Jurassic evolution of the southeastern Gulf of Mexico

A new two-stage opening model for the Gulf of Mexico basin is constrained by a refined oceanic crust definition and by the known kinematic framework of the large continental blocks (North America plate, Afro-South America plate). Jurassic to earliest Cretaceous plate movements were modeled using Plates2.0 plate reconstruction software. During the Late Triassic? to late Middle Jurassic syn-rift stage the relatively stable Yucatan block translated southeastward along a major transform zone in eastern Mexico. This motion accommodated a large amount of extension in the area of the future northern Gulf. Rock evidence from the rim of the basin indicates that throughout the rifting phase the basin was emergent and an area of erosion with only localized continental sedimentation and volcanism. A rotation pole for the Yucatan block in the southeastern Gulf of Mexico (23.18 N, 84.24 W) is proposed for the late Middle Jurassic (Callovian) to earliest Cretaceous (Berriasian) spreading stage. Around this pole the Yucatan block rotated about 42 degrees counterclockwise to accommodate the newly formed oceanic crust in the basin. Reconstruction of the Louann and Campeche salt provinces shows that some of the original salt was deposited in an already partially opened oceanic basin in Callovian to early Oxfordian time. The spreading stage was characterized by cessation of continental margin volcanism, major transgression and basinwide marine sedimentation. Seismic data provide clear evidence that in the southeastern Gulf of Mexico, between the relatively stable Yucatan and Florida blocks, Late Jurassic northwest-trending continental rift evolved contemporaneously with the Late Jurassic oceanic crust formation in the Gulf of Mexico. Rifting in the southeastern Gulf ceased by late Berriasian time, providing the only constraint for the completion of oceanic crust formation in the Gulf of Mexico. Callovian to late Berriasian syn-rift sedimentation in the southeastern Gulf of Mexico occurred in half- and full-graben settings. In the active grabens continental sedimentation is interpreted during the Callovian to Oxfordian? period. Shallow- to deep-marine sedimentation characterized the Kimmeridgian? to Berriasian when seaway between the Gulf of Mexico and the proto-Caribbean was established.