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Volcanoes of the McCullough Range, southern Nevada

Eugene Smith, Denise Honn and Racheal Johnsen
Volcanoes of the McCullough Range, southern Nevada (in Miocene tectonics of the Lake Mead region, central Basin and Range, Paul J. Umhoefer (editor), L. Sue Beard (editor) and Melissa A. Lamb (editor))
Special Paper - Geological Society of America (June 2010) 463: 203-219


The McCullough Range preserves a unique record of Miocene volcanism in the western Lake Mead area of Nevada. The basal part of the volcanic section is composed of interbedded basalt and dacite of the McClanahan Spring, Cactus Hill, and McCullough Wash volcanoes (Eldorado Valley volcanic section), and the Colony volcano, which is age-equivalent to, but does not crop out within, the Eldorado Valley volcanic section (18.5-15.2 Ma). These units lie on Precambrian basement and locally on the Peach Springs Tuff (18.5 Ma). Over 400 m of andesite lava, agglomerate, and breccia of the Farmer Canyon volcanic section forms the McCullough stratovolcano. Eruptions occurring after 15.2 Ma were lower in volume and are mainly present on the flanks of the McCullough stratovolcano. These include the eruption of (1) the McCullough Pass caldera and outflow tuff (14.1 Ma), (2) Hidden Valley andesite, including 300 m of andesite lavas erupted from local centers (mainly cinder cones), (3) four Sloan volcanoes on the west flank of the McCullough stratovolcano (Mount Ian, Mount Sutor, Center Mountain, and Mount Hanna) (13.1 Ma), and (4) the Hender son dome complex on the northern flank of the McCullough stratovolcano. The volcanic rocks in the McCullough Range are calc-alkaline and vary in composition from rhyolite to basalt. Intermediate compositions (andesite and dacite) prevail, while basalt and rhyolite are rare. The trace-element signature (low Nb, Ti, Zr, and P compared to primitive mantle) is an indication of either a magma source in the continental lithosphere or lithospheric contamination. Rhyolite and dacite probably formed by partial melting of crust, while mafic magmas (basalt and andesite) either originated by melting of lithospheric mantle or reflect asthenospheric magmas contaminated in the lithosphere.

ISSN: 0072-1077
EISSN: 2331-219X
Serial Title: Special Paper - Geological Society of America
Serial Volume: 463
Title: Volcanoes of the McCullough Range, southern Nevada
Title: Miocene tectonics of the Lake Mead region, central Basin and Range
Author(s): Smith, EugeneHonn, DeniseJohnsen, Racheal
Author(s): Umhoefer, Paul J.editor
Author(s): Beard, L. Sueeditor
Author(s): Lamb, Melissa A.editor
Affiliation: University of Nevada, Las Vegas, Department of Geoscience, Las Vegas, NV, United States
Affiliation: Northern Arizona University, Department of Geology, Flagstaff, AZ, United States
Pages: 203-219
Published: 201006
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 44
Accession Number: 2010-088820
Categories: Igneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sects., 1 table, geol. sketch map
N35°30'00" - N36°00'00", W115°10'00" - W114°45'00"
Secondary Affiliation: U. S. Geological Survey, USA, United StatesUniversity of Saint Thomas, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201047
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