GSOC members can attend geological field trips led by professional geologists.

Field trips include both short local field trips and more adventurous multi-day overnight trips. Most trips require registering participants to be GSOC members. Registrants should be logged in before attempting to register.

GSOC is working hard to plan field trips for 2025. Please stay tuned for more information, which will be announced in the bimonthly email to members. The posted schedule on the home page will be revised and official trip descriptions added below in the Field Trips preparing for registration section as plans are set.

Members should receive an email shortly after midnight on the eve of the registration kickoff date that will contain a registration link. Registration dates are shown on the field trip schedule on the home page of the website. Members should use the button on the email to register - please disregard the button shown on the website because our membership platform adds those automatically and they don’t go to the right page for signup. Each member will only be able to register themselves and one guest. If you want to go, register as soon as possible because our trips are popular and sell out quickly.

Field Trip Preliminary Descriptions

This section is included to give prospective field trip participants preliminary information about trips being planned, so they may reserve (refundable) lodging accommodations and add the trips they are interested in attending on their calendars. Most GSOC field trips are self-catered (we do not provide food, lodging, or transportation). We cannot guarantee that everyone who wants to participate on a particular trip will be able to register, as participation on most field trips is limited due to space requirements. Further information will be revealed in the registration section below these preliminary descriptions prior to commencement of registration.

Deep Time in the Spokane Area

June 20 - 23, 2025 plus optional overnight stay in Republic, Washington, on June 23.

Registration will open May 24. See registration info packet below. Members will receive a registration email on May 24 with registration link. Questions can be sent to Carol Hasenberg.

Middle Clackamas River Field Trip

August 23, 2025

Embark on a one-day geological field excursion through the breathtaking Middle Clackamas River Basin (MRCB), where nature has carved a masterpiece. Spanning Clackamas and Marion Counties, this remarkable region is shaped by the Clackamas River, which stretches 83 miles from its origins near Mount Jefferson to its confluence with the Willamette River. Along the way, the river has sculpted dramatic cliff walls—some towering over 1,600 feet—revealing layer upon layer of Miocene Columbia River Basalts. And the views? Simply spectacular.

This expedition also delves deep into geological wonders, exploring areas where these basalts have been overlain, underlain, and intertwined with the volcanic and volcaniclastic formations of the Oligocene to lower Miocene Little Buttes Volcanics—a glimpse into part of the Cascades’ ancient foundation. But that’s not all! Witness firsthand the fascinating alignment of the Clackamas River with the northwest-trending fault structures. Our journey will highlight the Clackamas River fault zone, a crucial geological corridor linking the Portland Hills fault system to the southeast extensions of the Brothers and Sisters fault zones in central Oregon.

Whether you're a seasoned expert or a curious explorer, this field trip is a must-attend! Engage in lively discussions, examine awe-inspiring rock exposures, and gain insight into the dynamic forces that have shaped the region. Leading the expedition is Clark Niewendorp, a retired geologist and past president of GSOC, whose expertise will bring the landscape to life. The trip date is Saturday, August 23. Car caravan from the City of Estacada, following OR Highway 214 through the canyon. Returning late afternoon.

Registration for this trip will commence August 2. Questions can be sent to Carol Hasenberg.

Geology of the Olympic Peninsula

September 5-7, 2025

GSOC is planning a 2-1/2 day trip to the Olympic Peninsula to learn about and view its geologic history. The trip will be a car caravan/carpool style of travel and require at least a two-night stay for most participants. The trip will be self-catered, which means participants are responsible for their own food, lodging and transportation.

The trip will commence at 5:00 pm (Sept 5) at Peninsula College in Port Angeles with a lecture by the trip leader Professor Dann May. May obtained his B.S. and M.S. degrees in geology from the University of Washington in Seattle (1978 & 1980) and his M.A. in anthropology and philosophy from the University of North Texas (1993). Before pursuing his teaching career, he worked as an exploration geologist with the Standard Oil Company in Dallas, Texas. He currently teaches courses in geology, anthropology and philosophy at Peninsula College. He also teaches courses in geology and anthropology for the Community Education program at Peninsula College. May has given many public presentations on the Cascadia Subduction Zone and future Megathrust Earthquakes.

Professor May’s Friday evening lecture will cover the tectonic history and setting of the Olympic peninsula and glacial history of the peninsula. There will also be some refresher info on rock types and the rocks found on the peninsula. It will provide the background needed for the next two days of exploration.

On Saturday (Sept 6) the field trip will cover the north side of the peninsula, from Hurricane Ridge to Dungeness Spit and Tongue Point. We will travel with Professor May to see the oldest exposed rock of the peninsula at Hurricane Ridge in Olympic National Park (bring your senior passes!). We’ll then travel to Dungeness Spit Bluffs and Tongue Point for more geologic history, especially that of the Vashon glaciation of the Puget Sound and the Juan de Fuca Strait.

On Sunday, we will travel with Professor May to three of the Pacific beaches of the western Olympic peninsula to view the changes wrought by the Cascadia Subduction Zone and its earthquakes. We’ll end the trip at Beach 4, where the GSOC participants can take Hwy 101 south to Aberdeen and then return home.

The trip may involve some light hiking but should not be too strenuous for active adults and seniors.

If you’d like to go on the trip, it would be a good idea to make your (refundable) lodging reservations right away. We’ll be based in Port Angeles for Friday and Saturday nights, September 5 and 6. If the drive home the last day of the trip seems too daunting, then we suggest making a (refundable) reservation somewhere in the Grays Harbor area for the night of September 7. The trip will be open for registration on August 16. Questions can be sent to Carol Hasenberg.

For you birders out there, this will be the optimal time of year to catch the migrating marbled godwits feeding along the shore, just after high tide in Tokeland and other places in the Grays Harbor area (high tide at 2 pm on Sept 7).

John Day Fossil Beds: A Record of Change

September 25-27, 2025

The John Day Fossil Beds, an area of about 20,000 sq. miles located about 50 miles east of Madras, Oregon, is the only site in North America that nearly spans the Cenozoic Era, known as the Age of Mammals. The strata and fossils found here record an extraordinary 40 million year record of climatic and evolutionary change in a very dynamic tectonic and volcanic region. The John Day Fossil Beds consist of eight overlapping fossil-bearing rock layers scattered through central and eastern Oregon. Along with the unique fossil assemblage, including trackways, there are remnants of past volcanic eruptions, soils, fluvial systems, lakes, prairies, and forests. This record occurs in an ordered sequence well interspersed with datatable rock layers. Exploration and study continue today with hundreds of specimens added to the collections each year.

On this trip, we will explore the three separate units of the John Day Fossil Beds National Monument: Clarno, Sheep Rock, and Painted Hills. Our trip guide will be Derek Loeb, a retired geophysicist living in central Oregon, with assistance from Dr. Nicholas Famoso, John Day Fossil Beds National Monument Paleontology Program Manager and Museum Curator, and his staff. Trip dates are September 25 – 27. We will travel by car caravan each day. Day one will be in the Clarno Unit, beginning at 11:00 am to allow for travel from Portland, and include an approximate 4-mile loop hike. Day two will include a behind the scenes tour of the Thomas Condon Palaeontology Center and a guided trip into the Sheep Rock Unit to dig for fossils. Any fossil found must remain as property of the museum. Day three will be in the Painted Hills Unit and will include several short hikes. The trip will finish by mid-afternoon on September 27 to allow time for the return trip to the Portland area.

GSOC has reserved lodging for participants at the River Bend Motel in Spray, Oregon, for the nights of September 25 and 26. The hotel can accommodate up to 18 people total (keep in mind that this necessitates sharing rooms or the house). Tent campsites are also available at Haystack Ranch in Spray. The area is very remote without a town of any size nearby. Food and transportation are the responsibility of the participants. Plan to bring all your food — we will have use of a kitchen that is part of the rental at the hotel. This trip will be limited to 20 participants. Trip fee (to be determined) will include options for your lodging choice.  Campsite reservations will be up to the participant to make. Registration will open September 2. Questions can be sent to Carole Miles.