Shoreline Butte

During the last Ice Age, melting Sierra Nevada glaciers fed prehistoric Lake Manly, which filled Death Valley because the basin had no outlet. Surrounded by trees, the lake reached depths of 500 to 600 feet and stretched about 100 miles, leaving Shoreline Butte as an island and covering this spot beneath about 400 feet of water. Wind-driven waves deposited sand and gravel and eroded cliffs along the shore, creating strandlines and terraces that record fluctuating lake levels; geologists have identified more than 12 strandlines on Shoreline Butte. Lake Manly formed through a chain of overflowing basins and dried up about 10,000 years ago, although a pond about 30 feet deep formed in the valley about 2,000 years ago and later disappeared. At the base of Shoreline Butte, the Amargosa River is an intermittent waterway that flows underground for most of its 185-mile length or after heavy rainstorms drain into the valley. Runoff from cooler, wetter conditions created five large lakes that gradually vanished as temperatures rose and moisture declined.

California · United States