Atmospheric carbon dioxide variations across the middle Miocene climate transition
The middle Miocene climate transition ∼ 14 Ma marks a fundamental step towards the current “ice-house” climate, with a ∼ 1 ‰ δ18O increase and a ∼ 1 ‰ transient δ13C rise in the deep ocean, indicating rapid expansion of the East Antarctic Ice Sheet associated with a change in the operation of the gl...
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fttriple:oai:gotriple.eu:oai:doaj.org/article:816f47f548874b949ab92136856194ea 2023-05-15T14:03:46+02:00 Atmospheric carbon dioxide variations across the middle Miocene climate transition M. Raitzsch J. Bijma T. Bickert M. Schulz A. Holbourn M. Kučera 2021-03-01 https://doi.org/10.5194/cp-17-703-2021 https://cp.copernicus.org/articles/17/703/2021/cp-17-703-2021.pdf https://doaj.org/article/816f47f548874b949ab92136856194ea en eng Copernicus Publications doi:10.5194/cp-17-703-2021 1814-9324 1814-9332 https://cp.copernicus.org/articles/17/703/2021/cp-17-703-2021.pdf https://doaj.org/article/816f47f548874b949ab92136856194ea undefined Climate of the Past, Vol 17, Pp 703-719 (2021) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2021 fttriple https://doi.org/10.5194/cp-17-703-2021 2023-01-22T19:30:49Z The middle Miocene climate transition ∼ 14 Ma marks a fundamental step towards the current “ice-house” climate, with a ∼ 1 ‰ δ18O increase and a ∼ 1 ‰ transient δ13C rise in the deep ocean, indicating rapid expansion of the East Antarctic Ice Sheet associated with a change in the operation of the global carbon cycle. The variation of atmospheric CO2 across the carbon-cycle perturbation has been intensely debated as proxy records of pCO2 for this time interval are sparse and partly contradictory. Using boron isotopes (δ11B) in planktonic foraminifers from Ocean Drilling Program (ODP) Site 1092 in the South Atlantic, we show that long-term pCO2 varied at 402 kyr periodicity between ∼ 14.3 and 13.2 Ma and follows the global δ13C variation remarkably well. This suggests a close link to precessional insolation forcing modulated by eccentricity, which governs the monsoon and hence weathering intensity, with enhanced weathering and decreasing pCO2 at high eccentricity and vice versa. The ∼ 50 kyr lag of δ13C and pCO2 behind eccentricity in our records may be related to the slow response of weathering to orbital forcing. A pCO2 drop of ∼ 200 µatm before 13.9 Ma may have facilitated the inception of ice-sheet expansion on Antarctica, which accentuated monsoon-driven carbon cycle changes through a major sea-level fall, invigorated deep-water ventilation, and shelf-to-basin shift of carbonate burial. The temporary rise in pCO2 following Antarctic glaciation would have acted as a negative feedback on the progressing glaciation and helped to stabilize the climate system on its way to the late Cenozoic ice-house world. Article in Journal/Newspaper Antarc* Antarctic Antarctica Ice Sheet Unknown Antarctic East Antarctic Ice Sheet Climate of the Past 17 2 703 719 |
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geo envir M. Raitzsch J. Bijma T. Bickert M. Schulz A. Holbourn M. Kučera Atmospheric carbon dioxide variations across the middle Miocene climate transition |
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geo envir |
description |
The middle Miocene climate transition ∼ 14 Ma marks a fundamental step towards the current “ice-house” climate, with a ∼ 1 ‰ δ18O increase and a ∼ 1 ‰ transient δ13C rise in the deep ocean, indicating rapid expansion of the East Antarctic Ice Sheet associated with a change in the operation of the global carbon cycle. The variation of atmospheric CO2 across the carbon-cycle perturbation has been intensely debated as proxy records of pCO2 for this time interval are sparse and partly contradictory. Using boron isotopes (δ11B) in planktonic foraminifers from Ocean Drilling Program (ODP) Site 1092 in the South Atlantic, we show that long-term pCO2 varied at 402 kyr periodicity between ∼ 14.3 and 13.2 Ma and follows the global δ13C variation remarkably well. This suggests a close link to precessional insolation forcing modulated by eccentricity, which governs the monsoon and hence weathering intensity, with enhanced weathering and decreasing pCO2 at high eccentricity and vice versa. The ∼ 50 kyr lag of δ13C and pCO2 behind eccentricity in our records may be related to the slow response of weathering to orbital forcing. A pCO2 drop of ∼ 200 µatm before 13.9 Ma may have facilitated the inception of ice-sheet expansion on Antarctica, which accentuated monsoon-driven carbon cycle changes through a major sea-level fall, invigorated deep-water ventilation, and shelf-to-basin shift of carbonate burial. The temporary rise in pCO2 following Antarctic glaciation would have acted as a negative feedback on the progressing glaciation and helped to stabilize the climate system on its way to the late Cenozoic ice-house world. |
format |
Article in Journal/Newspaper |
author |
M. Raitzsch J. Bijma T. Bickert M. Schulz A. Holbourn M. Kučera |
author_facet |
M. Raitzsch J. Bijma T. Bickert M. Schulz A. Holbourn M. Kučera |
author_sort |
M. Raitzsch |
title |
Atmospheric carbon dioxide variations across the middle Miocene climate transition |
title_short |
Atmospheric carbon dioxide variations across the middle Miocene climate transition |
title_full |
Atmospheric carbon dioxide variations across the middle Miocene climate transition |
title_fullStr |
Atmospheric carbon dioxide variations across the middle Miocene climate transition |
title_full_unstemmed |
Atmospheric carbon dioxide variations across the middle Miocene climate transition |
title_sort |
atmospheric carbon dioxide variations across the middle miocene climate transition |
publisher |
Copernicus Publications |
publishDate |
2021 |
url |
https://doi.org/10.5194/cp-17-703-2021 https://cp.copernicus.org/articles/17/703/2021/cp-17-703-2021.pdf https://doaj.org/article/816f47f548874b949ab92136856194ea |
geographic |
Antarctic East Antarctic Ice Sheet |
geographic_facet |
Antarctic East Antarctic Ice Sheet |
genre |
Antarc* Antarctic Antarctica Ice Sheet |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet |
op_source |
Climate of the Past, Vol 17, Pp 703-719 (2021) |
op_relation |
doi:10.5194/cp-17-703-2021 1814-9324 1814-9332 https://cp.copernicus.org/articles/17/703/2021/cp-17-703-2021.pdf https://doaj.org/article/816f47f548874b949ab92136856194ea |
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https://doi.org/10.5194/cp-17-703-2021 |
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Climate of the Past |
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17 |
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2 |
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703 |
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719 |
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