Earth Obsersation taken by the Expedition 11 crew

ISS011-E-09680 (27 June 2005) --- Searles Lake, California is featured in this image photographed by an Expedition 11 crewmember on the International Space Station. Searles Lake is known for the abundance of rare elements and evaporite minerals, such as trona, hanksite, and halite formed within its sediments. These minerals dissolve in water or very humid environments. According to NASA scientists who are studying the Space Station photography, during the Pleistocene Epoch (beginning approximately two million years ago), Searles Lake was one of a chain of lakes fed by streamflow from the Sierra Nevada to the west. Lake levels rose and fell dependant on glacial outwash from the Sierra Nevada as climates shifted. Successive layers of sediment were deposited as lake levels fluctuated, preserving an important record of regional climate change. The lakes gradually dried up completely as climatic conditions became hotter and drier (as today), forming a string of enclosed basins with no outlets (playas). This photograph depicts the Searles Lake playa (characterized by white surface mineral deposits) bounded by the Argus and Slate Mountains. The width of the playa is approximately 10 kilometers. The center of the image is dominated by mining operations that extract sodium- and potassium-rich minerals (primarily borax and salt) for industrial use. Minerals are primarily in naturally-occurring brines that are pumped to the surface and evaporated to crystallize the minerals. A large evaporation pond (black) is visible in the center of the image. Further processing concentrates the minerals and removes excess water.