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GEOREF RECORD

Matground structures and redox facies

Friedrich Pflueger
Matground structures and redox facies (in Unexplored microbial worlds, James W. Hagadorn (editor), Friedrich Pflueger (editor) and David J. Bottjer (editor))
Palaios (February 1999) 14 (1): 25-39

Abstract

A characteristic succession of sedimentary structures was observed in clastic Silurian tempestites of the Murzuk Basin of southwest Libya. The structures ("Manchuriophycus," syneresis cracks, "Astropolithon," load cracks, palimpsest ripples, "Kinneyia," microfault sets, and millimeter ripples) occur in sandstones and siltstones that show evidence of unusual cohesive behavior (cracks resulting from shrinking or degassing; resistance to erosion). In a sequence ranging from fully aerobic sandstones to anoxic graptolite shales, these structures characterize several zones of increasing redox stress, which correspond to ichnofacies zonation. It is postulated that microbial mats develop on the sediment surface whenever grazing and burrowing are suppressed. Depending on local conditions, biomats were leathery, felt-like, or gel-like. The observed matground structures resulted from the interaction of storm waves with microbial stabilization of progressively finer-grained sediments. Whereas such structures were ubiquitous in Precambrian clastics, they became restricted to hostile environments in the Phanerozoic, where they can be used to indicate environmental (mostly redox) stress, and possibly hydrocarbon potential, in sandstones and siltstones lacking other indicators.


ISSN: 0883-1351
Serial Title: Palaios
Serial Volume: 14
Serial Issue: 1
Title: Matground structures and redox facies
Title: Unexplored microbial worlds
Author(s): Pflueger, Friedrich
Author(s): Hagadorn, James W.editor
Author(s): Pflueger, Friedricheditor
Author(s): Bottjer, David J.editor
Affiliation: Yale University, Department of Geology and Geophysics, New Haven, CT, United States
Affiliation: California Institute of Technology, Division of Geological and Planetary Sciences, Pasadena, CA, United States
Pages: 25-39
Published: 199902
Text Language: English
Publisher: Society of Economic Paleontologists and Mineralogists, Tulsa, OK, United States
References: 82
Accession Number: 1999-057327
Categories: Sedimentary petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sects., strat. col., block diags., geol. sketch map
Secondary Affiliation: Yale University, USA, United StatesUniversity of Southern California, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 199919
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