Estimating seawater temperature variations in the Waccamaw (Pleistocene) and Duplin Formations (Pliocene), NC using macrofossil assemblages (2016)

Undergraduate: Eric Eubanks

Faculty Advisor: Joel Hudley
Department: Geology

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Existing studies of Pliocene micro- and macrofossil assemblages along the eastern North American coast (Pinecrest, Duplin, and Yorktown Formations) suggest that during the Mid-Pliocene Warm Period (3.29-2.97 Ma) a more vigorous Florida Current, relative to today, facilitated a northward extension of subtropical fauna past the modern faunal boundary of Cape Hatteras, North Carolina 2 (Ward et al., 1991; Williams et al., 2009). By the Pleistocene (2.1 ¿¿¿ 0.2 Ma), cooling, relative to the Pliocene, and an Atlantic-wide macrofaunal decimation (loss of biodiversity) occurred. The cause of the decimation is linked to significant changes in seawater variables (temperature, salinity, etc). Evidence supporting this interpretation also includes isotope and growth records from marine bivalves that estimate annual temperature range (Krantz, 1990; Jones and Allmon, 1995; Goewert and Surge, 2007). Associations were explored between western Atlantic shelf water patterns by comparing the combined temperature ranges of the common assemblages in the Plio-Pliestocene and the Recent Atlantic shelf using statistical dissimilarity procedures. Such procedures, along with Modern Analog Technique (MAT) were utilized and exhibited unique trends in macrofossil assemblages which suggested that temperature variations were a contributing factor in the decimation of biodiversity.