A Search for Controls on the Distribution of Natural, Submarine Oil Seeps in the Gulf of Mexico
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In this research, published literature is used to compile information on 94 submarine oil seeps in the Gulf of Mexico to better understand the factors that control their locations. The majority of Gulf of Mexico submarine, oil seeps are located in the US or Mexico salt provinces which were separated in late Jurassic time by the formation of an arcuate band of oceanic crust that underlies the deep Gulf of Mexico basin. Based on surveys of existing data, nearly no seeps have been identified from the shelves of either the Mexican or US Gulf of Mexico. Of the 57 natural oil seeps in the US Gulf of Mexico, 39 are found along the edges of minibasins, or sub-circular, sedimentary basins bounded on all sides by emergent, salt diapirs. Strata at the edges of mini- basins are usually steeply dipping and faulted along a rotated, normal fault that forms the upper edge of the rising diapir. The steep dip of the bedding and presence of faults provides conduits for the upward rise of oil and the predominance of natural seeps in this setting. Ten seeps were identified in the flat-bottomed centers of the minibasins that are commonly underlain by strata with low dips and fewer conduits for oil to reach the surface. Eight seeps are observed in the deep Gulf of Mexico basin in areas overlying late Jurassic oceanic crust and not overlying a significant salt body. The Mexican salt body however, lacks the high level resolution bathymetric data we have for the US Gulf of Mexico, and for this reason we are not confident that minibasins play the same prominent role in the control of seeps as observed in the US Gulf of Mexico. Of the 37 seeps from the Mexican Gulf of Mexico, nine are on the shelf, ten are on the slope, and 18 are in the deep basin.