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GEOREF RECORD

Extinction patterns in Paleogene benthic foraminiferal faunas; relationship to climate and sea level

Barbara A. Gaskell
Extinction patterns in Paleogene benthic foraminiferal faunas; relationship to climate and sea level
Palaios (February 1991) 6 (1): 2-16

Abstract

Five cycles of first and last appearances are discernible in Paleogene benthic foraminiferal faunas from the Gulf Coast states of Texas, Louisiana, Mississippi, and Alabama. These cycles were apparently caused by episodic increases in extinction rates followed by longer periods of recovery. In most respects they resemble cyclic patterns observed by other workers in Gulf Coast Paleogene molluscan faunas. Comparison of these cyclic patterns with global and local climatic trends shows an association between the increased extinction rate at two (Middle and Late Eocene) cycle boundaries and periods of climatic deterioration. Likewise, periods of climatic stability, indicated by stable Gulf Coast sporomorph diversity, coincide with lower than average extinction rates among benthic foraminifers. Comparison of the cyclic patterns with Gulf Coast sea level curves shows an association of increased extinction rates at three (Paleocene, Early Eocene, Middle Eocene) cycle boundaries with significant, widespread, rapid sea level falls that produced type 1 unconformities. Local and/or slow sea level falls do not appear to have effected extinction rates. Calculations using a species survivorship curve suggest that the time necessary for an average faunal assemblage to reach equilibrium following an extinction event is longer than the duration of any Paleogene cycle. Thus, Gulf Coast Paleogene benthic foraminiferal faunas were rarely if ever at equilibrium.


ISSN: 0883-1351
Serial Title: Palaios
Serial Volume: 6
Serial Issue: 1
Title: Extinction patterns in Paleogene benthic foraminiferal faunas; relationship to climate and sea level
Author(s): Gaskell, Barbara A.
Affiliation: 454 Jewett St., Ann Arbor, MI, United States
Pages: 2-16
Published: 199102
Text Language: English
Publisher: Society of Economic Paleontologists and Mineralogists, Tulsa, OK, United States
References: 108
Accession Number: 1991-038263
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. strat. cols.
N30°00'00" - N35°00'00", W88°30'00" - W85°00'00"
N29°00'00" - N33°00'00", W94°04'60" - W89°00'00"
N30°15'00" - N35°00'00", W91°40'00" - W88°04'60"
N25°45'00" - N36°30'00", W106°30'00" - W93°30'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by SEPM (Society for Sedimentary Geology), Tulsa, OK, United States
Update Code: 1991
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