Constraining Circulation Changes Through the Last Deglaciation with Deep-sea Coral Radiocarbon and Sedimentary Pa231/Th230
Radioactive isotopes can be used in paleoceanography both for dating samples and as tracers of ocean processes. Here I use radiocarbon and uranium series isotopes to investigate the ocean's role in climate change over the last deglaciation. I present a new method for rapid radiocarbon analyses...
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ftdtic:ADA550599 2023-05-15T13:41:11+02:00 Constraining Circulation Changes Through the Last Deglaciation with Deep-sea Coral Radiocarbon and Sedimentary Pa231/Th230 Burke, Andrea WOODS HOLE OCEANOGRAPHIC INSTITUTION MA 2012-02 text/html http://www.dtic.mil/docs/citations/ADA550599 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA550599 en eng http://www.dtic.mil/docs/citations/ADA550599 Approved for public release; distribution is unlimited. DTIC Isotopes *CORAL *ISOTOPES *RADIOCARBON DATING ANTARCTIC REGIONS ATMOSPHERES CARBON CLIMATE COMPUTATIONS CONSISTENCY CYCLES DEEP OCEANS GAS EXCHANGE(BIOLOGY) GLACIERS ICELAND INVERSION LOW TEMPERATURE MASS MODELS NORTH ATLANTIC OCEAN OCEANOGRAPHY OCEANS RADIOACTIVE ISOTOPES RATES RATIOS SAMPLING STRATIFICATION SURVEYS URANIUM Text 2012 ftdtic 2016-02-23T09:25:17Z Radioactive isotopes can be used in paleoceanography both for dating samples and as tracers of ocean processes. Here I use radiocarbon and uranium series isotopes to investigate the ocean's role in climate change over the last deglaciation. I present a new method for rapid radiocarbon analyses as a means of age-screening deep-sea corals for further study. Based on age survey results, I selected forty corals from the Drake Passage and thirteen from the Reykjanes Ridge off Iceland and dated them with uranium series isotopes. The uranium series dates give independent ages that allow radiocarbon to be used as a tracer of circulation and carbon cycle changes. The radiocarbon records generated from the Drake Passage corals show increased stratification in the Southern Ocean during the last glacial maximum (LGM) that disappeared during the start of the deglaciation as atmospheric CO2 began to rise during Heinrich Stadial 1 (H1). Considering these data and using a simple mass budget calculation, I show that the drop in atmospheric radiocarbon activity during H1 can be explained given direct carbon exchange between the radiocarbon-depleted deep ocean and atmosphere, e.g. through the Southern Ocean. The Drake Passage radiocarbon records also show evidence for decreased air-sea gas exchange in the Southern Ocean during the Antarctic Cold Reversal/B lling-Aller d coincident with the hiatus in the deglacial CO2 rise. During this time period in the North Atlantic, radiocarbon reconstructions from deep-sea corals collected from off Iceland show a similar ventilation rate to that observed today and during the Holocene. To further investigate changes in North Atlantic ventilation over the last deglaciation, I used an inverse model to assess the consistency of sedimentary 231Pa/230Th ratios from the Holocene, H1, and the LGM with the modern circulation. The original document contains color images. Text Antarc* Antarctic Drake Passage Iceland North Atlantic Southern Ocean Defense Technical Information Center: DTIC Technical Reports database Antarctic Drake Passage Reykjanes ENVELOPE(-22.250,-22.250,65.467,65.467) Southern Ocean The Antarctic |
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Defense Technical Information Center: DTIC Technical Reports database |
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ftdtic |
language |
English |
topic |
Isotopes *CORAL *ISOTOPES *RADIOCARBON DATING ANTARCTIC REGIONS ATMOSPHERES CARBON CLIMATE COMPUTATIONS CONSISTENCY CYCLES DEEP OCEANS GAS EXCHANGE(BIOLOGY) GLACIERS ICELAND INVERSION LOW TEMPERATURE MASS MODELS NORTH ATLANTIC OCEAN OCEANOGRAPHY OCEANS RADIOACTIVE ISOTOPES RATES RATIOS SAMPLING STRATIFICATION SURVEYS URANIUM |
spellingShingle |
Isotopes *CORAL *ISOTOPES *RADIOCARBON DATING ANTARCTIC REGIONS ATMOSPHERES CARBON CLIMATE COMPUTATIONS CONSISTENCY CYCLES DEEP OCEANS GAS EXCHANGE(BIOLOGY) GLACIERS ICELAND INVERSION LOW TEMPERATURE MASS MODELS NORTH ATLANTIC OCEAN OCEANOGRAPHY OCEANS RADIOACTIVE ISOTOPES RATES RATIOS SAMPLING STRATIFICATION SURVEYS URANIUM Burke, Andrea Constraining Circulation Changes Through the Last Deglaciation with Deep-sea Coral Radiocarbon and Sedimentary Pa231/Th230 |
topic_facet |
Isotopes *CORAL *ISOTOPES *RADIOCARBON DATING ANTARCTIC REGIONS ATMOSPHERES CARBON CLIMATE COMPUTATIONS CONSISTENCY CYCLES DEEP OCEANS GAS EXCHANGE(BIOLOGY) GLACIERS ICELAND INVERSION LOW TEMPERATURE MASS MODELS NORTH ATLANTIC OCEAN OCEANOGRAPHY OCEANS RADIOACTIVE ISOTOPES RATES RATIOS SAMPLING STRATIFICATION SURVEYS URANIUM |
description |
Radioactive isotopes can be used in paleoceanography both for dating samples and as tracers of ocean processes. Here I use radiocarbon and uranium series isotopes to investigate the ocean's role in climate change over the last deglaciation. I present a new method for rapid radiocarbon analyses as a means of age-screening deep-sea corals for further study. Based on age survey results, I selected forty corals from the Drake Passage and thirteen from the Reykjanes Ridge off Iceland and dated them with uranium series isotopes. The uranium series dates give independent ages that allow radiocarbon to be used as a tracer of circulation and carbon cycle changes. The radiocarbon records generated from the Drake Passage corals show increased stratification in the Southern Ocean during the last glacial maximum (LGM) that disappeared during the start of the deglaciation as atmospheric CO2 began to rise during Heinrich Stadial 1 (H1). Considering these data and using a simple mass budget calculation, I show that the drop in atmospheric radiocarbon activity during H1 can be explained given direct carbon exchange between the radiocarbon-depleted deep ocean and atmosphere, e.g. through the Southern Ocean. The Drake Passage radiocarbon records also show evidence for decreased air-sea gas exchange in the Southern Ocean during the Antarctic Cold Reversal/B lling-Aller d coincident with the hiatus in the deglacial CO2 rise. During this time period in the North Atlantic, radiocarbon reconstructions from deep-sea corals collected from off Iceland show a similar ventilation rate to that observed today and during the Holocene. To further investigate changes in North Atlantic ventilation over the last deglaciation, I used an inverse model to assess the consistency of sedimentary 231Pa/230Th ratios from the Holocene, H1, and the LGM with the modern circulation. The original document contains color images. |
author2 |
WOODS HOLE OCEANOGRAPHIC INSTITUTION MA |
format |
Text |
author |
Burke, Andrea |
author_facet |
Burke, Andrea |
author_sort |
Burke, Andrea |
title |
Constraining Circulation Changes Through the Last Deglaciation with Deep-sea Coral Radiocarbon and Sedimentary Pa231/Th230 |
title_short |
Constraining Circulation Changes Through the Last Deglaciation with Deep-sea Coral Radiocarbon and Sedimentary Pa231/Th230 |
title_full |
Constraining Circulation Changes Through the Last Deglaciation with Deep-sea Coral Radiocarbon and Sedimentary Pa231/Th230 |
title_fullStr |
Constraining Circulation Changes Through the Last Deglaciation with Deep-sea Coral Radiocarbon and Sedimentary Pa231/Th230 |
title_full_unstemmed |
Constraining Circulation Changes Through the Last Deglaciation with Deep-sea Coral Radiocarbon and Sedimentary Pa231/Th230 |
title_sort |
constraining circulation changes through the last deglaciation with deep-sea coral radiocarbon and sedimentary pa231/th230 |
publishDate |
2012 |
url |
http://www.dtic.mil/docs/citations/ADA550599 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA550599 |
long_lat |
ENVELOPE(-22.250,-22.250,65.467,65.467) |
geographic |
Antarctic Drake Passage Reykjanes Southern Ocean The Antarctic |
geographic_facet |
Antarctic Drake Passage Reykjanes Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Drake Passage Iceland North Atlantic Southern Ocean |
genre_facet |
Antarc* Antarctic Drake Passage Iceland North Atlantic Southern Ocean |
op_source |
DTIC |
op_relation |
http://www.dtic.mil/docs/citations/ADA550599 |
op_rights |
Approved for public release; distribution is unlimited. |
_version_ |
1766146598027395072 |