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The Messinian Mediterranean Crisis: A Model for the Permian Delaware Basin?

Abstract

Basin analysis and high resolution seismic sequence stratigraphy of the Delaware and Egyptian Mediterranean show the Mediterranean Messinian Crisis of evaporate deposition to bear similarities to the late Permian both on global and regional scales. Comparison of the two basins provides new insight which can assist petroleum exploration in both basins. During the Permian and its close, global sea level was unusually low. In addition to glaciation in the southern Gondwanaland, other contributions to globally low sea level are a globally decreased rate of sea floor spreading and ocean basin water transfer such as that occurred during the closing and opening of the Mediterranean during the Messinian. With such a lowering of sea level, methane hydrate gasification would provide an enormous increase in methane as a greenhouse gas leading to the documented elevation in global temperatures, restricted oceanic circulation. Without shelves for carbonate deposition a significant transfer of inorganic carbon to organic carbon and with increased evaporation rates a transfer of reduced sulfur to oxidized sulfur exogenic reservoirs, and with oceanic and basinal anoxic conditions led to the preservation of significant amounts of organic carbon which led to the formation of extensive source rocks. As the sea level continued to fall, and with accompanying Mesozoic Pangea break-up exacerbating localized uplifts owing incipient rifting nuclei, borders to inlets closed and vast aqueous evaporite deposition occurred not only in the Delaware but in numerous basins around the world. With this evaporation, the water would be gradually transferred back into the global system, and sea level began to rise once again to its preceding levels. The comparison of the Delaware and Mediterranean basin evaporate fill is remarkably similar in salt mineralogical distribution, following an approximate Usiglio sequence away from the inlets (Hovie and Gilbratar, respectively) laterally of calcite, anhydrite, gypsum, and halite. During times of low intrabasinal relative sea level, significant downcutting and fluvial incision occurs with basin floor fan deposition. The subsequent flooding sealed these incised valleys and the Regressive System Tract fluvial terraces in the paleo Nile-delta. Analogous traps in the Delaware basin margins for the overlying Triassic-Jurassic have yet to be fully exploited, while analogous deep water fans are continuing to be successfully explored in both basins.