Salt deposition, loading and gravity drainage in the Campos and Santos salt basins
Ian Davison, Lee Anderson, Peter Nuttall, 2012. "Salt deposition, loading and gravity drainage in the Campos and Santos salt basins", Salt Tectonics, Sediments and Prospectivity, G. I. Alsop, S. G. Archer, A. J. Hartley, N. T. Grant, R. Hodgkinson
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The southern Brazilian salt basin, comprising the three sub-basins Santos, Campos and Espirito Santo, was deposited over a pre-existing rifted basin with c. 1–2 km of relief bordered by an outer basin high that separated the basin from the conjugate African margin. The evaporites are interpreted to have been deposited very rapidly (<1 Ma) during the waning of extension. Deposition of salt caused rapid loading of the basin, so that further basin subsidence occurred and mobile salt drained from structurally higher zones into the subsiding basins. Seismic evidence indicates that downslope salt drainage occurred before any sediment overburden accumulated. Withdrawal synclines within salt units developed adjacent to diapirs, which have intruded the evaporite sequence, and salt extrusions are observed which were buried by later salts. The early movement of the salt probably contributed to significant fault reactivation and redistribution of salt load, so that the final half-graben salt fill reached up to 4.5 km thick where only 1–2 km of salt was originally deposited.
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Salt Tectonics, Sediments and Prospectivity
In this timely volume, geoscientists from both industry and academia present a contemporary view of salt at a global scale. The studies examine the influence of salt on synkinematic sedimentation, its role in basin evolution and tectonics, and ultimately in hydrocarbon prospectivity. Recent improvements in seismic reflection, acquisition and processing techniques have led to significant advances in the understanding of salt and sediment interactions, both along the flanks of vertical or overturned salt margins, and in subsalt plays such as offshore Brazil. The book is broadly separated into five major themes covering a variety of geographical and process-linked topics. These are: halokinetic sequence stratigraphy, salt in passive margin settings, Central European salt basins, deformation within and adjacent to salt, and salt in contractional settings and salt glaciers.