We will see abundant evidence for this lake, such as shorelines carved by wave action and sediments deposited in the lake. We will see pebbles that are highly polished by natural tumbling along the shores of the lake. Today, remnants of Pleistocene Lake Lahontan include Pyramid Lake and Walker Lake. Along the Truckee River on the way to Fernley and in the mountains around Fallon we will see volcanic rocks that range in age from about 20 million years old to younger than 1 million years. Many of the older volcanic rocks are part of the same geologic phenomenon that produces volcanoes of the Cascade Mountains today.
White tuffs are evidence of some of the violent eruptions.
You might notice that you rarely see balanced rocks or boulders that appear about to fall over and roll downhill. Geoscientists at UNR believe that such rocks have been toppled during past earthquakes in the region. Nevada is the third most seismically active state in the country. The pebbles that we will collect along the shore of ancient Lake Lahontan were altered by hydrothermal fluids, much like waters in modern hot springs, which are common in Nevada. Such hot waters are used by geothermal power plants to produce electricity.