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Pyrite ooids in Devonian black shales record intermittent sea-level drop and shallow-water conditions

Juergen Schieber and Lee R. Riciputi
Pyrite ooids in Devonian black shales record intermittent sea-level drop and shallow-water conditions
Geology (Boulder) (April 2004) 32 (4): 305-308

Abstract

Upper Devonian black shales of the eastern United States contain in places unusual beds of pyrite ooids. Textural and geochemical studies show that these originated as chamositic iron ooids that were replaced by pyrite during early diagenesis. Pyrite mimics the laminated texture of the precursor grain, yet inclusions of silicate minerals and instances of partial replacement reveal the secondary nature of the pyrite. Pyrite ooids occur above erosion surfaces that are considered sequence boundaries because of large lateral extent. Chamositic precursor ooids indicate an oxygenated water column and wave interaction with seafloor sediments at the time of their formation. This scenario agrees with earlier work that stipulates that erosion surfaces in Devonian black shales reflect lowering of sea level that allowed wave reworking and erosion of earlier-deposited black shales. Pyrite ooid beds thus furnish direct evidence of significant sea-level drops during the accumulation of Upper Devonian black shales in eastern North America.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 32
Serial Issue: 4
Title: Pyrite ooids in Devonian black shales record intermittent sea-level drop and shallow-water conditions
Affiliation: Indiana University, Department of Geological Sciences, Bloomington, IN, United States
Pages: 305-308
Published: 200404
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 26
Accession Number: 2004-060777
Categories: StratigraphySedimentary petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sketch map
N38°43'00" - N39°02'60", W86°19'60" - W85°47'60"
Secondary Affiliation: Oak Ridge National Laboratory, 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: 200418
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