Radiocarbon microanalysis on ice impurities for dating of Alpine glaciers
The main objective of this thesis is the deployment of radiometric dating on Alpine ice archives, where conventional, stratigraphical dating techniques fail. To this end a 14C analysis of particulate and, in a novel attempt, also of dissolved organic carbon contained in the ice matrix is developed....
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ftunivheidelb:oai:archiv.ub.uni-heidelberg.de:10185 2023-11-05T03:42:36+01:00 Radiocarbon microanalysis on ice impurities for dating of Alpine glaciers May, Barbara Luise 2009 application/pdf https://archiv.ub.uni-heidelberg.de/volltextserver/10185/ https://archiv.ub.uni-heidelberg.de/volltextserver/10185/1/Dissertation_May_2009.pdf https://doi.org/10.11588/heidok.00010185 https://nbn-resolving.org/urn:nbn:de:bsz:16-opus-101853 eng eng https://archiv.ub.uni-heidelberg.de/volltextserver/10185/1/Dissertation_May_2009.pdf doi:10.11588/heidok.00010185 urn:nbn:de:bsz:16-opus-101853 May, Barbara Luise (2009) Radiocarbon microanalysis on ice impurities for dating of Alpine glaciers. [Dissertation] info:eu-repo/semantics/openAccess http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html 530 530 Physics Dissertation info:eu-repo/semantics/doctoralThesis NonPeerReviewed 2009 ftunivheidelb https://doi.org/10.11588/heidok.00010185 2023-10-10T12:05:45Z The main objective of this thesis is the deployment of radiometric dating on Alpine ice archives, where conventional, stratigraphical dating techniques fail. To this end a 14C analysis of particulate and, in a novel attempt, also of dissolved organic carbon contained in the ice matrix is developed. Aimed at minimizing the required ice sample size, the designed ice processing line allows for handling of up to 700 g ice and is shown to involve blank levels small enough to ensure reliable 14C analyses down to a modern carbon fraction of fm = 0.33 at a minimum sample mass of about 20 µg carbon. Deployment of the system at the high altitude drilling area Colle Gnifetti (Monte Rosa, 4 550 m.a.s.l.) and, in contrast, to an ice core at the low altitude Vadret dal Corvatsch ice cap (Upper Engadin, 3 433 m.a.s.l.) reveals a quite significant 14C excess, not explained by any blank contribution and in contrast to the expected age range. The hypothesis that in situ produced 14C might contribute to the 14C content of dissolved organic carbon reveals strong short comings in applying this carbon fraction for radiometric dating of glacier ice, but also the new possibility to infer past accumulation changes. The particulate fraction, mostly unaffected by excess 14C, allows to connect an upper age limit of (7.5 ± 0.2) ka with the base of the Vadret dal Corvatsch, suggesting a minimal glacier extent during that time. For the Colle Gnifetti drill sites a tentative upper age constrain indicates pre-Holocene ice remains in the basal layer, while an enhanced 14C profile in the dissolved organic carbon fraction at core bottom suggests a large in situ produced 14C contribution most likely as a result of low accumulation during much colder periods. Doctoral or Postdoctoral Thesis Ice cap ice core Heidelberg University: HeiDok |
institution |
Open Polar |
collection |
Heidelberg University: HeiDok |
op_collection_id |
ftunivheidelb |
language |
English |
topic |
530 530 Physics |
spellingShingle |
530 530 Physics May, Barbara Luise Radiocarbon microanalysis on ice impurities for dating of Alpine glaciers |
topic_facet |
530 530 Physics |
description |
The main objective of this thesis is the deployment of radiometric dating on Alpine ice archives, where conventional, stratigraphical dating techniques fail. To this end a 14C analysis of particulate and, in a novel attempt, also of dissolved organic carbon contained in the ice matrix is developed. Aimed at minimizing the required ice sample size, the designed ice processing line allows for handling of up to 700 g ice and is shown to involve blank levels small enough to ensure reliable 14C analyses down to a modern carbon fraction of fm = 0.33 at a minimum sample mass of about 20 µg carbon. Deployment of the system at the high altitude drilling area Colle Gnifetti (Monte Rosa, 4 550 m.a.s.l.) and, in contrast, to an ice core at the low altitude Vadret dal Corvatsch ice cap (Upper Engadin, 3 433 m.a.s.l.) reveals a quite significant 14C excess, not explained by any blank contribution and in contrast to the expected age range. The hypothesis that in situ produced 14C might contribute to the 14C content of dissolved organic carbon reveals strong short comings in applying this carbon fraction for radiometric dating of glacier ice, but also the new possibility to infer past accumulation changes. The particulate fraction, mostly unaffected by excess 14C, allows to connect an upper age limit of (7.5 ± 0.2) ka with the base of the Vadret dal Corvatsch, suggesting a minimal glacier extent during that time. For the Colle Gnifetti drill sites a tentative upper age constrain indicates pre-Holocene ice remains in the basal layer, while an enhanced 14C profile in the dissolved organic carbon fraction at core bottom suggests a large in situ produced 14C contribution most likely as a result of low accumulation during much colder periods. |
format |
Doctoral or Postdoctoral Thesis |
author |
May, Barbara Luise |
author_facet |
May, Barbara Luise |
author_sort |
May, Barbara Luise |
title |
Radiocarbon microanalysis on ice impurities for dating of Alpine glaciers |
title_short |
Radiocarbon microanalysis on ice impurities for dating of Alpine glaciers |
title_full |
Radiocarbon microanalysis on ice impurities for dating of Alpine glaciers |
title_fullStr |
Radiocarbon microanalysis on ice impurities for dating of Alpine glaciers |
title_full_unstemmed |
Radiocarbon microanalysis on ice impurities for dating of Alpine glaciers |
title_sort |
radiocarbon microanalysis on ice impurities for dating of alpine glaciers |
publishDate |
2009 |
url |
https://archiv.ub.uni-heidelberg.de/volltextserver/10185/ https://archiv.ub.uni-heidelberg.de/volltextserver/10185/1/Dissertation_May_2009.pdf https://doi.org/10.11588/heidok.00010185 https://nbn-resolving.org/urn:nbn:de:bsz:16-opus-101853 |
genre |
Ice cap ice core |
genre_facet |
Ice cap ice core |
op_relation |
https://archiv.ub.uni-heidelberg.de/volltextserver/10185/1/Dissertation_May_2009.pdf doi:10.11588/heidok.00010185 urn:nbn:de:bsz:16-opus-101853 May, Barbara Luise (2009) Radiocarbon microanalysis on ice impurities for dating of Alpine glaciers. [Dissertation] |
op_rights |
info:eu-repo/semantics/openAccess http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html |
op_doi |
https://doi.org/10.11588/heidok.00010185 |
_version_ |
1781699862531670016 |