 13 to get some quality high altitude climbing and descending, and tasting the ever changing alpine weather.

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Dave Zerkle, at the Sante Fe Ski Basin after a wet run up Santa Fe Baldy.

The geologic story of Santa Fe Baldy

New Mexico is an arid state. In fact, it has the lowest water-to-land ratio of any of the 50 states in the US, and more than three quarters of the few lakes that exist are actually man made reservoirs. Despite this lack of water, or perhaps because it is so scarce, the human history of the state is dominated by a narrow ribbon of water that bisects New Mexico, the Rio Grande River.  The Rio Grande is long, but not wide, and only in New Mexico would the name “Grande” be applied to this river.  The stream gauge at Otowi Bridge — on the hiway route from Los Alamos to the Sangre de Cristo Mountains – read 2500 cubic ft per second the morning of June 13, 2015 (the Mississippi River flow was 220 times larger at St Louis this morning).  However, this modest flow supports the state, and 75 percent of the state’s population lives within 50 miles of the Rio Grande.

The Rio Grande River is also a remarkable geologic marker. The headwaters are in the San Juan Mountains of Colorado, and entire course of the river through New Mexico follows a topographic depression that traces the Rio Grande Rift (RGR).  The RGR is relatively uncommon geologic phenomena, a continental rift (there are only three others in world), and it represents a stable continental plate slowly being torn apart; or more correctly, stretched apart.  The RGR stated about 25-30 million year before the present, and represents the end stages of extensive crustal extension throughout the southwest. The crust between the California-Nevada border and the Tucson, Arizona extended by as much as 50% during this time. The RGR is presently opening at less than 2 mm per year, but integrated over millions of years this has created a “hole” where the crust has been stretched apart. This hole is instantiated by a series of basins that have been filled with the sediments transported down the Rio Grande River.

Basins

The trace of the Rio Grande Rift is marked by a deep graben, which is mostly filled with sediments that have washed down the Rio Grande River over the last 25 million years. Los Alamos sits on the western margin of the Rift, and the Sangre de Cristo Mountains are along the eastern margin. Between Los Alamos and Sante Fe Baldy is the Espanola Basin.

The figure above shows the largest of these basins, including the location of the Espanola Basin which sits between Los Alamos and Santa Fe, and is more than 10,000 ft deep and filled with ancient river sediments.  The flanks of rifts are almost always elevated relative to pre-opening of the rift.  This may seem counter intuitive given that the opening of the rift creates a “hole”.  However, the opening of the rift is usually associated with ascending hot mantle material, which “lifts” the region overall.

riftdynamics

Conceptional cartoon for continental rift dynamics. Ascending hot mantle materials raise the elevation, and as the crust is extended a rift valley forms. The flanks of the rift are often uplifted high mountains with steep faces sloping into the rift valley.

This is the case for the entire eastern flank of the Rio Grande Rift in northern New Mexico.  The present topography of the Sangre de Cristo Mountains owes its existence to the opening of the RGR.  The Sangres are an ancient mountain range and certainly were part of a proto-Rocky Mountains.  However, studies of erosional surfaces indicate that 35 million years ago the prominence of the Sangres was only a thousand feet.  Opening of the rift allowed the rocks of the range to rise to their present elevation and develop and prominence of over 7,500′.

pecosmapRobertsonMoench1979

Geologic map of the Pecos Wilderness Area. The western margin is a block of plutonic granitic rocks that have been uplifted during the opening of the Rio Grande Rift. This block contains all the high peaks of the Sangre de Cristo range (from Robertson and Moench, 1979).

The core of the Sangre de Christo Mountains in the Pecos Wilderness area are Precambrian plutonic granites (and granitic gneiss).  In the figure shown above, the large elongate block on the western side of the map shows the extent of this plutonic rocks which are approximately 1.6 billion years old.  They are fragments of the original North American crust that were probably formed 5 to 10 km beneath the surface of the Earth.

The topography from the Jemez Mountains to the Sangre de Cristo Range are due to the dynamics of the Rio Grande Rift.  In fact, the entire landscape of the New Mexico has been influenced and shaped by the RGR.  As a geologic architect, the rift is Frank Lloyd Wright.

lookinguptobaldy

Looking up at Santa Fe Baldy from the Winsor Trail just beyond the Rio Nambe crossing. 2000 feet to climb in about 2.5 miles. Steep and sweet.

Sky running in the Sangre 

The Mountain Trail Series group (meaning Dave Coblentz from Los Alamos) organized a trail run for the high country of Pecos Wilderness.  The run (route shown below) climbed several of the peaks, and included some cross-country (no trails).  Several of the less ambitious (I am actually always ambitious, but my athletic ambitions do not match my actual skill) chose to run a section of the course.  The IDEA was to run up Santa Fe Baldy and then loop back over Lake Peak.

Coblentz.map

Map of the “course” for Beyond Baldy, a Mountain Trail Series Event. A group of us chose a slightly less ambitious versions that topped Santa Fe Baldy and Lake Peak without venturing cross country to Redondo Peak.

The forecast called for rain, but gave a glimmer of hope that the precipitation would hold off until noon.  However, at the start of the run at 7 am it was clear that a storm was brewing.  The Winsor Trailhead has an elevation of about 10,200′, and that is the low point of the run. The trail starts with a steep, switchback climb – about 500 feet in the first half mile – and by the top of first segment the fast runners have baked me off the end of the group.  This is good because it gives me time to look at the rocks and not feel pressure.  The trail is soft and not particularly rocky, but there are ample outcrops to see large blocks of granitic gneiss/schist glistening in the morning light.  The schist is rich in mica – and it is a marvel to imagine that this delicate mineral could last for over a billion years!

Once the trail enters the Pecos Wilderness boundary it is fairly flat for about 4 miles.  Easy running, along with a couple nice stream crossings.  When you arrive at the Winsor-Nambe trail fork the serious business of climbing begins.  However, today is a training run, so the pace is steady and easy. About 1/2 hour from the summit of Baldy we can see the fast runners along the ridge nearly to the top.

terryontop

Standing on the summit of Santa Fe Baldy. Behind me is the silhouette of Truchas Peak and ridge, about 30 miles north. There is no sunshine this June morning.

The views from the summit of Santa Fe Baldy are usually breathtaking.  However, today, hanging clouds at the front edge of a storm surround the ridges and obscures any distant vistas.  There is a fine view down to Katherine Lake, which still has some ice!  Lake Katherine is within a cirque on the northeast side of Baldy.  This cirque was formed by alpine glaciers that were extensive about 11,000 years ago.  Based on the number and character of the cirques on Baldy and Lake Peak the annual average temperature of the region must have been about 10 degrees F less than today. Katherine Lake is the largest alpine lake in the New Mexico (although small), and has an unbelievable connection to J. Robert Oppenheimer – he named it.  The lake is on maps that were produced before 1930 with no name, but in 1933 a map was produced that included the name “Katherine Lake”, and a reference to Oppenheimer as the namer.  It turns out that on J. Robert’s first visits to Pecos he became infatuated with a young woman of an old New Mexico family, Katherine Chaves.  His affections were apparently unreturned (it would appear that Oppenheimer was a nerd as far as the opposite sex was concerned, and he may have never even approach Chaves), but on his many trips riding horses in the Pecos came to love the small lake beneath Baldy, and wistfully named it Katherine Lake.

lookingatkatherine

a view from Santa Fe Baldy down to Katherine Lake. There was still a thin covering of ice on most of the lake, extremely unusual for June!

After a short break at the summit it was clear that it would soon start storming, and we began the descent down Baldy back towards Lake Peak.

zerkle

Dave Zerkle on the flank of Santa Fe Baldy. Over his right shoulder is Lake Peak and the cirque that contains Nambe Lake.

Soon there was grapple falling – then hail – then rain – then hard hail.  All those things are just an enjoyable part of trail running.  However, they were accompanied by thunder and lightning, and it was prudent to get off the exposed ridge lines as fast as possible. At this point I am reminded that being an old, slow runner has advantages – feet close together makes for less potential drop during a close-by lightning strike!

lightning

Most lightning fatalities are NOT from direct strikes. Rather, they are from close by strikes and the fact that humans make a grounding loop. Strangely, if your feet are together the potential drop from one foot to the other is much lower than if you have a wide stance….So, run with a shuffle.

The down pour dictated a change of plans, and we had to delay the run up to Lake Peak for another day.  Nevertheless, the run up Baldy is a great adventure!

moonrise

Moonrise over Santa Fe Baldy seen from Los Alamos. Another outstanding photo from Jim Stein. Full moon, mid-April, 2015.

Super Volcano in the Backyard: The Valles Caldera Marathon

Some things will never change. Some things will always be the same. Lean down your ear upon the earth and listen…..All things belonging to the earth will never change–the leaf, the blade, the flower, the wind that cries and sleeps and wakes again, the trees whose stiff arms clash and tremble in the dark, and the dust of lovers long since buried in the earth–all things proceeding from the earth to seasons, all things that lapse and change and come again upon the earth–these things will always be the same, for they come up from the earth that never changes, they go back into the earth that lasts forever. Only the earth endures, but it endures forever – Thomas Wolfe, in You Can’t Go Home Again (1940).

fromtheplane

Ariel view of the Valles Caldera and Jemez Mountains. This view is taken from a small plane at an elevation of 14,000′ looking south-southeast across the Valles Caldera. Photo by L. Crumple. (Click on pictures to get full sized view)

There are numerous influences in my childhood that propelled me to a career in the Earth sciences;  a father that loved to prospect and collect minerals, hundreds of family camping trips to the most interesting geologic province in the world (the Rocky Mountains!), and a progressive high school that offered a rich course in geology.  In hindsight, one of the most important influences was the fact that I grew up on the flank of a huge volcanic complex, the Jemez Mountain Volcanic Field.  The terrain of deep canyons, flat mesas, and a beautiful grass valley, the Valle Grande, surrounded by ponderosa pine covered peaks frame my childhood memories and help define home for me. The Jemez Mountains rise some 5000′ above the Rio Grande River and are remnants of a massive volcanic system that experienced two “super” eruptions about 1.4 million years ago.  The Jemez don’t really look like a volcano today if one’s idea of an active volcano is Mt. St. Helens or Kilauea – it is a large circular depression surrounded by the high peaks that once where the steep slopes of a series of craters that spewed forth hundreds of cubic km of hot ash. The figure at the top of this column is an aerial view of the Jemez, and the depression and surrounding peaks protect a series of valleys that once were filled with rain water after the great eruptions.  These valleys, or valles in spanish, are a unique feature of the Jemez. These mountains shaped me in many ways.  Out my back door was a riveting geologic panorama that provided an open invitation to explore nature.  Although most of the Valle Grande proper was off limits during my youth – it was a working cattle ranch that we just called “The Baca” in recognition that it was part of a old Land Grant called Baca Location Number 1 –  the surrounding mountains and forest lands were our play ground.

vallesgrande

View from within the Valle Grande to the west. The high peak is Redondo Peak, and the smaller rise on the righthand shoulder is Redondito Peak. The Valles Caldera marathon traverses around the base on Redondo on the edge of the Valles.

I learned about hiking, camping, wildlife, and calm call of nature.  I even learned some things about mineral collecting; in general, there is not much “mineral wise” in the Jemez, with the one exception. My first vehicle was a hand-me-down four wheel drive Toyota Land Cruiser.  Not many things worked on it (including the gas gauge which more than once left me stranded), but it did afforded me the freedom to explore the Jemez on my own.  My favorite trip was to the ghost town of Bland, a short-lived gold mining center located a few miles south of the Valles Caldera.  The mineral deposits were not formed by the volcanic processes that built the Jemez Mountains, but were from an earlier epoch of magmatic activity that injected quartz dikes into surrounding bedrock.  The Jemez volcanics covered these dikes, and later, through the randomness of erosion, were exposed in a narrow canyon (Bland Canyon).  In 1893 the first of a dozen claims was staked on these dikes for gold and silver.  A rush ensued, and soon a town was built and the population grew to more than a 1000 people.  The town was named Bland in honor of Richard Bland who had advocated for the governmental purchase of silver, and in turn, that bullion was minted into silver dollars.  The Bland act, and further requirements for the government to purchase silver (in particular, the Sherman Silver Purchase Act) were repealed in 1893 causing a collapse in silver prices — just as the mines in Bland were being discovered.

bland.1900

The boom town of Bland, circa 1900. Many of these same building were identifiable in the early 1970s when I searched for artifacts (with some success) and traces of gold or silver (without any success!). Unfortunately, all traces of Bland were destroyed in the 2011 Las Conchas fire – it is even impossible to find most of the old mine dumps.

I drove to the ghost town of Bland every chance I got in the early 1970s.  There was a “back way” in that required delicate 4WD navigation;  I was rewarded with a harrowing journey through the Jemez Mountains, and a chance to search through all the old building looking for artifacts and the mining dumps for some sign of gold or silver.  Mostly my searches were unsuccessful, but I had taste of the treasure hunter.

insulator

An insulator I collected near Bland in the early 1970s. The screw on glass has a patent date of 1893.

In the year 2000 the Federal Government purchased the “Baca” and it became the Valles Caldera Natural Preserve.  The charge of the Preserve was to remediate the effects of logging and cattle/sheep grazing, and eventually make the Valles Caldera a multi-use facility.  Although access is still carefully controlled to the Valles it has become the home to several special events.  In 2006 it became the site of a trail run – first a marathon, and later a half marathon and 10 km run were added.  The course has changed over the years, and a fire in late May of 2013 forced a change to a partial out-and-back route. The chance to run in a certified super volcano, only a few miles from my house is a huge draw – the Valles Grande Caldera Runs are a geologist’s dream.

IDL TIFF file

A recent NASA satellite image of the Valles and Jemez Mountains (click on the map to get a large, and clearer view). The circular depression of the caldera is obvious; left of the depression (east of the caldera) is Los Alamos. The brown-gray color is due to the denudation of the ponderosa pine and other vegetation after the 2000 Cerro Grande and 2011 Las Conches fires.

The volcano in my backyard

The Jemez Mountains and Valles Caldera are a spectacular sight from space. The satellite image above shows the circular depression that is about 13 miles across that formed after a series of very large eruptions of ash-flow tuffs emptied a large, shallow magma chamber.  Nearly 800 cubic km of ash were propelled from various volcanic vents, and the “hole” left by this erupting ash caused the volcanic edifice to collapsed back into itself producing a broad valley. Later, renewed magmatic activity pushed rhyolitic magmas up through the fractures formed during the collapse, producing a ring of domes breaking up the original valley into smaller, isolated valleys.  The largest of these magma extrusions, known as resurgent domes, is Redondo Peak, which has an elevation of 11,258′ and towers some 2500′ above the valley floor.  Redondo Peak is not a volcano – it was not “erupted” but extruded from the magma chamber beneath the Valles much like tooth paste would be extruded from a tube as it is slowly squeezed.

Vallea cauldera section 700

Geologic evolution of the Valles Caldera. The Valles volcanic center was active for 12 to 13 million years before a pair of major eruptions (1.5 and 1.2 million years before the present) caused the edifice of the volcanic system to collapse forming a large circular depression. Eventually this depression was dotted with a number of volcanic plugs or domes, forming the mottled landscape of Valles Caldera today (Image from the New Mexico Museum of Natural History).

The Valles Caldera remarkable symmetric, and incredibly well preserved — there were no major eruptions after the last collapse a million years ago to obscure the valley, resurgent domes and ring fractures that were formed during that collapse.  These qualities attracted geologists from around the world, and it has become the archetype volcanic caldera referenced in hundreds of studies and textbooks.  Although the Jemez Mountains were recognize being volcanic by the later part of the 19th century, it was not until the 1920s when C.S. Ross of the USGS visited, and later teamed with R.L. Smith in 1946 that the area was mapped in detail.  This mapping was done in part to understand the potential for supplying the new Los Alamos Scientific Laboratory with fresh water, and whether it was possible to bring a large natural gas line across the Valles to provide energy for my home town.  In 1970 Smith, Bailey and Ross published a beautiful geologic map of the Jemez Mountains and the Valles Caldera (figure below), and was the first map to grace the wall of my bedroom (I wish I could find that original wall hanging, but alas, it was packed away when I left for college and no doubt is today been composted and returned to the soil…).

jemez.htm_txt_smithmapjemez2

A section of the Smith, Bailey and Ross map (1970) showing the geology of the Valles Caldera. The yellow domes circling Redondo Peak (the brown color in the center of the figure) are the post collapse rhyolite resurgent domes.  The olive green color is the Bandelier Tuff – the base rock beneath Los Alamos.

The colors of the map hint at the extraordinary history of the Jemez Mountain Volcanic Field (JMVF).  The exact reason that the JMVF exists remains a bit of a mystery; it is located at the intersection of the western margin of the Rio Grande Rift and a trend of volcanic fields called the Jemez Lineament that has been postulated as a ancient “zone of weakness” that allows magma generated in the mantle to rise up into the crust.  I think that it is far more likely that the Jemez Lineament is the lucky connection of dots on a map, and that a more plausible explanation is that marks the boundary between a thick and stable crust (the Colorado Plateau) and thinner, more tectonically active crust.  Irregardless, it is clear that the opening of the Rio Grande rift caused volcanic activity to began about 13 million years ago in the vicinity of present day Los Alamos.  For about 10 million years the volcanism was dominated by basaltic lava flows.  Black Mesa, near Espanola, is one of the most famous landmarks representing this period of volcanism (Black Mesa is about 3.7 million years old).  About 3 million years ago eruption of more silica rich magmas commenced and the Jemez Mountain began to grow — there were probably 6 to 10 major volcanoes that tapped interconnected magma bodies.  These volcanoes conspired to create a major eruption about 1.5 million years ago that erupted what is known as the Otowi Member of the Bandelier Tuff.  Nearly 450 cubic kilometers of ash was erupted over a short period (probably a few years, but certainly less than a few decades).  This resulted in a collapse of the volcanic system, and the creation of the Valle Toledo Caldera.  This caldera is obscured by a similar sized eruption about 1.2 million years ago that ejected about 350 cubic kilometers of ash, the Tshirege Member of the Bandelier Tuff.  On the eastern margin of the Valle Toledo is the highest peak in the Jemez, Tschicoma Peak (elevation 11,561′), an remnant that survived both collapses.  The second eruption, and subsequent collapse created the now familiar Valles Caldera.

ashfall

Extent of ash fall from the second major Jemez Mountains Volcanic field eruption (1.2 million years ago). Ash has been identified in Kansas and Wyoming, and a large volume of the ash was transported down the Rio Grande (the blue streak in the map down the center of New Mexico).

The widely popular phrase “super volcano” has its roots in the 20th century, but mostly it is a phrase invented by the media around 2002 to dramatize the power of big volcanoes.  By 2003 the phrase appeared in more than 100 stories that covered everything from global warming and cooling to mass extinctions.  The USGS tied the phrase to the Volcano Explosivity Index (VEI), a measure of “explosiveness of eruptions”, and a VEI value of 8 became the definition of a super volcano, and implies a volume of material erupted that is at least 250 cubic km.  There have been 3 super volcanic eruptions in the US in the last 1.2 million years; the Jemez, Long Valley, California and Yellowstone in Montana/Wyoming.  All three of these eruptions resulted in the creation of a caldera.  Of course, our human centric view of geologic time — i.e, a million years is a long time — distorts the sense of “super” volcanic eruptions. Although Yellowstone was a large eruption, it was dwarfed by an eruption 28 million years ago that created the La Garita Caldera near Creede, Colorado.  Over the same time that it took the Jemez to erupt the Tshirege tuff, the La Garita erupted the Fish Canyon Tuff — all 5,000 cubic km of it (more than 15 times larger!).  Despite the size of La Garita,  Los Alamos is perched on the shoulder of a real super volcano.

VCC.copy

Comparisons of volumes of eruptions – Yellowstone and the Valles are “super volcanoes”, while more recent eruptions like Crater Lake and Krakatau have to settle for being “big” and Mt. St. Helens is just puny.

The relative tranquility of the Valles Caldera belies its violent history and magnificent history.  The most recent significant volcanic activity in the Jemez is the Banco Bonito rhyolite flow, which is located smack dab in the middle of the Jemez Caldera marathon.  The Banco Bonito is a very silica-rich rhyolite, and filled with large blocks of obsidian.  Although most everyone recognizes obsidian, and thinks arrowheads and black shiny pebbles, the geologist thinks about very rapid cooling of a volcanic rock.  Obsidian is silica glass – same material as a chunk of quartz, but it has no crystalline structure due to the rapid quenching of the hot lava. The Banco Bonito rhyolite was extruded (probably not erupted) 40,000 years ago.  Although the Jemez Mountain Volcanic Field will be active again in the future, it is mainly showing signs of exhaustion, and the likelihood of a future, large scale eruption is extremely small. Running through the Valles Caldera on a marathon is a unique experience.  Laid out along the course is every aspect of a few million years of violent tectonic history.  Ash fall, resurgent domes, ancient lake beds that filled with water in cooler and wetter times.

Vallesroute

A view from the southeast to the northwest across the Valle Grande, Redondo Peak, the the Colorado Plateau on the horizon. A little over 1/2 of the marathon course is an out-and-back from El Cajete to Cerro Pinon – right through the heart of the Valles Caldera. Also shown is the head of Bland Canyon, home of the ghost town. Picture from 2011 Nature article on Southwest drought.

The Valles Caldera Marathon

The Valles Caldera runs – there is a marathon, half marathon, and a 10 km – are not classic trail runs per se.  Most of the courses utilize dirt roads that once were used to move cattle or cut timber, and only some short segments are single track.  However, this does not diminish the spectacular setting of the race. It does mean that most people run the distances much faster than a typical trail run (I say “most” because single track versus tire rutted roads has nearly zero impact on my speed – sadly).  The races start at Banco Bonito Staging Area within Valles Caldera National Preserve.  The name “Banco Bonito” is applied to a modest plateau that is composed of the rhyolite-obsidian conglomerate that goes by the same name.  It is easy to find very attractive pieces of obsidian at the starting line — just look down.  There are more than 300 people signed up for the half marathon and 10k, but only about 45 of us toe the line for the full marathon at 7:30 in the morning.

start

Gathering of the runners for the start of the Valles Caldera marathon. Temperature at the start was 34 degrees, and throughout the day the weather alternated between sun, clouds and occasional grapple. Perfect.

The course for the marathon heads due east, climbing up the Banco Bonito lava flow along a logging road.  The lava flow is probably not obvious to most of the runners as it now is forested, and only along certain sections are there stratigraphic sections exposed.  But the topography of the lava flow is evident;  over the first three miles we climb about 450 feet (not much elevation gain, but enough to slow old runners down).  The pack of runners sorts out pretty rapidly, and good runners like Dave Coblentz disappear with a doppler shift over the horizon.  At the three mile mark the course comes to an aid station on the edge of a large bowl shaped depression — El Cajete.  This is a very significant geologic formation (but not such a significant aid station).  El Cajete is the crater that last had significant volcanic activity in the Valles Caldera.  It is responsible for the Banco Bonito lava flow 40,000 years ago, as well as a massive eruption of pumice sometime after the lava flow.  The pumice fell close to the El Cajete, and dammed the Jemez river creating a lake in the Valle Grande.

Cajete.elk

Aid station at mile 3 – looking out on El Cajete. If you click to enlarge the photo you can see a herd of elk scurrying across the crater on the right hand side — the crater is big, so the elk look small.

From El Cajete the course drops off the plateau and the run is downhill for 2 miles.  Fast and easy.  Unfortunately, the elevation lost is a penalty for the next part of the race.  At mile five there is a steep climb up a pass between Redondo Peak and another resurgent dome called South Mountain.  In a little bit more than a mile we climb 550 feet to the high point of the race, 9150′.  The top of the pass is a reward, but also a harbinger of things to come since we have to repeat this climb on the return from the Valle Grande.

profile

Course elevation profile. By my watch the course of 25.8 miles long.

From mile 6 to mile 12 the course is in the Valle Grande – well, strictly speaking, skirting around the edge of the Valle.  The grass “meadow” of the Valle Grande is due to the fact that it was a reoccurring lake bed in the last million years, and it is not particularly friendly nutrition wise to trees.  The last time the lake had a significant extent was after the El Cajete pumice eruption, and probably lasted for 4 to 7 thousand years (there have been smaller lakes during damp cool periods usually associated with glacial epochs).  The picture below is a view across the Valle towards Pajarito Mountain.  That summit, all 10,400 feet of it, is the high point of the Jemez Mountain Trail Runs — which will be run a month from now.

ValleGrande

A view across the Valle Grande to Pajarito Mountain. The weather alternated between sun and dark clouds through the entire run. The temperature was mostly in the high 40s, perfect for running a marathon.

Running through the Valle is always wonderful.  It is sensational scenery, and mostly flat topography.  At mile 9.4 I get passed by the leader of the pack returning towards the finish.  This means that the leader is about 4 miles ahead of me already.  Once the first runner passes by me it is a steady stream;  strangely, all the runners that are ahead of me look like they are strong and running very easily.  I, on the other hand, am beginning to lose focus and daydreaming of the geology.  Dave Coblentz passes me with a group of 5 or 6 runners at mile 9.7. The course “turns around” is at a point just beyond another resurgent dome — Cerro Pinon.  The milage here is just about 12 miles; there is a mental boost knowing that the “out and back” is done, but I also realize that there are 14 miles to go.  For the next 5 miles I pass by a few runners (a very few) that are slower than me, but mostly see no one.  I am alone – happy, but alone.  The climb back up the pass at South Mountain is brutal, but once that is done I am certain that I will finish the race largely unscathed.  The run down from South Mountain is fast, but as I expected, hard on my legs. The run between miles 18 and 22 is a descent of nearly 800 feet.  It should be fast, but my legs are tired.  There is a great aid station at mile 19, and I stop for way too long to eat oreo cookies.  The descent ends at a broad meadow called Redondo Meadow.  This meadow is an wildlife experiential station, and there are lots of people working in the area.  The course route is always confusing here because there is no real trail across the meadow, and there are meandering streams.  The course is marked, but that means you actually have to pay attention to the flagging (not my best skill – however, I have memorized the maps, so I don’t get detoured).  Once across the meadow the home stretch begins.  A steep climb up the Banco Bonito lava flow, and then a lonely run back to the finish.  I pass a couple of slowest runners of the 1/2 marathon, and try to encourage them (however, they are really tired).

finishline

Crossing the finish line – photo curtesy of Petra Pirc. I finish in a little over 5 1/2 hours. Long after the good runners, but happy for the experience.

I rambled into the finish line in a little over 5 1/2 hours.  It is a nice marathon – not exactly a trail run, but much harder than a street run.  The total elevation gain is about 3000 feet and the average elevation along the course is 8400′.  However, it is the geology that makes this run so great.  The Valles Caldera is truly a marvel….

101 spinel twins: symmetry and beauty in silver

The universe is built on a plan the profound symmetry of which is somehow present in the inner structure of our intellect, Paul Valery, 19th century French Poet

michigan.silver.2

Silver, Kearsarge Mine, Houghton Co., Michigan. The specimen is 3.5 cm across. This native silver is a lustrous example of a “weave” of sliver crystals exhibiting spinel twinning. Photograph by Jeff Scovil. Click on any photo in the article to get a larger view.

When I first started building a mineral collection — back about 1960 — the single most compelling criteria for determining if a specimen was a “keeper” or just something for the beer flats filled with colorful, yet, unworthy rocks, was whether there was a euhedral crystal.  My fascination with the perfection of a sharp crystal face is not at all uncommon for beginning collectors.  The fact that nature could take time to construct something so perfect strikes a deep chord; the vast universe created by the ultimate act of violence – the big bang – and ruled by entropy, and inevitable decay, still values symmetry.  I recall an early discussion with my mother on the beauty of spring flowers – I asked her why she thought they were beautiful, and she responded with a joyful exposition on the bright and varied colors and the delicate nature of the pistil, and remarkable symmetry of the petals.  I told her that the petals were exactly like crystals since they are always alike, and must be following some sort of “rules”.

The English word symmetry comes from the Greek symmetria;  in turn, symmetria is a concatenation of  Greek words sun and metron, meaning “together” and “measure”. There is a substantial body of Greek literature that refers to symmetry as  “harmonious and beautiful proportion and balance”.  This philosophical definition of symmetry deviates from the strictly mathematical definition, but still projects the power of something that is predictable and has a geometric balance to be pleasing to the eye.  This “pleasing to the eye” is a euphemism for beauty — hard to define exactly, but beauty excites our aesthetic senses.

To me, there is nothing more pleasing to the eye than a silver specimen exhibiting spinel twinning – repeating patterns of crystals that produces a highly geometric weave.  The photograph at the top of the column is a silver from the Kearsarge Mine, Houghton Co., in the Upper Peninsula of Michigan. The specimen is defined by a central rib — an elongated stack of silver octahedrons, and branches intersecting the this rib at angles of approximately 60 degrees.  In turn, these branches have secondary branches exiting at similar angles.  The repeating geometry yields a specimen architecture that is clean and sharp – an exemplar of what the Greeks meant by symmetry.

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Silver, from a locality near Tongchong, Yunnan Province, China. Specimen height is 6cm. The wires are the result of decomposition of acanthite.  Jeff Scovil photograph.

Silver:  a special element

Silver is a remarkable element that can form an array of minerals; about 180 different species.  Thankfully, elemental silver is sufficiently inert to occur in nature and is widely distributed throughout the world.  Native silver is a metal of bright white color; it has the highest reflectivity of any metal.  Silver is also the best metallic conductor of heat and electricity and extremely malleable and ductile. These properties are, of course, a result of crystal and atomic structure, which is a face-centered cube with metallic bonds.  The atomic radius of silver is nearly identical to that of gold – and gold commonly substitutes into the silver crystal lattice.

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Native silver crystal forms, from Goldschmidt (1913). The octahedron is most common, although cubes are much coveted by collectors. The bottom 3 figures show spinel twinning.

Silver crystallizes in the isometric system, and although individual, sharp macro crystals are rare, the octahedron and cube forms are most common.  The largest individual crystals are from Kongsberg, Norway, where some octahedrons 3-5 cm on a side grace a few fortunate collections.

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Cubic silver in calcite; Kongsberg, Norway.Each of the large cubes are approximately 1 cm on a side.  Jeff Scovil photograph.

As a rule, crystals of silver are equi-dimensional or platy. The platy nature comes from the propensity from silver to twin (this is similarly seen in gold and copper) on octahedral faces {111}.  This twinning is known as spinel twinning and is described below.  The conditions for when spinel twinning occurs appears limited – although silver masses of spinel twins are known from hundreds of locations, there are only three or four localities where this type of silver crystallization is common.  The two most famous localities are Batopilas, Mexico and Chanarcillo, Chile.

By far, the most common form of silver in a mineral collections is the wire – which is a secondary growth from the decomposition of silver sulfides and sulfosalts. Any silver deposit that undergoes supergene enrichment inevitably has silver wire specimens.  The picture at the top of this section of the article is a fine silver wire mass from Tongchong in China.  The wires in this specimen are attached to a very small piece of acanthite, no doubt the host material that provided the silver.  All silver sulfides and most silver sulfosalts will produce silver wire upon disassociation — especially promoted by heating.  Although wires can be extremely interesting and coveted specimens for collectors, there are been numerous cases where the wires were “grown” by unscrupulous collector/dealers and passed off as “natural” specimens.

Beauty in Nature

When I hear the word “beautiful” used to describe minerals by collectors I often ask what they mean.  More often than not, the answers seem wanting to me.  Mostly, it is about color — pink and red minerals are always “beautiful”, but black and brown minerals are “interesting”.  Although color can transfix, and certainly evoke emotion, I can not relate to it as the primary metric of natural beauty.  I am also looking for structure in my surroundings – a window into the soul of nature, order out of the chaos all around me.

A seminal event for me was attending “math summer camp” during the summer between 7th and 8th grade.  The instructor was an outstanding teacher named Jack Gehre, and his focus was geometry and trigonometry. Early in the class Mr. Gehre introduced Euler’s formula; for any normal polyhedron, the sum of the number of faces plus the number of vertices, minus the number of edges always equals 2.  I spent the rest of the summer camp trying to understand why.  I suddenly had a “rule” in nature that I could apply to my mineral collection — a rule mysterious and powerful, but incredibly simple.  It was beautiful.  I did not know much about Euler then, but later in college I was introduced to another “law” by Leonhard Euler — an incredible 18th century Swiss mathematician — that has to be the most beautiful equation in all of nature.  I was in a class on series analysis, and the professor, Alan Sharples, walked in the first day of the semester and wrote the following on the black board:

theidentity

Sharples said, “this is Euler’s identity, a remarkable assertion.  Prove it.  That is all for this first day of class.”  Turns out that this is pretty easy to prove, but when I viewed this on the blackboard I was transfixed — it was pure beauty.  Imagine three essential mathematical constants – e, pi, and  – combined to equal -1.  Wow – simple, brief, and exact.  To this day I view this as a definition of beauty (Euler’s identity is routinely identified as the one of the most beautiful equations in science).

Euler’s identify may seem a long ways from realm of beauty in the mineral kingdom.  However, to me, they are very much related.  Simple, surprising, and an expression of natural symmetry.

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Herringbone silver mass, Batopilas, Chihuahua, Mexico. The Specimen is 3.75 cm across. Jeff Scovil, photograph.

Respect the Spinel Twin

Crystal growth in nature is quite complex; the crystal form, crystal size, crystal chemistry all are expressions of the paragenesis. Crystallization for most geologic materials involves the precipitation of a solid (the crystal) out of a solution or solvent (usually hot thermal fluids, although solutions of nearly any temperature can carry dissolved loads of ions and cations).  Crystals start with nucleation of a few molecules from the solution, and then growth occurs by pulling the necessary ionic components out of solution.  The rate at which individual crystals grows depends strongly on the saturation level of the ions of interest – supersaturated solutions appear to be able to grow crystals at extraordinary rates (at least compared to geologic time!), sometimes at several cubic cm per hour.

It is not clear who first recognized twinning in crystals, but it was first written about in detail by Rene-Just Haüy in his epic tome Traité de Minéralogie, published in 1801. In the beginning part of the 20th century there were a number of studies to understanding twinning in minerals. The classic definition was introduced by Friedel in 1926: A twin is a complex crystalline edifice built up of two or more homogeneous portions of the same crystal species in contact (juxtaposition) and orientated with respect to each other according to well-defined laws. The “well-defined laws” all are based on some simple ideas, the most important of which is that within a crystal core that a least one lattice row (i.e., a crystal edge) is common to two different crystals. The figures below illustrate this concept — the lattice of a cubic crystal is defined by four points, and a plane can be drawn through these points that allows a second crystal to share lattice points but have a rotated orientation. Twinning adds symmetry to a crystal aggregate, most commonly about a rotation axis or reflection across a plane. In the metals copper, gold and silver, a particular type of twin is common, called the spinel twin.

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Spinel twins are so-named because it is a very common habit seen in the mineral spinel. They are contact twins, meaning that have a planar composition surface shared by two individual crystals; this surface is along an octahedral face (written as {111}), and means that there is a rotation of 180o about the contact plane. This is illustrated by the lower figure above – there are two octahedrons joined along a contact plane, but the top terminations “point” in directions and are separated by 120o. The figure below shows how spinel twins can be flattened, and give the characteristic triangular faces that are seen on platy crystals of silver (and gold).

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Notional relationship between an octahedron and a spinel twin producing a triangular type crystal face. This is “notional” in that this is NOT how the spinel twin evolves with time, but rather, a visual guide to compare an octahedron (left) and triangular face (right).

In silver, spinel twinning almost always repeats itself with regularity, producing a pattern that resembles a weave of wires.  The silver at the top of this section of the article is from Batopilas, Chihuahua, Mexico, and is an example of a mass of spinel twins.  Through the middle of the specimen is a series of parallel elongated crystals, and growing “off” these strands are regular strands oriented at 60 degrees (or 120 degrees, strictly speaking). These are all spinel twins – repeating some natural frequency that is due to a long lost geologic condition.  Once assembled, the spinel twins from an aggregate of crystals that has been called a “herringbone” silver in reference to the similarity to the shape of the rib cage of the smelly game fish beloved by the peoples of the Baltic.

Why do spinel twins form in silver?  Under certain ideal conditions, a single large crystal represents a “minimum” energy condition, and thus is due to an important thermodynamic rule — a chemical system will stabilize at state of least energy.  If individual crystals are a minimum energy state, then twinned crystals are by necessity at state of higher energy, and thus should be rare. However, environmental conditions tend to localize energy states; for a supersaturated solution, the crystal growth is extremely rapid, and twinned crystal allow more ions to join a crystallize aggregate faster, thus minimizing a local energy state.  For all “herringbone” silver specimens it appears that the conditions of formation require a supersaturated solution, low in concentrations of sulfur, and extremely rapid crystal growth.  These conditions are relatively rare in most epithermal vein deposits; it is very uncommon to find a spinel twinned silver specimen from the great silver deposits of Colorado, Ontario or Freiberg!

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Large silver plate (7.5 cm from side-to-side) from Chanarcillo, Chile. The specimen is a weave of spinel twins – and is my favorite silver specimen in my collection. Jeff Scovil photograph.

The silver pictured above is my favorite native silver in my entire mineral collection.  This is a large “herringbone” plate with a three dimensional repeating pattern of twins.  The specimen represents something remarkable in turns of crystal growth.  The tiniest variations in chemistry or temperature during growth would have truncated the growth of this silver weave.

spineltwin.closeup

Close up of the Chanarcillo specimen shown above. The central rib is an elongated chain of octahedrons. Field of view is 3 cm. Repeatedly, silver crystal “twin” off the octahedral face(s). At the very top of the specimen there are identifiable octahedrons.

A close examination of the Chanarcillo herringbone yields views of spectacular detail – endlessly repeating, and shouting the fundamental rules for symmetry in crystals. Along the edges of the crystalline mass you can see individual octahedrons – the termination of various elongated crystals.

Beauty and the pretenders

Rapid growth in silver often produces crystalline masses that are complex.  However, spinel twins are distinct, and uncommon.  Rapid growth often leads to dendritic masses – mostly silver feather patterns or strings of stacked cubes. These dendrites are not spinel twins; in fact, instead of fundamental order, they represent chaotic growth.  Although there is some sense of beauty in the randomness of dendrites, it is mostly through “self-similarity” – various patterns that appear to scale with size.  This is fundamentally different than ordered spinel twins – and in many ways points to disordered processes.  I am always shocked (okay, probably an overly harsh expression of emotion) when I find dealers selling “herringbone” silvers that are in fact dendrites.  That is like marketing hamburger as Filet Mignon.  Similarly, silver wires can certainly be attractive; however, they are products of mineral destruction not construction.  To me, beauty in silver spinel twins is about construction, order, and symmetry.  Defining beauty will allows be in the eye of the beholder — it is just better when there are rules involved.