What kind of names do the rocks have?
The 1st grade, Wiley Elementary, Wake County Here’s a few of the rock types in the park: rhyolite, andesite, basalt, limestone, sandstone, shale and welded tuff. These names might not mean much to a non-geologist, so here’s an explanation of a few of the more common types. Rhyolite is one of the most common rocks in the park. It is a light-colored volcanic rock. Most of the rhyolite in the Park erupted from the Yellowstone volcano between 640,000 and 70,000 years ago. Welded tuff is formed when hot ash falls during a volcanic eruption and it is welded together by its own heat. There are two different tuffs in the park, one formed during the first explosive eruption about 2.1 million years ago (the Huckleberry Ridge Tuff) and one during the third eruption about 640,000 years ago (the Lava Creek Tuff). Tuff outcrops helped geologists figure out that Yellowstone is actually a huge volcano!
