Late Pleistocene Palehydrologic Reconstructions and Radiocarbon Dating in the Southeastern Basin and Range, USA
A dearth of reliably-dated paleolake records from the southern Basin and Range has limited knowledge of past water balance changes there, precluding a more complete understanding of late Pleistocene atmospheric circulation across western North America. Paleoshorelines in closed basins throughout the...
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ftunivarizona:oai:repository.arizona.edu:10150/347134 2023-05-15T16:41:37+02:00 Late Pleistocene Palehydrologic Reconstructions and Radiocarbon Dating in the Southeastern Basin and Range, USA Kowler, Andrew Holliday, Vance T. Cohen, Andrew S. Davis, Owen K. Quade, Jay 2015 http://hdl.handle.net/10150/347134 en_US eng The University of Arizona. http://hdl.handle.net/10150/347134 Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Lakes Paleoclimate Pleistocene Radiocarbon Stable Isotopes Geosciences Geoarchaeology text Electronic Dissertation 2015 ftunivarizona 2020-06-14T08:11:33Z A dearth of reliably-dated paleolake records from the southern Basin and Range has limited knowledge of past water balance changes there, precluding a more complete understanding of late Pleistocene atmospheric circulation across western North America. Paleoshorelines in closed basins throughout the region can provide accurately dated records of local effective moisture variations, representing a largely untapped source of paleohydrologic information. This dissertation presents paleohydrologic reconstructions from depositional successions in two basins at 32°N, approximately 100 km apart: Willcox basin, in southeastern Arizona, and Playas Valley, in southwestern New Mexico. Also presented are the results of ¹⁴C dating of charcoal samples from the El Fin del Mundo Clovis archaeological site, in northwestern Sonora, Mexico. In depth analysis of these results allowed constraint of the "small sample effect" on the charcoal ages, found to be smaller than 1σ of analytical uncertainty. The magnitude of the problem in ages from miniscule shell samples in the Willcox and Playas chronologies was found to be similar. The successions record moist pluvial conditions from ~20-13 ka in Playas, and>37-11 ka in Willcox, with most dates younger than 19 ka--before which there is no solid evidence for lake transgressions. There is clear evidence for overlapping highstands between ~18.3 and 17.9 ka and a brief highstand of Cochise at ~12.9 ka, coinciding with Heinrich events H1b and H0, respectively. Temporal concordance between wet periods and perturbations in the North Atlantic ocean and/or southern Laurentide ice sheet supports the idea that abrupt paleoclimatic changes in the southwestern U.S. occurred in response to large-scale atmospheric linkages to the northern high latitudes. The H1b highstands fill a hiatus in ¹⁴C dates compiled from paleoshorelines throughout the western U.S., and correspond to the first part of a lowstand in paleo-Lake Estancia (35°N), in north-central New Mexico. Anti-phasing within New Mexico suggests that the newly documented highstands resulted from an increase in southerly-sourced precipitation. This is consistent with paleoenvironmental evidence from southern Arizona and New Mexico that points toward periodic intensification of the summer monsoon during the late Pleistocene. Release after 14-Jan-2017 Doctoral or Postdoctoral Thesis Ice Sheet North Atlantic The University of Arizona: UA Campus Repository |
institution |
Open Polar |
collection |
The University of Arizona: UA Campus Repository |
op_collection_id |
ftunivarizona |
language |
English |
topic |
Lakes Paleoclimate Pleistocene Radiocarbon Stable Isotopes Geosciences Geoarchaeology |
spellingShingle |
Lakes Paleoclimate Pleistocene Radiocarbon Stable Isotopes Geosciences Geoarchaeology Kowler, Andrew Late Pleistocene Palehydrologic Reconstructions and Radiocarbon Dating in the Southeastern Basin and Range, USA |
topic_facet |
Lakes Paleoclimate Pleistocene Radiocarbon Stable Isotopes Geosciences Geoarchaeology |
description |
A dearth of reliably-dated paleolake records from the southern Basin and Range has limited knowledge of past water balance changes there, precluding a more complete understanding of late Pleistocene atmospheric circulation across western North America. Paleoshorelines in closed basins throughout the region can provide accurately dated records of local effective moisture variations, representing a largely untapped source of paleohydrologic information. This dissertation presents paleohydrologic reconstructions from depositional successions in two basins at 32°N, approximately 100 km apart: Willcox basin, in southeastern Arizona, and Playas Valley, in southwestern New Mexico. Also presented are the results of ¹⁴C dating of charcoal samples from the El Fin del Mundo Clovis archaeological site, in northwestern Sonora, Mexico. In depth analysis of these results allowed constraint of the "small sample effect" on the charcoal ages, found to be smaller than 1σ of analytical uncertainty. The magnitude of the problem in ages from miniscule shell samples in the Willcox and Playas chronologies was found to be similar. The successions record moist pluvial conditions from ~20-13 ka in Playas, and>37-11 ka in Willcox, with most dates younger than 19 ka--before which there is no solid evidence for lake transgressions. There is clear evidence for overlapping highstands between ~18.3 and 17.9 ka and a brief highstand of Cochise at ~12.9 ka, coinciding with Heinrich events H1b and H0, respectively. Temporal concordance between wet periods and perturbations in the North Atlantic ocean and/or southern Laurentide ice sheet supports the idea that abrupt paleoclimatic changes in the southwestern U.S. occurred in response to large-scale atmospheric linkages to the northern high latitudes. The H1b highstands fill a hiatus in ¹⁴C dates compiled from paleoshorelines throughout the western U.S., and correspond to the first part of a lowstand in paleo-Lake Estancia (35°N), in north-central New Mexico. Anti-phasing within New Mexico suggests that the newly documented highstands resulted from an increase in southerly-sourced precipitation. This is consistent with paleoenvironmental evidence from southern Arizona and New Mexico that points toward periodic intensification of the summer monsoon during the late Pleistocene. Release after 14-Jan-2017 |
author2 |
Holliday, Vance T. Cohen, Andrew S. Davis, Owen K. Quade, Jay |
format |
Doctoral or Postdoctoral Thesis |
author |
Kowler, Andrew |
author_facet |
Kowler, Andrew |
author_sort |
Kowler, Andrew |
title |
Late Pleistocene Palehydrologic Reconstructions and Radiocarbon Dating in the Southeastern Basin and Range, USA |
title_short |
Late Pleistocene Palehydrologic Reconstructions and Radiocarbon Dating in the Southeastern Basin and Range, USA |
title_full |
Late Pleistocene Palehydrologic Reconstructions and Radiocarbon Dating in the Southeastern Basin and Range, USA |
title_fullStr |
Late Pleistocene Palehydrologic Reconstructions and Radiocarbon Dating in the Southeastern Basin and Range, USA |
title_full_unstemmed |
Late Pleistocene Palehydrologic Reconstructions and Radiocarbon Dating in the Southeastern Basin and Range, USA |
title_sort |
late pleistocene palehydrologic reconstructions and radiocarbon dating in the southeastern basin and range, usa |
publisher |
The University of Arizona. |
publishDate |
2015 |
url |
http://hdl.handle.net/10150/347134 |
genre |
Ice Sheet North Atlantic |
genre_facet |
Ice Sheet North Atlantic |
op_relation |
http://hdl.handle.net/10150/347134 |
op_rights |
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. |
_version_ |
1766032066359590912 |