acase@tulane.edu / Deltas are highly complex landscapes characterized by dynamic processes of growth and decline that may be driven by a multitude of factors. A greater level of understanding of deltaic processes is now possible through luminescence dating approaches, which enable the direct dating of clastic deposits. This dissertation applies luminescence dating to identify fundamental mechanisms of delta evolution in a pre-anthropogenic system over centennial to millennial timescales. Topics explored here include the rates and patterns of land-building, and the primary drivers, rates, and spatial variability of subsidence. In addition to applications, this dissertation makes contributions to the science of luminescence dating through the development of new techniques and assessments of luminescence characteristics of sediment in two megadeltas, the Mississippi and Ganges-Brahmaputra-Meghna deltas. The results herein show that river-dominated deltas operating under natural conditions grow in a radial pattern where sediment resources are directed by avulsions that occur over a broad spatial zone extending well landward of the delta, and decline in elevation due largely to compaction induced by sediment loading. Zeroing (or bleaching) of the luminescence clock is tested through a new "Bleaching Index" that compares multiple signals obtained from polymineral sediment, and through measurements of modern analogues. These tests show that quartz silt is likely to be well-bleached in large river-delta systems, a finding which extends the prospects and geographic range of luminescence dating. / 1 / Elizabeth L. Chamberlain

No description available.

Thesis (Ph.D.) - University of Glasgow, 2007. / Ph.D. thesis submitted to the Department of Geographical & Earth Sciences, University of Glasgow, 2007. Includes bibliographical references. Print version also available.

Thesis (Doctor)--Technische Universiteit Delft, 2006. / Includes bibliography (p. 134-136).

No description available.

published_or_final_version / abstract / Earth Sciences / Doctoral / Doctor of Philosophy

The objective of this project is to apply the Optical Stimulated Luminescence (OSL) technique to date the palaeo sediment from Mu Us Desert, part of the Inner Mongolia in northern China and reconstruct the palaeo environment. Five OSL samples were collected from Dagouwan, Salawusu River Valley at Inner Mongolia by Dr S. H. Li and his team in 2009. Extraction of 150μm to 180μm silt-size feldspar from collected dune sand, lacustrine facies and fluvial facies samples and running of luminescence dating therefore to obtain the age from 50ka to 90ka. Climate proxies - magnetic susceptibility, grain size, fossil vertebrates and fossil pollens have been analyzed and it is concluded that significant climate change occurred within this period, which change from domination of warm, humid and rainy summer monsoons (before 70ka) to cold, wind, windy strengthened dry winter wind and back to warm and humid again after 55ka. / published_or_final_version / Applied Geosciences / Master / Master of Science

abstract / Earth Sciences / Doctoral / Doctor of Philosophy

Thesis (Ph. D.)--University of Hong Kong, 2008. / Also available in print.

Thesis (M. Phil.)--University of Hong Kong, 2008. / Also available in print.