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October 26, 2011
7:00-8:30 PM

Schlafly Bottleworks, Maplewood, MO

Earthquakes, Volcanoes, Geysers and Fires:
A Geological Tour of Yellowstone National Park

Robert F. Dymek, Ph.D.
Professor of Earth and Planetary Sciences

Moderated by: Cynthia Wichelman, M.D.

Touted as the first national park in the world—having been established in 1872, some 44 years before the U.S. National Park Service came into existence—Yellowstone boasts an impressive assortment of features formed by volcanic, hydrothermal, glacial, and fluvial processes. Early explorers told tales of the boiling waters and geysers found throughout this region, and remarked on the “yellow rocks” along the cliffs of a great river canyon, from which the name Yellowstone was derived. These colors, in shades of red and brown in addition to yellow, are the result of alteration by through-going volcanic gases and heated waters. The “Grand Canyon of the Yellowstone” itself, repeatedly filled with debris from volcanic eruptions and deposits from glaciers, was sculpted into its present V-shape by the Yellowstone River.

The park sits above a magma chamber that, during the past 2 million years or so, has produced some of the largest pyroclastic eruptions. The giant, ~50-km wide Yellowstone caldera reflects the vigor of these eruptions, and two resurgent domes (Mallard Lake and Sour Creek) within the caldera could be the foci of future major eruptions. Intermittent eruptions of various lavas, including obsidian flows, together with widespread glaciations, have modified the interior of the caldera into a broad regional plateau. Violent earthquakes, such as the 1959 magnitide 7.1 event at Hegben Lake, further attest to the geologic unrest of this region.

Approximately 2/3 of the world’s geysers and hot springs are found in Yellowstone National Park. These geothermal features arise from the unique convergence of a near-surface magmatic heat source, a plumbing system provided by porous glacial deposits, and abundant water from rainfall and snowmelt that penetrates to significant depths to be heated and cycled back to the surface.

Science On Tap highlighted on St. Louis Public Radio and Voice of America!

Science On Tap is a place where, for the price of a beverage, anyone can come to explore the latest ideas in science and technology. Meetings take place outside a traditional academic context, in the Crown Room at Schlafly Bottleworks.

Meetings are held on the last Wednesday of the month during the academic year, usually from 7:00 - 8:30 PM. The standard format is as follows: 20 minutes of presentation, followed by a 7 minute break for attendees to introduce themselves to each other at the table, and then an hour of discussion. Seating is limited to the first 100 people.  No reservations accepted.

Crown Room at the Schlafly Bottleworks
7260 Southwest Ave.
Maplewood, MO 63143
(314) 241-2337

Register to receive e-mail announcements of future Science On Tap events.

Interested in learning about medicine? Check out Washington University's Mini-Medical School!

For more information: e-mail scienceontap@wustl.edu
or call (314) 935-9495