_version_ 1867169944315101184
author Vincent, Edith
Killingley, John S
Berger, Wolfgang H
author_facet Vincent, Edith
Killingley, John S
Berger, Wolfgang H
collection Datos científicos de ciencias marinas y ambientales
contents Tropical Indian Ocean planktonic and benthic foraminifera have 13C/12C ratios which change abruptly within Magnetic Epoch 6 about 6.2 million years ago. All species analyzed in the Late Miocene section of DSDP Site 238 show a shift towards lighter values of delta13C by about 0.8‰. The oxygen isotope signal indicates that the pre-shift period is climatically quiet while the post-shift period has strong fluctuations. We suggest that the shift reflects a sudden increase in the rate of supply of organic carbon from coastal lowlands and from shelves exposed by regression, as well as a change in deep circulation patterns and ocean fertility. The event marks the transition of the ocean-atmosphere system from a quiet Early and Middle Neogene climatic regime toward a Late Neogene regime characterized by climatic amplifying mechanisms (albedo feedback, bottom water production) located around the northern North Atlantic. The beginning of this regime may have been strongly influenced by the isolation of the Mediterranean basin.
format Dataset Open Access
id pangaea_https___doi_org_10_1594_PANGAEA_682289
institution PANGAEA
language en
publishDate 1980
publisher PANGAEA
record_format pangaea
spellingShingle Stable isotope ratios of benthic and planktonic foraminifera from Late Miocene sediments of DSDP Hole 24-238 on the Central Indian Ocean Ridge (Appendix 1)
Vincent, Edith
Killingley, John S
Berger, Wolfgang H
24-238; Cassidulina subglobosa, δ13C; Cassidulina subglobosa, δ18O; Deep Sea Drilling Project; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Favocassidulina favus, δ13C; Favocassidulina favus, δ18O; Globigerinoides sacculifer, δ13C; Globigerinoides sacculifer, δ18O; Globoquadrina altispira, δ13C; Globoquadrina altispira, δ18O; Globoquadrina venezuelana, δ13C; Globoquadrina venezuelana, δ18O; Glomar Challenger; Indian Ocean//FRACTURE ZONE; Leg24; Oridorsalis umbonatus, δ13C; Oridorsalis umbonatus, δ18O; Planulina wuellerstorfi, δ13C; Planulina wuellerstorfi, δ18O; Sample code/label; Uvigerina spp., δ13C; Uvigerina spp., δ18O
Tropical Indian Ocean planktonic and benthic foraminifera have 13C/12C ratios which change abruptly within Magnetic Epoch 6 about 6.2 million years ago. All species analyzed in the Late Miocene section of DSDP Site 238 show a shift towards lighter values of delta13C by about 0.8‰. The oxygen isotope signal indicates that the pre-shift period is climatically quiet while the post-shift period has strong fluctuations. We suggest that the shift reflects a sudden increase in the rate of supply of organic carbon from coastal lowlands and from shelves exposed by regression, as well as a change in deep circulation patterns and ocean fertility. The event marks the transition of the ocean-atmosphere system from a quiet Early and Middle Neogene climatic regime toward a Late Neogene regime characterized by climatic amplifying mechanisms (albedo feedback, bottom water production) located around the northern North Atlantic. The beginning of this regime may have been strongly influenced by the isolation of the Mediterranean basin.
title Stable isotope ratios of benthic and planktonic foraminifera from Late Miocene sediments of DSDP Hole 24-238 on the Central Indian Ocean Ridge (Appendix 1)
topic 24-238; Cassidulina subglobosa, δ13C; Cassidulina subglobosa, δ18O; Deep Sea Drilling Project; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Favocassidulina favus, δ13C; Favocassidulina favus, δ18O; Globigerinoides sacculifer, δ13C; Globigerinoides sacculifer, δ18O; Globoquadrina altispira, δ13C; Globoquadrina altispira, δ18O; Globoquadrina venezuelana, δ13C; Globoquadrina venezuelana, δ18O; Glomar Challenger; Indian Ocean//FRACTURE ZONE; Leg24; Oridorsalis umbonatus, δ13C; Oridorsalis umbonatus, δ18O; Planulina wuellerstorfi, δ13C; Planulina wuellerstorfi, δ18O; Sample code/label; Uvigerina spp., δ13C; Uvigerina spp., δ18O
url https://doi.org/10.1594/PANGAEA.682289