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摘要
Nine back barrier marshes from Onslow Bay, North Carolina, were cored to a 3-m depth in search of paleohurricane deposits. Only two marshes, Alligator Bay and Tar Landing Bay, contained sand layers enriched with displaced marine foraminifers indicative of storm deposition. Ten discrete storm layers, representing four storms, were recovered at Tar Landing Bay, and 16 storm deposits, representing five storms, were recovered at Alligator Bay. Radiocarbon analysis indicates these storm layers were all deposited during the last 1500 years. Foraminiferal assemblages from the sediments directly below the coarser-grained storm layers indicate that the paleostorms were depositing marine and beach/dune sediment into a variety of marsh subenvironments and that preservation was not necessarily greater in the high marsh (lower bioturbation) subenvironment. Onslow Bay has sustained more than 10 hurricane strikes in the last 200 years. The scarcity of storm deposits detected in the strata from these nine marshes (representing approximately 1500 years of deposition) suggests that sand layers enriched with displaced marine foraminifers may significantly underestimate the frequency of storms in the region and may be limited as a paleotempest proxy. The preserved storm layers probably represent only the largest, most robust storm deposits from intense hurricanes.
- 出版日期2014-11
