Identifier

etd-11102016-092057

Degree

Master of Science (MS)

Department

Geology and Geophysics

Document Type

Thesis

Abstract

Barataria Bay, one of the largest receiving basins for the Mississippi deltaic complex, is the location of a proposed river-sediment diversion for delta restoration. In order to determine how the sediment in the receiving-basin may respond to diversion flows, twenty-five sediment vibracores were collected from a 115 km2 study area located near Myrtle Grove and Bayou Dupont, southeast of New Orleans, LA. These cores were subject to multiple tests, including gamma bulk density scans, grain size analysis, and loss-on-ignition, in order to identify the lithology and stratigraphy. In addition, 137Cs and 14C dating techniques were employed in order to construct a geochronology. A subdelta lithofacies succession was identified and stratigraphically correlated across the basin, indicating more than one subdelta cycle in the sediment record. Geochronology suggests at least one St. Bernard subdelta entered dormancy within the range of 2130 to 2770 ± 30 14C years BP, a period that lasted a minimum of 860 ± 30 14C years, followed by Plaquemines-Belize subdelta progradation that ceased between 280 to 870 ± 30 14C years BP. The presence of channel sands and surviving St. Bernard age peats in the near-surface suggests resistance to compression and subsidence at depths greater than 2 m, providing a viable foundation for stable platform development from the mineral sediment nourishment of a large-scale diversion.

Date

2016

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Bentley, Samuel

DOI

10.31390/gradschool_theses.4427

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