Persistent Link:
http://hdl.handle.net/10150/184418
Title:
Northern Australian paleofloods as paleoclimatic indicators.
Author:
Wohl, Ellen Eva.
Issue Date:
1988
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.
Abstract:
Paleoflood data are restrictive reflections of climatic conditions, representing one component of a region's climate; high rainfall intensity storms. In regions with a fairly simplistic, uniform hydroclimatological setting (floods above a given magnitude threshold are caused by predominantly one type of atmospheric circulation pattern), the temporal distribution of floods reflects that of the causal circulation pattern. Slackwater-deposit-based paleoflood reconstructions for three rivers in northern Australia cover an aggregate of 1200 years. Slackwater deposits (SWD) are fine-grained sediments which settle from suspension in low velocity areas during floods. These deposits approximate the flood's high water level, and allow reasonably accurate estimation of discharge. Radiocarbon dating of associated organics, and thermoluminescence (TL) dating of the 90-125 μm quartz fraction of the sediments, produce a paleoflood chronology. In this study, radiocarbon ages on SWD ranged from 1200 yr BP to modern, while TL ages on SWD and other fluvial sediments ranged from 2.6 to 60 ka. TL dating appears to have a large temporal range (1-100 ka) and a restricted spatial range (the lower reaches of a basin), while radiocarbon dating has a more restricted temporal range (0-35,000 yr BP) and a large spatial range (anywhere in the basin). The northern Australian paleoflood data formed clusters at 300-440 yr BP and 160 yr BP-present. This distribution is attributed to variations in the intensity of the El Nino/Southern Oscillation (ENSO) circulation (which prevents floods from occurring in northern Australia), and the anti-ENSO circulation (which is associated with large floods).
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Paleoclimatology -- Australia.; Floods -- Australia.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Geosciences; Graduate College
Degree Grantor:
University of Arizona

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleNorthern Australian paleofloods as paleoclimatic indicators.en_US
dc.creatorWohl, Ellen Eva.en_US
dc.contributor.authorWohl, Ellen Eva.en_US
dc.date.issued1988en_US
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.abstractPaleoflood data are restrictive reflections of climatic conditions, representing one component of a region's climate; high rainfall intensity storms. In regions with a fairly simplistic, uniform hydroclimatological setting (floods above a given magnitude threshold are caused by predominantly one type of atmospheric circulation pattern), the temporal distribution of floods reflects that of the causal circulation pattern. Slackwater-deposit-based paleoflood reconstructions for three rivers in northern Australia cover an aggregate of 1200 years. Slackwater deposits (SWD) are fine-grained sediments which settle from suspension in low velocity areas during floods. These deposits approximate the flood's high water level, and allow reasonably accurate estimation of discharge. Radiocarbon dating of associated organics, and thermoluminescence (TL) dating of the 90-125 μm quartz fraction of the sediments, produce a paleoflood chronology. In this study, radiocarbon ages on SWD ranged from 1200 yr BP to modern, while TL ages on SWD and other fluvial sediments ranged from 2.6 to 60 ka. TL dating appears to have a large temporal range (1-100 ka) and a restricted spatial range (the lower reaches of a basin), while radiocarbon dating has a more restricted temporal range (0-35,000 yr BP) and a large spatial range (anywhere in the basin). The northern Australian paleoflood data formed clusters at 300-440 yr BP and 160 yr BP-present. This distribution is attributed to variations in the intensity of the El Nino/Southern Oscillation (ENSO) circulation (which prevents floods from occurring in northern Australia), and the anti-ENSO circulation (which is associated with large floods).en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectPaleoclimatology -- Australia.en_US
dc.subjectFloods -- Australia.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGeosciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.identifier.proquest8814286en_US
dc.identifier.oclc701247335en_US
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