Ray G. Martin, 1978. "Northern and Eastern Gulf of Mexico Continental Margin: Stratigraphic and Structural Framework", Framework, Facies, and Oil-Trapping Characteristics of the Upper Continental Margin, Arnold H. Bouma, George T. Moore, James M. Coleman
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The continental margin of the northern Gulf of Mexico extends from DeSoto Canyonto northern Mexico and from more than 300km in land in the central Gulf Coast to the deepgulf floor.It is composed of abroadwedge of Mesozoic and Cenozoic strata that accumulated almost continuously from Jurassic time to the present. Mesozoic and Cenozoic deposits are more than 15km thick beneath the lower coastal plain and adjacent continental shelf. Forthe mostpart,the margin is a Cenozoic clastic embankment built by the inpouring of sediments from the continental interior after the Late Cretaceous-Paleocene Laramide orogeny.Sediment supplies generally exceeded the subsidence rate,prograding the seaward face of the margin more than 400 km from the edge of Cretaceous carbonate platform deposits under the coastalplain,to the present position of the continental slope.Along the inner regions of the coastal plain from Alabama to southwestern Texas,updip members of Mesozoic and Cenozoic units rest unconformably on complexly folded and faulted Paleozoic rocks of the Ouachita and Appalachian tectonicbelts.
Major structural anomalies affecting the Mesozoic-Cenozoic sequence of the coastalplain,shelf,and slope are salt diapirs,growth faults,and shale uplifts.Salt structures are concentrated in interior basins in the inner coastal plain,along the lower coast from central Texas to DeSoto Canyon,and across the continental shelf to the foot of the slope.Regional systems of growth faults slice through Cenozoic units beneath coastal Texas and Louisiana and in the adjacent shelf.Many of these faults formed as a response to sediment overloads along Tertiary and Quaternary shelf edges,to differential compaction associated with abrupt changes insediment thickness and gross lithology,and(locally)to the withdrawal of large volumes of salt from depth during diapiric growth.
The continental margin of the eastern Gulf of Mexico is dominated by the Florida platform,compose do fathick accumulation of bathyal to neritic carbonate rocks and evaporite deposits of Mesozoic and Cenozoicage.The platform is fronted by aprominent escarpment built by shelf-edge reef complexes during the Early Cretaceous.The northern half of the platform was built on a continental foundation composed of upper Precambrian and lower Paleozoic igneous and meta mor-phic rocks and capped by undeformed clastic sediments of Ordovician, Silurian, and Devonian age.Triassic red beds and associated diabase are common in the extensive graben systems that underlie northwestern Florida.Southern peninsular Florida is underlain by basement composed of volcanic and hypabyssal rocks of Triassic and Early Jurassic age. Geophysical data suggest similar basement complexes beneath the West Florida Shelf and Slope.
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Framework, Facies, and Oil-Trapping Characteristics of the Upper Continental Margin
The Gulf of Mexico covers an area of more than 1,500,000sq km, has a maximum depth of about 3,700m, and includes many of the geomorphic features of large oceans.The continental shelf, slope, rise, and abyssal plain comprise the major physiographic provinces of the guldf and contain avariety of subprovinces distinguished by topographic character and geomorphic history.
The gulf shelf is a relatively smooth, gently sloping surface marked locally bylow-relief featuresformed by sea-level fluctuation during the Pleistocene, reef growth, near-surface movement of diapiric salt and mud, and faulting. Shelf width varies from about 280km off the Florida and Yucatan Peninsulas to less than 10km at the Mississippi Delta. The continental slope consists of a considerable variety of physiographic subprovinces and individual features that encircle the deep gulf floor.
The distinctive subprovinces of the gulf slope have evolved in response to reef building and constructional sedimentation on the Florida and Yucatan carbonate platforms; erosion, nondeposition, slumping, and fault ing in the Straits of Florida and Yucatan Channel; salt diapirism and differential sedimentation in the region off Texas and Louisiana; the largeaccumulation of mainly Pleistocene sediment on a former continental slope seaward of the Mississippi Delta; tectonic uplift and diapirism in theGolfo de Campeche; and shale mobilization of feastern Mexico. In contrast to the greatly varied, irregular topography of the continental slope,thedeep seafloor of the gulf (composed of continental rise and abyssal plainprovinces) is an almost featureless plain smoothed by turbidite and pelagic sedimentation and marked locally bylow-relief knolls, sedimentary aprons, and small-leveed channels.