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Geology, geochronology, and potential volcanic hazards in the Lava Ridge-Hells Half Acre area, eastern Snake River Plain, Idaho

Open-File Report 79-1657

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Abstract

The evaluation of volcanic hazards for the proposed Safety Test Reactor Facility (STF) at the Argonne National Laboratory-West (ANLW) site, Idaho National Engineering Laboratory (INEL), Idaho, involves an analysis of the geology of the Lava Ridge-Hells Half Acre area and of K-At age determinations on lava flows in cored drill holes. The ANLW site at INEL lies in a shallow topographic depression bounded on the east and south by volcanic rift zones that are the locus of past shield-type basalt volcanism and by rhyolite domes erupted along the ring fracture of an inferred rhyolite caldera. The K-At age data indicate that the ANLW site has been flooded by basalt lava flows at irregular intervals from perhaps a few thousand years to as much as 300,000-400,000 years, with an average recurrence interval between flows of approximately 80,000-100,000 years. At least five major lava flows have covered the ANLW site within the past 500,000 years.

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Geology, geochronology, and potential volcanic hazards in the Lava Ridge-Hells Half Acre area, eastern Snake River Plain, Idaho
Series title:
Open-File Report
Series number:
79-1657
Edition:
-
Year Published:
1979
Language:
ENGLISH
Publisher:
U.S. Geological Survey,
Description:
v, 66 leaves, [9] leaves of plates :ill. (some col.), maps ;28 cm.; (72 p. - PGS)