Workshop Reports HOTSPOT: The Snake River Scientifi c Drilling Project— Tracking the Yellowstone Hotspot Through Space and Time

doi:10.2204/iodp.sd.3.14.2006 Mantle plumes play a crucial role in Earth’s thermal and tectonic evolution. Plumes have long been implicated in the breakup and rifting of continents, and plume-derived melts play a signifi cant role in the creation and modifi cation of the sub-continental mantle lithosphere. Hotspot volcanism in the oceanic lithosphere has been the subject of intense recent study by the Hawaii Scientifi c Drilling Project, and studies conducted by the Integrated Ocean Drilling Program (IODP) will examine further the role of mantle plumes in oceanic settings. These drilling efforts provide baseline information about where mantle plumes originate, how they behave, and what the volcanic products of these processes are. In contrast, the impacts of hotspot volcanism on the continental lithos-phere are poorly understood because active continental hotspot systems are limited to surface exposures of volcanic provinces that are too young to be exposed by erosion. The Snake River Plain volcanic province, which begins under eastern Oregon, U.S.A. and ends at the Yellowstone plateau about 350 km to the east, represents a hotspot track beneath the continental crust (Fig. 1). Basalts of the Snake River Plain are compositionally similar to ocean-island basalts and preserve a record of volcanic activity that spans over 12 Ma. The Snake River province is still active today, with fl ows as young as 6000 years, and it represents a world-class example of active, intra-continental, mantle-plume volcanism. In addition, the western Snake River Plain preserves an archive of late Neogene paleoclimatic evolution hosted within deep-water lacustrine sediments. The complete record of volcanic activity can only be sampled by drilling because the plain is young and tectonically undisturbed, with limited exposure of the stratigraphic sequence