Drive rises up to the top of an alluvial fan fed by a deep canyon cut into the Black Mountains. Artist's Palette is an area on the face of the Black Mountains noted for a variety of rock colors. These colors are caused by the oxidation of different metals (iron compounds produce red, pink and yellow, decomposition of tuff-derived mica produces green, and manganese produces purple). Called the Artist Drive Formation, the rock unit provides evidence for one of the Death Valley area's most violently explosive volcanic periods. The Miocene-aged formation is made up of cemented gravel, playa deposits, and volcanic debris, perhaps thick. Chemical weathering and hydrothermal alteration cause the oxidation and other chemical reactions that produce the variety of colors displayed in the Artist Drive Formation and nearby exposures of the Furnace Creek Formation. Badwater Basin The Badwater Basin is a salt flat adjacent to the Black Mountains that descends to the lowest elevation in North America at below sea level. The massive expanse of white is made up of almost pure table salt. The basin is the second lowest depression in the Western Hemisphere, eclipsed only by Laguna del Carbón in Argentina at . This pan was first created by the drying-up of deep Recent Lake 2000 to 3000 years ago. Unlike at the Devils Golf Course, significant rainstorms flood Badwater, covering the salt pan with a thin sheet of standing water. Each newly formed lake doesn't last long though, because the average rainfall is overwhelmed by a annual evaporation rate. This, the nation's greatest evaporation potential, means that even a deep, long lake would dry up in a single year. While flooded, some of the salt is dissolved, then is redeposited as clean, sparkling crystals when the water evaporates. Charcoal Kilns The Wildrose Charcoal Kilns were completed in 1877 by the Modock Consolidated Mining Company, above Death Valley in the Panamint Range, and were used to reduce pinyon and juniper tree wood to charcoal in a process of slow burning in low oxygen. This fuel was then transported to mines in The Argus Range, 25 miles to the west, to feed smelting and ore extraction operations. Although the mines themselves were worked intermittently until about 1900, there is no clear evidence that the charcoal kilns were operational after 1879. They were restored by Navajo Indian stonemasons from Arizona in 1971. The kilns were located here as