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 ‰ δ 18 O increase and a ∼ 1 ‰ transient δ 13 C rise in the deep ocean, indicating rapid expansion of the East Antarctic Ice Sheet associated with a change in the operation of th...

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Published in:Climate of the Past
Main Authors: M. Raitzsch, J. Bijma, T. Bickert, M. Schulz, A. Holbourn, M. Kučera
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2021
Subjects:
Online Access:https://doi.org/10.5194/cp-17-703-2021
https://doaj.org/article/816f47f548874b949ab92136856194ea
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spelling ftdoajarticles:oai:doaj.org/article:816f47f548874b949ab92136856194ea 2023-05-15T13:57:20+02:00 Atmospheric carbon dioxide variations across the middle Miocene climate transition M. Raitzsch J. Bijma T. Bickert M. Schulz A. Holbourn M. Kučera 2021-03-01T00:00:00Z https://doi.org/10.5194/cp-17-703-2021 https://doaj.org/article/816f47f548874b949ab92136856194ea EN eng Copernicus Publications https://cp.copernicus.org/articles/17/703/2021/cp-17-703-2021.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 doi:10.5194/cp-17-703-2021 1814-9324 1814-9332 https://doaj.org/article/816f47f548874b949ab92136856194ea Climate of the Past, Vol 17, Pp 703-719 (2021) Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 article 2021 ftdoajarticles https://doi.org/10.5194/cp-17-703-2021 2022-12-31T05:47:05Z The middle Miocene climate transition ∼ 14 Ma marks a fundamental step towards the current “ice-house” climate, with a ∼ 1 ‰ δ 18 O increase and a ∼ 1 ‰ transient δ 13 C 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 CO 2 across the carbon-cycle perturbation has been intensely debated as proxy records of p CO 2 for this time interval are sparse and partly contradictory. Using boron isotopes ( δ 11 B) in planktonic foraminifers from Ocean Drilling Program (ODP) Site 1092 in the South Atlantic, we show that long-term p CO 2 varied at 402 kyr periodicity between ∼ 14.3 and 13.2 Ma and follows the global δ 13 C 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 p CO 2 at high eccentricity and vice versa. The ∼ 50 kyr lag of δ 13 C and p CO 2 behind eccentricity in our records may be related to the slow response of weathering to orbital forcing. A p CO 2 drop of ∼ 200 µ atm 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 p CO 2 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 Directory of Open Access Journals: DOAJ Articles Antarctic East Antarctic Ice Sheet Climate of the Past 17 2 703 719
institution Open Polar
collection Directory of Open Access Journals: DOAJ Articles
op_collection_id ftdoajarticles
language English
topic Environmental pollution
TD172-193.5
Environmental protection
TD169-171.8
Environmental sciences
GE1-350
spellingShingle Environmental pollution
TD172-193.5
Environmental protection
TD169-171.8
Environmental sciences
GE1-350
M. Raitzsch
J. Bijma
T. Bickert
M. Schulz
A. Holbourn
M. Kučera
Atmospheric carbon dioxide variations across the middle Miocene climate transition
topic_facet Environmental pollution
TD172-193.5
Environmental protection
TD169-171.8
Environmental sciences
GE1-350
description The middle Miocene climate transition ∼ 14 Ma marks a fundamental step towards the current “ice-house” climate, with a ∼ 1 ‰ δ 18 O increase and a ∼ 1 ‰ transient δ 13 C 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 CO 2 across the carbon-cycle perturbation has been intensely debated as proxy records of p CO 2 for this time interval are sparse and partly contradictory. Using boron isotopes ( δ 11 B) in planktonic foraminifers from Ocean Drilling Program (ODP) Site 1092 in the South Atlantic, we show that long-term p CO 2 varied at 402 kyr periodicity between ∼ 14.3 and 13.2 Ma and follows the global δ 13 C 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 p CO 2 at high eccentricity and vice versa. The ∼ 50 kyr lag of δ 13 C and p CO 2 behind eccentricity in our records may be related to the slow response of weathering to orbital forcing. A p CO 2 drop of ∼ 200 µ atm 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 p CO 2 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://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 https://cp.copernicus.org/articles/17/703/2021/cp-17-703-2021.pdf
https://doaj.org/toc/1814-9324
https://doaj.org/toc/1814-9332
doi:10.5194/cp-17-703-2021
1814-9324
1814-9332
https://doaj.org/article/816f47f548874b949ab92136856194ea
op_doi https://doi.org/10.5194/cp-17-703-2021
container_title Climate of the Past
container_volume 17
container_issue 2
container_start_page 703
op_container_end_page 719
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