A high-resolution hydroclimate record of the last three millennia from a cored stalagmite at Desoto Caverns (Alabama, USA)
Electronic Thesis or Dissertation Late Holocene climate changes in the Southeast USA are poorly documented due to the paucity of high-resolution paleo-records. This study provides high-resolution records of rapid hydroclimate changes in the Southeast over the last three millennia. The records are ba...
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ftunivalabama:oai:ir.ua.edu:123456789/1016 2023-05-15T17:34:57+02:00 A high-resolution hydroclimate record of the last three millennia from a cored stalagmite at Desoto Caverns (Alabama, USA) Dhungana, Rajesh Aharon, Paul Andrus, C. Fred T. Tick, Geoffrey R. Kopaska-Merkel, David C. 2010 93 p. https://ir.ua.edu/handle/123456789/1016 English eng University of Alabama Libraries The University of Alabama Electronic Theses and Dissertations The University of Alabama Libraries Digital Collections https://ir.ua.edu/handle/123456789/1016 All rights reserved by the author unless otherwise indicated. Paleoclimate Science Atmospheric Sciences thesis text 2010 ftunivalabama 2023-01-07T16:40:58Z Electronic Thesis or Dissertation Late Holocene climate changes in the Southeast USA are poorly documented due to the paucity of high-resolution paleo-records. This study provides high-resolution records of rapid hydroclimate changes in the Southeast over the last three millennia. The records are based on stable isotope rainfall proxies whose time series are constrained by precise U/Th dates from a stalagmite sampled at DeSoto Caverns. The average growth rate of the stalagmite was 149 µm/yr prior to 1400 years and it has been growing with an average growth rate of 42 µm/yr in the last 1400 years. During the past three thousand years stable isotope time series document six wet episodes (at ~ 2950, 2450, 1675, 1200, 700 and 70 years ago) alternating with six drier periods (at ~ 3100, 2800, 1900, 1500, 800 and 300 years ago). The biannually resolved 18O record agrees well with the contemporaneous SST record from the Sargasso Sea cores suggesting that changes in moisture availability in the Southeast are likely linked to subtropical North Atlantic SST variability. Power spectra analysis of the stalagmite-based oxygen isotope record reveals statistically significant periodicities at 24±1 and 36±1 year that are consistent with those observed in the contemporaneous atmospheric 14C production record. The 24 years periodicity is also consistent with the 24-year NAO Index periodicity. On the basis of our analysis we propose that the hydroclimate in the Southeast USA over the last three millennia was intimately linked to NAO variability powered by solar activity fluctuations. Thesis North Atlantic University of Alabama Institutional Repository Alabama |
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Open Polar |
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University of Alabama Institutional Repository |
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ftunivalabama |
language |
English |
topic |
Paleoclimate Science Atmospheric Sciences |
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Paleoclimate Science Atmospheric Sciences Dhungana, Rajesh A high-resolution hydroclimate record of the last three millennia from a cored stalagmite at Desoto Caverns (Alabama, USA) |
topic_facet |
Paleoclimate Science Atmospheric Sciences |
description |
Electronic Thesis or Dissertation Late Holocene climate changes in the Southeast USA are poorly documented due to the paucity of high-resolution paleo-records. This study provides high-resolution records of rapid hydroclimate changes in the Southeast over the last three millennia. The records are based on stable isotope rainfall proxies whose time series are constrained by precise U/Th dates from a stalagmite sampled at DeSoto Caverns. The average growth rate of the stalagmite was 149 µm/yr prior to 1400 years and it has been growing with an average growth rate of 42 µm/yr in the last 1400 years. During the past three thousand years stable isotope time series document six wet episodes (at ~ 2950, 2450, 1675, 1200, 700 and 70 years ago) alternating with six drier periods (at ~ 3100, 2800, 1900, 1500, 800 and 300 years ago). The biannually resolved 18O record agrees well with the contemporaneous SST record from the Sargasso Sea cores suggesting that changes in moisture availability in the Southeast are likely linked to subtropical North Atlantic SST variability. Power spectra analysis of the stalagmite-based oxygen isotope record reveals statistically significant periodicities at 24±1 and 36±1 year that are consistent with those observed in the contemporaneous atmospheric 14C production record. The 24 years periodicity is also consistent with the 24-year NAO Index periodicity. On the basis of our analysis we propose that the hydroclimate in the Southeast USA over the last three millennia was intimately linked to NAO variability powered by solar activity fluctuations. |
author2 |
Aharon, Paul Andrus, C. Fred T. Tick, Geoffrey R. Kopaska-Merkel, David C. |
format |
Thesis |
author |
Dhungana, Rajesh |
author_facet |
Dhungana, Rajesh |
author_sort |
Dhungana, Rajesh |
title |
A high-resolution hydroclimate record of the last three millennia from a cored stalagmite at Desoto Caverns (Alabama, USA) |
title_short |
A high-resolution hydroclimate record of the last three millennia from a cored stalagmite at Desoto Caverns (Alabama, USA) |
title_full |
A high-resolution hydroclimate record of the last three millennia from a cored stalagmite at Desoto Caverns (Alabama, USA) |
title_fullStr |
A high-resolution hydroclimate record of the last three millennia from a cored stalagmite at Desoto Caverns (Alabama, USA) |
title_full_unstemmed |
A high-resolution hydroclimate record of the last three millennia from a cored stalagmite at Desoto Caverns (Alabama, USA) |
title_sort |
high-resolution hydroclimate record of the last three millennia from a cored stalagmite at desoto caverns (alabama, usa) |
publisher |
University of Alabama Libraries |
publishDate |
2010 |
url |
https://ir.ua.edu/handle/123456789/1016 |
geographic |
Alabama |
geographic_facet |
Alabama |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
The University of Alabama Electronic Theses and Dissertations The University of Alabama Libraries Digital Collections https://ir.ua.edu/handle/123456789/1016 |
op_rights |
All rights reserved by the author unless otherwise indicated. |
_version_ |
1766133951288573952 |