June Speaker: Volcanology of the Oregon Cascades

presented by Dr. Richard P. Tollo, Professor of Geology

by Cindy Schmidtlein, MSDC Vice President

The South Sister volcano showing the summit area draped in reddish pyroclastic deposits (left), a glacial cirque (center), and a dike complex at Hodge Crest (right). There are signs that this volcano might be preparing to erupt again.

Our speaker for June 1 is Dr. Richard P. Tollo, a Professor of Geology at the George Washington University (GWU) in Washington, DC. He is a geologist who specializes in petrologic and geochemical studies of Precambrian rocks. He will talk to us about the Oregon Cascades as a prime site for geologic adventure and learning.

The Cascade Magmatic arc in Oregon includes a wide spectrum of numerous volcanic vents ranging from silicic to mafic in composition that developed east of the Cascadia subduction zone in the eastern Pacific. Edifices include large stratovolcanoes, caldera, volcanic fields, scoria and spatter cones, and many lava flows and pyroclastic deposits. The talk is meant to be fun and will focus on geology and volcanology at a level that everyone should be able to understand and be able to raise questions in order to learn more.

An overview of Newberry caldera from atop an intra-caldera lava dome showing much of the opposite caldera wall, two intra-caldera lakes, and a large rhyolite lava flow (gray) that moved from right to left.

Throughout his career, Dr. Tollo has emphasized involvement of undergraduate students as research collaborators, making it possible for students to become regularly engaged in all levels of the research process. Many of these students have been co-authors with him of major research papers and field trip guides.

Professor Tollo teaches courses designed for all levels of undergraduate education, including physical geology, mineralogy, igneous and metamorphic petrology, geological field methods, volcanology, and field experience in volcanology which involves an 8-10 day summer field exercise. He is currently writing a textbook about the volcanic evolution of the Cascades volcanic arc in Oregon and the contributions made by researchers working in the region during the past six decades.

Dr. Tollo has been repeatedly recognized for his dedication to teaching, receiving, among others, the Trachtenberg Award for Excellence in Teaching from GWU, Professor of the Year Award from the GWU Department of Athletics and Recreation (twice), and a Carnegie Foundation award for the advancement of teaching. He is the former Director of the Geological Sciences Program where he continues to teach today.