Come see billion-year-old building stones and the fossils hidden under our feet. Join us for a two-hour outdoor walking tour of downtown Portland’s geological mysteries and oddities. This tour is open to the public.
Progress report on an integrated study of an Eocene subtropical shelf-margin delta, Coos Bay, Oregon
The Middle to Late Eocene Coaledo Formation and underlying Beds of Sacchi Beach record a marine history of forearc sedimentation. The sediments aggrade from slope turbidites to shoreface deltaic sandstone encased in deep-water silty mudstone. This talk is a progress report on a multiyear, multidiscipline research program, testing the hypothesis that the Sacchi Beach-Coaledo succession represents a shelf-margin lowstand of sealevel deltaic system. A team of 12 geoscientists is collecting an interdisciplinary database for reassessing the depositional history of the rocks exposed along the Cape Arago, Shore Acres and Sunset Bay State Parks.
President Sheila Alfsen will give a pre-lecture on the Tyee formation for participants in this weekend’s Mary’s Peak field trip and for anyone else interested.
PSU Geology doctoral candidate Vanessa Swenton will discuss her research investigating some of the volcanic eruptions that occurred in eastern Oregon approximately 16 million years ago (Ma) to present day. There are two dominant volcanic provinces that have had episodes of high-silica (silicic/felsic) volcanism in eastern Oregon. The older episode is known to be associated with the Yellowstone mantle plume and Columbia River Basalt Group volcanism. The younger episode is within the High Lava Plains, and it is debated as being solely a result of the initial Yellowstone plume, or as a result of Cascadia slab rollback processes.
Dedicated to Pacific Northwest Geology since 1935
The Geological Society of the Oregon Country (GSOC) is a non-profit organization based in Portland, Oregon. The society is dedicated to the study of geology in the Pacific northwest and is open to persons with all levels of education and professional backgrounds.