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Granite Mountain is a solid dome, also known as a bornhardt, of pink granite (pink granite is also known as Sunset Red) rising over 860 feet one mile west of Marble Falls, Texas. Since quarry operations began in the late 19th century, the distinctive pink-red colored rock has been used in the construction of the Texas State Capitol in Austin ...
The area is part of the Rio Grande rift, where the Earth's crust is being stretched and thinned. The rift is characterized by deep sedimentary basins, recent faulting and volcanic activity, and unusually high heat flow upwards from the Earth's mantle. Kilbourne Hole and Hunt's Hole are located on the same north-trending fault of the Fitzgerald ...
The Rio Grande rift is a north-trending continental rift zone. It separates the Colorado Plateau in the west from the interior of the North American craton on the east. [ 1 ] The rift extends from central Colorado in the north to the state of Chihuahua , Mexico , in the south. [ 2 ]
Early and middle Mesozoic strata are, on the whole, poorly represented in Texas. Triassic rocks are limited to sandstone and shale in the Panhandle, while the Jurassic record is almost nonexistent at the surface. [7] During the Late Triassic and Jurassic, the Gulf of Mexico was formed from a rift southeast of the Ouachita Mountains. [8]
The southern Archean province is the Superior Craton, it is formed by the combination of a greenstone-granite and a gneiss terrane. [5] The margins of the Canadian Shield have been covered by sedimentary rocks, such as in Michigan where a series of sediments has filled in the Michigan Basin . [ 4 ]
The Midcontinent Rift System (MRS) or Keweenawan Rift is a 2,000 km (1,200 mi) long geological rift in the center of the North American continent and south-central part of the North American plate. It formed when the continent's core, the North American craton , began to split apart during the Mesoproterozoic era of the Precambrian , about 1.1 ...
Lake-filled half-graben showing sedimentation dominantly from the 'hinge' margin. Four zones of sedimentation can be defined in a half-graben. The first is "escarpment margin" sedimentation, found along the major border faults bounding the half graben, where the deepest part of the basin meets the highest rift-shoulder mountains. [6]
Llano Uplift - geologic map. The Llano Uplift can be considered an uplift by either its pattern on a geological or structural map of the top of the Precambrian rocks. It qualifies as an uplift because it consists of an extensive Precambrian basement high that is exposed by virtue of its surface lying significantly above in elevation the surface of surrounding Precambrian basement.