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Pliocene volcanic rocks of the Coso Range, Inyo County, California.

Novak, Steven W; Bacon, Charles R (1986) Pliocene volcanic rocks of the Coso Range, Inyo County, California. U. S. Geological Survey Professional Paper. 1986.

AuthorsNovak, Steven W; Bacon, Charles R
Year1986
TitlePliocene volcanic rocks of the Coso Range, Inyo County, California.
SourceU. S. Geological Survey Professional Paper. 1986.
PublisherU. S. Geological Survey. Reston, VA, United States. Pages 44. 1986.
Document typeSerial; Report
ISSN1044-9612
GeoRef1986-059530
Keywordsbasaltic-composition; basalts-; California-; Cenozoic-; Coso-Range; differentiation-; eastern-California; extension-tectonics; fractional-crystallization; genesis-; geochemistry-; hybridization-; igneous-rocks; Inyo-County-California; magmas-; major-elements; metals-; Neogene-; periodicity-; petrography-; petrology-; Pliocene-; pollution-; rare-earths; rhyodacites-; rhyolites-; tectonics-; Tertiary-; trace-elements; United-States; USGS-; volcanic-fields; volcanic-rocks; volcanism-; volcanology-

Abstract

Volcanic rocks that erupted 4 m.y. to 2.5 m.y. ago in the Coso Range consist of basalt, andesite, dacite, rhyodacite, and high-silica rhyolite. Petrography, mineral analyses, and major- and trace-element geochemistry show that compositional variation among these rocks was produced by a combination of fractional crystallization of basaltic magma, contamination with silicic partial melts of crustal rocks, and magma mixing. Increasingly differentiated magma was erupted as the volcanic field developed. This eruption may have been caused by greater crustal residence time of magma in response to an increasing tectonic extension rate during the Pliocene.

47 samples from this reference

SampleRock nameMajorTraceIsotope
9-85-2Rhyolite yesyes
13-108-1Basalt yesyes
I-88-2Andesite yesyes
9/12/03Basalt yes
13-114-2Basalt yesyes
I-103-1Basalt yesyes
8-128-4Basalt yes
8-194-8Basalt yesyes
8-128-5Basalt yes
I-87-3Basalt yesyes
9/7/02Basalt yes
8-193-1Basalt yes
8-195-1Basalt yes
8-194-6Basalt yesyes
9/10/03Basalt yes
8-196-5Basalt yesyes
I-89-1Basalt yes
8-128-3Andesite yesyes
I-106-6Basalt yes
I-106-7Andesite yes
I-106-3Andesite yesyes
I-103-2Andesite yesyes
13-114-3Andesite yesyes
8-194-4Andesite yesyes
13-111-2Andesite yes
13-111-7Andesite yesyes
13-113-21Andesite yes
I-101-12Andesite yes
I-103-4Andesite yes
13-47-3Andesite yesyes
9-87-2Andesite yes
I-101-12Andesite yesyes
I-101-13Andesite yesyes
13.111-4Andesite yesyes
I-101-10Andesite yesyes
I-101-4Andesite yesyes
13-113-8Andesite yes
13-113-19Dacite yesyes
I-103-7Andesite yesyes
13-45-1Dacite yesyes
13-42-4Dacite yesyes
13-43-4Dacite yes
13-42-5Dacite yesyes
13-43-13Dacite yesyes
13-45-5Dacite yes
9-86-4Rhyodacite yesyes
I-103-5