Meteoric 10Be as a Tracer for Subglacial Chemical Weathering in East Antarctica
Indiana University-Purdue University Indianapolis (IUPUI) Subglacial chemical processes in Antarctica are potentially significant contributors to global geochemical cycles, but current understanding of their scale and nature is limited. A sequential chemical extraction procedure was developed and te...
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ftiupui:oai:scholarworks.indianapolis.iu.edu:1805/27242 2024-09-15T17:48:08+00:00 Meteoric 10Be as a Tracer for Subglacial Chemical Weathering in East Antarctica Arnardóttir, Eiríka Ösp Licht, Kathy Graly, Joseph Bird, Broxton Gilhooly, William 2021-12 application/pdf https://hdl.handle.net/1805/27242 https://doi.org/10.7912/C2/83 en_US eng https://hdl.handle.net/1805/27242 http://dx.doi.org/10.7912/C2/83 Subglacial Chemical Weathering Meteoric 10Be Cosmogenic Nuclides Sequential Chemical Extractions Antarctica Thesis 2021 ftiupui https://doi.org/10.7912/C2/83 2024-08-08T03:18:33Z Indiana University-Purdue University Indianapolis (IUPUI) Subglacial chemical processes in Antarctica are potentially significant contributors to global geochemical cycles, but current understanding of their scale and nature is limited. A sequential chemical extraction procedure was developed and tested to investigate the utility of meteoric 10Be as a tracer for chemical weathering processes beneath the East Antarctic Ice Sheet. Subglacial meltwater is widely available under the Antarctic Ice Sheet and chemical constituents within it have the potential to drive geochemical weathering processes in the subglacial environment. Meteoric 10Be is a cosmogenic nuclide with a half-life of 1.39×106 years that is incorporated into glacier ice, therefore its abundance in the subglacial environment in Antarctica is meltwater dependent. It is known to adsorb to fine-grained particles in aqueous solution, precipitate with amorphous oxides, and/or be incorporated into authigenic clay structures during chemical weathering. The presence of 10Be in weathering products derived from beneath the ice therefore indicates chemical weathering processes in the subglacial environment. Freshly emerging subglacial sediments from the Mt. Achernar blue ice moraine were subject to chemical extractions where these weathering phases were isolated and 10Be concentrations therein quantified. Optimization of the phase isolation was developed by examining the effects of each extraction on the sample mineralogy and chemical composition. Experiments on 10Be desorption revealed that pH 3.2-3.5 was optimal for the extraction of adsorbed 10Be. Vigorous disaggregation of the samples before grain size separations and acid extractions is crucial due to the preferential fractionation of the nuclide with clay-sized particles. 10Be concentrations of 2-22×107 atoms g-1 measured in oxides and clay minerals in freshly emerging sediments strongly indicate subglacial chemical weathering in the catchment of the Mt. Achernar moraine. Sediment-meltwater contact in ... Thesis Antarc* Antarctic Antarctica East Antarctica Ice Sheet Indiana University - Purdue University Indianapolis: IUPUI Scholar Works |
institution |
Open Polar |
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Indiana University - Purdue University Indianapolis: IUPUI Scholar Works |
op_collection_id |
ftiupui |
language |
English |
topic |
Subglacial Chemical Weathering Meteoric 10Be Cosmogenic Nuclides Sequential Chemical Extractions Antarctica |
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Subglacial Chemical Weathering Meteoric 10Be Cosmogenic Nuclides Sequential Chemical Extractions Antarctica Arnardóttir, Eiríka Ösp Meteoric 10Be as a Tracer for Subglacial Chemical Weathering in East Antarctica |
topic_facet |
Subglacial Chemical Weathering Meteoric 10Be Cosmogenic Nuclides Sequential Chemical Extractions Antarctica |
description |
Indiana University-Purdue University Indianapolis (IUPUI) Subglacial chemical processes in Antarctica are potentially significant contributors to global geochemical cycles, but current understanding of their scale and nature is limited. A sequential chemical extraction procedure was developed and tested to investigate the utility of meteoric 10Be as a tracer for chemical weathering processes beneath the East Antarctic Ice Sheet. Subglacial meltwater is widely available under the Antarctic Ice Sheet and chemical constituents within it have the potential to drive geochemical weathering processes in the subglacial environment. Meteoric 10Be is a cosmogenic nuclide with a half-life of 1.39×106 years that is incorporated into glacier ice, therefore its abundance in the subglacial environment in Antarctica is meltwater dependent. It is known to adsorb to fine-grained particles in aqueous solution, precipitate with amorphous oxides, and/or be incorporated into authigenic clay structures during chemical weathering. The presence of 10Be in weathering products derived from beneath the ice therefore indicates chemical weathering processes in the subglacial environment. Freshly emerging subglacial sediments from the Mt. Achernar blue ice moraine were subject to chemical extractions where these weathering phases were isolated and 10Be concentrations therein quantified. Optimization of the phase isolation was developed by examining the effects of each extraction on the sample mineralogy and chemical composition. Experiments on 10Be desorption revealed that pH 3.2-3.5 was optimal for the extraction of adsorbed 10Be. Vigorous disaggregation of the samples before grain size separations and acid extractions is crucial due to the preferential fractionation of the nuclide with clay-sized particles. 10Be concentrations of 2-22×107 atoms g-1 measured in oxides and clay minerals in freshly emerging sediments strongly indicate subglacial chemical weathering in the catchment of the Mt. Achernar moraine. Sediment-meltwater contact in ... |
author2 |
Licht, Kathy Graly, Joseph Bird, Broxton Gilhooly, William |
format |
Thesis |
author |
Arnardóttir, Eiríka Ösp |
author_facet |
Arnardóttir, Eiríka Ösp |
author_sort |
Arnardóttir, Eiríka Ösp |
title |
Meteoric 10Be as a Tracer for Subglacial Chemical Weathering in East Antarctica |
title_short |
Meteoric 10Be as a Tracer for Subglacial Chemical Weathering in East Antarctica |
title_full |
Meteoric 10Be as a Tracer for Subglacial Chemical Weathering in East Antarctica |
title_fullStr |
Meteoric 10Be as a Tracer for Subglacial Chemical Weathering in East Antarctica |
title_full_unstemmed |
Meteoric 10Be as a Tracer for Subglacial Chemical Weathering in East Antarctica |
title_sort |
meteoric 10be as a tracer for subglacial chemical weathering in east antarctica |
publishDate |
2021 |
url |
https://hdl.handle.net/1805/27242 https://doi.org/10.7912/C2/83 |
genre |
Antarc* Antarctic Antarctica East Antarctica Ice Sheet |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica Ice Sheet |
op_relation |
https://hdl.handle.net/1805/27242 http://dx.doi.org/10.7912/C2/83 |
op_doi |
https://doi.org/10.7912/C2/83 |
_version_ |
1810289285043060736 |