Measurements of 14C in ancient ice from Taylor Glacier, Antarctica constrain in situ cosmogenic 14CH4 and 14CO production rates.
Carbon-14 (14C) is incorporated into glacial ice by trapping of atmospheric gases as well as direct near-surface in situ cosmogenic production. 14C of trapped methane (14CH4) is a powerful tracer for past CH4 emissions from “old” carbon sources such as permafrost and marine CH4 clathrates. 14C in tr...
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ftansto:oai:apo-prod.ansto.gov.au:10238/6617 2023-05-15T13:36:16+02:00 Measurements of 14C in ancient ice from Taylor Glacier, Antarctica constrain in situ cosmogenic 14CH4 and 14CO production rates. Petrenko, VV Severinghaus, JP Schaefer, H Smith, AM Kuhl, TW Baggenstos, D Hua, Q Brook, EJ Rose, P Kulin, R Bauska, TK Harth, C Buizert, C Orsi, A Emanuele, G Lee, JE Brailsford, G Keeling, R Weiss, RF 2016-03-10 http://apo.ansto.gov.au/dspace/handle/10238/6617 https://doi.org/10.1016/j.gca.2016.01.004 en eng Elsevier 0016-7037 http://dx.doi.org/10.1016/j.gca.2016.01.004 http://apo.ansto.gov.au/dspace/handle/10238/6617 Antarctica Carbon Glaciers Methane Ice Sampling Journal Article 2016 ftansto https://doi.org/10.1016/j.gca.2016.01.004 2020-07-13T22:28:26Z Carbon-14 (14C) is incorporated into glacial ice by trapping of atmospheric gases as well as direct near-surface in situ cosmogenic production. 14C of trapped methane (14CH4) is a powerful tracer for past CH4 emissions from “old” carbon sources such as permafrost and marine CH4 clathrates. 14C in trapped carbon dioxide (14CO2) can be used for absolute dating of ice cores. In situ produced cosmogenic 14C in carbon monoxide (14CO) can potentially be used to reconstruct the past cosmic ray flux and past solar activity. Unfortunately, the trapped atmospheric and in situ cosmogenic components of 14C in glacial ice are difficult to disentangle and a thorough understanding of the in situ cosmogenic component is needed in order to extract useful information from ice core 14C. We analyzed very large (≈1000 kg) ice samples in the 2.26–19.53 m depth range from the ablation zone of Taylor Glacier, Antarctica, to study in situ cosmogenic production of 14CH4 and 14CO. All sampled ice is >50 ka in age, allowing for the assumption that most of the measured 14C originates from recent in situ cosmogenic production as ancient ice is brought to the surface via ablation. Our results place the first constraints on cosmogenic 14CH4 production rates and improve on prior estimates of 14CO production rates in ice. We find a constant 14CH4/14CO production ratio (0.0076 ± 0.0003) for samples deeper than 3 m, which allows the use of 14CO for correcting the 14CH4 signals for the in situ cosmogenic component. Our results also provide the first unambiguous confirmation of 14C production by fast muons in a natural setting (ice or rock) and suggest that the 14C production rates in ice commonly used in the literature may be too high. © 2016, Elsevier Ltd. Article in Journal/Newspaper Antarc* Antarctica Ice ice core permafrost Taylor Glacier Australian Nuclear Science and Technology Organisation: ANSTO Publications Online Taylor Glacier ENVELOPE(162.167,162.167,-77.733,-77.733) Geochimica et Cosmochimica Acta 177 62 77 |
institution |
Open Polar |
collection |
Australian Nuclear Science and Technology Organisation: ANSTO Publications Online |
op_collection_id |
ftansto |
language |
English |
topic |
Antarctica Carbon Glaciers Methane Ice Sampling |
spellingShingle |
Antarctica Carbon Glaciers Methane Ice Sampling Petrenko, VV Severinghaus, JP Schaefer, H Smith, AM Kuhl, TW Baggenstos, D Hua, Q Brook, EJ Rose, P Kulin, R Bauska, TK Harth, C Buizert, C Orsi, A Emanuele, G Lee, JE Brailsford, G Keeling, R Weiss, RF Measurements of 14C in ancient ice from Taylor Glacier, Antarctica constrain in situ cosmogenic 14CH4 and 14CO production rates. |
topic_facet |
Antarctica Carbon Glaciers Methane Ice Sampling |
description |
Carbon-14 (14C) is incorporated into glacial ice by trapping of atmospheric gases as well as direct near-surface in situ cosmogenic production. 14C of trapped methane (14CH4) is a powerful tracer for past CH4 emissions from “old” carbon sources such as permafrost and marine CH4 clathrates. 14C in trapped carbon dioxide (14CO2) can be used for absolute dating of ice cores. In situ produced cosmogenic 14C in carbon monoxide (14CO) can potentially be used to reconstruct the past cosmic ray flux and past solar activity. Unfortunately, the trapped atmospheric and in situ cosmogenic components of 14C in glacial ice are difficult to disentangle and a thorough understanding of the in situ cosmogenic component is needed in order to extract useful information from ice core 14C. We analyzed very large (≈1000 kg) ice samples in the 2.26–19.53 m depth range from the ablation zone of Taylor Glacier, Antarctica, to study in situ cosmogenic production of 14CH4 and 14CO. All sampled ice is >50 ka in age, allowing for the assumption that most of the measured 14C originates from recent in situ cosmogenic production as ancient ice is brought to the surface via ablation. Our results place the first constraints on cosmogenic 14CH4 production rates and improve on prior estimates of 14CO production rates in ice. We find a constant 14CH4/14CO production ratio (0.0076 ± 0.0003) for samples deeper than 3 m, which allows the use of 14CO for correcting the 14CH4 signals for the in situ cosmogenic component. Our results also provide the first unambiguous confirmation of 14C production by fast muons in a natural setting (ice or rock) and suggest that the 14C production rates in ice commonly used in the literature may be too high. © 2016, Elsevier Ltd. |
format |
Article in Journal/Newspaper |
author |
Petrenko, VV Severinghaus, JP Schaefer, H Smith, AM Kuhl, TW Baggenstos, D Hua, Q Brook, EJ Rose, P Kulin, R Bauska, TK Harth, C Buizert, C Orsi, A Emanuele, G Lee, JE Brailsford, G Keeling, R Weiss, RF |
author_facet |
Petrenko, VV Severinghaus, JP Schaefer, H Smith, AM Kuhl, TW Baggenstos, D Hua, Q Brook, EJ Rose, P Kulin, R Bauska, TK Harth, C Buizert, C Orsi, A Emanuele, G Lee, JE Brailsford, G Keeling, R Weiss, RF |
author_sort |
Petrenko, VV |
title |
Measurements of 14C in ancient ice from Taylor Glacier, Antarctica constrain in situ cosmogenic 14CH4 and 14CO production rates. |
title_short |
Measurements of 14C in ancient ice from Taylor Glacier, Antarctica constrain in situ cosmogenic 14CH4 and 14CO production rates. |
title_full |
Measurements of 14C in ancient ice from Taylor Glacier, Antarctica constrain in situ cosmogenic 14CH4 and 14CO production rates. |
title_fullStr |
Measurements of 14C in ancient ice from Taylor Glacier, Antarctica constrain in situ cosmogenic 14CH4 and 14CO production rates. |
title_full_unstemmed |
Measurements of 14C in ancient ice from Taylor Glacier, Antarctica constrain in situ cosmogenic 14CH4 and 14CO production rates. |
title_sort |
measurements of 14c in ancient ice from taylor glacier, antarctica constrain in situ cosmogenic 14ch4 and 14co production rates. |
publisher |
Elsevier |
publishDate |
2016 |
url |
http://apo.ansto.gov.au/dspace/handle/10238/6617 https://doi.org/10.1016/j.gca.2016.01.004 |
long_lat |
ENVELOPE(162.167,162.167,-77.733,-77.733) |
geographic |
Taylor Glacier |
geographic_facet |
Taylor Glacier |
genre |
Antarc* Antarctica Ice ice core permafrost Taylor Glacier |
genre_facet |
Antarc* Antarctica Ice ice core permafrost Taylor Glacier |
op_relation |
0016-7037 http://dx.doi.org/10.1016/j.gca.2016.01.004 http://apo.ansto.gov.au/dspace/handle/10238/6617 |
op_doi |
https://doi.org/10.1016/j.gca.2016.01.004 |
container_title |
Geochimica et Cosmochimica Acta |
container_volume |
177 |
container_start_page |
62 |
op_container_end_page |
77 |
_version_ |
1766076289039466496 |