Sinha, Devesh K. and Singh, Ashutosh Kumar (2008): Late Neogene planktic foraminiferal biochronology of the ODP Site 763A, Exmouth Plateau, southeast Indian Ocean

Leg/Site/Hole:
ODP 122
ODP 122 763
Identifier:
2008-110295
georefid

10.2113/gsjfr.38.3.251
doi

Creator:
Sinha, Devesh K.
Delhi University, Department of Geology, Delhi, India
author

Singh, Ashutosh Kumar
Physical Research Laboratory, India
author

Identification:
Late Neogene planktic foraminiferal biochronology of the ODP Site 763A, Exmouth Plateau, southeast Indian Ocean
2008
Journal of Foraminiferal Research
Cushman Foundation for Foraminiferal Research, Ithaca, NY, United States
38
3
251-270
The late Neogene section of ODP Hole 763A, Exmouth Plateau, southeast Indian Ocean, has been biostratigraphically subdivided into eight planktic foraminiferal zones. The zones are similar to those of the tropical northern Indian and tropical western Pacific Oceans. The sequential order of planktic foraminiferal events has been determined, and 32 late Neogene planktic foraminiferal events have been identified. A major faunal turnover (22 events) occurs between 80 and 45 meters below seafloor (mbsf), spanning 1.6 million years between 3.6 Ma and 2 Ma and may be related to the stresses transmitted to the upper ocean due to major cooling associated with Northern Hemisphere glaciation. Based on integration with magnetostratigraphy, numerical age estimates of planktic foraminiferal events have been determined for the first time from the southeast Indian Ocean. A comparison with the published dates for these events from other parts of the world suggests that 14 events are reliable for correlation over a wide geographic range. The useful synchronous events are the Globorotalia tosaensis FO (2.84 Ma), the Globorotalia tosaensis LO (0.59 Ma), the Globigerinoides extremus LO (1.87 Ma), the Globigerinoides fistulosus FO (3.26 Ma), the Globigerinoides fistulosus LO (1.73 Ma), the Dentoglobigerina altispira LO (3.05 Ma), the Dentoglobigerina globosa LO (3.18), the Neogloboquadrina dutertrei FO (2.77 Ma), the Sphaeroidinellopsis LO (3.35), the Globorotalia margaritae LO (3.38 Ma), the Globorotalia crassaformis FO (4.41 Ma), the Globoturborotalita nepenthes LO (3.44 Ma), the Globorotalia tumida tumida FO (5.10 Ma) and the Pulleniatina primalis FO (5.70 Ma). In contrast, the other events are diachronous and considered unsuitable for inter-oceanic correlation. The Pliocene-Pleistocene boundary is marked at ODP Hole 763A by the LO of Globigerinoides fistulosus, which is a synchronous event over a wide latitudinal range and occurs close to the top of the Olduvai Event (Chron C2n; 1.77 Ma). The Miocene-Pliocene boundary is approximated by the first evolutionary appearance of Globorotalia tumida tumida from its ancestor Globorotalia plesiotumida and occurs close to base of Thvera magnetic event (C3n.4n; 5.23 Ma). Recognition of both of these epoch boundaries is in accord with the International Commission on Stratigraphy. The detailed planktic foraminiferal biochronology developed for Hole 763A will aid correlation and dating of various paleoceanographic events over the last 6 million years in the southeast Indian Ocean.
English
Serial
Coverage:Geographic coordinates:
North:-20.3511
West:112.1231East: 112.1232
South:-20.3512

Stratigraphy; assemblages; biochronology; biostratigraphy; biozones; Cenozoic; East Indian Ocean; Exmouth Plateau; Foraminifera; Indian Ocean; Invertebrata; Leg 122; marine environment; microfossils; Miocene; Neogene; Ocean Drilling Program; ODP Site 763; paleoenvironment; planktonic taxa; Pleistocene; Pliocene; Protista; Quaternary; stratigraphic boundary; Tertiary;

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