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The study area is physiographically located between the Sierra Madre Oriental (mountain range) at the east, Neovolcanic axis on the south, Sierra Madre Occidental (mountain range) at the west, and the eastern part of the Province of Chihuahua on the north and northeast.
Platform rocks that crop out in the Sierra Madre Oriental possibly limit the Tampico-Misantla basin to the east and the Mexican Jurassic-Cretaceous geosyncline to the west. It is considered that part of the Sierra Madre Occidental served as a limit to the geosyncline from the west of Jalisco to the east of Sonora. A large part of the area is covered by extrusive igneous rocks, especially the region bordering the Neovolcanic axis, the eastern part of the Sierra Madre Occidental, and the Provinces of Chihuahua and Coahuila. The rocks that were studied consist of limestones, dolomites, shales, sandstones, and marls, mostly of marine origin.
Results of petroleum drilling indicate that some rocks show a degree of metamorphism, especially Jurassic and Triassic rocks. In places, rocks in allochthonous blocks were drilled that showed repetition of the formations, and the drilling objectives could not be reached. In the northern part of Chihuahua, some wells were drilled in bolsons or grabens filled by Tertiary and Quaternary clastic material or overflows and volcanic rocks.
According to the results obtained from this study, the following steps should be taken: (1) increase the studies of geologic and geochemical detail, (2) determine which parts of the area, from the thickness of Mesozoic sediments, are prospects for more detailed studies, (3) use mining information to locate and classify areas of metamorphism, which will surely condemn some areas, especially near the Sierra Madre Occidental, (4) increase drilling of stratigraphic tests as well as those with petroleum objectives, (5) construct Mesozoic isopach maps of Mesozoic formations from geophysical information and surface and subsurface geology, (6) study drilling records to obtain related to geohydrology, ecology, and electrical log information from the surface to total depth of the well. The cost of this program would be very high, but is justified inasmuch as it is so large an area to be explored and the prospects are excellent.
The Mexican Plateau comprises several future oil provinces; however, the southeast of Chiapas, the Gulf of California, and the Balsas trough must be considered to be of great interest.
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