Source materials for the main phase of the Columbia River Basalt Group: Geochemical evidence and implications for magma storage and transport

Igneous Rock Associations 15. The Columbia River Basalt Group: A Flood Basalt Province in the Pacific Northwest, USA

“…Volume 42 (2008) and Wolff and Ramos (2013) argue that the plume was centred near the western Snake River Plain, where the Oregon-Idaho graben and Chief Joseph dyke swarm converge; the magma moved north through a system of dykes similar to that suggested for the Mull complex in Scotland. Camp et al (2003) and Camp and Ross (2004), however, argue that the plume originated in the Steens area and the plume head moved north over time reaching the northern part of the Chief Joseph dyke swarm.…”

“…The geochemical and isotopic data have also been invaluable for understanding the origin of CRBG magma (e.g. Wright et al 1973Wright et al , 1989Reidel 1983;Hooper and Hawkesworth 1993;Durand and Sen 2004;Ramos et al 2005Ramos et al , 2013Camp and Hanan 2008;Wolff et al 2008;Wolff and Ramos 2013;Rodriguez and Sen 2013). A major reason why a regional CRBG geochemical stratigraphy is possible is that many lava flows have a remarkable 'bulk' geochemical homogeneity despite their huge volumes and distances traveled.…”

“…Arguments include: a mantleplume origin (e.g. Duncan 1982;Goles 1988, 1995;Draper 1991;Hooper and Hawkesworth 1993;Geist and Richards 1993;Camp 1995Dodson et al 1997;Mege and Ernst 2001;Hooper et al 2002Hooper et al , 2007Camp et al 2003;Camp and Ross 2004;Ramos et al 2005;Camp and Hanan 2008;Wolff et al 2008;Humphreys and Schmandt 2011;Wolff and Ramos 2013); simple melting of the upper mantle (Carlson and Hart 1987;Smith 1992;Christiansen et al 2002;Hales et al 2005;Tikoff et al 2008;James et al 2011;Liu and Stegman 2012;Long et al 2012); backare extension resulting in the passive rise and adiabatic melting of the shallow mantle (Dickinson 1997;Sears et al 2005;Tikoff et al 2008), similar to that proposed for the Chilcotin Plateau Basalts of British Columbia (Bevier 1983); convective upwelling of upper mantle along the western edge of North America (King and Anderson 1998); lithospheric delamination (Hales et al 2005); melting of buoyant peridotitic diapirs (Ivanov 2007); and upper mantle convection through or around the Farrallon-Juan de Fuca slab (e.g. James et al 2011;Lui and Stegman 2012;Long et al 2012).…”

“…Reidel and Fecht 1987;Martin 1989;Reidel and Tolan 1992;Reidel et al 1994Self et al 1996Self et al , 1997Ho and Cashman 1997;Reidel 1998Reidel , 2005Vye et al 2013), and developing geochemical and petrogenetic models (e.g. Hooper and Hawkesworth 1993;Durand and Sen 2004;Ramos et al 2005Ramos et al , 2013Camp and Hanan 2008;Wolff et al 2008;Wolff and Ramos 2013;Rodriguez and Sen 2013).…”

Field-trip guide to Columbia River flood basalts, associated rhyolites, and diverse post-plume volcanism in eastern Oregon

“…Many researchers, including Duncan (1982), Goles (1988, 1995), Draper (1991), Geist and Richards (1993), Hooper and Hawkesworth (1993), Camp (1995, Dodson and others (1997), Hooper andothers (2002, 2007), Camp and others (2003), Camp and Ross (2004), Camp and Hanan (2008), Wolf and others (2008), Wolf and Ramos (2013), and Benson and Mahood (2016), see a link between the CRBG and a Yellowstone hotspot, with both being part of a larger volcanic province. This larger volcanic province includes the voluminous, middle Miocene rhyolite eruptive centers of northern Nevada and southeastern Oregon and the diverging bimodal and time-transgressive rhyolitic volcanic Figure 2.…”