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Bathymetric and isotopic evidence for a short-lived Late Ordovician glaciation in a greenhouse period

P. J. Brenchley, J. D. Marshall, G. A. F. Carden, D. B. R. Robertson, D. G. F. Long, T. Meidla, L. Hints and T. F. Anderson
Bathymetric and isotopic evidence for a short-lived Late Ordovician glaciation in a greenhouse period
Geology (Boulder) (April 1994) 22 (4): 295-298

Abstract

The end Ordovician glaciation is distinct among Phanerozoic glaciations in that CO (sub 2) levels were generally high, yet major continental ice sheets accumulated on the Gondwana supercontinent. New oxygen isotopic data indicate substantial changes in sea-water temperatures and ice volume coinciding with glacio-eustatic changes in sea level reflecting the growth and decay of the Gondwana ice cap. Major glaciation was apparently confined to the Hirnantian and was 0.5-1 m.y. long, rather than the 35 m.y. of earlier estimates. Carbon isotope values indicate significant changes in carbon cycling as the oceans changed from a state with warm saline bottom waters to a state with cold deep-water circulation and then back again. We believe that the changes in the carbon cycle effected a reduction in p (sub CO2) levels in the oceans and atmosphere and thus promoted glaciation but were unable to sustain icehouse conditions in a greenhouse world.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 22
Serial Issue: 4
Title: Bathymetric and isotopic evidence for a short-lived Late Ordovician glaciation in a greenhouse period
Affiliation: University of Liverpool, Department of Earth Sciences, Liverpool, United Kingdom
Pages: 295-298
Published: 199404
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 37
Accession Number: 1994-025813
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
N49°04'00" - N49°57'00", W64°31'60" - W61°43'00"
N39°10'00" - N39°10'00", W84°30'00" - W84°30'00"
N58°00'00" - N59°30'00", E22°00'00" - E27°00'00"
N36°30'00" - N39°10'00", W89°40'00" - W82°00'00"
N56°00'00" - N58°00'00", E21°00'00" - E28°00'00"
N55°15'00" - N69°15'00", E11°00'00" - E24°15'00"
Secondary Affiliation: Laurentian University, Sudbury, ON, CAN, CanadaTartu University, Tartu, EST, EstoniaEstonian Academy of Sciences, Tallinn, EST, EstoniaUniversity of Illinois, Urbana, IL, 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: 199412
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