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Paleogeographic setting of the Schoonover sequence, Nevada, and implications for the late Paleozoic margin of western North America

William B. Whiteford
Paleogeographic setting of the Schoonover sequence, Nevada, and implications for the late Paleozoic margin of western North America (in Paleozoic and early Mesozoic paleogeographic relations; Sierra Nevada, Klamath Mountains, and related terranes, David S. Harwood (editor) and M. Meghan Miller (editor))
Special Paper - Geological Society of America (1990) 255: 115-136

Abstract

Details of the stratigraphy, depositional setting, and clastic petrography of the upper Paleozoic Schoonover sequence in the Independence Mountains, northern Nevada, provide the basis for a better understanding of the paleogeography of the continental margin of western North America during the late Paleozoic. The Schoonover sequence represents the northernmost exposures of the Golconda allochthon, which was thrust over the outer edge of the continental margin of western North America during the Permo-Triassic Sonoma orogeny. The Schoonover sequence, like the Havallah sequence and other units of the Golconda allochthon, is an imbricated assemblage of thrust-bound packages of radiolarian "ribbon" chert, basaltic greenstone, silty limestone turbidites, and siliciclastic sandstones that range in age from Late Devonian to Early Permian. Detailed mapping, and facies and petrographic analysis of lithostratigraphic units, combined with paleontologic control, indicate that the Schoonover sequence consists of a coherent stratigraphic succession of basinal deposits with paleogeographic ties to the autochthonous shelf margin and to a volcanic arc. Latest Devonian- to earliest Mississippian-age basaltic and andesitic greenstones and tuffaceous sedimentary rocks form the stratigraphic base of the sequence and are succeeded by Lower Mississippian siliciclastic sandstones. The petrography of these sandstones indicates that they consist of mixed detritus derived from volcanic and continental shelf source terranes, indicating the proximity of an arc to the continental margin. In addition, stratigraphic relations between autochthon and allochthon indicate that the Schoonover basin evolved adjacent to the continental shelf throughout the late Paleozoic, its history punctuated by periods of basaltic volcanism and pulses of continent-derived clastic input. The onset of the Sonoma orogeny resulted in closure of the basin and emplacement of its deposits on the continental margin.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 255
Title: Paleogeographic setting of the Schoonover sequence, Nevada, and implications for the late Paleozoic margin of western North America
Title: Paleozoic and early Mesozoic paleogeographic relations; Sierra Nevada, Klamath Mountains, and related terranes
Author(s): Whiteford, William B.
Author(s): Harwood, David S.editor
Author(s): Miller, M. Meghaneditor
Affiliation: Stanford Univ., Dep. Geol., Stanford, CA, United States
Affiliation: U. S. Geol. Surv., Menlo Park, CA, United States
Pages: 115-136
Published: 1990
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
ISBN: 0-8137-2255-1
References: 75
Accession Number: 1992-002330
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 4 tables, chart, sect., strat. cols., geol. sketch maps
Secondary Affiliation: Calif. Inst. Technol., USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 1992
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