Middle to late Miocene oxygen isotope stratigraphy of ODP site 1085 (SE Atlantic): new constrains on Miocene climate variability and sea-level fluctuations
The middle Miocene delta18O increase represents a fundamental change in earth's climate system due to a major expansion and permanent establishment of the East Antarctic Ice Sheet accompanied by some effect of deepwater cooling. The long-term cooling trend in the middle to late Miocene was supe...
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ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.694041 2023-05-15T13:42:09+02:00 Middle to late Miocene oxygen isotope stratigraphy of ODP site 1085 (SE Atlantic): new constrains on Miocene climate variability and sea-level fluctuations Westerhold, Thomas Bickert, Torsten Röhl, Ursula MEDIAN LATITUDE: -29.971784 * MEDIAN LONGITUDE: 14.367473 * SOUTH-BOUND LATITUDE: -31.465220 * WEST-BOUND LONGITUDE: 13.990110 * NORTH-BOUND LATITUDE: -29.374410 * EAST-BOUND LONGITUDE: 15.310880 * DATE/TIME START: 1997-09-26T00:15:00 * DATE/TIME END: 1997-10-06T07:05:00 2005-05-28 application/zip, 7 datasets https://doi.pangaea.de/10.1594/PANGAEA.694041 https://doi.org/10.1594/PANGAEA.694041 en eng PANGAEA https://doi.pangaea.de/10.1594/PANGAEA.694041 https://doi.org/10.1594/PANGAEA.694041 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess CC-BY Supplement to: Westerhold, Thomas; Bickert, Torsten; Röhl, Ursula (2005): Middle to late Miocene oxygen isotope stratigraphy of ODP site 1085 (SE Atlantic): new constrains on Miocene climate variability and sea-level fluctuations. Palaeogeography, Palaeoclimatology, Palaeoecology, 217(3-4), 205-222, https://doi.org/10.1016/j.palaeo.2004.12.001 175-1085A 175-1087C Benguela Current South Atlantic Ocean DRILL Drilling/drill rig Joides Resolution Leg175 Ocean Drilling Program ODP Dataset 2005 ftpangaea https://doi.org/10.1594/PANGAEA.694041 https://doi.org/10.1016/j.palaeo.2004.12.001 2023-01-20T07:31:11Z The middle Miocene delta18O increase represents a fundamental change in earth's climate system due to a major expansion and permanent establishment of the East Antarctic Ice Sheet accompanied by some effect of deepwater cooling. The long-term cooling trend in the middle to late Miocene was superimposed by several punctuated periods of glaciations (Mi-Events) characterized by oxygen isotopic shifts that have been related to the waxing and waning of the Antarctic ice-sheet and bottom water cooling. Here, we present a high-resolution benthic stable oxygen isotope record from ODP Site 1085 located at the southwestern African continental margin that provides a detailed chronology for the middle to late Miocene (13.9-7.3 Ma) climate transition in the eastern South Atlantic. A composite Fe intensity record obtained by XRF core scanning ODP Sites 1085 and 1087 was used to construct an astronomically calibrated chronology based on orbital tuning. The oxygen isotope data exhibit four distinct delta18O excursions, which have astronomical ages of 13.8, 13.2, 11.7, and 10.4 Ma and correspond to the Mi3, Mi4, Mi5, and Mi6 events. A global climate record was extracted from the oxygen isotopic composition. Both long- and short-term variabilities in the climate record are discussed in terms of sea-level and deep-water temperature changes. The oxygen isotope data support a causal link between sequence boundaries traced from the shelf and glacioeustatic changes due to ice-sheet growth. Spectral analysis of the benthic delta18O record shows strong power in the 400-kyr and 100-kyr bands documenting a paleoceanographic response to eccentricity-modulated variations in precession. A spectral peak around 180-kyr might be related to the asymmetry of the obliquity cycle indicating that the response of the dominantly unipolar Antarctic ice-sheet to obliquityinduced variations probably controlled the middle to late Miocene climate system. Maxima in the delta18O record, interpreted as glacial periods, correspond to minima in 100-kyr ... Dataset Antarc* Antarctic Ice Sheet South Atlantic Ocean PANGAEA - Data Publisher for Earth & Environmental Science Antarctic East Antarctic Ice Sheet The Antarctic ENVELOPE(13.990110,15.310880,-29.374410,-31.465220) |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
175-1085A 175-1087C Benguela Current South Atlantic Ocean DRILL Drilling/drill rig Joides Resolution Leg175 Ocean Drilling Program ODP |
spellingShingle |
175-1085A 175-1087C Benguela Current South Atlantic Ocean DRILL Drilling/drill rig Joides Resolution Leg175 Ocean Drilling Program ODP Westerhold, Thomas Bickert, Torsten Röhl, Ursula Middle to late Miocene oxygen isotope stratigraphy of ODP site 1085 (SE Atlantic): new constrains on Miocene climate variability and sea-level fluctuations |
topic_facet |
175-1085A 175-1087C Benguela Current South Atlantic Ocean DRILL Drilling/drill rig Joides Resolution Leg175 Ocean Drilling Program ODP |
description |
The middle Miocene delta18O increase represents a fundamental change in earth's climate system due to a major expansion and permanent establishment of the East Antarctic Ice Sheet accompanied by some effect of deepwater cooling. The long-term cooling trend in the middle to late Miocene was superimposed by several punctuated periods of glaciations (Mi-Events) characterized by oxygen isotopic shifts that have been related to the waxing and waning of the Antarctic ice-sheet and bottom water cooling. Here, we present a high-resolution benthic stable oxygen isotope record from ODP Site 1085 located at the southwestern African continental margin that provides a detailed chronology for the middle to late Miocene (13.9-7.3 Ma) climate transition in the eastern South Atlantic. A composite Fe intensity record obtained by XRF core scanning ODP Sites 1085 and 1087 was used to construct an astronomically calibrated chronology based on orbital tuning. The oxygen isotope data exhibit four distinct delta18O excursions, which have astronomical ages of 13.8, 13.2, 11.7, and 10.4 Ma and correspond to the Mi3, Mi4, Mi5, and Mi6 events. A global climate record was extracted from the oxygen isotopic composition. Both long- and short-term variabilities in the climate record are discussed in terms of sea-level and deep-water temperature changes. The oxygen isotope data support a causal link between sequence boundaries traced from the shelf and glacioeustatic changes due to ice-sheet growth. Spectral analysis of the benthic delta18O record shows strong power in the 400-kyr and 100-kyr bands documenting a paleoceanographic response to eccentricity-modulated variations in precession. A spectral peak around 180-kyr might be related to the asymmetry of the obliquity cycle indicating that the response of the dominantly unipolar Antarctic ice-sheet to obliquityinduced variations probably controlled the middle to late Miocene climate system. Maxima in the delta18O record, interpreted as glacial periods, correspond to minima in 100-kyr ... |
format |
Dataset |
author |
Westerhold, Thomas Bickert, Torsten Röhl, Ursula |
author_facet |
Westerhold, Thomas Bickert, Torsten Röhl, Ursula |
author_sort |
Westerhold, Thomas |
title |
Middle to late Miocene oxygen isotope stratigraphy of ODP site 1085 (SE Atlantic): new constrains on Miocene climate variability and sea-level fluctuations |
title_short |
Middle to late Miocene oxygen isotope stratigraphy of ODP site 1085 (SE Atlantic): new constrains on Miocene climate variability and sea-level fluctuations |
title_full |
Middle to late Miocene oxygen isotope stratigraphy of ODP site 1085 (SE Atlantic): new constrains on Miocene climate variability and sea-level fluctuations |
title_fullStr |
Middle to late Miocene oxygen isotope stratigraphy of ODP site 1085 (SE Atlantic): new constrains on Miocene climate variability and sea-level fluctuations |
title_full_unstemmed |
Middle to late Miocene oxygen isotope stratigraphy of ODP site 1085 (SE Atlantic): new constrains on Miocene climate variability and sea-level fluctuations |
title_sort |
middle to late miocene oxygen isotope stratigraphy of odp site 1085 (se atlantic): new constrains on miocene climate variability and sea-level fluctuations |
publisher |
PANGAEA |
publishDate |
2005 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.694041 https://doi.org/10.1594/PANGAEA.694041 |
op_coverage |
MEDIAN LATITUDE: -29.971784 * MEDIAN LONGITUDE: 14.367473 * SOUTH-BOUND LATITUDE: -31.465220 * WEST-BOUND LONGITUDE: 13.990110 * NORTH-BOUND LATITUDE: -29.374410 * EAST-BOUND LONGITUDE: 15.310880 * DATE/TIME START: 1997-09-26T00:15:00 * DATE/TIME END: 1997-10-06T07:05:00 |
long_lat |
ENVELOPE(13.990110,15.310880,-29.374410,-31.465220) |
geographic |
Antarctic East Antarctic Ice Sheet The Antarctic |
geographic_facet |
Antarctic East Antarctic Ice Sheet The Antarctic |
genre |
Antarc* Antarctic Ice Sheet South Atlantic Ocean |
genre_facet |
Antarc* Antarctic Ice Sheet South Atlantic Ocean |
op_source |
Supplement to: Westerhold, Thomas; Bickert, Torsten; Röhl, Ursula (2005): Middle to late Miocene oxygen isotope stratigraphy of ODP site 1085 (SE Atlantic): new constrains on Miocene climate variability and sea-level fluctuations. Palaeogeography, Palaeoclimatology, Palaeoecology, 217(3-4), 205-222, https://doi.org/10.1016/j.palaeo.2004.12.001 |
op_relation |
https://doi.pangaea.de/10.1594/PANGAEA.694041 https://doi.org/10.1594/PANGAEA.694041 |
op_rights |
CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1594/PANGAEA.694041 https://doi.org/10.1016/j.palaeo.2004.12.001 |
_version_ |
1766163339195449344 |