The Louann Salt is a widespread evaporite formation that formed in the Gulf of Mexico during the Callovian in the mid Jurassic. The Louann formed in a rift as the South American and North American Plates separated, from an embayment of the Pacific Ocean. The Louann underlies much of the northern Gulf coast from Texas to the Florida panhandle and extends beneath large areas of the Gulf coastal plain of Mississippi, Louisiana and Texas.