Death Valley Field Trip, page 4
Stop 11 Artists Palette
The extension of the crust in this area began 30 million years ago. There were earlier troughs here though. We see the remnants of those troughs which date back 37 million years. Death Valley is about 14 million years old and is filling with sediments now. The Artists Drive Formation is older than Death Valley, about 10 to 15 million years. It is more colorful with volcanic ash because of trace impurities. The ash is mixed with silt and sand. There are no volcanics here, but volcanic components. More of this formation is buried under the valley. The older basins were smaller than today's Death Valley. This was high even terrain then the ocean ridge went under the continent and the stretching started creating small basins. The bedding here is hard to see because of all the deformation over the years. The Furnace Creek Formation, 2 - 3 million years old is exposed a lot. The Funeral Formation is old alluvial fans washed into basins from both side walls of the conglomerates. The Funeral Fm has been faulted down from above the Artists Drive Fm to below it.
Stop 12 Golden Canyon
In the 1970's a flash flood tore out the road through here,
dropping the floor two and a half feet. August is the wet month in
Death Valley. The heat pushes up the clouds. The rain is spotty but
intense so there is a lot of erosion in a short time. It is water
that creates the greatest landscape change, not wind. The wall rocks
in this canyon are the Furnace Creek Fm. It is siltstone and soft
sandstones. It accumulated in lake beds which indicates a more moist
climate at that time. It was then submerged a long time. It was an
alkaline lake but there are few fossils found. There are a few conglomerate
layers and a brown stripe is a lava flow. There are gypsum crystals,
an evaporate sediment rock, so the lake had highs and lows.
Stop 13 Harmony Borax Works
In 1883 this was the biggest borax production in Death Valley. The borax is from volcanic ash in the Furnace Creek Fm. This is from ashy lakebed deposits about 2 - 3 million years old. Boron minerals are very soluble. Drainage brought borax through the lake bed deposits and to here where the water surfaced at Cottonball. The borax concentrated in this area. Borax production here only lasted from 1883-1888 because it was too expensive to transport it out. Its lasting legacy is the 20 mule team and wagons used for this purpose.the borax was dissolved out, the water evaporated and the mineral scraped out and loaded in cakes into the wagons. Forty to sixty thousand pounds were loaded on each wagon. They used from 20 to 60 mules to pull the wagons down through the Mojave desert. Borax was soon discovered in Searles Lake, CA, a less expensive source, and this site became too expensive to continue operation. This is named ulexite Cottonball borax. It also contains sodium chloride, Glauber's and Epsom salts, carbonate of soda and ulexite.
Stop 14 Kit Fox Hills
These low brown mounds are Miocene, thus older than the Artists Drive Fm. They are the result of local basins filled with sediments 15-20 million years ago. They consist of sandstones, siltstones and there are mudcracks and ripple marks. The water was not here long but came and went. The fringe of the lake was forested and fossil footprints can be found here.