About the Talk
Geologic Hot Spots Under Our National Parks
Jim Aldrich presents an intriguing picture of geologic hot spots through the lens of some U.S. National Parks. Geologic hotspots are the manifestation of thermally expanded, buoyant mantle “plumes” that rise through the lithosphere. On reaching the Earth’s crust they can erupt as relatively quite basalt flows and/or by violent explosive eruptions of rhyolite.
This hour-long presentation will address the basics of the mantle-plume processes. Emphasis will be on the Yellowstone hotspot, which has a long and varied eruption history that began on the seafloor before being overridden by the North American continent. During the Quaternary, the hotspot has fueled three massive caldera eruptions that distributed volcanic ash around the world. Today the hotspot beneath Yellowstone National Park is reflected in the presence of numerous geothermal features.