Show simple item record

dc.contributor.advisorSletten, Ronald Sen_US
dc.contributor.authorToner, Jonathan Danielen_US
dc.date.accessioned2012-09-13T17:33:28Z
dc.date.available2013-03-13T11:04:55Z
dc.date.issued2012-09-13
dc.date.submitted2012en_US
dc.identifier.otherToner_washington_0250E_10523.pdfen_US
dc.identifier.urihttp://hdl.handle.net/1773/20756
dc.descriptionThesis (Ph.D.)--University of Washington, 2012en_US
dc.description.abstractTaylor Valley, Antarctica, preserves a record of late Cenozoic Antarctic glaciations. The incursion of the Sea Ice Sheet (RSIS) into lower Taylor Valley during the Last Glacial Maximum is believed to have dammed large proglacial paleolakes. These inundation events are studied by analyzing soluble salt distributions along elevation transects. To better interpret the salt record, factors controlling salt composition and concentration are studied in detail in a soil sampled to 2.1 m depth. In addition, the deposition age of fluvial sediments and possible deltas are dated using luminescence of quartz and feldspar minerals. Soluble salts in Taylor Valley vary with distance from McMurdo Sound. In western Taylor Valley, soluble salts are high and are similar to seawater. In eastern Taylor Valley, soluble salts are low and are comprised primarily of Na-HCO<sub>3</sub>. Soluble salt distributions indicate that during the Last Glacial Maximum, the RSIS filled eastern Taylor Valley, thereby damming paleolakes in western Taylor Valley to approximately 300 m elevation. As the RSIS retreated, smaller paleolakes formed in eastern Taylor Valley up to about 120 m elevation. Na-HCO<sub>3</sub> salts in eastern Taylor Valley derive from calcite dissolution and cation exchange reactions as water percolates into soils. This mechanism of Na-HCO<sub>3</sub> formation predicts that Ca-Cl will evolve as a byproduct. Reactive transport at freezing temperatures was modeled using the modified versions of the geochemical speciation programs PHREEQC and FREZCHEM. This model reveals that cation exchange reactions may account for the Ca-Cl enrichment often found in Dry Valley groundwaters, including the enigmatic Don Juan Pond. To complement the soluble salt record, fluvial terraces in Taylor Valley were dated using both quartz and feldspar luminescence. Quartz and feldspar luminescence results are consistent and indicate that terraces in eastern Taylor Valley are between 4 to 10 Ka old. These luminescence ages are 5 to 12 Ka younger than published <super>14</super>C dates. It is suggested that the <super>14</super>C ages date older glaciolacustrine sediments underlying fluvial terrace sediments and reflect a deglaciation record as the RSIS retreated from Taylor Valley. The luminescence ages indicate that terraces were deposited during warmer climatic conditions that followed deglaciation.en_US
dc.format.mimetypeapplication/pdfen_US
dc.language.isoen_USen_US
dc.rightsCopyright is held by the individual authors.en_US
dc.subjectAntarctica; Don Juan Pond; Dry Valleys; luminescence; paleolakes; transport modelingen_US
dc.subject.otherGeologyen_US
dc.subject.otherGeochemistryen_US
dc.subject.otherEnvironmental geologyen_US
dc.subject.otherEarth and space sciencesen_US
dc.titleUsing Salt Accumulations and Luminescence Dating to Study the Glacial History of Taylor Valley, Antarcticaen_US
dc.typeThesisen_US
dc.embargo.termsRestrict to UW for 6 months -- then make Open Accessen_US


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record