Late Cenozoic stable isotope record of benthic and planktonic foraminifera from the Pacific Ocean


Autoria(s): Keigwin, Lloyd D
Cobertura

MEDIAN LATITUDE: 15.367260 * MEDIAN LONGITUDE: -124.647720 * SOUTH-BOUND LATITUDE: -1.761700 * WEST-BOUND LONGITUDE: 176.901500 * NORTH-BOUND LATITUDE: 36.868500 * EAST-BOUND LONGITUDE: -85.236000 * DATE/TIME START: 1971-02-12T00:00:00 * DATE/TIME END: 1973-09-19T00:00:00

Data(s)

19/12/1979

Resumo

Stable isotopic analyses of Middle Miocene to Quaternary foraminiferal calcite from east equatorial and central north Pacific DSDP cores have provided much new informatlon on the paleoceanography of the Pacific Neogene The history of delta18O change in planktonic foraminifera reflects the changing Isotopic composition and temperature of seawater at the time of test formation. Changes in the isotopic composition of benthonic foraminifera largely reflect changes m the volume of continental ice. Isotopic data from these cores indicates the following sequence of events related to continental glaciation (1) A permanent Antarctic ice sheet developed late in the Middle Miocene (about 13 to 11.5 m.y. ago) (2) The Late Miocene (about 11.5 to 5 m.y. ago) is marked by significant variation in delta18O of about 0.5? throughout, indicating instability of Antarctic ice cap size or bottom-water temperatures (3) The early Pliocene (5 to about 3 m.y. ago) was a time of relative stability in ice volume and bottom-water temperature (4) Growth of permanent Northern Hemisphere ice sheets is referred to have begun about 3 m.y. ago (5) The late Pliocene (3 to about 1.8 m.y. ago) is marked by one major glaciation or bottom-water cooling dated between about 2.1 to 2.3 m.y. (6) There is some evidence that the frequency of glacial-interglacial cycles increased at about 0.9 m.y. There is significant variation in delta13C at these sites but no geochemical interpretation is offered in this paper. The most outstanding feature of delta13C results is a permanent shift of about -0.8? found at about 6.5 m.y. in east equatorial and central north Pacific benthonic foraminifera. This benthonic carbon shift may form a useful marker in deep-sea cores recovering Late Miocene carbonates.

Formato

application/zip, 5 datasets

Identificador

https://doi.pangaea.de/10.1594/PANGAEA.710854

doi:10.1594/PANGAEA.710854

Idioma(s)

en

Publicador

PANGAEA

Direitos

CC-BY: Creative Commons Attribution 3.0 Unported

Access constraints: unrestricted

Fonte

Supplement to: Keigwin, Lloyd D (1979): Late Cenozoic stable isotope stratigraphy and paleoceanography of DSDP sites from the east equatorial and central north Pacific Ocean. Earth and Planetary Science Letters, 45(2), 361-382, doi:10.1016/0012-821X(79)90137-7

Palavras-Chave #16-157; 16-158; 32-310; Calculated; conversion of G. subglobosa to Uvigerina sp.; conversion of Oridorsalis sp. to Uvigerina sp.; Deep Sea Drilling Project; Depth; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP; G. sacculifer d13C; G. sacculifer d18O; G. subglobosa d13C; G. subglobosa d18O; Globigerinoides sacculifer, d13C; Globigerinoides sacculifer, d18O; Globocassidulina subglobosa, d13C; Globocassidulina subglobosa, d18O; Glomar Challenger; Label; Leg16; Leg32; Mass spectrometer VG Micromass 602; North Pacific/CONT RISE; North Pacific/RIDGE; O. universa d13C; O. universa d18O; ODP sample designation; Orbulina universa, d13C; Orbulina universa, d18O; Ordiorsalis d18O; Oridorsalis d13C; Oridorsalis sp., d13C; Oridorsalis sp., d18O; Sample code/label; size fraction >175 µm; size fraction 175-295 µm; size fraction 295-717 µm; South Pacific/RIDGE; Uvigerina sp., d13C; Uvigerina sp., d18O; Uvigerina sp. d13C; Uvigerina sp. d18O
Tipo

Dataset