Generation of Overpressures, Fluid Migration, Mass Transport and Diagenesis Associated with Deformation and Dissolution of Allochthonous Salt Sheets in the Deep Water Gulf of Mx..

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9805459NunnLarge-scale vertical and lateral migration of salt bodies in the Gulf of Mexico sedimentary basin has played an important role in the stratigraphic, structural, and hydrogeologic evolution of this portion of the earth's crust. We propose to extend our previous work in older onshore sediments out into the deep water Gulf, where active salt deformation, fluid flow, and heat and solute transport makes it an ideal area to test hypotheses regarding coupling between fluid flow, mass transfer, diagenesis, and tectonic processes.We will carry out a three-year study of fluid flow and chemical reaction on the tens of kilometer minibasin scale. Numerical modeling will be used to investigate the generation of overpressure and compaction-driven flow, coupled density-driven and compaction driven flow, over pressuring and episodic fluid flow within ductile shearing zones, and physical controls on salt dissolution and pore water salinity on the minibasin scale. Integrated into this work will be field-documented spatial variations in formation water and sediment properties derived from wireline logs and calculations of sediment-fluid diagenetic reactions in systems of widely varying salinity.While our studies will be focused on the Gulf Basin, the results will be broadly applicable to any sedimentary basin containing salt. Study of this currently active basin will provide important clues to the evolution of basins now tectonically inactive or which have been largely destroyed through major tectonic processes.