Dissertation/Thesis Abstract

Controls on Sediment Supply and Erosion in the Song Gianh, Central Vietnam
by Hoang, Tina Hong, M.S., University of Louisiana at Lafayette, 2016, 128; 10163262
Abstract (Summary)

Basins located on continental margins hold important sedimentary records and are useful in determining how tectonics and climate have influenced landscape, erosion, and sediment supply. The Song Gianh drainage basin, located in north central Vietnam, is set in a tectonically inactive area within the East Asian Monsoon (EAM) system. Furthermore, it is a relatively small (∼100 km long) basin, allowing spatially more detailed sampling and characterization.

A suite of geochemical techniques is used to constrain sediment source regions and areas of high chemical alterations, including X-ray fluorescence (XRF) analyses of bulk elemental concentrations, together with 87Sr/ 86Sr and ϵNd isotope analyses. In addition, U-Pb detrital zircon ages are analyzed for provenance and used to quantify sediment contributions from different parts of the catchment. Spatial analyses using Digital Elevation Model (DEM) and Tropical Rainfall Measuring Mission (TRMM) characterize areas of heavy rainfall, high elevations, and steep slopes. These datasets contrast each other with the former analyses of bulk major element compositions, suggesting significant contributions from the upper, wetter, steeper areas of the basin, while zircons indicate contributions from the lower and less wet areas of the Rao Tro tributary. This discrepancy is attributed to anthropogenic influences, as supported by Optically Stimulated Luminescence (OSL) dating of fluvial terraces. These ages determine sedimentation ages of terraces, indicating construction during several time periods, during monsoon strengthening (∼7.5-8.5 ka) and during human settlement at times of increased agriculture, ∼320 ± 90 and 150 ± 140 years ago.

Indexing (document details)
Advisor: Richter, Carl, Clift, Peter
Commitee: Duex, Timothy, Lock, Brian
School: University of Louisiana at Lafayette
Department: Geology
School Location: United States -- Louisiana
Source: MAI 56/01M(E), Masters Abstracts International
Subjects: Geology, Sedimentary Geology
Publication Number: 10163262
ISBN: 9781369179545
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