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Early to Middle Eocene Planktonic Foraminifera Biostratigraphy of OPD Site 998 on the Cayman Rise, Caribbean Sea

Abstract

Ocean Drilling Program (ODP) Leg 165 site 998, located on the Cayman Rise, contains a section through the early to middle Eocene transition. This age assignment is based on magnetostratigraphy and preliminary planktonic foraminiferal and calcareous nannofossil biostratigraphy. ODP Site 998's early to middle Eocene planktonic foraminifera are currently being studied to obtain a more precise correlation with the Global Stratotype Section and Point (GSSP) for the Lutetian located at Gorrondaxte Beach, northern Spain. Lithologic unit IV at site 998 is the focus of this investigation was sampled and thin sectioned in cores 28R through 37R. The upper part of the studied interval contains Morozovella aragonensis and Globigerinatheka kugleri and has already been correlated with biozone E9. Subbotina eocaena, Acarinina pentacomerata, and Acarinina praetopilensis have been identified throughout out the study interval. We have also able to extend the range of Astrorotalia palmerae from its known biozone location, E7, up into the lower E9, which can be correlated to the magnetostratigraphic Chron C20R/C21n. By correlating the lower sections of the ODP site 998 with the Lutetian GSSP we can understand the early to middle Eocene transition in the Caribbean region. A more detailed planktonic foraminiferal biostratigraphy will facilitate correlation studies with other early to middle Eocene age sections in the Caribbean such as the Calle G (Avenida de los Presidentes) section in Cuba and the Rio Sambre section in Jamaica.