Eruption and emplacement of flood basalt. An example from the large-volume Teepee Butte Member, Columbia River Basalt Group

Journal Article · Tue Dec 01 04:00:00 EST 1992 · Geological Society of America, Bulletin; (United States)

DOI:https://doi.org/10.1130/0016-7606(1992)104<1650:EAEOFB>2.3.CO;2· OSTI ID:6565741

Reidel, S P ^[1]; Tolan, T L ^[2]

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1. Washington State Univ., Pullman (United States)
2. Portland State Univ., OR (United States)

Flows of the Teepee Butte Member, Grande Ronde Basalt, issued from a vent system in southeastern Washington, northeastern Oregon, and western Idaho. Three distinct basalt flows were erupted: the Limekiln Rapids flow, the Joseph Creek flow, and the Pruitt Draw flow. Together these mappable flows cover more than 52,000 km[sup 2] and have a volume exceeding 5,000 km[sup 3]. A portion of the vent system for the Joseph Creek flow is exposed in cross section in Joseph Canyon, Washington; it is one of the best preserved Columbia River Basalt Group vent complexes known. The vent complex is about 1 km in cross section, 30 m high, and composed of deposits characteristic of Hawaiian-type volcanism. The vent is asymmetrical; the eastern rampart consists of intercalated pyroclastic deposits and thin pahoehoe flows; the western rampart is composed wholly of pahoehoe flows. Flows of the Teepee Butte Member are compositionally homogeneous and were emplaced as sheet flows, each having several local flow units. Our study supports the importance of linear vent systems and the westward Palouse Slope, along with the large-volume lava flows, in controlling the distribution of Columbia River Basalt Group flows. Other factors, including the number of active fissure segments and topography, modified the shape of the flows and the number of flow units. 45 refs., 19 figs., 2 tabs.

• DOE Contract Number: FG06-91ER14172
• OSTI ID: 6565741
• Journal Information: Geological Society of America, Bulletin; (United States), Journal Name: Geological Society of America, Bulletin; (United States) Vol. 104:12; ISSN 0016-7606; ISSN BUGMAF
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical &amp; Physicochemical Properties
58 GEOSCIENCES
580000* -- Geosciences
BASALT
CHEMICAL COMPOSITION
DIKES
GEOLOGIC STRUCTURES
GEOLOGY
IGNEOUS ROCKS
LAVA
LITHOLOGY
PETROGRAPHY
PETROLOGY
ROCKS
VOLCANIC ROCKS
VOLCANISM