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GEOREF RECORD

The Pennsylvanian fire clay tonstein of the Appalachian Basin; its distribution, biostratigraphy, and mineralogy

Charles L. Rice, Harvey E. Belkin, Thomas W. Henry, Robert E. Zartman and Michael J. Kunk
The Pennsylvanian fire clay tonstein of the Appalachian Basin; its distribution, biostratigraphy, and mineralogy (in Elements of Pennsylvanian stratigraphy, central Appalachian Basin, Charles L. Rice (editor))
Special Paper - Geological Society of America (1994) 294: 87-104

Abstract

This Middle Pennsylvanian tonstein, mostly kaolinite and minor accessory minerals, is an altered and lithified volcanic ash preserved as a thin, isochronous layer associated with the Fire Clay coal bed. Seven samples of the tonstein, taken along a 300 km traverse of the central Appalachian basin, contain cogenetic phenocrysts and trapped silicate-melt inclusions of a rhyolitic magma. The phenocrysts include beta -quartz, apatite, zircon, sanidine, pyroxene, amphibole, monazite, garnet, biotite and various sulphides. An inherited component of the zircons (determined from U-Pb isotope analyses) provides evidence that the source of the Fire Clay ash was Middle Proterozoic (Grenvillian) continental crust inboard of the active North American margin. The (super 40) Ar/ (super 39) Ar plateau ages of seven sanidine samples from the tonstein have a mean age of 310.9 + or - 0.8 m.y., which suggests that it is the product of a single, large-volume, high-silica, rhyolitic eruption possibly associated with one of the Hercynian granitic plutons of the Piedmont. Biostratigraphic analyses correlate the Fire Clay coal bed with a position just below the top of the Trace Creek member of th Atoka formation in the North American mid-continent and near the Westphalian B-C boundary in W Europe.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 294
Title: The Pennsylvanian fire clay tonstein of the Appalachian Basin; its distribution, biostratigraphy, and mineralogy
Title: Elements of Pennsylvanian stratigraphy, central Appalachian Basin
Affiliation: U. S. Geological Survey, Reston, VA, United States
Affiliation: U. S. Geological Survey, Reston, VA, United States
Pages: 87-104
Published: 1994
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
ISBN: 0-8137-2294-2
References: 52
Accession Number: 1995-019462
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. chart, 3 tables, sketch maps
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United KingdomTwickenhamUKUnited Kingdom
Update Code: 199508
Program Name: USGSOPNon-USGS publications with USGS authors
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