Geology of Great Basin National Park

The Great Basin National Park is often described as “mountains in a sea of sage brush” which is actually a pretty apt description. The Great Basin gets its name because that’s exactly what it is, a basin, the majority of the rivers and streams within the area never reach the sea, there’s no way out, the water just stays there, collecting in marshes, mud flats and the occasional shallow lake before evaporating in the desert air. There are a multitude of basins here, separated by narrow mountain ranges running through the park from north to south. It’s a very unique place indeed.

You may be forgiven for getting the impression, on first glance, that the landscape in Great Basin National Park is somewhat monotonous – mile upon mile of sagebrush – nothing but pale green shrubs for as far as the eye can see – but nothing could actually be further from the truth. The life there isn’t immediately apparent but it’s certainly there. There’s a rich variety of animals and plants living high up in the mountain ranges for starters, where the air is cooler and there’s more water, all types of life thrives here which would not be able to survive in the desert far below.

Part of the Great Basin National Park is the southern Snake Range, itself a fantastic example of a desert mountain island. The “center piece” of the park is the majestic Wheeler Peak reaching to a summit of an almighty 13,063 feet – add to that the alpine plants, lakes, streams, forest groves of ancient bristlecone pines and the beautiful Lehman Caves, yes, there’s definitely plenty of life, beauty and diversity to be found in Great Basin National Park.

Great Basin National Park – The Lehman Caves

The Lehman Caves have a plural name but are actually a singular cavern. Anyway, the beautiful, enormous Lehman Caves extend a full quarter of a mile into the low-grade marble and limestone which is found at the Snake Range base. First discovered in 1885 (by Absalom Lehman – no less), this is an example of one of the most decorative and beautiful caves in the entire country, nay – the world. The story of the caves began a very long time ago, millions of years, the climate was much wetter then than it is today (well, maybe the climate but not todays weather exactly, I’m writing this in the middle of the mother of all rain storms), but generally speaking it was much wetter in those days. Anyway, the abundant rainfall seeped past vegetation turning it ever so slightly acidic before it trickled down into the hairline cracks of the limestone below. This began to dissolve the stone and enlarge the cracks until it reached the water table, collecting in vast quantities, there was even an underground stream here long ago, there are still the ripple marks to prove it.

Time went by and the climate became much drier, the water eventually drained from the caves and left hollow rooms and smoothed down walls, but small amounts of water still managed to percolate from above, this time it did not enlarge the cavern but filling it up with mineral rich water. The wondrous results of this drip by drip development, over centuries, is now clear for all to see. There’s a rich display of some of the most beautiful and unusual structures – stalactites and stalagmites (remember, the tites come down and the mites go up), as well as draperies and flowstone, speleothems, shields which are remarkably reminiscent of flattened out clam shells. The Lehman Caves really are a sight to behold.

Great Basin National Park – Mountains, Lakes & Forests

Lying just beneath the Wheeler Peak there’s a little bit of the Ice Age which remains to this day. It’s only a token, once upon a time the Snake Range was entirely capped by mighty glaciers, just a few thousand short years ago, and you can find glacial activity all across the park. There are piles of glacial debris evident, sand, gravel and boulders formed into ridges and mounds. Stella and Teresa Lakes now exist in hollows which were gouged out by great moving mountains of ice. The ice in this region didn’t actually reach the valley floor as it did in the more northerly parts of the continent, it simply melted high above the valleys at around 9,000 feet in elevation (you can see evidence of this at Baker Creek). So, higher than 9,000 feet, above the melting point the glaciers carried bedrock make wide, smooth mountain slopes, and below that height there were cascading streams which cut out the sharper sided canyons.