Post mid-Cretaceous sequence stratigraphy and depositional history of northeastern Gulf of Mexico

A sequence stratigraphic analysis of the post mid-Cretaceous sedimentary rocks in the northeastern Gulf of Mexico, based on an extensive seismic grid, has resulted in the recognition and mapping of fifteen depositional sequences. Integrated information from isochron maps of each sequence, seismic facies, paleontological and lithological information from wells, and regional depositional background were used to recognize different depositional environments and their distribution for each sequence. Mapping results show that depositional environments of this area had changed dramatically both temporally and spatially. Sediment supply, tectonic setting and relative sea level all influence these changes.; The northeastern Gulf of Mexico consists of four main tectono-stratigraphic areas. THE CENTRAL DEEP BASIN was a basinal environment, sediment starved from mid-Cretaceous to Oligocene and subsequently an active clastic depositional setting receiving large volume of Neogene coarse clastic sediment. THE MISSISSIPPI/ALABAMA SHELF was a stable area with mixed/alternating carbonate and clastic sedimentation from mid-Cretaceous to Oligocene, followed by rapid clastic sedimentation since the Early Miocene. THE DESOTO TROUGH/CANYON area was a more rapidly subsiding region separating the Alabama Shelf from the western Florida Shelf. It has formed an important sedimentary boundary between a clastic depositional area to the west and a carbonate depositional area to the east since the Late Cretaceous. THE WESTERN FLORIDA SHELF was mainly a stable carbonate setting since the Early Cretaceous.; Three major changes in depositional environment changes have occurred since the Early Cretaceous: (1) between the Early and Late Cretaceous, the widespread Early Cretaceous carbonate platform environment changed to a deeper mixed clastic/carbonate environment; (2) in the late Oligocene, the depositional environment reverted to a widespread regional carbonate setting with an associated large and well developed reef system; and (3) this carbonate environment was replaced in Early Miocene by a thick clastic sequence, sourced by the Mississippi River, that prograded about 450 km to the SE during the Neogene.; A large yet short lived (6.9–4.5 Ma) canyon system (Alabama Canyon), oriented NE and dipping to the SW, developed on the Alabama Shelf when the main clastic depositional system approached this area.