Late Devonian sea-level changes, catastrophic events, and mass extinctions

GSA Special Papers
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Late Devonian history is explained through event stratigraphy comprising a sequence of 18 sea-level changes, catastrophic events, and mass extinctions. Generally rising sea level during the initial Frasnian Stage, beginning with the Taghanic onlap and ending with a sea-level fall and major mass extinction, was interrupted by several exceptionally rapid, very high rises of sea level. These rises may be related to a series of comet showers, as suggested by the coincidence of the Alamo Impact in Nevada and the older Amo¨nau Event in Germany with two of the sea-level rises. The subcritical, off-platform marine Alamo Impact is demonstrated to have produced greatly different effects in deep water from those previously recorded on the carbonate platform. The series of comet showers, most notably those around the Frasnian-Famennian boundary, evidenced by microtektites in widely separated regions, not only produced the late Frasnian mass extinction, but also induced global cooling. This cooling resulted in Southern Hemisphere glaciation. Generally falling sea level during the later Famennian Stage was interrupted by several warmer, interglacial episodes, evidenced by glacio-eustatic rises. Another, less severe mass extinction occurred during an abrupt sea-level fall near the end of the Famennian. This glacio-eustatic fall is interpreted to have resulted from a severe, terminal glacial episode. Interpretation of Late Devonian history suggests that impacts and comet showers coincided with sea-level rises, whereas mass extinctions occurred during, not at the start of, sea-level falls.

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Publication type Article
Publication Subtype Journal Article
Title Late Devonian sea-level changes, catastrophic events, and mass extinctions
Series title GSA Special Papers
DOI 10.1130/0-8137-2356-6.473
Volume 356
Year Published 2002
Language English
Publisher Geological Society of America
Contributing office(s) Geology, Geophysics, and Geochemistry Science Center
Description 15 p.
First page 473
Last page 487
Country Germany
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