Photogeo Gallery : Eastern Sierra Nevada Mountains and the Owens Valley
One of our very favorite Photogeo all-season areas. Wonderful outdoor photography in an area that is accessible only by roads that are for the most part less well traveled. For many years we thought of this area as one of north America's best kept secrets! Incredible panoramic and rugged, semi-barren scenery, relatively undeveloped, and a fascinating geological and human history.
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We open with an early spring-time, dawn panorama taken from the Alabama Hills (foreground) of perhaps the best known peaks of the Eastern Sierra: Mount Lone Pine just to the right of center with Mount Whitney to its right in the distance, just below the setting moon. Mount Whitney is of course the highest mountain in the lower forty eight states of the US at 14,505 feet.
Almost all the rock you see are "igneous" rocks ("born of fire"). Geologists call them granite or granodiorite. All were emplaced deep in the Earth's crust as so-called "plutonic intrusions" (or "batholiths") during the Cretaceous Period, 63-104 million years before present as a result of Plate Tectonics.
The theory of Plate Tectonics was formulated in the 1960's and 1970's as a result of post World War II nuclear submarine warfare plans. As nuclear powered submarines were developed, detailed sea-floor maps were required to guide their sonar navigation systems. The allied navies of the US and UK combined with the geoscience teams at Columbia and Oxford universities to produce a much more sophisticated understanding of the world's ocean floors than was previously known. For years these data were kept secret, but eventually, out of it emerged a whole new understanding of the ocean's floor and an entirely new notion about how the world "works". This was the birth of Plate Tectonic theory. Since then, test after test has confirmed the earliest findings and this robust hypothesis has endured to become accepted as one of the greatest scientific discoveries of the 20th century. Ironically, it is also one that even today, relatively few people have heard of or understand.
As a result of Plate Tectonics, we now have an explanation for the presence of the granites and granodiorite comprising the great Sierra Batholith complex photographed in this gallery. We now know they are the result of heat generated by frictional forces that occur when an oceanic plate begins to sink back down into the Earth's Mantle layer and is overridden by the less dense but much thicker continental crust. We call this process "subduction", a process which occurs between the sea floor and some 30 kilometers below the earth's surface. During subduction, molten rock is both injected in to and transforms the pre-existing rock before it, melting and recrystallizing everything in its path. With time, subduction eventually slows and stops, following which, is a long period of cooling and congealing of the molten rock. As it sets, it forms granite and granodiorite.
And the reason we now see these granites at the surface is because of further, also plate tectonically related, faulting, uplift and erosion. About 2-10 million years ago, the eastern Sierra mountains became heavily fractured by huge continental scale faults that tilted the entire eastern Sierra mountains upwards. The rocks that we know previously covered the granites were progressively eroded until the tops of the batholiths became exposed at the surface. This was dramatically exacerbated during the Pleistocene period (we generally call this the "Ice Age") when repeated periods of glaciation over a period of two million years, scoured deeply into the granite and granodiorite, leaving behind it deep "U" shaped valleys in the mountains. And where these mountain valleys meet the Owens Valley floor, huge piles of granite boulders, gravel and sand piled up in what are called moraines; literally dumps of physically gouged granite and granodiorite debris.
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The main access to the Owens Valley and the eastern Sierra Nevada mountains is via Highway 395, which snakes its way from south to north along the floor of one of North America's most spectacular topographic gashes. The valley is over 100 miles long and a couple of miles wide with the Sierra Nevada mountains on the western side and the Inyo and White Mountains to the east. Topographically spectacular, the Sierra Nevada mountains to the west rear up dramatically from the generally flat valley floor. Peak after peak, all around 13 to 14,000 feet in altitude sit just literally a few miles away from the highway and clearly in view. The western flank of the valley is also the moist side with the lower mountain flanks dotted by pine trees.
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The valley floor, once the floor of a long and deep ribbon lake, in contrast is partly farmed and part semi-barren with sage, rabbit brush and wild grasses, except where the Owens River still runs or springs create wetlands where cotton wood trees grow tall and fat. On the east side, the mountains are parched with bare mountain slopes, massive, hulking, their colors reflecting their underlying geology. From a geologists viewpoint, one of the spectacular aspects of this valley comes from the fact that the eastern side bears no semblance to the western side. The two sides represent completely different geological provinces with entirely different origins while the valley between them represents a boundary between the two. With the Sierras at your back, as you walk across the valley floor to the east, you are stepping from the Sierra Nevada into the Great Basin province, also called the "Basin and Range". From here eastwards across all of Nevada and the western flanks of Utah, you are in a unique and spectacular geological terrain.
Technically, the Owens Valley is described as a "graben", meaning a valley that is created by opposing major "normal" faults on each side of the valley. The valley's western margin is defined by the Owens Valley Fault system, the eastern side by the Inyo Mountain fault system. These faults are big faults whose surface expression runs for many scores of miles and whose vertical displacement has now reached some 10,000 feet with significant amounts of horizontal displacement too. They are also quite active fault systems and potentially very dangerous. The Lone Pine Fault is an off-shoot of the Owens Valley Fault, and in 1872, this fault ruptured creating an earthquake that is estimated to have been as much as a 7.4 on the Richter scale. It was so significant a temblor that it created rock slides as far away as the Yosemite Valley on the western side of the Sierra Nevada mountains and was even felt on the streets of Sacramento. In a single event, the rocks on the western side of the fault plane jumped up relative to the eastern side by some 15-20 feet and moved northwards (horizontally) in what is called a "right-lateral" displacement of some 35-40 feet. As a result, most of the dwellings in the village of Lone Pine and surrounding area collapsed, killing some 27 souls. This earthquake created a small cliff-like structure that is still visible today and it can be seen alongside the cemetery, which is a state monument, where those killed are still buried.
But getting back to the geology, unlike the granites of the Sierra mountains, the Inyo mountains are made up of even older metamorphic rocks. These are rocks that were originally laid down as sediment in an undersea environment, but were subsequently buried to a level that the heat and pressure changed the minerals of the rock, especially so in the proximity of the invading magma that subsequently became the granites of the Sierra batholith. But just like the Sierras, and many eons after their deepest burial, these rocks were also uplifted to the surface where they were subsequently exposed by weathering and erosion. Today they reach heights of just over 12,000 feet and have been the location of large and historical quarrying and mining operations for a wide range of building materials and minerals, the most significant being silver and gold.
Although the east side is the dry side of the valley, there is still sufficient moisture to create two highly unusual and unlikely forms of forest. At the highest altitudes, the White Mountains to the north are dotted by Bristlecone Pines. While these appear to be twisted and wizened, they are still very much alive, but they are very ancient. In fact the oldest of the Bristlecones is over 5000 years old making it the oldest single species alive on the planet. To the south in the Inyo mountains, the upper slopes have groves of Joshua Trees, an organism normally associated with and found much lower in the Mojave Desert!
The Owens Valley floor is scarred by modern volcanic features that are associated with the recent faulting that caused the uplift of the mountains. Cinder cones, vents and lava flows lie frozen in place, largely unchanged from the day they cooled and set in place some 200,000 years ago. And at its southern end, the dried up remains of the once massive Owens Lake, lie quietly, draping the valley floor with a carpet of evaporated salt and carbonate. Throughout much of the last hundred years, this dry lake bed has been the source of an alkaline, toxic dust cloud that developed anytime the winds got much over 20 miles per hour - which is often. This rendered the Owens Valley an unhealthy place to live, but over the last ten years, efforts have been underway to anchor this dust by a combination of wetting the lake floor with water from the Owens River and by planting a variety of salt-tolerant grasses, plants and algii. These efforts are considered one of California's most successful environmental rehabilitation's. Not only has the air quality been improved, but since the lake historically was a significant element of the Pacific Flyway, there has now been a return of hundreds of species of migratory birds who have discovered a benign wetland and more importantly, an abundant source of food and nutrients in the form of Brine Flys and many other insects.
Despite being over 200 miles away, the Owens Valley also has played a major role in the development of Los Angeles. We have written a short description of this in our "Lost World's" gallery. We hope you find it of interest.
In the coming year we plan to add a lot more images of the many physical features of the Owens Valley to this gallery, so please stay tuned.
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Many of the glaciated valleys of the eastern Sierra are pock-marked with lakes. The Hoover Wilderness is no exception. Our family camped entirely alone for a week on a granite bluff directly above the still waters of the lake shown below. It was blissful. The mountains in this part of the Sierra are multi-colored, largely because they are mineralized to varying degrees. They represent different types of so-called "country rock" in to which the granitic intrusions invaded. As they did so these granite intrusions introduced rich mixes of rock-altering, super-heated fluids from which came gold, silver, copper and tin, to name a few. It was the "color" in these mountains to which so many miners and treasure seekers were inexorably drawn in the late nineteenth century, enduring all manner of hardship in the search for wealth-giving minerals. Today, evidence of their enterprises dot the landscape in the form of "ghost" settlements and ruined, dilapidated mining structures. We show some of these in the Lost World's of the West Gallery.
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