Geological Society of the Oregon Country


Friday Night Meetings

There is free parking at PSU after 5 pm on Fridays in Parking Structure 2 on Broadway Ave. directly across from Cramer Hall, and on Level One of Parking Structure 1, on Broadway between Harrison and Hall St. Also, due to recent security concerns at PSU, please use the door between Smith Hall and Cramer Hall.

For additional information, check your monthly newsletter or contact Janet Rasmussen or (541) 760-7846.

Meeting Schedule

April 11, 2014 Friday 7:30 PM Speaker Dr. Michael Cummings, Portland State University Professor of Geology, will present "Buried by Pumice--Hydrologic and Landscape Response."

The eruption of Mount Mazama covered the upper Klamath Basin in pumice. Dr. Cummings will discuss recent investigations into the effects of this rock layer on groundwater and the landscape.

Dr. Cummings has taught at Portland State University for 35 years, and is retiring at the end of this year. In addition to teaching and research, Mike Cummings is the undergraduate advisor of geology students and is also department chair. Just last year he was given the 2013 Neil Miner Award by the National Association of Geoscience Teachers (NAGT) for his work in bringing Earth Sciences to middle schools in Portland and to remote rural schools throughout Oregon.

Join GSOC members at: Pizzicato, 1708 SW 6th Ave., at 6:00 before the lecture for dinner and conversation. Click on link to view menu.

May 9, 2014 Friday 7:30 PM Speaker Dr. Curt Peterson, Portland State University Professor of Geology, will present "Accommodation Space in the Lower Columbia River Valley: Infilling and Outflowing, From latest Pleistocene (16 ka) to Latest Holocene (2.5 ka)."

The Columbia River has the largest discharge of any river emptying into the Pacific Ocean from North America, yet it does not form a delta at its mouth. In the past 16 thousand years, sea level has continued to rise from its low stand during the ice ages, over 100 meters lower than its present level. As the sea level rose, ice age floods scoured the channel and deposited sediments during multiple events up until about 13,000 years ago. As rising seas increased the depth and width of the ancestral channel, the accommodation space for sediment accumulation also increased.

Dr. Peterson will discuss the role of this increasing space on sediment size and distribution within the lower 225 km of the Columbia River. His research is based on seismic reflection profiling and borehole testing, with a number of cross-sectional analyses of channel fill.

Dr. Peterson earned his B.A. in Geology at San Francisco State University and his Ph.D. in Oceanography, Marine Geology, at Oregon State University. He has taught at Portland State for 25 years, and is retiring at the end of this year.

Join GSOC members at: Pizzicato, 1708 SW 6th Ave., at 6:00 before the lecture for dinner and conversation. Click on link to view menu.

June 13, 2014 Friday 7:30 PM Speaker Dr. Maxwell Rudolph, Portland State University Assistant Professor of Geology, will present "Initiation, Dynamics, and Longevity of the Lusi Mud Eruption, East Java Indonesia."

The ongoing Lusi mud eruption began on May 29, 2006, near the town of Sidoarjo, East Java, Indonesia. Lusi is the largest and longest-lasting mud eruption ever witnessed and has had tremendous social and economic impacts, displacing several tens of thousands of people and causing total economic losses >$4 billion USD. Dr. Rudolph will discuss the initiation of the eruption and explain why we know that the eruption was not triggered by an earthquake. He will present satellite-based radar interferometry (InSAR) observations of ground deformation near the eruption. These contribute to our understanding of the processes occurring in the subsurface and provide some insight into how the eruption may progress in the future.

Dr. Rudolph earned his B.A. in Physics with Honors in Geology Astrophysics Concentration at Oberlin College, and a Ph.D. in Earth-Planetary Science at UC Berkeley. His research includes numerical modeling of the Earth's interior, eruption dynamics in Yellowstone, California, and other locations worldwide. As a new Assistant Professor at Portland State University, he will be teaching the Numerical Modeling course and some field study courses as well.

Join GSOC members at: Pizzicato, 1708 SW 6th Ave., at 6:00 before the lecture for dinner and conversation. Click on link to view menu.

GSOC inclement weather meeting policy is...if weather closes Portland schools, GSOC meetings are also cancelled.


What to bring on a GSOC field trip

Field Trip Schedule

April 30-May 3, 2014 Wednesday evening-Saturday See below A field trip, "Geology of the Lewiston Basin and Vicinity", has been organized by GSOC member Dave Olcott and will be led by geologists Dean Garwood and Dr. Keegan Schmidt.

Dean Garwood is a geologist at the Idaho Geological Survey. He has contributed to geologic maps in the Lewiston vicinity and also has co-authored papers on the Columbia River Basalts.

Dr. Schmidt is a geology professor at Lewis-Clark State College in Lewiston, Idaho. He has done geologic mapping in the Lewiston Basin. His expertise includes basement rock and suture zone geology east of Lewiston, and the geology of Hells Canyon. The trip will be based out of the Lewiston, Idaho, area, about 360 miles from Portland, OR. Participants are expected to travel to and from Lewiston on the days before and after the trip, so please include April 30 and May 4 as travel days. Suggested stops and points of interest along the way will be shared in a future communication with registered participants.


Wednesday, April 30: At 6:30 pm, we will have an orientation program at Lewis-Clark State College in Lewiston for an overview of the trip and details of meeting places and times.

Thursday, May 1: Clearwater Embayment and related Columbia River Basalt phenomena as well as Missoula and Bonneville Flood features. Dean Garwood will be trip leader.

Friday, May 2: Basement rock and suture zone geology as well as fragments of the Blue Mountain Composite Terrane. Dr. Schmidt will lead Days 2 and 3.

Saturday, May 3: 8:15 am. Jet-boating up the Snake River with Riverquest Excursions. While GSOC will provide geological interpretation during the river trip, the boat ride is independently contracted between participants and Riverquest Excursions (see below.) The geology from Lewiston to the mouth of the Imnaha River (60 miles south) will be evaluated with recognition of some of the cultural/historic sites and wildlife in this northern portion of Hells Canyon. The river trip will include stops. The boat will return around 6 pm, so attendees from the Portland area may want to stay over an extra night before returning home.

LODGING: Lodging opportunities range from campgrounds, RV parks to motel/hotels. Lodging can be as reasonable as $17.00/night (camping) to more for local motels. Camping is available at Hells Gate State Park, reserve online or call 888-922-6743. Some local motels include Guesthouse Inn and Suites, about $60 for a two-bed room, or the Motel 6 in nearby Clarkston, WA, for about $50 per night.

TRANSPORTATION: Individuals not wishing to drive can car pool from Portland. Dave will assist with organizing car pools to get to and from Lewiston. During the field trip, ground transportation will be by private car, coordinated to minimize the number of vehicles. There will not be any long walks involved, and 4-wheel-drive vehicles are not required.

You must reserve and pay for your seat on the jet boat excursion independently by calling Alison Oman at Lewis-Clark State College at (208) 792-2749. Alison will take your payment of $89.00 by card or by check. Please do not send the money to GSOC. The jet boat ride is not covered under GSOC liability.

Also,contact Dave ASAP if you plan to go on this field trip: 503-695-5219 or email at Click on link above to go to registration form with details.

Weather can vary at this time of year. Come prepared for warm and sunny to cold, windy, and wet.

Fee: $50, plus $89 for jet-boat excursion (includes lunch)

Limit of participants: TBA

Deadline for registration: April 11, 2014

NOTE: You must be a GSOC member or guest of a member to attend GSOC field trips. You may join GSOC at any time, for $25.

September 3-6, 2014 Wednesday-Saturday TBA The President's Field Trip is being organized by GSOC President Sheila Alfsen to the Silver Creek Falls area for several days, then moving to the eastern section of the Cascade Range.

Lodging will be at the Silver Creek State Park lodge the first two nights. Arrangements are still being made for the second portion of the trip. While at Silver Creek Falls, participants will learn about paleontological studies of the local fossil flora and fauna. On the east side of the Cascades, the emphasis will be on sedimentation response.

Details will follow, this is a "save the date" announcement.

Fee: TBA

Limit of participants: TBA

Deadline for registration: TBA

NOTE: You must be a GSOC member or guest of a member to attend GSOC field trips. You may join GSOC at any time, for $25.

Last updated April 4, 2014