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 2024. Please stay tuned for more information, which will be announced in the monthly email to members. The posted schedule on the home page will be revised and trip descriptions added below as plans are set.

PRELIMINARY 2024 GSOC FIELD TRIP DESCRIPTIONS

Please note that trips are being planned and the full descriptions will be posted prior to registration. Our purpose in posting these descriptions is to give enough information for potential participants to decide whether to save the date and arrange any necessary lodging.

GSOC Downtown Portland Building Stone Tour – North Side May 19

Ancient Walls North Tour: A Geological Walking Tour of Downtown Portland Building Stone

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. Tour is a one-mile loop on accessible sidewalks and in public buildings. Note: this is the NORTH tour leaving from Pioneer Courthouse, so a different set of buildings than the usual South tour.

Wasco County Geology with Clark Niewendorp June 7-9

GSOC is organizing a 2½ day field trip to examine the oldest rocks, the lower to middle Miocene Columbia River Basalts, and overlying lahars of the upper Miocene to lower Pliocene Dalles Formation in the field trip area. We will observe a series of late High Cascade Pliocene volcanic and sedimentary rocks and the products of regional Quaternary volcanoes. Lastly, we will look at discontinuous blankets of Pleistocene loess that cap the plateaus, along with mima mounds, belts of glacial outwash, and Late Pleistocene Missoula Flood deposits in some creek drainages near The Dalles. That’s not all. We will also examine some of the folding and faulting of the rocks related to the developing Yakima Fold Belt.

This car caravan style, self-catered trip will explore the geology in The Dalles, Dufur, and Tygh Valley areas. It will commence at 9 am on Friday, June 7, in The Dalles and end with a half-day in the Tygh Valley area on Sunday, June 9. The trip will be based out of The Dalles, so you may book your lodging in The Dalles for a minimum two night stay there, depending on your travel time to and from the area.

The Holiday Inn Express (HIE) is Clark’s first choice for lodging (he has membership points there, and likes their complimentary breakfast). There are several other motels located near the HIE on the west side of The Dalles. Tentatively, the assembly area for Days 1 & 2 of the trip will be the Home Depot parking lot, located near the HIE.

Detroit Lake with Clark Niewendorp July 20

Did you know the cliffs on Highway 22 along the Detroit Reservoir, a nine-mile-long reservoir completed in 1953 by the U.S. Army Corp of Engineers, and the slopes and valleys to the south are part of a granodiorite stock (called the Detroit stock)? The Detroit stock is a mass of Late Miocene (~23 million years old) andesitic magma that didn’t reach the surface and is the largest pluton in the Western Cascades of Oregon, covering at least 6 square miles. It intruded into the older volcanic rocks of the Sardine Formation and was significant due to its association with nearby mineral deposits within those rocks.

GSOC is organizing a one-day field trip to examine the Detroit stock's geology and mineralization on the reservoir's south side. Then, our attention turns to aspects of the Middle and Late Miocene Sardine Formation exposed about four miles north of Detroit. One stop examines a major northeast-trending Hoover fault exposed along East Humbug Creek. An array of white zeolites, quartz, or both outline the offset fracture planes in the adjacent rocks—spectacular, and participants can collect some mineral specimens from a deposit nearby.

Yamhill County Wineries with Scott Burns August 28

Scott Burns is planning to lead a one-day terroir trip to Yamhill County, Oregon in late summer. This will be a bus tour of three wineries and their associated geology. The trip will be run with a budgeting model designed to keep fees to a minimum. So come along and enjoy the fruits of the harvest!

Iron Mountain with Clark Niewendorp September 7

GSOC (Geological Society of the Oregon Country) is organizing a half-day field trip to explore Iron Mountain’s Prosser Mine and geology. Participants will walk along the Oswego Iron Heritage Trail that once followed the path of a local narrow-gauge steam railroad that historically connected the mine to the Oswego furnace.

Johnson Creek Bike Geotour with Ian Madin September 22

This will be a one-day bicycling geotrip that will follow (mostly) the Springwater Corridor Trail from Gresham to Milwaukie. We will be looking at Boring volcanoes, Missoula flood deposits and other sedimentary layers that fill the Portland Basin along the path of Johnson Creek. The approximately 14-mile route of the trip will be fairly level with a net drop of about 260 feet.

Portland/Willamette Valley Landslides with Scott Burns September 28

Scott Burns is planning to lead a car caravan style trip visiting 8 to ten landslides in the Portland West Hills, including three of the most famous ones! This 3-hour tour will visit the sites, discussing the origin of the slides and steps taken to remediate them.