Jyoti Bora Pandey

Biostratigraphy and Paleoceanography of Pliocene-pleistocene Radiolaria: - Odp Leg 119 Site 745 Jyoti Bora Pandey

Leg 119 Site 745 lies between 59°35.71'S and 85° 51.60'E at the base of the southern slope of the Southern Kerguelen Plateau in the southern ocean region. The length of the studied core is 99.55 meters which is collected at a water depth of 4082.5 meters. Core is divided into eleven sections 1H-11H having 134 samples, although stratigraphically the hole core is subdivided into subunit IA and IB consisting of radiolaria along with diatoms ooze, minor silt, feldspar; alternations of clay, diatomaceous sediments with minor silt and radiolaria respectively. After examination of 134 samples 77 radiolarian taxa have been identified and illustrated. Four radiolarian zones (Phi (?), Chi (?), Psi (?) and Omega (?) in ascending order) have been established on the basis of upward last appearance, consistent appearance and highest common occurrence of the radiolarian species. Biostratigraphically the total age of the core is ~0-1.85 Ma and Pliocene Pleistocene boundary is also marked at 1.7 Ma. Investigation suggests that the study area lies in mixed zone and contains a diverse radiolarian assemblage i.e. cold water, bipolar cold water and cosmopolitan in nature.