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Integration of Deep Image Seismic Reflection Surveys and A New Reflection Refraction Profile To Clarify Basin-Wide Gulf of Mexico Interpretation: Part 2, Mesozoic and Tertiary Framework


Study of Gulf of Mexico Geology has been hindered by poor seismic imaging of Mesozoic and Early Tertiary section and by datasets that lack regional extent. Five PSDM seismic surveys acquired in the past seven years are integrated and interpreted, and present a unique, mega-regional view of the full extent of the stratigraphic and tectonic elements in the GoM basin. Integration of 3 reprocessed legacy-data surveys, spanning 6 states and Mexican deep water, with 2 offshore, long offset and deep tow surveys provides a consistently processed and tied dataset that allows the interpreter to compare and contrast geologic features from different sides of the basin. This view provides important constraints on GoM post-rift events from onshore west Texas to Florida, from the GoM shelf areas into deep water, and from Mexican waters across the Yucatan. The data reveal robust Gulf margin fairways of Wilcox in the western and Mexican Gulf shedding sediments into deep water, but those sediments are confined by the significant barrier to the east of the steeply rising Cretaceous carbonate margins. The northern Gulf shows a linked extension-to-contraction gravity-driven system with accompanying salt response, ranging in age from Upper Jurassic through Tertiary. The highlights include an onshore Gulf rim characterized by the development of highly faulted Mesozoic section soling out onto a base Louann detachment, and the development in shelf to deep water of several major salt evacuation events of large regional extent, including one in Early Cretaceous and one in Early Oligocene. The early event proposes active salt extrusion of a regional salt canopy onto Upper Jurassic sediments sitting on oceanic crust and is consistent with ideas of a continental/oceanic crustal boundary placed well-northward of present-day Sigsbee Escarpment. Both canopies are remobilized in Oligocene to Present, forming numerous salt welds, and the present-day canopy. At a similar time, contraction is additionally accommodated in the GoM by the deepwater fold belts. A second-stage, Lower Cretaceous rift event is documented in the southeastern Gulf data and suggests new play ideas. A high resolution, reflection/refraction profile that spans from the onshore of East Texas to the abyssal plain of Keathley Canyon is integrated with refraction models and previous long offset data, and has potential to further clarify the nature and timing of early structuring and deposition of the GoM basin.