Carbon cycle feedbacks during the Oligocene-Miocene transient glaciation
Ice sheet models suggest that once formed, the large, high- altitude East Antarctic Ice Sheet was relatively self-stabilizing, due to its cold upper surface. The ice sheet hysteresis problem results from an inability to reconcile this expectation with geological evidence for episodes of ice sheet re...
Published in: | Geology |
---|---|
Main Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Geological Society of America
2013
|
Subjects: | |
Online Access: | https://orca.cardiff.ac.uk/id/eprint/48744/ https://doi.org/10.1130/G34422.1 https://orca.cardiff.ac.uk/id/eprint/48744/1/Mawbey_LearGeology.pdf |
id |
ftunivcardiff:oai:https://orca.cardiff.ac.uk:48744 |
---|---|
record_format |
openpolar |
spelling |
ftunivcardiff:oai:https://orca.cardiff.ac.uk:48744 2023-05-15T13:38:47+02:00 Carbon cycle feedbacks during the Oligocene-Miocene transient glaciation Mawbey, Elaine M. Lear, Caroline Helen 2013 application/pdf https://orca.cardiff.ac.uk/id/eprint/48744/ https://doi.org/10.1130/G34422.1 https://orca.cardiff.ac.uk/id/eprint/48744/1/Mawbey_LearGeology.pdf en eng Geological Society of America https://orca.cardiff.ac.uk/id/eprint/48744/1/Mawbey_LearGeology.pdf Mawbey, Elaine M. https://orca.cardiff.ac.uk/view/cardiffauthors/A127259H.html and Lear, Caroline Helen https://orca.cardiff.ac.uk/view/cardiffauthors/A048848V.html orcid:0000-0002-7533-4430 orcid:0000-0002-7533-4430 2013. Carbon cycle feedbacks during the Oligocene-Miocene transient glaciation. Geology 41 (9) , pp. 963-966. 10.1130/G34422.1 https://doi.org/10.1130/G34422.1 file https://orca.cardiff.ac.uk/48744/1/Mawbey_LearGeology.pdf doi:10.1130/G34422.1 cc_by CC-BY QE Geology Article PeerReviewed 2013 ftunivcardiff https://doi.org/10.1130/G34422.1 2022-10-27T22:36:16Z Ice sheet models suggest that once formed, the large, high- altitude East Antarctic Ice Sheet was relatively self-stabilizing, due to its cold upper surface. The ice sheet hysteresis problem results from an inability to reconcile this expectation with geological evidence for episodes of ice sheet retreat. A classic example of this problem is manifested in benthic foraminiferal oxygen isotope records across the Oligocene-Miocene boundary (ca. 23 Ma), which display a transient ~1‰ excursion to higher values. The inferred increase and subsequent decrease in ice volume has been linked to advance and retreat of the Antarctic ice sheet across the continental shelf. However, oxygen isotope records alone do not provide unambiguous records of temperature and ice volume, hindering assessment of the driving mechanism for these variations. Here we present new benthic foraminiferal Mg/Ca, Li/Ca, and U/Ca records across the Oligocene- Miocene boundary from Ocean Drilling Program Sites 926 and 929. Our records demonstrate that Atlantic bottom-water temperatures varied cyclically, with the main cooling and warming steps followed by ice growth and decay respectively. We suggest that enhanced organic carbon burial acted as a positive feedback as climate cooled. Several lines of evidence suggest that the deglaciation was associated with an input of carbon to the ocean-atmosphere system, culminating in a previously unidentified seafloor dissolution event. We suggest that one of the initial sources of carbon was organic matter oxidation in ocean sediments. This study demonstrates that carbon cycle feedbacks should be considered when evaluating the stability of ancient ice sheets. Article in Journal/Newspaper Antarc* Antarctic Ice Sheet Cardiff University: ORCA (Online Research @ Cardiff) Antarctic East Antarctic Ice Sheet The Antarctic Geology 41 9 963 966 |
institution |
Open Polar |
collection |
Cardiff University: ORCA (Online Research @ Cardiff) |
op_collection_id |
ftunivcardiff |
language |
English |
topic |
QE Geology |
spellingShingle |
QE Geology Mawbey, Elaine M. Lear, Caroline Helen Carbon cycle feedbacks during the Oligocene-Miocene transient glaciation |
topic_facet |
QE Geology |
description |
Ice sheet models suggest that once formed, the large, high- altitude East Antarctic Ice Sheet was relatively self-stabilizing, due to its cold upper surface. The ice sheet hysteresis problem results from an inability to reconcile this expectation with geological evidence for episodes of ice sheet retreat. A classic example of this problem is manifested in benthic foraminiferal oxygen isotope records across the Oligocene-Miocene boundary (ca. 23 Ma), which display a transient ~1‰ excursion to higher values. The inferred increase and subsequent decrease in ice volume has been linked to advance and retreat of the Antarctic ice sheet across the continental shelf. However, oxygen isotope records alone do not provide unambiguous records of temperature and ice volume, hindering assessment of the driving mechanism for these variations. Here we present new benthic foraminiferal Mg/Ca, Li/Ca, and U/Ca records across the Oligocene- Miocene boundary from Ocean Drilling Program Sites 926 and 929. Our records demonstrate that Atlantic bottom-water temperatures varied cyclically, with the main cooling and warming steps followed by ice growth and decay respectively. We suggest that enhanced organic carbon burial acted as a positive feedback as climate cooled. Several lines of evidence suggest that the deglaciation was associated with an input of carbon to the ocean-atmosphere system, culminating in a previously unidentified seafloor dissolution event. We suggest that one of the initial sources of carbon was organic matter oxidation in ocean sediments. This study demonstrates that carbon cycle feedbacks should be considered when evaluating the stability of ancient ice sheets. |
format |
Article in Journal/Newspaper |
author |
Mawbey, Elaine M. Lear, Caroline Helen |
author_facet |
Mawbey, Elaine M. Lear, Caroline Helen |
author_sort |
Mawbey, Elaine M. |
title |
Carbon cycle feedbacks during the Oligocene-Miocene transient glaciation |
title_short |
Carbon cycle feedbacks during the Oligocene-Miocene transient glaciation |
title_full |
Carbon cycle feedbacks during the Oligocene-Miocene transient glaciation |
title_fullStr |
Carbon cycle feedbacks during the Oligocene-Miocene transient glaciation |
title_full_unstemmed |
Carbon cycle feedbacks during the Oligocene-Miocene transient glaciation |
title_sort |
carbon cycle feedbacks during the oligocene-miocene transient glaciation |
publisher |
Geological Society of America |
publishDate |
2013 |
url |
https://orca.cardiff.ac.uk/id/eprint/48744/ https://doi.org/10.1130/G34422.1 https://orca.cardiff.ac.uk/id/eprint/48744/1/Mawbey_LearGeology.pdf |
geographic |
Antarctic East Antarctic Ice Sheet The Antarctic |
geographic_facet |
Antarctic East Antarctic Ice Sheet The Antarctic |
genre |
Antarc* Antarctic Ice Sheet |
genre_facet |
Antarc* Antarctic Ice Sheet |
op_relation |
https://orca.cardiff.ac.uk/id/eprint/48744/1/Mawbey_LearGeology.pdf Mawbey, Elaine M. https://orca.cardiff.ac.uk/view/cardiffauthors/A127259H.html and Lear, Caroline Helen https://orca.cardiff.ac.uk/view/cardiffauthors/A048848V.html orcid:0000-0002-7533-4430 orcid:0000-0002-7533-4430 2013. Carbon cycle feedbacks during the Oligocene-Miocene transient glaciation. Geology 41 (9) , pp. 963-966. 10.1130/G34422.1 https://doi.org/10.1130/G34422.1 file https://orca.cardiff.ac.uk/48744/1/Mawbey_LearGeology.pdf doi:10.1130/G34422.1 |
op_rights |
cc_by |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1130/G34422.1 |
container_title |
Geology |
container_volume |
41 |
container_issue |
9 |
container_start_page |
963 |
op_container_end_page |
966 |
_version_ |
1766111070423875584 |