Late Cenozoic oxygen and carbon isotopic changes at DSDP Site 284; implications for glacial history of the Northern Hemisphere and Antarctica

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doi: 10.2973/dsdp.proc.29.120.1975
Author(s): Shackleton, N. J.; Kennett, J. P.
Author Affiliation(s): Primary:
Univ. R.I., Kingston, R.I., United States
Volume Title: Initial Reports of the Deep Sea Drilling Project
Source: Initial Reports of the Deep Sea Drilling Project, Vol.29, p.801-807. Publisher: Texas A & M University, Ocean Drilling Program, College Station, TX, United States. ISSN: 0080-8334 CODEN: IDSDA6
Note: In English. Isotopic studies on Uvigerina; illus. incl. table, sketch map
Summary: Stable isotope analyses of the benthonic foraminiferal genus Uvigerina from 39 samples at Site 284, covering an interval from the Late Miocene to Early Pleistocene (approximately 6 to 1.5 m.y. BP), are interpreted in terms of glacially induced isotopic changes in the ocean. The Antarctic ice sheet was present throughout this interval. During the Late Miocene its dimensions were less constant than they were during the Pliocene; during the New Zealand Kapitean Stage (Latest Miocene; 4.7 to 4.3 m.y. BP) it was probably substantially greater than today, and a lesser advance may have occurred about 3.5 m.y. ago within the Early Pliocene. Prior to the Kapitean Stage the ice sheet may have been smaller than today, and perhaps less stable. About 2.6 m.y. ago a substantial Northern Hemisphere ice sheet accumulated rather rapidly, and related isotopic and foraminiferal changes mark the base of the Waipipian Stage of New Zealand. A more extensive Northern Hemisphere glaciation occurred during the Early Pleistocene (Hautawan Stage), and was of similar extent to the well-documented glaciations of the later Pleistocene. The oxygen isotopic changes coincide with changes in planktonic foraminiferal faunas considered by Kennett and Vella to represent significant Late Cenozoic paleotemperature changes of surface waters. Carbon isotope analyses also document significant changes associated with these events, the cooling in the Kapitean Stage being particularly marked. We propose the term "Pre-glacial Pliocene" to distinguish that part of the Pliocene prior to about 2.6 m.y. BP, when extensive Northern Hemisphere glaciations had not developed, from the Late Pliocene after development of these ice sheets.
Year of Publication: 1975
Research Program: DSDP Deep Sea Drilling Project
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Antarctica; Biostratigraphy; Buliminacea; C-13/C-12; Carbon; Cenozoic; Changes; DSDP Site 284; Deep Sea Drilling Project; Foraminifera; Glaciation; Indicators; Invertebrata; Isotopes; Leg 29; Marine geology; Microfossils; Miocene; Neogene; Northern Hemisphere; O-18/O-16; Oxygen; Pacific Ocean; Paleoclimatology; Paleoecology; Pliocene; Protista; Quaternary; Ratios; Rotaliina; South Pacific; Southwest; Southwest Pacific; Stable isotopes; Stratigraphy; Tasman Sea; Temperature; Tertiary; Uvigerina; Uvigerinidae; West Pacific
Coordinates: S403029 S403029 E1674049 E1674049
Record ID: 1976016973
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data supplied by Institute of Geological and Nuclear Sciences Limited (GNS Science), Lower Hutt, New Zealand