Stratigraphic evolution, eruption history and structure of the Columbia River Flood-Basalt Province

Post-meeting field trip, August 19-25; max/min participants, 25/15

This field trip will transect a large and salient portion of the Miocene Columbia River Flood Basalt Province—the youngest, best-preserved, and best-studied continental flood basalt province on earth. Unparalleled exposures of lavas, dikes, and pyroclastic rocks through the heart of the flood-basalt source region will provide a superb setting for discussing the tectonic conditions of hotspot volcanism, exploring the eruption and emplacement processes of giant basalt flows and flow fields, and examining the causes and consequences of vast outpourings of basalt lava.  The evolution of the province through time can be used as a model for older, less well-preserved provinces. Topics that will be covered on the trip include: (a) magma genesis and transport; (b) tectonic setting and structural evolution; (c) stratigraphic evolution, up-section petrochemical changes and the evolution of magmatic processes; (d) emplacement mechanisms and timing of giant pāhoehoe flows and their implications for global climate change, ecological perturbations, and mass extinctions; and, (e) eruption mechanisms associated with large, long-lived fissures and the construction of proximal pyroclastic edifices.  This trip also provides a rare and unexpected opportunity for viewing a total eclipse of the sun. We will position ourselves for a midmorning viewing of totality on the third day of the field trip.

Logistics:
7 days, leave from and return back to Portland (afternoon on the 25th)

Estimated cost:
US$ 700 (includes breakfast (except the morning of departure) and lunch, but not dinners; double-occupancy lodging

Leaders:
Vic Camp, San Diego State University
Steve Reidel, Washington State University
Marty Ross, Northeastern University
Richard Brown, Durham University
Steve Self, U.S. Nuclear Regulatory Commission
Anita Grunder, Oregon State University