A Landscape as Bizarre as They Come: The Volcanic Tableland of the Eastern Sierra Nevada

The Volcanic Tableland, with the White Mountains beyond.

There is a bizarre landscape on the far side of the Sierra Nevada between Bishop and Mammoth Lakes. It's not one of stark beauty exactly, it's barren and covered by little more than sagebrush. It's got few roads or trails, primarily because very little of this landscape is of much use to anybody. From above, the surface is riddled with scarps and grabens from numerous faults. This is a broken-up land. It's not...normal.

Source: US Geological Survey

The surface of this landscape isn't "right" either. There are no dark rich soils here. The underlying rock is pink or white, and so is the weathered soil and debris that covers it. Although the surface has an area of several hundred square miles or more, the underlying rock is remarkably uniform. It is a volcanic rock called rhyolite tuff. And with that name, the explanation for this landscape is revealed: it is the remnant of an ancient disaster beyond imagining.

767,000 years ago, an explosion took about 125 cubic miles of pasty magma from the crust and blew it into the atmosphere. The huge void collapsed inwards, forming an oval-shaped depression 20 miles long, 10 miles wide, and a mile or more in depth. The resulting ash spread far and wide, blanketing the western United States. Measureable deposits can be found in Kansas and Nebraska. But most of the ash came straight down. Some of it refilled the caldera, but much of the remainder buried the regional landscape hundreds of feet deep in hot ash. All life would have been extinguished for miles in every direction.

It is difficult to understand the magnitude of such events. From a human perspective, we have nothing to compare it to. An eruption at Tambora in Indonesia in 1815 produced less than a tenth of the ash as Long Valley, and that was enough to cause global cooling with related summer snowfall, crop failures, and famine across the northern hemisphere. The effects of an eruption the size of Long Valley on modern civilization would be appalling. I've heard it said that modern agricultural production has a month-long lead on consumption demand (No, I can't cite a source. It's a factoid I'm sure I heard or read somewhere). Try to imagine a disruption of agricultural production lasting several years. Governmental and societal structures would collapse, and the death toll would be unimaginable. Humans would no doubt survive, but it would be a dystopian landscape as bad as any sci-fi action movie, and maybe worse.

The only good thing that I can think of to say on this possibility is that studies of calderas like Long Valley or Yellowstone suggest that the eruptions will be predictable on a scale of decades or centuries. There would be time to prepare the eruption, or, however unlikely, geo-engineer the caldera to lessen the intensity and effect of the cataclysm.

What happens when a singular event completely reshapes a landscape? The eruption of Long Valley completely disrupted the drainage patterns of the eastern Sierra Nevada and Owens Valley. The land had to start over. Where there had once been river valleys and canyons, there was now a gaping pit miles wide and long. The evidence suggests that for 600,000 years the caldera depression contained a huge lake similar in plan if not in scale to Crater Lake. Crater Lake has no outlet, with the lake level determined by evaporation and seepage. The Long Valley Lake would have been similar, as no evidence exists for an outlet, at least until around 150,000 years ago.

Source: U.S. Geological Survey

For 600,000 years sediment washed into the basin, slowly filling it. Finally, along the south rim of the caldera near the present day site of Crowley Lake, the basin spilled over. In just 150,000-160,000 years, the Owens River carved a 400-500 foot deep gorge down the surface of the Volcanic Tableland, laying bare the full extent and history of the climactic eruption of the caldera. The rate averages out to about a foot every 400 years, but the rate was probably higher at the beginning. The small creek that flows through the gorge today is a mere shadow of its former self. The Los Angeles Department of Water and Power has co-opted most of the water, but a court order several years ago mandated that a minimum flow must be maintained.

Because the LADWP has utilized the water from the Mono Lake Basin to the north, they have constructed penstocks and pipelines that allow them to produce energy as they transport water down the long slope of the Tablelands. That means access roads, and it is thus easy to visit the gorge, and it is fascinating.

The mounds seen occasionally along the rim are the eroded remnants of fumaroles, where steam would have emanated from the interior of the ashflow, leaving mineral deposits that toughened the rock. The tuff at the rim is relatively soft, but as one walks deeper into the gorge, the rock becomes harder (it tuffons up?). When the hot ash landed, it was hot enough to remelt, forming welded tuff, or ignimbrite. Pieces of pumice caught up in the eruption became flattened and smeared in places.

As the rock cooled, it contracted to form columnar joints. Unlike Devils Postpile, a few miles away on the other side of the crest of the Sierra Nevada, these columns are not vertical. Most columnar jointing is not. The intense fracturing of the rock into these columns aided the Owens River in the carving of the gorge, as the crumbling rock could be quarried by the rushing water much more readily than solid rock.

The columns average six sides, but columns with 4, 5, or 7 sides are occasionally seen.

The Volcanic Tableland and the Owens Gorge are otherworldly, but they provide a hint of how quickly landscapes can adjust to new geological conditions. It took 600,000 years to fill a basin 10 by 20 miles with at least 2,000 feet of sediment, and 150,000 years to carve a 400 foot deep gorge. This is fast by geologic standards, but humans, had they been around this region at the time, would not have noticed much change in course of their lifetimes. Just like we aren't noticing the changes now...

Ghosts of the Empty Lands East of the Sierra Nevada: The Town of Bodie

The Matterhorn Crest of the Sierra Nevada from Bridgeport. Bodie is another twenty miles to the east.

Central California is almost literally a "land flowing with milk and honey". The Great Valley (called by those who live elsewhere the Central Valley) is one of the richest agricultural regions on planet Earth, producing most of the nation's nuts, and a significant portion of its vegetables and fruits. And lots of honey, from the bee colonies used to pollinate the crops, and milk from the hundreds of dairy farms. The rich harvest is made possible by the imposing wall of the Sierra Nevada, a 400-mile-long mountain range that wrings out practically all the moisture in the storm systems that roll in from the northwestern Pacific Ocean. It is in so many ways a gentle land where extreme weather events are relatively rare (recent floods and droughts notwithstanding). The fault lines for which California is famous are relatively far to the west, so earthquakes don't often affect the towns and cities of the valley (although the possibility is certainly there).

But...rise above the valley floor and into mountains, and over the crest to the lands beyond to the east, and things change. The storms that bring so much richness to the west slopes are used up by the time they cross the crest, and often all they bring to the east is bitter cold dry winds. The forests, if they exist at all, are scraggly Pinon Pines and Utah Junipers. Most slopes are covered with drought tolerant sagebrush and rabbit brush. The growing season is measured in weeks, not months. Agricultural efforts in a harsh land like this are generally doomed to failure. In fact, the written history of the region is generally one of failure and disaster (the indigenous peoples of this land tell a different story of course; there is a difference between imposing one's will on a landscape versus surviving on the resources available).

In 1848, gold was discovered in the Sierra Nevada foothills, and hundreds of thousands of hopeful people converged on the Mother Lode with their dreams of avarice, or at least dreams of a better life. A few of them got rich, some of them barely got by, and many failed. Many of them walked and rode from Mexico and Central America, others came from the east coast by ship, and some courageous, but perhaps foolhardy people walked across the vast desert between the Rocky Mountains and the Sierra Nevada. Mere survival was the challenge for many of them, and a fair number didn't. Imaginative minds could hear the cries of those lost in the howling winds.

The damage at the top of the brick building was from a 5.7 magnitude earthquake last year. It closed the park for several months.

The Gold Rush lasted for half a decade before the rivers were depleted of their riches, and most of the gold that remained could only be mined by methods that required vast amounts of money from investors. There wasn't much left for the individual prospector to search for, and thousands of hungry miners began to consider the barren lands east of the Sierra Nevada that they had traversed years earlier. Men began to creep back over the Sierra Nevada and began searching the empty lands beyond. As usual, most failed in their efforts, but others found riches. One man managed both. W.S. Bodey found a ledge of gold ore in the barren hills north of Mono Lake in 1859, but before he could enjoy his discovery, he froze to death in the harsh winter. A few others worked the ledges in the years that followed, but it wasn't until 1876 that a truly rich lode was found. Investors were brought in, a series of mines, including the Standard Mine, were established, and by 1880, a town of 10,000 people had risen from the sagebrush. The city was called Bodie (Bodey's name was apparently altered to make the pronunciation clearer).

The town developed a fearsome reputation. In the harsh climate, there were few amenities besides drinking, and deadly conflicts were a constant part of life. One legend stated that a young girl, upon finding that she would be moving there wrote "Goodbye God, I'm going to Bodie" (a town has pride, and an editor for the local paper said the punctuation was wrong; she had actually said "Good, by God, I'm going to Bodie").

The mines were successful for a few decades, producing perhaps 2 million ounces of gold, but by 1913 the Standard Mine shut down, and people drifted away. 2,000 buildings were scattered across the valley, occupied by perhaps a few hundred people. A fire in 1932 destroyed most of the buildings, but 167 of them survived. Concerns about vandalism led to the establishment of Bodie Historical State Park in 1962, and efforts were made to stabilize what buildings remained. What's left is one of the most picturesque ghost towns to be found in the American West. The only residents today are a few rangers, and the ghosts. I'm not usually superstitious, but I would be just a little creeped out living there. I see the signs that say that all visitors must be gone by nightfall, and I wonder...why?

We visited the park at the end of September during our fall field studies trip, and the day was comfortable, not too warm, not too windy, but I found out later that overnight Bodie had been the coldest spot in the entire United States at 16 degrees (the hottest spot at 104 degrees was Death Valley; we were halfway between the two that night). Snow had fallen less than a week earlier, and snow fell again a few days later. And this was the "nice" time of year.

The Standard Mine mill and the once-proposed open pit mine on the hill beyond.

The Bodie Hills are the remains of four stratovolcanoes that were active 8-14 million years ago. Hydrothermal activity around hot springs associated with the volcanism was responsible for the emplacement of the ores. Gold resources certainly remains, and because the gold claims were still valid, efforts were made in the 1990s to mine the hill above the town by way of open pit mining. Millions were expended in exploration and public relations, but eventually the lands were withdrawn from mineral speculation, and the ghosts of Bodie will be able to rest in relative peace.

If you want to visit, information about the park can be found here: http://www.parks.ca.gov/?page_id=509.

Fall Colors in the Eastern Sierra Nevada!

We've returned from a field studies expedition to the eastern Sierra Nevada, and I can report that fall has arrived! We've had a very warm summer, and the heat waves continued into September, but then we had a sudden cold snap, and even some snow. Tioga and Sonora Passes briefly closed, but opened again in time for our trip. The aspens and cottonwoods have responded to the sudden cold conditions.

Our route took us over Sonora Pass, where fresh snow still lingered on the high slopes. It's a sight I'm not used to. We spent a lot of time in the Bodie area and in the White Mountains where there aren't many deciduous trees, but late in the weekend we moved into the canyons below the Sierra Crest.

One of the special places is Convict Lake, which is dammed by a moraine of the Tioga glaciation that ended about 13,000 years ago. Aspens and cottonwoods crowd the shoreline, providing vivid color.

On our last day, we took the June Lake Loop, and stopped to explore Silver Lake. The canyon of Reversed Creek and Rush Creek is a spectacular glacial valley with high peaks above, and a string of beautiful lakes.

As we wandered among the trees, we heard a rockfall on the slopes high above. It wasn't all that big, leaving little dust in the air, but it was exciting to listen to geology in action.

It's been a long summer, but the drought finally broke, and the forest was looking healthy. Our mountains might not have the color range of the eastern hardwood forests, but then again, those forests don't have the mountain backdrop of our beloved Sierra Nevada.

The Sierra Beyond Yosemite: Where the Sierra Ends (maybe), and Gold

In some places it is pretty clear where the Sierra Nevada ends. For a hundred miles or more there is a solid rock wall that reaches a height of two miles in the Owens Valley. There is no mistaking that the mountains end at the cliffs above Lone Pine. Likewise, it's an unmistakeable demarcation between the flat Great Valley and the Sierra Nevada foothills. But in the central and northern Sierra Nevada, the division between "Sierra" and "not Sierra" is a line not so easily drawn.

From Mono Lake to the north, there are fault lines that mark the edge of the Sierra Nevada structural block, but they diverge from the watershed crest of the range, forming a series of north-trending ranges and valleys. These ranges, the Bodie Hills, the Sweetwater Mountains, the Pine Nut Mountains, and the Carson Range, are connected directly to the Sierra Nevada, are composed of rocks related to the Sierra Nevada, but are often considered "not" the Sierra Nevada. Geologically, the Sierra Nevada block is moving northwest from the adjacent Basin and Range province, making it a so-called "microplate", a much smaller version of the North American or Pacific tectonic plates. The mountains mentioned above are the jagged edge of the incipient plate boundary that has not yet completely separated from the rest of North America. If you are patient enough, buy up some desert scrublands  in the Great Basin of Nevada. In a few million years they may be oceanfront property!

Our journeys last fall through the "Sierra Beyond Yosemite" took us over Sonora Pass and into the lands east of the Sierra Nevada crest, a land that is both "Sierra" and "not Sierra". Our first destination was the ghost town of Bodie, between Mono Lake and Bridgeport Valley in the Bodie Hills.

"Hills" in this instance is a deceiving term. In any other setting, the Bodie Hills would be considered mountains, reaching elevations of more than 9,000 feet, and rising steeply above the Mono Basin. Still, the hills around the ghost town are more gently rolling, having not been glaciated, or deeply eroded by rivers. They lie in the rain shadow of the main Sierra crest, receiving only 12 inches of precipitation a year, making the region technically a desert (in climate terms, a dry-summer subarctic environment). Bodie competes with Barrow, Alaska as the place in America with the most freezing days per year: 308 of them on average. I just can't help thinking that this was a miserable place to live. Why would anyone...oh yeah, gold.

As I've described before, Bodie was a gold mining town. In the decades following the fabled Gold Rush, hungry miners started to explore the region east of the Mother Lode, and over the crest of the Sierra, and a lucky few found the elusive metal. W. S. Bodey was one of these; his exploration party found gold in 1859 in what later came to be known as the Bodie Hills (apparently the spelling was changed to help with the pronunciation). He may have found the gold, but he wasn't lucky. He froze to death the following year while making a supply run near Mono Lake.

The mines took some time to take off. The discovery of a rich lode in 1876 led to the development of the Standard Mine, and thousands of people came to the town of Bodie. The population peaked at 10,000 in 1880. The town developed a fearsome reputation for lawlessness, and one legend declared that a young girl, finding that Bodie would be her new home, said "Goodbye God, I'm going to Bodie". The town had its pride, too: an editor of the town newspaper insisted the punctuation was wrong; she had really said "Good, by God, I'm going to Bodie".

The mines were active for years, producing $34 million in gold (at a mixture of prices, $20/ounce in the 1800's and early 1900's, and $36/ounce in the 1930's). The gold is worth a great deal more at today's prices, perhaps $1 or 2 billion. As time went on, gold production waned, and the town began to die away. The Standard Mine shut down in 1913, although sporadic efforts at mining continued through 1942. A disastrous fire in 1932 destroyed most of the buildings in the town (only 110 of the original 2,000 buildings remain).

The gold at Bodie resulted from hydrothermal activity in the heart of a volcanic center that was active between about 14.7 and 8.0 million years ago. The field included at least 20 vents, including four trachyandesite stratovolcanoes. The town lies along the boundary between the deeply eroded Silver Hill and the Potato Peak cones, while the access road to Highway 395 meanders between the Willow Spring and Mt. Biedeman complexes. The sage covered hills reveal little of the volcanic violence that formed this landscape, but they do provide an analog for the appearance of the pre-glacial Sierra Nevada crest. The alpine topography of the present-day Sierra Nevada crest is a very recent geologic event. Without the glaciers, the Sierra Nevada would have been a different place entirely.

Today the town is a popular state park, and it has been declared California's official Gold Rush Ghost Town (as opposed to California's official Silver Rush Ghost Town in Southern California). I have a hard time envisioning a life here. I imagine that it was a relief on the coldest winter days to get out of the house or tent and get underground in the mines where it was warmer. Today, during a visit in the warm summer months, it is a photographer's playground, and an interesting place to learn about ancient Sierra Nevada geography.

A Gallery of Sierra Nevada Scenes: Part I

Tufa towers on southwest shore of Mono Lake

If Geotripper has been quiet of late, there is a pretty good reason: I've been on the road and off the grid. I may have plenty to say about these scenes later on, but for now I've just gone through the entire collection and picked out the images that caught my eye for some reason or another. In the picture above, it was the one strip of sunlight on the Mono Lake tufa towers in a sky full of smoke. The lake is a vast saline evaporation pond that serves as a temporary stopover for millions of migrating birds.

Bodie Ghost Town

Bodie is a fascinating place. I picked this shot because it shows the close clustering of houses as a hedge against the barrenness of the hills beyond. I visit places like this and realize that you can choose to live comfortably in an equitable climate, or you choose to try and survive in a pitched battle with the elements. Bodie sits at 8,000 feet and suffers horrible bitter winters. It was an outpost of civilization on the edge of a hard wilderness.

Bodie Ghost Town

I still find it hard to believe that a gold mining company wanted to turn the slope behind the town into an open pit mine just a few years ago. Some places should remain as they are.

Owens River Gorge

Owens River Gorge is a little-known corner of the eastern Sierra Nevada that reveals some of the awesome power of earth processes. The 400 feet gorge has walls of rhyolite tuff, erupted in the space of a few hours or a few days in one of the most incredible explosions in earth history. Yellowstone's supervolcano might get all the press, but Long Valley Caldera put 150 cubic miles of hot ash into the atmosphere 760,000 years ago, blanketing the entire American West. Some deposits are found in Kansas and Nebraska. A lake formed in the caldera and eventually overflowed, allowing the Owens River to carve this deep gorge...in only a few hundred thousand years.

Lake Crowley and the Long Valley Caldera

We soon found ourselves standing on the floor of the vast Long Valley Caldera. The eruption caused the crust to collapse in a massive hole 20 miles wide and 11 miles long. The two-mile deep hole was filled with ash and lake sediments over the years, but is still a striking feature. We were standing on one edge of the vast hole, while the mountain ridge in the far distance is the other.

Mt. Tom and Pine Creek

The eastern Sierra Nevada is an astounding wall of rock that developed when the Owens Valley fault graben collapsed and sank, forming a two mile deep valley more than a hundred miles long. Mt. Tom (above) is a 13,652 feet peak rising above Round Valley near Bishop. It lies at the edge of an intrusion of granitic rock and previously existing metamorphic rock. The interaction of the hot fluids around the intrusion produced tungsten minerals that were mined for years in Pine Creek. The mine is currently mothballed.

Minaret Vista

The Minarets lie just west of the Sierra Nevada crest in the vicinity of Mammoth Lakes. The high jagged peaks reveal Triassic metamorphic rocks that developed as an ancient caldera, perhaps similar to  the modern day Long Valley Caldera, collapsed into the underlying magma chamber during a giant eruption. The stunning view is from Minaret Vista on the Sierra crest just above Mammoth Ski Resort.

More to come!

Geological Excursions in the Sonora Pass Region now available at Sunbelt!

Our field guide to the geology of the Sonora Pass region and the eastern Sierra Nevada region is now available for sale at Sunbelt Publishing for $24.95 (here is the link)! This was the roadguide for our recent meeting of the Far Western Section of the National Association of Geoscience Teachers. There are quite a few geological road guides out there for the eastern Sierra Nevada, especially around the Mono Lake area, but there have been fewer guides for the area to the north. It is a fascinating region, with widespread Miocene volcanism, faulting and Pleistocene glaciations (the largest glaciers of the eastern Sierra Nevada traversed the West Walker River gorge).

One of California's most intriguing ghost towns can be found at Bodie (above), and one can also find a strange "fluvial forest" in the West Walker River, a group of long-dead Ponderosa pines that provide evidence of a century-long mega drought only a thousand years ago (below).

The western slope of the Sierra along the Stanislaus River hides some geological treasures as well, including the Columns of the Giants and the Natural Bridges in the cave country north of Columbia State Park (below).

Here is the table of contents...

A Geographical Sketch of the Central Sierra Nevada
A Brief Overview of the Basement Rocks of the Central Sierra Nevada
Trip 1: The Sierra Crest Graben: A Miocene Walker Lane Pull-Apart in the Ancestral
Cascades Arc at Sonora Pass by Cathy Busby, Alice Koerner, Jeanette Hagan, and Graham Andrews at the University of California, Santa Barbara
Trip 2: A Guide to the Geology of the Eastern Sierra Nevada between Sonora Pass
and June Lake, California by Garry Hayes, Modesto Junior College
Trip 3: Geology and Climatology of the Saddlebag Lake Region near
Tioga Pass, CA by Laura and Ryan Hollister
Trip 4: Sword Lake Debris Flow by Jeff Tolhurst, Columbia College
Trip 5: Unique Geology along the Stanislaus River, Western Central Sierra Nevada by Noah Hughes, Modesto Junior College
 Appendix A: The Flora of Central California: Central Valley to the Great Basin by Mary Cook

A reminder: Sales of this guide will fund the scholarship program of the Far Western Section of the NAGT, which supports geology majors throughout California, Nevada and Hawaii. The book can also be purchased directly from the Far Western Section at this link. Check it out!

The Abandoned Lands...A bit of the Wild West remains at Bodie

The Colorado Plateau obviously is not the only harsh and difficult environment for the survival and well-being of human beings. For several months I have been producing a series of blogposts about our journey through the plateau country, and we have looked at numerous examples of people trying to make a life from the riches (or lack thereof) of the land, in most cases failing. I'll will return to the theme soon, but in the meantime I am back from our fall field studies excursion to the eastern Sierra Nevada. I have little doubt this will also turn into a series, as the region is fascinating. But today I wanted to introduce you to another abandoned land: the ghost town of Bodie.

Bodie was one of many towns in the Basin and Range Province of Nevada, California and Utah that appeared as a result of gold discoveries after the end of the celebrated California Gold Rush in the 1850s. It was more successful than most, with a rich ore body that allowed mines to operate for several decades. The initial discovery was made by W. S. Bodey in 1859, but Bodey himself died before benefiting from his "luck". A rich lode was found in 1876 and the Standard Mine (the gray buildings on the hillside in the picture above) ultimately produced several million ounces of gold before closing in 1913.

The town reached a peak population of around 8,000-10,000 people and two thousand buildings once filled the valley before several disastrous fires decimated the town, the most recent in 1932. Today less than 200 buildings remain. They were suffering from vandalism and neglect, so in 1962 the state of California stepped in to preserve what remained of the town as a state park. The remaining buildings are kept in a state of "arrested decay". Bodie was declared California's "official" gold mining ghost town in 2002.

The gold at Bodie was the result of hydrothermal activity in the heart of a volcanic center that was active here between about 14.7 and 8.0 million years ago. The field included at least 20 vents, including four trachyandesite stratovolcanoes. The town lies along the boundary between the deeply eroded Silver Hill and the Potato Peak cones, while the access road to Highway 395 meanders between the Willow Spring and Mt. Biedeman complexes. The sage covered hills reveal little of the volcanic violence that formed this landscape.

The volcanic complex is related to extensional and transtensional forces related to the northwestward movement of the Sierra Nevada microplate. There are a number of these complexes along the eastern margin of the Sierra, especially at Sonora Pass and Ebbetts Pass. The active Lassen Peak complex provides a modern analog to the appearance of Bodie millions of years ago.

Life must have been unimaginably miserable during much of the year. The town lies at an elevation of 8,000 feet and the winter winds are constant. Snowdrifts are deep. Bodie is often the coldest location in the state with winter temperatures often falling below zero. What relief was there at the end of the work day? The town sported dozens of bars, and violent gunfights were legendary. One of the most famous stories of the town involve a note from a young girl that said "Good-bye God, I'm going to Bodie" (the town took umbrage at the insult and insisted the punctuation was wrong; it should have said "Good, by God! I'm going to Bodie").

Today the town is a popular state park, and yet wandering the streets produces an overwhelming feeling of loneliness and abandonment. The former homes and businesses contain the artifacts of daily life and photographers will find endless possibilities. But I don't recommend a wintertime visit!

The town of Bodie lies 13 miles east of Highway 395 between Bridgeport and Conway Summit. The access road is paved for the first ten miles, but is a bumpy gravel road for the last three miles. Passenger cars will not have any trouble negotiating the route, however. There is no gas, food or other necessities at the town other than a small museum. The state charges a $7/person fee to visit.