Eruptive history and magmatic system of Mount Hood, Oregon

Pre-meeting field trip, August 10-12; max/min participants, 27/15

Mount Hood is an archetypal andesitic-dacitic continental-arc volcano, whose future eruptions threaten a major metropolitan area; energy, transportation, and recreational infrastructure; and important agricultural regions. This three-day, two-night, pre-meeting field trip will focus on its 500,000-year eruptive history and will highlight detailed geologic mapping and accompanying geochronologic, paleomagnetic, and petrologic studies that reveal an eruptive behavior characterized by low explosivity and restricted compositional range. Among topics explored will be (1) tectonic setting; (2) eruptive history, style, and hazards; (3) coeval regional mafic volcanism that surrounds Mount Hood; (4) geochemistry and proposed models of Hood’s magmatic system; (5) glacier-volcano interactions; (6) recently discovered evidence of latest Quaternary surface faulting; and (7) geophysical monitoring. Most stops will be along roads, but each day there will be a moderate hike on trails of about 2-hour duration covering 3–4 km with a maximum elevation gain of 150 m.

Logistics:
The trip will depart from Portland, Oregon (location to be determined) by 8 a.m. on Thursday, August 10th, and end at the Oregon Convention Center late afternoon or early evening, August 12th.  The route will circumnavigate the volcano travelling through the scenic Columbia River Gorge, orchards of the Hood River Valley, and the Sandy River valley.  The first night will be at rustic Cooper Spur Inn on Hood’s northeast flank; the second night at historic Timberline lodge on the south flank.

Estimated cost:
$375/person, includes transportation, dormitory-style lodging (several people to a room), breakfast Friday and Saturday, all lunches and snacks, and dinner Thursday night. Participants are responsible for their own dinner Friday night.  

Leaders:
William Scott, U.S. Geological Survey
Cynthia Gardner, U.S. Geological Survey
Adam Kent, Oregon State University
Alison Koleszar, University of Texas