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Mapping is based on both ground observations and aerial observations from a helicopter, August 11-19 and September 1-5, 1970, and supplemented by interpretation from aerial photographs. Bedrock geology chiefly by R.M. Chapman, and surficial geology chiefly by W.E. Yeend.
The U.S. Geological Survey is conducting a geological and geophysical study of the northeastern United States Outer Continental Shelf and the adjacent slope from Georges Bank to Cape Hatteras. The study also includes the adjacent Coastal Plain because it is a more accessible extension of the shelf. The total study area is about 324,000 sq km, of which the shelf and slope constitute about 181,000 sq km and the Coastal Plain constitutes 143,000 sq km. The shelf width ranges from about 30 km at Cape Hatteras to about 195 km off Raritan Bay and on Georges Bank. Analyses of bottom samples make it possible to construct a preliminary geologic map of the shelf and slope to a water depth of 2,000 m. The oldest beds cropping out in the submarine canyons and on the slope are of early Late Cretaceous age. Beds of Early Cretaceous and Jurassic age are present in deep wells onshore and probably are present beneath the shelf in the area of this study. Such beds are reported beneath the Scotian Shelf to the northeast where they include limestone, salt, and anhydrite. Preliminary conclusions suggest a considerably thicker Mesozoic sedimentary sequence than has been previously described. The region is large; the sedimentary wedge is thick; structures seem favorable, and the hydrocarbon potential may be considerable.
This data set consists of digital data and accompanying documentation of the surficial geology of the 1:250,000-scale Tulsa quadrangle, Oklahoma. The original data are from the Geologic Map, sheet 1 of 4, included in the Oklahoma Geological Survey publication, 'Reconnaissance of the water resources of the Tulsa quadrangle, northeastern Oklahoma', Hydrologic Atlas 2, Marcher and Bingham, 1971. The geology was compiled by M.V. Marcher, in 1969.
Regional geological and geophysical studies are being conductedby the U.S. Geological Survey to determine the structural framework of the area from Cape Hatteras to the northeastern edge of Georges Bank in order to assess the petroleum potential of the Atlantic Outer Continental Shelf. Preliminary interpretations of geophysical data and integrating gravity and magnetic data from the U.S.Naval Oceanographic.Office with seismic surveys, suggest that the linear ridge reported by Drake and others in 1959 is deeper and is farther west than previously suspected. Although it is not observed under the seaward extension of the Norfolk arch, it can be traced trough from the south side of the Baltimore Canyon trough northeastward toward the eastern edge of Georges Bank trough. This ridge seems to form the eastward edge of a Mesozoic depocenter in the Baltimore Canyon area in which more than 10 km of relatively undisturbed post-Paleozoic sediments accumulated. The types of structures mapped are ingeneral agreement with the sedimentary structural models hypothesized for the Baltimore Canyon trough by Kraft and others in 1971. More than 8 km of sediments are present beneath the continental shelf on Georges Bank. On the basis of the preliminary regional geophysical studies, it appears that thick sedimentary sections and structural traps favorable for the accumulation of petroleum exist under the Atlantic Continental Shelf off the northeastern part of the United States.
The U.S. Geological Survey, in cooperation with the U.S. Department of State, quantitatively assessed the potential for unconventional oil and gas resources within the onshore portions of the Tampico-Misantla Basin, Burgos Basin, and Sabinas Basin provinces of northeastern Mexico. Unconventional resources of the Veracruz Basin were not quantitatively assessed because of a current lack of required geological information. Unconventional resources include shale gas, shale oil, tight gas, tight oil, and coalbed gas. Undiscovered conventional oil and gas resources were assessed in Mexico in 2012.
Petroleum deposits (primarily gas) in northeastern Mexico occur in two main basins, the Tertiary Burgos basin and the Mesozoic Sabinas basin. About 90 gas fields are present in the Burgos basin, which has undergone active exploration for the past 30-40 years. Production in this basin is from Oligocene and Eocene nearshore marine and deltaic sandstone reservoirs. Most of the fields are small to medium in size on faulted anticlinal or domal structures, some of which may be related to deep-seated salt intrusion. Cumulative production from these fields is about 4 trillion cubic feet gas and 100 million barrels condensate and oil. Since 1975, about 10 gas fields, some with large production rates, have been discovered in Cretaceous carbonate and Jurassic sandstone reservoirs in the Sabinas basin and adjacent Burro-Picachos platform areas. The Sabinas basin, which is in the early stages of exploration and development, may have potential for very large gas reserves. The Sabinas basin is oriented northwesterly with a large number of elongate northwest- or west-trending asymmetric and overturned Laramide anticlines, most of which-are faulted. Some of the structures may be related to movement of Jurassic salt or gypsum. Lower Cretaceous and in some cases Jurassic rocks are exposed in the centers of the larger anticlines, and Upper Cretaceous rocks are exposed in much of the remainder of the basin. A thick section of Upper Cretaceous clastic rocks is partly exposed in tightly folded and thrust-faulted structures of the west-east oriented, deeply subsided Parras basin, which lies south of the Sabinas basin and north of the Sierra Madre Oriental fold and thrust belt south and west of Monterrey. The sedimentary cover of Cretaceous and Jurassic rocks in the Sabinas and Parras basins ranges from about 1,550 m (5,000 ft) to 9,000 m (30,000 ft) in thickness. Upper Jurassic rocks are composed of carbonate and dark organic shaly or sandy beds underlain by an unknown thickness of Late Jurassic and older redbed clastics and evaporites, including halite. Lower Cretaceous rocks are mainly platform carbonate and fine clastic beds with some evaporites (gypsum or anhydrite) deposited in two main rudist reef-bearing carbonate cycles. Upper Cretaceous rocks are mainly continental and marine clastic beds related to early development of the Laramide orogeny. This Upper Cretaceous sequence contains a marine shale and deltaic clastic complex as much as 6,000 m (20,000 ft) or more thick in the Parras basin, which grades northward and eastward to open marine, fine clastic beds. The Burgos basin, which is an extension of the Rio Grande embayment of the western Gulf of Mexico basin province, contains an eastward-thickening wedge of Tertiary continental and marine clastics. These beds are about 1,550 to 3,000 m (5,000-10,000 ft) thick in the outcrop belt on the west side of the basin and thicken to more than 16,000 m (50,000 ft) near the Gulf Coast.
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