Gulf of Mexico numerous bays and smaller inlets. A number of rivers empty into the gulf, most notably the Mississippi River and Rio Grande in the northern gulf, and the Grijalva and Usumacinta rivers in the southern gulf. The land that forms the gulf's coast, including many long, narrow barrier islands, is almost uniformly low-lying and is characterized by marshes and swamps as well as stretches of sandy beach. The Gulf of Mexico is an excellent example of a passive margin. The continental shelf is quite wide at most points along the coast, most notably at the Florida and Yucatán Peninsulas. The shelf
Structural evolution of the Louisiana gulf coast The observation of minibasins (small sedimentary basins) and other features have suggested that the salt in the Gulf of Mexico primarily moves by spreading under differential sedimentary loading, which needs many conditions (e.g. huge amounts of deposited material above the salt) to be met. However, models and observation of the northern Gulf of Mexico favor gliding via slope instability. Controversies such as this example indicate that this area is structurally complicated. During the Mesozoic Era, the supercontinent Pangaea began to rift apart, forming the Gulf of Mexico basin within the late Triassic and early Jurassic periods. The rifting was accompanied