Structural Modeling of Salt Tectonics in Central Portion of Santos Basin, Brazil

Abstract

Salt tectonics is one of the most complex deformation processes operating in sedimentary basins. To restore its complex evolution, several gross and poorly controlled simplifications are generally available in sequential methods and tools. A comprehensive restoration technique integrating data, tools and models is proposed here to minimize impacts of such simplifications. The study area in the Santos Basin was intensely deformed by salt tectonics. Two dip sections (A-A’ and B-B’) was restored based on classical backwards cyclic steps: (1) isostatic flexural response to unloading and decompaction; (2) modular fault-related restoration to fit a paleo-bathymetric constraint (a morphologic model supported by well and seismic data); and (3) adjustments in the salt layer to fit bathymetric and isostatic results. Supplementary 1D analysis was used as calibration tool for the restoration, improving the whole process and summarizing the continuous progradation noticed in 2D outcomes. The workflow power is reflected by coherent results. Uncoupling rifting and drifting phases, the salt layer worked as element of local compensation. A depression with highs and lows characterized the relief before salt deposition. The salt deposition virtually buried the basin, producing strong isostatic response. The oceanic sedimentation interacted with salt gravitational gliding affected by the relief heterogeneities.