Late Pleistocene Palehydrologic Reconstructions and Radiocarbon Dating in the Southeastern Basin and Range, USA

Persistent Link:
http://hdl.handle.net/10150/347134
Title:
Late Pleistocene Palehydrologic Reconstructions and Radiocarbon Dating in the Southeastern Basin and Range, USA
Author:
Kowler, Andrew
Issue Date:
2015
Publisher:
The University of Arizona.
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.
Embargo:
Release after 14-Jan-2017
Abstract:
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.
Type:
text; Electronic Dissertation
Keywords:
Lakes; Paleoclimate; Pleistocene; Radiocarbon; Stable Isotopes; Geosciences; Geoarchaeology
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Geosciences
Degree Grantor:
University of Arizona
Advisor:
Holliday, Vance T.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen
dc.titleLate Pleistocene Palehydrologic Reconstructions and Radiocarbon Dating in the Southeastern Basin and Range, USAen_US
dc.creatorKowler, Andrewen_US
dc.contributor.authorKowler, Andrewen_US
dc.date.issued2015-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © 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.en_US
dc.description.releaseRelease after 14-Jan-2017en_US
dc.description.abstractA 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.en_US
dc.typetexten
dc.typeElectronic Dissertationen
dc.subjectLakesen_US
dc.subjectPaleoclimateen_US
dc.subjectPleistoceneen_US
dc.subjectRadiocarbonen_US
dc.subjectStable Isotopesen_US
dc.subjectGeosciencesen_US
dc.subjectGeoarchaeologyen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineGeosciencesen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorHolliday, Vance T.en_US
dc.contributor.committeememberCohen, Andrew S.en_US
dc.contributor.committeememberDavis, Owen K.en_US
dc.contributor.committeememberQuade, Jayen_US
dc.contributor.committeememberHolliday, Vance T.en_US
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