Volcanoes of the California Cascades

California Cascades

Post-meeting field trip, August 19-24; max/min participants, 30/20

This 6-day trip to northern California will visit and explore the three major Quaternary volcanic systems of the southern Cascades arc – Mount Shasta, the Lassen Volcanic Center, and Medicine Lake volcano. The trip will begin with the broad rear-arc Medicine Lake volcano, continue to the southernmost part of the arc at Lassen Volcanic Center, a volcanic field that spans the arc, and end with Mount Shasta, a large fore-arc stratocone. At each of these three distinctive California volcanic centers, leaders will provide a geologic and tectonic overview and petrologic interpretation. A variety of rock types with a range of compositions from basalt through rhyolite will be featured including some of the best-exposed Holocene lavas in the United States. Other highlights will include young faults, thermal features, a lava-tube cave, and spectacular views. The first day of the trip will include a stop to view central Oregon volcanoes (Three Sisters and Newberry Volcano).

Participants will travel by vans beginning early on August 19th from Portland, travel south along the east side of the Oregon High Cascades, and return to Portland on the evening of August 24th, covering about 1,000 miles. Walks at a few of the stops along the route will require sturdy shoes and a small daypack. Conditions could range from hot to cool and rainy.

Field trip cost of $950 includes 5 nights double-occupancy lodging (note: additional charge of $200 for single room). Lunch and snacks are provided every day and breakfast is included on days 2-5. Two group dinners (on August 19 and 24) are also included.

Leaders at Medicine Lake volcano:
Julie Donnelly-Nolan, U.S. Geological Survey

Leaders at Lassen Volcanic Center:
Mike Clynne, U.S. Geological Survey
Patrick Muffler, U.S. Geological Survey

Leaders at Mount Shasta:
Bob Christiansen, U.S. Geological Survey
Andy Calvert, U.S. Geological Survey