Occasionally I like to highlight a mountain I like for Mountain Monday. Today it’s Telescope Peak, in Death Valley National Park, California. This has long been one of my favorite national parks. I started visiting when it was still a national monument. My first visit was a college seminar and field trip. My second time was freelancing with friends, and we climbed Telescope Peak.
The top is just over 11,000 feet high, and since it was early spring, we waded through hip-deep snow drifts to get there. After the all-day climb, we drove back down into the valley, took our sleeping bags, and tumbled out into the sand dunes to sleep under the stars. What a contrast! An icy morning at 8000 feet, a snowy climb, then sleeping out in balmy weather at sea level.
Telescope is the highest point in the park and crowns the Panamint Range. The Panamints are an upraised block of the earth’s crust, lifted along the west side of a fault zone that at the same time dropped Death Valley down. And down a lot! The floor of the valley is a few hundred feet below sea level.
But the valley is filled with thousands of feet of sediments that were eroded from the Panamints and other ranges as they rose. The top of the the bedrock that was dropped down by the fault lies some 11,000 feet beneath the valley floor. This enormous wedge of valley fill is made of gravels, sands and clays. But overall it’s quite salty. There are thick sections of salts of various kinds, including good old NaCl, table salt.
Geologists call these types of deposits evaporites because they are formed when large bodies of water evaporate away in a drying climate. In Death Valley’s case it was a large lake called Lake Manly. From about 2 million to 10,000 years ago, mega ice sheets lay to the north. Because of this, the climate was quite wet in the now ultra-dry Death Valley region. Early hunter-gatherers, recently migrated in from Siberia, were able to spread south because of this climate, which supported a diversity of life much greater than today’s desert does.
But when the ice sheets retreated during inter-glacial periods, the climate grew more arid, and Lake Manly shrank. Because of how fault-block mountains border almost all sides of Death Valley, often there was little or no chance for the lake to drain in the normal way, via rivers.
Evaporation was (and is) the main way that water left the valley. Salts that were dissolved in the water grew more concentrated as the lake grew smaller. A brine was the result, and as the lake grew and shrank many times, often down to nothing, the salts were precipitated out. They built up layers and layers of evaporite deposits. The famous 20 mule-team wagon trains transported tons of borax from the borates (a type of salt) mined from the valley (image above).
BADWATER SALT FLATS
The current desert climate of Death Valley is one in which standing water from paltry winter rains evaporates rapidly, leaving behind fresh salt. The salt can take very interesting forms (image above). The mix of fine muds and salt, combined with repeated wet/dry cycles, can form fantastic polygonal patterns, as the bottom image shows. Salt is also eroded away occasionally by the Amargosa River when infrequent storms allow it to flow south out of the valley.
The water in the image at the top of the post is really not part of this equation. It’s fresh not salty, and comes from the amazingly strong Saratoga Springs in southern Death Valley. I camped nearby one time and captured this view early the next morning. Saratoga is well off the beaten track and most visitors to the park miss it. There’s a very cool dune field nearby.