The Tuscaloosa Marine Shale (TMS) is a sedimentary rock formation that consist of organic-rich fine-grained materials (sediments) deposited in a marine environment that existed across the Gulf Coast region approximately 90 million years ago.
The TMS includes the Eagle Ford Shale being similar in geological age.
The August, 1987 Bulletin (Volume 7) of the LSU-Basin Research Institute (BRI), Baton Rouge, indicates a potential reserve of about 7 billion barrels of oil in the TMS.
Its thickness varies from 500 feet in southwestern Mississippi to more than 800 feet in the southern part of the Florida Parishes in southeastern Louisiana, within an approximate depth range of 11,000 feet to the north to more than 15,000 feet to the south.