Paleoenvironmental Significance of Late Cretaceous Foraminifers from ODP Site 1138 Samples, a Dredge and Eltanin Core E54-7, Kerguelen Plateau, Indian Ocean

Abstract

Late Campanian and Maastrichtian benthic foraminifers are recorded from 12 samples from Ocean Drilling Program (ODP) Leg 183, Cores 183-1138A-52R through 63R (487.3-602.4 meters below seafloor), Kerguelen Plateau, Indian Ocean, and Danian benthics from one sample in the same section. The entire late Maastrichtian foraminifer fauna is noted from a dredge sample 220 km to the north. The structure of the fauna is compared with the Cenomanian-Turonian of the nearby Eltanin core E54-7. Faunas are reviewed in terms of planktonic percentage, composition, epifaunal/infaunal ratios, and dominance/diversity indices. The region was in the cool Austral Faunal Province through the Campanian-Maastrichtian and was probably warmer in the Cenomanian-Turonian. The ODP section is now 1600 meters below sea level and has subsided several hundred meters since deposition. Its fauna is dominated by epifaunal species suggesting little influence of upwelling. The dredge location has subsided little. Its fauna has a high infaunal content consistent with significant influence of upwelling near the plateau edge. The dominant benthic species remain constant through the ODP Cretaceous section, but subdominance changes, and the section is divided into three informal zones based on dominance/subdominance characteristics of the benthic fauna.

Paleobiogeografía y paleogeografía del Maastrichtiense Marino de la Patagonia, Tierra del Fuego y la plataforma continental Argentina, según sus foraminíferos bentónicos

“…Es relativamente abundante en el Santoniense-Campaniense inferior de Kerguelen y también se reconoce en el Maastrichtiense inferior (Quilty, 1992). En el sitio 1138, se distribuye hasta el Campaniense superior (Quilty, 2002). Pero Kaiho (1998) le asigna un biocrón Coniaciense-Campaniense (88-72Ma) basado en la distribución reconocida en el sitio DSDP 258, y considera que se origina de Notoplanulina primitiva Kahio, 1998, del Turoniense.…”