MESOZOIC EVOLUTION OF GULF OF MEXICO: INTERACTION BETWEEN TECTONICS AND SEDIMENTATION

The formation of The Gulf of Mexico (GoM) Basin started during the Triassic - Early Cretaceous rifting between the North American plate and Yucatan micro plate. Opening of the basin commenced with ~60 Ma long rifting throughout Late Triassic to Middle Jurassic followed by sea floor spreading and counter clockwise rotation of the Yucatan block during Late Jurassic-Early Cretaceous. The rifting was initiated probably along the tectonically weak zone inherited from the Late Paleozoic Ouachita Orogeny. Non-marine siliciclastic sediments (red beds) and associated volcanic rocks deposited in rapidly subsiding grabens represent the Late Triassic-Middle Jurassic rifting phase. Moreover, the shelfal position of marine carbonates as well as fluvial and deltaic siliciclastic characterizes Late Jurassic-Early Cretaceous phase of thick salt accumulation as well as crustal cooling and subsidence.

During the early stage of rifting and extension, Triassic syn-rift graben-fill red-beds of Eagle Mills Formation were deposited above pre-rift Paleozoic basement. This locally deposited sequence were designated as the oldest Mesozoic strata in the Basin. Marine transgression into the GoM during Middle Jurassic initiated the deposition of syn rift Werner Formation and Louann Salt. Basement topography influenced the differential thickness of the salt deposits over the basin as well as the distribution of Late Jurassic post rift deposits (Norphlet, Smackover, Haynesville Formations, and Cotton Valley Group). Late Jurassic post rift deposits represents a wide range of depositional environments, from shallow shelf to aeolian, indicating multiple local transgression-regression cycles of the sea. A major lowering of sea level in the GoM during the Lower Cretaceous exposed the shelf margin and an erosional event started. A transgression followed by this erosional episode in combination with the Laramide orogeny affected the Late Cretaceous depositions.