Sedimentary processes and instability on the Mississippi River Delta Front near the shipwreck of the SS Virginia

Nathan Figueredo; Samuel J. Bentley; Jason Chaytor; Kehui Xu; Navid H. Jafari; Iaonnis Georgiou; Melanie D'amour; Jeffrey Duxbury; Jeffrey B. Obelcz; Jillian Maloney

doi:10.3390/w16030421

Sedimentary processes and instability on the Mississippi River Delta Front near the shipwreck of the SS Virginia

Water

By: Nathan Figueredo, Samuel J. Bentley, Jason Chaytor, Kehui Xu, Navid H. Jafari, Iaonnis Georgiou, Melanie D'amour, Jeffrey Duxbury, Jeffrey B. Obelcz, and Jillian Maloney

https://doi.org/10.3390/w16030421

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Abstract

Sediment cores were collected from a mudflow lobe (80 m water depth) offshore of the Mississippi River’s Southwest Pass in 2017 to better understand the sedimentology near the lobe entraining the SS Virginia shipwreck (sunk by a German U-boat in 1942) and surrounding Mississippi River delta front. Core analyses included ²¹⁰Pb/¹³⁷Cs geochronology, granulometry, and X-radiography. Sediment accumulation rates (SAR) calculated from excess ²¹⁰Pb activity in multicores are 0.22–0.29 cm/y at seabed depths less than 20 cm and 0.29–0.51 cm/y at depths greater than 20 cm. Accumulation rates for ¹³⁷Cs have been ~0.15 to ~0.37 cm/y since 1954 and 1963, respectively. Sediment accumulation rates from ²¹⁰Pb, ¹³⁷Cs geochronology and indicators of relative sedimentation and bioturbation from X-radiographs suggest that rates of sediment accumulation near the Virginia have declined since the mid-20th century. This may be explained by the multi-decade downslope mass transport of the mudflow lobe in which the shipwreck is embedded and decreases in sediment supply delivered offshore from the Mississippi river. Mass transport calculations of the Virginia lobe derived from core properties and published lobe advection rates suggest downslope mass transport is far higher than sediment resupply from the Mississippi river, consistent with recent studies of delta retreat.

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Additional publication details
Publication type	Article
Publication Subtype	Journal Article
Title	Sedimentary processes and instability on the Mississippi River Delta Front near the shipwreck of the SS Virginia
Series title	Water
DOI	10.3390/w16030421
Volume	16
Issue	3
Year Published	2024
Language	English
Publisher	MDPI
Contributing office(s)	Woods Hole Coastal and Marine Science Center
Description	421, 18 p.
Country	United States
State	Mississippi
Google Analytic Metrics	Metrics page