Extraction of paleohydrology and paleoclimate proxies from vadose zones and paleolake records in the southwestern Great Basin
Thick vadose zones in arid regions recorded past climate changes up to 100 ka, so they are unique archives for continental paleoclimate change and groundwater recharge during the late Quaternary. Despite extensive research on flow and transport in arid regions, the transport properties and general r...
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ftuninevadalveg:oai:digitalscholarship.unlv.edu:rtds-3590 2023-05-15T16:30:11+02:00 Extraction of paleohydrology and paleoclimate proxies from vadose zones and paleolake records in the southwestern Great Basin Dong, Weiquan 2004-01-01T08:00:00Z application/pdf https://digitalscholarship.unlv.edu/rtds/2591 https://digitalscholarship.unlv.edu/cgi/viewcontent.cgi?article=3590&context=rtds English eng Digital Scholarship@UNLV https://digitalscholarship.unlv.edu/rtds/2591 https://digitalscholarship.unlv.edu/cgi/viewcontent.cgi?article=3590&context=rtds IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/ UNLV Retrospective Theses & Dissertations Basin Chloride Extraction Great Great Basin Paleoclimate Paleohydrology Paleolake Proxies Records Southwestern Vadose Zones text 2004 ftuninevadalveg 2023-01-16T16:45:44Z Thick vadose zones in arid regions recorded past climate changes up to 100 ka, so they are unique archives for continental paleoclimate change and groundwater recharge during the late Quaternary. Despite extensive research on flow and transport in arid regions, the transport properties and general response of arid vadose zones to climate regimes are still not well understood. Some of these issues are addressed with four distinct studies in this dissertation. The first study investigates effects of soil texture, vegetation coverage, and macropores on soil moisture variation at Nevada Test Site (NTS). The simulations show that bare soils have higher soil water content than vegetated soils. Effects of macropore flow on soil water content are insignificant; The second study evaluates the impacts of climate change on solute transport in arid vadose zones. Undisturbed soil cores were collected at ground surface, directly below where tension infiltrometer measurements were made. The water fluxes and Br dispersion coefficients at investigated matric heads were very high due to the coarseness of the soils and possibly due to preferential flow pathways. These high water fluxes are more likely to occur in ephemeral washes. However, higher fluxes through the surface soil would be more likely during wetter climates; The third study simulates paleolake extent in Owens Valley in the last 18 ka. A coupled catchment-lake model is developed in this study, and used to reconstruct the observed paleolake levels for Owens Lake and Searles Lake. Finally, a quantitative time-series of paleoclimate information was obtained; The fourth study models the actual measured chloride profile in Amargosa Desert Research Site (ADRS) with the modified version of the HYDRUS-1D computer code by using variable boundary conditions. The paleoinformation estimated from the third study, and chloride concentration in Greenland ice core (GISP2) are used to prepare the atmospheric boundary file. The simulated chloride profile is in agreement with the ... Text Greenland Greenland ice core ice core University of Nevada, Las Vegas: Digital Scholarship@UNLV Greenland |
institution |
Open Polar |
collection |
University of Nevada, Las Vegas: Digital Scholarship@UNLV |
op_collection_id |
ftuninevadalveg |
language |
English |
topic |
Basin Chloride Extraction Great Great Basin Paleoclimate Paleohydrology Paleolake Proxies Records Southwestern Vadose Zones |
spellingShingle |
Basin Chloride Extraction Great Great Basin Paleoclimate Paleohydrology Paleolake Proxies Records Southwestern Vadose Zones Dong, Weiquan Extraction of paleohydrology and paleoclimate proxies from vadose zones and paleolake records in the southwestern Great Basin |
topic_facet |
Basin Chloride Extraction Great Great Basin Paleoclimate Paleohydrology Paleolake Proxies Records Southwestern Vadose Zones |
description |
Thick vadose zones in arid regions recorded past climate changes up to 100 ka, so they are unique archives for continental paleoclimate change and groundwater recharge during the late Quaternary. Despite extensive research on flow and transport in arid regions, the transport properties and general response of arid vadose zones to climate regimes are still not well understood. Some of these issues are addressed with four distinct studies in this dissertation. The first study investigates effects of soil texture, vegetation coverage, and macropores on soil moisture variation at Nevada Test Site (NTS). The simulations show that bare soils have higher soil water content than vegetated soils. Effects of macropore flow on soil water content are insignificant; The second study evaluates the impacts of climate change on solute transport in arid vadose zones. Undisturbed soil cores were collected at ground surface, directly below where tension infiltrometer measurements were made. The water fluxes and Br dispersion coefficients at investigated matric heads were very high due to the coarseness of the soils and possibly due to preferential flow pathways. These high water fluxes are more likely to occur in ephemeral washes. However, higher fluxes through the surface soil would be more likely during wetter climates; The third study simulates paleolake extent in Owens Valley in the last 18 ka. A coupled catchment-lake model is developed in this study, and used to reconstruct the observed paleolake levels for Owens Lake and Searles Lake. Finally, a quantitative time-series of paleoclimate information was obtained; The fourth study models the actual measured chloride profile in Amargosa Desert Research Site (ADRS) with the modified version of the HYDRUS-1D computer code by using variable boundary conditions. The paleoinformation estimated from the third study, and chloride concentration in Greenland ice core (GISP2) are used to prepare the atmospheric boundary file. The simulated chloride profile is in agreement with the ... |
format |
Text |
author |
Dong, Weiquan |
author_facet |
Dong, Weiquan |
author_sort |
Dong, Weiquan |
title |
Extraction of paleohydrology and paleoclimate proxies from vadose zones and paleolake records in the southwestern Great Basin |
title_short |
Extraction of paleohydrology and paleoclimate proxies from vadose zones and paleolake records in the southwestern Great Basin |
title_full |
Extraction of paleohydrology and paleoclimate proxies from vadose zones and paleolake records in the southwestern Great Basin |
title_fullStr |
Extraction of paleohydrology and paleoclimate proxies from vadose zones and paleolake records in the southwestern Great Basin |
title_full_unstemmed |
Extraction of paleohydrology and paleoclimate proxies from vadose zones and paleolake records in the southwestern Great Basin |
title_sort |
extraction of paleohydrology and paleoclimate proxies from vadose zones and paleolake records in the southwestern great basin |
publisher |
Digital Scholarship@UNLV |
publishDate |
2004 |
url |
https://digitalscholarship.unlv.edu/rtds/2591 https://digitalscholarship.unlv.edu/cgi/viewcontent.cgi?article=3590&context=rtds |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Greenland ice core ice core |
genre_facet |
Greenland Greenland ice core ice core |
op_source |
UNLV Retrospective Theses & Dissertations |
op_relation |
https://digitalscholarship.unlv.edu/rtds/2591 https://digitalscholarship.unlv.edu/cgi/viewcontent.cgi?article=3590&context=rtds |
op_rights |
IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/ |
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