Arnie Miller, University of Cincinnati professor of paleontology in the McMicken College of Arts & Sciences, and co-author Michael Foote of the University of Chicago publish their research in the Nov. 20 issue of Science with their paper, "Epicontinental Seas Versus Open-Ocean Settings: The Kinetics of Mass Extinction and Origination."
For many years, paleobiological researchers interested in the history of biodiversity have focused on charting the many ups (evolutionary radiations) and downs (mass extinctions) that punctuate the history of life. Because the preserved record of marine (sea-dwelling) animals is unusually extensive in comparison, say, to that of terrestrial animals such as dinosaurs, it's been easier to accurately calibrate the diversity and extinction records of marine organisms.
"Paleontologists now recognize that there were five particularly large, worldwide mass extinction events during the history of life, known among the cognoscenti as 'The Big Five,'" says Miller. "Much ink in research journals has been spilled over the past few decades on papers investigating the causes of these events."
Although researchers have long understood the potential value of "dissecting" mass extinctions, to ask whether some environments and organisms were affected more dramatically than others, little attention has been paid to a major dichotomy observed among marine sedimentary rocks and fossils: the distinction between epicontinental seas, which were broad shallow seas (typically less than 100 meters in depth) that once covered large regions of present-day continents, and open-ocean-facing coastlines, such as the continental shelves that rim many continents.
Today, it is difficult to appreciate that there was a time when regions such as Cincinnati were once covered by epicontinental seas, which gradually diminished over time so that almost none are left in the present day. And yet, a large percentage of Earth's
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