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Title: The ash-fall pattern of the Fire Clay tonstein, central Appalachian basin: Paleogeographic and plate tectonic implications

Abstract

Thickness data for the Fire Clay tonstein bed (Middle Pennsylvania, Breathitt Formation) of Kentucky and its correlatives in West Virginia, Virginia, and Tennessee show a moderately complex ash-fall pattern across the central Appalachian basin. Within the tonstein bed are four or possibly more distinct graded units, which may represent multiple ash-fall events. The mineralogical and chemical signatures for all tonstein beds are similar and suggest a single magmatic source. The absence of coal or non-ash-fall detrital bands between the individual graded units demonstrates that the events occurred in rapid succession. The ash-fall deposits are elongated and thin generally from southwest to northeast. The longest and thickest part of the deposits lies along the southeastern side of the basin, where the deposit's southwestern end is up to 12 in. thick. The areal distribution indicates ash deposition on unstable surfaces and probably changes in wind patterns. Paleogeographic interpretation suggest that the Fire Clay ash fall or falls were deposited from a western source near the paleoequator. This source is thought to be on the Yucatan block, which was involved in collisional tectonics and eastward-directed subduction during the Middle Pennsylvanian. The block contained a volcanic chain from which the deposits may have originated.more » This composite ash-fall bed, which became the Fire Clay tonstein, formed the most important isochron in the Middle Pennsylvanian of North America.« less

Authors:
;  [1];  [2]
  1. Geological Survey, Reston, VA (United States)
  2. West Virginia Geological and Economic Survey, Morgantown (United States)
Publication Date:
OSTI Identifier:
5695943
Resource Type:
Journal Article
Journal Name:
AAPG Bulletin (American Association of Petroleum Geologists); (United States)
Additional Journal Information:
Journal Volume: 75:8; Journal ID: ISSN 0149-1423
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; APPALACHIAN BASIN; GEOLOGIC DEPOSITS; SHALES; GEOCHEMISTRY; MINERALOGY; VOLCANIC ROCKS; DEPOSITION; ASHES; BITUMINOUS COAL; CARBONIFEROUS PERIOD; CHEMICAL COMPOSITION; COAL SEAMS; GEOLOGIC HISTORY; KAOLINITE; KENTUCKY; PLATE TECTONICS; TENNESSEE; VIRGINIA; WEST VIRGINIA; ALUMINIUM COMPOUNDS; ALUMINIUM SILICATES; BLACK COAL; CARBONACEOUS MATERIALS; CHEMISTRY; COAL; COAL DEPOSITS; COMBUSTION PRODUCTS; DEVELOPED COUNTRIES; ENERGY SOURCES; FOSSIL FUELS; FUELS; GEOLOGIC AGES; GEOLOGIC STRUCTURES; IGNEOUS ROCKS; MATERIALS; MINERAL RESOURCES; MINERALS; NORTH AMERICA; OXYGEN COMPOUNDS; PALEOZOIC ERA; RESIDUES; RESOURCES; ROCKS; SEDIMENTARY BASINS; SEDIMENTARY ROCKS; SILICATE MINERALS; SILICATES; SILICON COMPOUNDS; TECTONICS; USA; 580000* - Geosciences

Citation Formats

Outerbridge, W F, Lyons, P C, and Keiser, A F. The ash-fall pattern of the Fire Clay tonstein, central Appalachian basin: Paleogeographic and plate tectonic implications. United States: N. p., 1991. Web.
Outerbridge, W F, Lyons, P C, & Keiser, A F. The ash-fall pattern of the Fire Clay tonstein, central Appalachian basin: Paleogeographic and plate tectonic implications. United States.
Outerbridge, W F, Lyons, P C, and Keiser, A F. 1991. "The ash-fall pattern of the Fire Clay tonstein, central Appalachian basin: Paleogeographic and plate tectonic implications". United States.
@article{osti_5695943,
title = {The ash-fall pattern of the Fire Clay tonstein, central Appalachian basin: Paleogeographic and plate tectonic implications},
author = {Outerbridge, W F and Lyons, P C and Keiser, A F},
abstractNote = {Thickness data for the Fire Clay tonstein bed (Middle Pennsylvania, Breathitt Formation) of Kentucky and its correlatives in West Virginia, Virginia, and Tennessee show a moderately complex ash-fall pattern across the central Appalachian basin. Within the tonstein bed are four or possibly more distinct graded units, which may represent multiple ash-fall events. The mineralogical and chemical signatures for all tonstein beds are similar and suggest a single magmatic source. The absence of coal or non-ash-fall detrital bands between the individual graded units demonstrates that the events occurred in rapid succession. The ash-fall deposits are elongated and thin generally from southwest to northeast. The longest and thickest part of the deposits lies along the southeastern side of the basin, where the deposit's southwestern end is up to 12 in. thick. The areal distribution indicates ash deposition on unstable surfaces and probably changes in wind patterns. Paleogeographic interpretation suggest that the Fire Clay ash fall or falls were deposited from a western source near the paleoequator. This source is thought to be on the Yucatan block, which was involved in collisional tectonics and eastward-directed subduction during the Middle Pennsylvanian. The block contained a volcanic chain from which the deposits may have originated. This composite ash-fall bed, which became the Fire Clay tonstein, formed the most important isochron in the Middle Pennsylvanian of North America.},
doi = {},
url = {https://www.osti.gov/biblio/5695943}, journal = {AAPG Bulletin (American Association of Petroleum Geologists); (United States)},
issn = {0149-1423},
number = ,
volume = 75:8,
place = {United States},
year = {Thu Aug 01 00:00:00 EDT 1991},
month = {Thu Aug 01 00:00:00 EDT 1991}
}