The shallow stratigraphy and sand resources offshore from Cat Island, Mississippi

Open-File Report 2014-1070
Prepared in cooperation with the U.S. Army Corps of Engineers
By: , and 

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Abstract

In collaboration with the U.S. Army Corps of Engineers, scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center collected over 487 line kilometers (> 300 miles) of high-resolution geophysical data around Cat Island, Mississippi, to improve understanding of the island's geologic evolution and identify potential sand resources for coastal restoration. In addition, 40 vibracores were collected on and around the island, generating more than 350 samples for grain-size analysis.


The results indicate that the geologic evolution of Cat Island has been influenced by deltaic, lagoonal/estuarine, tidal, and oceanographic processes, resulting in a stratigraphic record that is quite complex. The region north of the island is dominated by lagoonal/estuarine deposition, whereas the region south of the island is dominated by deltaic and tidal deposition. In general, the veneer of modern sediment surrounding the island is composed of newly deposited sediment and highly reworked relict sediments. The region east of the island shows the interplay of antecedent barrier-island change with delta development despite a significant ravinement of sediments. The data show from little to no modern sediment east of the island, exposing relict sediments at the seafloor.


Finally, the data reveal four subaqueous sand units around the island. Two of the units are northwest of the modern island and one is southwest. Given the dominant, westward, longshore transport along the Mississippi and Alabama barrier islands, the geographic location of these three units suggests that they do not contribute to the modern sediment budget of Cat Island. The last unit is directly east of the island and represents the antecedent island platform that has supplied sand over geologic time for creation of the spits that form the eastern shoreline. Because of its location east of the island, the antecedent island unit may still supply sediment to the island today.

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Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title The shallow stratigraphy and sand resources offshore from Cat Island, Mississippi
Series title Open-File Report
Series number 2014-1070
DOI 10.3133/ofr20141070
Year Published 2014
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) St. Petersburg Coastal and Marine Science Center
Description viii, 74 p.
Country United States
State Mississippi
Other Geospatial Cat Island
Online Only (Y/N) Y
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