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Biomere boundaries; a possible test for extraterrestrial perturbation of the biosphere

A. R. Palmer
Biomere boundaries; a possible test for extraterrestrial perturbation of the biosphere (in Geological implications of impacts of large asteroids and comets on the Earth, Leon T. Silver (editor) and Peter H. Schultz (editor))
Special Paper - Geological Society of America (1982) 190: 469-495

Abstract

Remarkable extinctions of shelf and epicontinental sea trilobite faunas at several times in the Cambrian, separated by periods of several millions of years, provide markers for the boundaries of Biomeres. At several boundaries, the abrupt change from a high diversity fauna with low individual dominances to a low diversity fauna dominated by only one or two species takes place within a few centimeters of section. There is no evidence in the beds below the extinction event of any signs of community deterioration. The best documented change, between the Late Cambrian Crepicephalus and Aphelaspis Zones can be recognized in sections from Nevada to Tennessee. Such a widespread event, involving an extremely short-lived shock to an established and successful community of shallow marine organisms, is difficult to explain by conventional causes. The pattern of extinction is remarkably similar to that of the calcareous plankton at the Cretaceous-Tertiary boundary and may be a response to a similar cause.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 190
Title: Biomere boundaries; a possible test for extraterrestrial perturbation of the biosphere
Title: Geological implications of impacts of large asteroids and comets on the Earth
Author(s): Palmer, A. R.
Author(s): Silver, Leon T.editor
Author(s): Schultz, Peter H.editor
Affiliation: Geol. Soc. Amer., Boulder, CO, United States
Affiliation: Calif. Inst. Technol., Dep. Geol. Planet. Sci., Pasadena, CA, United States
Pages: 469-495
Published: 1982
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
Meeting name: Conference on geological implications of impacts of large asteroids and comets on the Earth
Meeting location: Snowbird, UT, USA, United States
Meeting date: 19810919Oct. 19-22, 1981
References: 10
Accession Number: 1983-039501
Categories: Invertebrate paleontologyStratigraphy
Document Type: Serial Conference document
Bibliographic Level: Analytic
Illustration Description: illus. incl. sketch map
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N35°00'00" - N36°45'00", W90°15'00" - W81°40'00"
N31°15'00" - N37°00'00", W115°00'00" - W109°00'00"
N29°00'00" - N43°30'00", W122°00'00" - W102°30'00"
N38°34'60" - N39°34'60", W114°04'60" - W112°02'60"
N25°45'00" - N36°30'00", W106°30'00" - W93°30'00"
N41°00'00" - N45°00'00", W111°04'60" - W104°04'60"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 1983
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