Friday Night Lecture, Dr. Martin Streck: East Oregon Rhyolites Provide New Clues to CRB Mysteries

  • 1825 SW Broadway Portland State University Portland, OR

Dr. Martin Streck: New insights into our understanding of co-Columbia River Basalt rhyolite volcanism in eastern Oregon

Friday November 14, 2014, 7:30 p.m., Dr. Martin Streck, Portland State University Department of Geology, will present " Eastern Oregon Rhyolites Provide New Clues to CRB Mysteries" in PSU's Cramer Hall S17 (sub-basement). Dr. Streck's recent work on mid-Miocene rhyolites in eastern Oregon provides a critical clue to the origins of Columbia River Basalt magmatism. Our understanding of the Columbia River Basalt province and its likely connection to the Yellowstone hotspot has grown tremendously over the last decades since the Yellowstone volcanic field was first proposed as the present location of a continental hotspot. There is now strong support for a plume origin of the entire Yellowstone hotspot track and flood basalts of the Columbia River Basalt Group (CRBG). However, the decades-long controversy as to whether this Large Igneous Province (LIP) is indeed due to the arrival of a deep mantle plume is far from over and new non-plume models for the origin of the CRBG have been proposed. 

Our understanding of the Columbia River Basalt province and its likely connection to the Yellowstone hotspot has grown tremendously over the last decades since the Yellowstone volcanic field was first proposed as the present location of a continental hotspot by Morgan in 1972. There is now strong support for a plume origin of the entire Yellowstone hotspot track and flood basalts of the Columbia River Basalt Group (CRBG) (Pierce and Morgan, 2009). However, the decades-long controversy as to whether this Large Igneous Province (LIP) is indeed due to the arrival of a deep mantle plume is far from over and new non-plume models for the origin of the CRBG have been proposed (e.g. Liu and Steman, 2012). Age-progressive rhyolites of the Snake River Plain have been a centerpiece in the model to associate flood basalts with the present location of the Yellowstone hotspot (e.g. Pierce and Morgan, 1992, 2009). On the other hand, also viewing rhyolites as critical component of the early flood basalt stage has occurred just recently. Rhyolite volcanism can provide complementary information on the development of continental LIPs but it is important to first document and understand this silicic component of the entire province before drawing conclusions. A critical missing piece in our understanding of silicic magmatism of the Columbia River Basalt province are the understudied mid-Miocene rhyolite occurrences in eastern Oregon that have received little attention but are subject of this study.

Join GSOC members at Pizzicato Pizza, 1708 SW 6th Ave., at 6:00 p.m. before the lectures for an informal dinner and conversation. 

Free parking is available at Portland State University Friday nights after 5 p.m. in Parking Structure 2 on Broadway Ave. directly across from Cramer Hall and on level one of Parking Structure 1, bounded by Broadway and 6th Aves. and Harrison and Hall Streets.