The Columbia River flood basalt province: Stratigraphy, areal extent, volume, and physical volcanology

Intracanyon basalt lavas of the Debed River (northern Armenia), part of a Pliocene–Pleistocene continental flood basalt province in the South Caucasus

“…5a) may represent a palaeovalley wall. Thick pahoehoe lava flows with pillowed bases, or the so-called "pillow-palagonite complexes", formed due to the entry of lavas into river valleys, are widespread in the Columbia River CFB province, as well as in Scotland, Ireland and Iceland (e.g., Saemundsson, 1970;Swanson and Wright, 1981;Long and Wood, 1986;Hooper, 1997;Lyle, 2000;Reidel et al, 2013).…”

“…Alternatively, the hyaloclastites may represent the mechanical plucking of fresh lava from a slow-moving lava flow front by a vigorous river, followed by transport and deposition of the glassy fragmental debris downstream (cf. Tolan and Beeson, 1984;Reidel et al, 2013). Pillow lavas also outcrop in the Dzoraget River canyon near Stepanavan ( Fig.…”

“…Note the typical stepped "Trap" landscape, and how the basalts have partly filled valleys between highlands made up of the basement rocks. This is how the Columbia River flood basalt province would have looked after the thick, intracanyon, Imnaha basalt lavas had erupted (e.g., Hooper, 1997;Reidel et al, 2013; S. P. Reidel, official review). isotherms, and therefore columns develop in random orientations, everywhere perpendicular to the local shape of the isotherms.…”

Extensive middle Miocene weathering interpreted from a well-preserved paleosol, Cricket Flat, Oregon, USA

“…1, inset). The largest-volume formations of the CRBG (77.8% of the CRBG; Reidel et al, 2013) are chemically homogeneous basalts and basaltic andesites erupted between about 16 and 15 Ma (Barry et al, 2013 and references therein). As volcanic activity waned after 15 Ma, lava flows became more local and chemically varied.…”

Large-volume lava flows fed by a deep magmatic reservoir at Ağrı Dağı (Ararat) volcano, Eastern Turkey

“…The type and composition of magma feeding an eruption can also influence the eruptive Deccan Plateau and the Columbia Basalt Plateau (Reidel et al 2013). …”