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Molluscan paleoecology and sedimentation patterns of the Cenomanian-Turonian extinction interval in the southern Colorado Plateau region

William P. Elder
Molluscan paleoecology and sedimentation patterns of the Cenomanian-Turonian extinction interval in the southern Colorado Plateau region (in Stratigraphy, depositional environments, and sedimentary tectonics of the western margin, Cretaceous Western Interior Seaway, J. Dale Nations (editor) and Jeffrey G. Eaton (editor))
Special Paper - Geological Society of America (1991) 260: 113-137

Abstract

Lithology, carbonate and organic carbon geochemistry, and molluscan macrofauna were investigated in fine-grained clay-dominated strata spanning the Cenomanian-Turonian Stage boundary in the southern Colorado Plateau region. Analyses of these data show basinal and onshore to offshore changes in sedimentologic and molluscan assemblage trends through the upper Cenomanian Sciponoceras gracile and Neocardioceras juddii and lower Turonian Watinoceras coloradoense Biozones. Diverse infaunal/epifaunal bivalve assemblages are best developed in the Sciponoceras gracile Biozone and at the more clay-rich nearshore sections. Gastropod and infaunal bivalve abundance and diversity decrease in an offshore and up-section direction as carbonate and organic carbon percentages generally increase. The Neocardioceras juddii Biozone precedes the stage boundary and is characterized in Utah and Arizona by pulsed increases in organic carbon and detrital-feeding gastropods, and by a shift in infaunal bivalve dominance toward species adapted for soft-substrate conditions. These data suggest that pulses of increased organic detrital resources and decreased substrate firmness were associated with the stage boundary extinctions. The stage boundary is marked by a change to depauperate epifaunal assemblages at western sections. At all sections, the base of the Watinoceras coloradoense Biozone is reflected by an abrupt increase in carbonate and decrease in organic carbon percentages as well as by the immigration of Mytiloides bivalves. Periods of progressive recovery through this biozone were associated with carbonate-rich depositional periods.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 260
Title: Molluscan paleoecology and sedimentation patterns of the Cenomanian-Turonian extinction interval in the southern Colorado Plateau region
Title: Stratigraphy, depositional environments, and sedimentary tectonics of the western margin, Cretaceous Western Interior Seaway
Author(s): Elder, William P.
Author(s): Nations, J. Daleeditor
Author(s): Eaton, Jeffrey G.editor
Affiliation: U. S. Geol. Surv., Menlo Park, CA, United States
Affiliation: North. Ariz. Univ., Dep. Geol., Flagstaff, AZ, United States
Pages: 113-137
Published: 1991
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
ISBN: 0-8137-2260-8
References: 38
Accession Number: 1991-075955
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. strat. cols., sketch maps
N31°15'00" - N37°00'00", W115°00'00" - W109°00'00"
N33°40'00" - N40°30'00", W114°00'00" - W106°19'60"
N37°00'00" - N42°00'00", W114°04'60" - W109°04'60"
Secondary Affiliation: Mus. North. Ariz., USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 1991
Program Name: USGSOPNon-USGS publications with USGS authors
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