--> Extraterrestrial Collisions: An Explanation for High-Frequency Changes in Accommodation Misinterpreted as Eustatic Sea Level Changes, by C. G. St. C. Kendall, R. Ehrlich, L. Andria, B. Christensen, P. A. Levine, L. Mwakahesya, I. L. Nesteroff, R. E. Prueser, P. Thibodeau, Y. Al Safouri, P. H. Siregar, and M. L. Wong; #90986 (1994).

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Abstract: Extraterrestrial Collisions: An Explanation for High-Frequency Changes in Accommodation Misinterpreted as Eustatic Sea Level Changes

Christopher G. St. C. Kendall, Robert Ehrlich, Ludy Andria, Beth Christensen, Phillip A. Levine, Lutengowa Mwakahesya, Ivan L. Nesteroff, Robert E. Prueser, Peter Thibodeau, Yasser Al Safouri, Parvita H. Siregar, Mei Leng Wong

Eustatic variation has been proposed as a major controlling influence on the character of the sedimentary record, particularly the distribution of hydrocarbon reservoir, seal, and source rocks. Causes for sea level change have been attributed to mid-oceanic spreading and glaciation. However, some interpreted sea level changes are recognized to be produced by changes in accommodation related to tectonic activity associated with the release of stress and plate motion. We believe that a valid cause for changes in accommodation, interpreted as fourth order high frequency (1-3 m.y.) eustatic events, is the development and recurring release of stress along plate boundaries. Release of this latent stress changes the surface inclination of ocean basins and results in new accommodation. We con end that impacts of extraterrestrial bodies with the earth can cause these changes in accommodation and so indirectly affect the stratigraphic record. Extraterrestrial objects collide with the earth frequently. At least 130 major impacts are recognized for the Phanerozoic, 80 of which are accurately dated and can be related to the Haq et al. sea level curve. Evidence for these collisions includes impact craters, tektites, iridium anomalies, tsunamis with their accompanying sedimentary record, and extinctions. We propose that random extraterrestrial collisions trigger the regional release of stress in ocean basins, distort the continental crust at points of impact, and create many of the high-frequency sequences recognized in the stratigraphic record. These sequences may include the produ ts of local tsunamis that erode the basin surface and produce a suite of deposits that may occur on regional unconformities. A suite of normal marine fill follows. Although meteorite impact may trigger sequences in the stratigraphic record, the mechanism that links impacts to modified basin-floor inclination awaits detailed analysis.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994