Luminescence-dating zeroing tests in Lake Hoare, Taylor Valley, Antarctica
In two of the perennially ice-covered lakes in the McMurdo Dry Valleys, lakes Hoare and Bonney in the Taylor Valley, bottom water has 14C ages of ∼2.7 ka and ∼10 ka (respectively), rendering 14C ages of bottom sediments highly problematic. Consequently, we tested the effectiveness of thermolumin...
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ftlouisianastuir:oai:repository.lsu.edu:geo_pubs-1673 2024-09-15T17:47:55+00:00 Luminescence-dating zeroing tests in Lake Hoare, Taylor Valley, Antarctica Berger, Glenn Doran, Peter 2001-06-26T07:00:00Z https://repository.lsu.edu/geo_pubs/674 https://doi.org/10.1023/A:1011144502713 unknown LSU Scholarly Repository https://repository.lsu.edu/geo_pubs/674 doi:10.1023/A:1011144502713 Faculty Publications Antarctica Dating Geochronology Lakes Luminescence Sediments text 2001 ftlouisianastuir https://doi.org/10.1023/A:1011144502713 2024-08-08T04:27:15Z In two of the perennially ice-covered lakes in the McMurdo Dry Valleys, lakes Hoare and Bonney in the Taylor Valley, bottom water has 14C ages of ∼2.7 ka and ∼10 ka (respectively), rendering 14C ages of bottom sediments highly problematic. Consequently, we tested the effectiveness of thermoluminescence (TL) zeroing in polymineral fine silt material from several depositional environments around and on the lake (stream suspensions, ice-surface sand dune, and silty sand from near the top of the more-than-3m-thick ice). We also conducted TL and infrared-stimulated-luminescence (IRSL) dating tests on material from three box cores recovered from the bottom of Lake Hoare, in a transect away from the abutting Canada Glacier. We observed effective zeroing of light-sensitive TL in suspended silt from one input stream and less effective zeroing from another stream. We observed effective zeroing of light-sensitive TL also in silt from a glacier-proximal eolian ice-surface dune and from sand from within the upper 5 cm of ice. In contrast, in box-core 1, the bottom sediment yielded minimum TL apparent ages of 1500-2600 yrs, with no discernable stratigraphic depth trend. IRSL dating applied to the same box-core samples produced significantly lower age estimates, ranging from ∼600 ± 200 yrs to 1440 ± 270 yrs top-to-bottom, an improvement over the depth-constant ∼2200 yrs TL ages. In two other cores closer to the Canada Glacier, IRSL ages from ∼600 ± 200 yrs (top) to ∼2900 ± 300 yrs (at depth) were measured. Not only are the IRSL ages a significant improvement over the TL results, but the near-core-top IRSL ages are also a dramatic improvement over the 14C results (∼2.7 ka). IRSL dating has a demonstrated potential to supplant 14C dating for such antarctic lacustrine deposits. Text Antarc* Antarctic Antarctica Canada Glacier glacier* McMurdo Dry Valleys LSU Digital Commons (Louisiana State University) |
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LSU Digital Commons (Louisiana State University) |
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Antarctica Dating Geochronology Lakes Luminescence Sediments |
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Antarctica Dating Geochronology Lakes Luminescence Sediments Berger, Glenn Doran, Peter Luminescence-dating zeroing tests in Lake Hoare, Taylor Valley, Antarctica |
topic_facet |
Antarctica Dating Geochronology Lakes Luminescence Sediments |
description |
In two of the perennially ice-covered lakes in the McMurdo Dry Valleys, lakes Hoare and Bonney in the Taylor Valley, bottom water has 14C ages of ∼2.7 ka and ∼10 ka (respectively), rendering 14C ages of bottom sediments highly problematic. Consequently, we tested the effectiveness of thermoluminescence (TL) zeroing in polymineral fine silt material from several depositional environments around and on the lake (stream suspensions, ice-surface sand dune, and silty sand from near the top of the more-than-3m-thick ice). We also conducted TL and infrared-stimulated-luminescence (IRSL) dating tests on material from three box cores recovered from the bottom of Lake Hoare, in a transect away from the abutting Canada Glacier. We observed effective zeroing of light-sensitive TL in suspended silt from one input stream and less effective zeroing from another stream. We observed effective zeroing of light-sensitive TL also in silt from a glacier-proximal eolian ice-surface dune and from sand from within the upper 5 cm of ice. In contrast, in box-core 1, the bottom sediment yielded minimum TL apparent ages of 1500-2600 yrs, with no discernable stratigraphic depth trend. IRSL dating applied to the same box-core samples produced significantly lower age estimates, ranging from ∼600 ± 200 yrs to 1440 ± 270 yrs top-to-bottom, an improvement over the depth-constant ∼2200 yrs TL ages. In two other cores closer to the Canada Glacier, IRSL ages from ∼600 ± 200 yrs (top) to ∼2900 ± 300 yrs (at depth) were measured. Not only are the IRSL ages a significant improvement over the TL results, but the near-core-top IRSL ages are also a dramatic improvement over the 14C results (∼2.7 ka). IRSL dating has a demonstrated potential to supplant 14C dating for such antarctic lacustrine deposits. |
format |
Text |
author |
Berger, Glenn Doran, Peter |
author_facet |
Berger, Glenn Doran, Peter |
author_sort |
Berger, Glenn |
title |
Luminescence-dating zeroing tests in Lake Hoare, Taylor Valley, Antarctica |
title_short |
Luminescence-dating zeroing tests in Lake Hoare, Taylor Valley, Antarctica |
title_full |
Luminescence-dating zeroing tests in Lake Hoare, Taylor Valley, Antarctica |
title_fullStr |
Luminescence-dating zeroing tests in Lake Hoare, Taylor Valley, Antarctica |
title_full_unstemmed |
Luminescence-dating zeroing tests in Lake Hoare, Taylor Valley, Antarctica |
title_sort |
luminescence-dating zeroing tests in lake hoare, taylor valley, antarctica |
publisher |
LSU Scholarly Repository |
publishDate |
2001 |
url |
https://repository.lsu.edu/geo_pubs/674 https://doi.org/10.1023/A:1011144502713 |
genre |
Antarc* Antarctic Antarctica Canada Glacier glacier* McMurdo Dry Valleys |
genre_facet |
Antarc* Antarctic Antarctica Canada Glacier glacier* McMurdo Dry Valleys |
op_source |
Faculty Publications |
op_relation |
https://repository.lsu.edu/geo_pubs/674 doi:10.1023/A:1011144502713 |
op_doi |
https://doi.org/10.1023/A:1011144502713 |
_version_ |
1810497647199387648 |