This is a Central Oregon Geoscience Society field trip.
This field trip will explore recent mafic volcanism in the McKenzie Pass and Santiam Pass areas, with a focus on the Sand Mountain volcanic field. We will look at recent lava flows and tephra deposits, and at rivers, lakes, and groundwater that have been shaped by volcanic activity. We will also discuss hazards associated with mafic volcanic activity, including forest fires, disruption of water routes, and damage to infrastructure, agriculture, and tourism.
Our sister club Central Oregon Geoscience Society (COGS) has extended an invitation for this field trip to GSOC members. This offers a great opportunity for meeting fellow geology enthusiasts and for building ties between our two organizations. More information and registration on the COGS website.
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.
Two Day Field Trip to Oregon’s Coast Range
Mary’s Peak, Sat. July 13
Join President Sheila Alfsen on a trip to the tallest point in Oregon’s Coast range. We will explore the rocks and geologic processes that made Oregon’s Island in the Sky. Participants will drive to Corvallis and carpool for the day-trip up to the top.
Hwy 20 from Corvallis to Newport, Sun. July 14
A tour along the newly constructed Hwy 20 from Corvallis to Newport. This one day trip will explore the fantastic road cuts of the Tyee formation of the Coast range. GSOC’s Clay Kelleher will show us the mitigation procedures that were employed to make this once unlucky and seemingly doomed highway a reality. Participants will gather at Ellmaker State Wayside near Blodgett to consolidate cars for the tour.
$45 Registration fee includes field guide. However lodging and meals are on your own.
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.