US Geological Survey


Date of this Version



USGS science for a changing world (April 2004)


Pyramid Lake is the site of some of the Earth’s most spectacular tufa deposits. Tufa is a rock composed of calcium carbonate (CaCO3) that forms at the mouth of a spring, from lake water, or from a mixture of spring and lake water. The explorer John C. Fremont (1845) wrote about the tufas during his 1843- 44 expedition and named the lake after the pyramidal-shaped island that lies along the east shore of the lake (fig. 1). The Paiute name for the island is Wono, meaning cone-shaped basket. The Paiute name for the lake is Cui-Ui Panunadu, meaning fish in standing water.

The U.S. Geological Survey, in cooperation with the Pyramid Lake Paiute Tribe, has obtained radiocarbon ages of many of the tufa deposits that border Pyramid Lake in order to obtain a record of lake level change for the past 35,000 years (Benson, 1994).