The most comprehensive geological review ever undertaken of the upper U.S. Gulf Coast suggests that a combination of rising seas and dammed rivers could flood large swaths of wetlands this century in one or more bays from Alabama to Texas.
"In terms of sea-level increases and river sediments flowing into the bays, we're rapidly approaching a time when bays will face conditions they last saw in the Holocene, from about 9,600 until 7,000 years ago," said lead researcher John Anderson, the W. Maurice Ewing Professor in Oceanography and professor of Earth science at Rice University. "That period was marked by dramatic and rapid flooding events in each of these bays -- events that saw some bays increase their size by as much as one-third over a period of 100 or 200 years."
Anderson is presenting the findings at next week's annual meeting of the Geological Society of America (GSA) at Houston's George R. Brown Convention Center. Anderson said the magnitude of flooding seen in bays during the Holocene -- the geological epoch that began 10,000 years ago -- would be noticeable and apparent, even on a year-to-year timescale.
"If you lived at the head of Galveston Bay, near Anahuac (Texas), you could see the bayhead move northward by as much as the length of a football field each year," Anderson said.
Anderson and colleagues, including Antonio Rodriguez of the University of North Carolina at Chappell Hill, compiled their research in a new 146-page monograph published by the GSA, "Response of Upper Gulf Coast Estuaries to Holocene Climate Change and Sea-Level Rise."
Their findings stemmed from an analysis of 30 years of data from hundreds of bayfloor sediment samples, radiocarbon tests and seismic surveys from Galveston, Matagorda and Corpus Christi bays in Texas, Mobile Bay in Alabama, Calcasieu Bay in Louisiana and Sabine Lake on the Texas-Louisiana border.
"There is no question that sea levels are rising in this regio
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