Pliocene-Pleistocene distribution of benthic foraminifers from ODP Hole 110-672A (Table 2)

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Site 672 is located on the Atlantic abyssal plain to the east of the Lesser Antilles forearc region. It serves as a stratigraphic reference section for sediments entering the Barbados accretionary prism. A relatively complete Pliocene through lower Pleistocene section was recovered from Site 672 that contains a moderately well-preserved population of benthic foraminifers. Q-mode factor analysis of the benthic population data identified three Pliocene-Pleistocene assemblages that inhabited this site. The Factor 1 fauna, characterized by Nuttallides umboniferus, is commonly associated with the presence of Antarctic Bottom Water (AABW). The Factor 2 assemblage is characterized by Globocassidulina subglobosa, Epistominella exigua, and a combined category of unilocular species. The Factor 3 assemblage is characterized by Epistominella exigua, and Planulina wuellerstorfi. The Factor 2 and 3 faunas are associated with bottom water significantly warmer than that preferred by the Factor 1 assemblage. The distribution of these assemblages has been used to distinguish three climatic intervals in the abyssal environment during the Pliocene-Pleistocene. An early Pliocene warm interval occurred from the Ceratolithus rugosus Subzone to the middle of the Discoaster tamalis Subzone. The upper Pliocene is characterized by oscillations between the Factor 1 and Factor 2 assemblages, which suggests climatic deterioration and increased pulses of AABW flow. The persistence of an essentially modern (Factor 1) fauna throughout the early Pleistocene suggests full glacial development at both poles and a substantial volume of AABW production.

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