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This digital dataset represents the geology of the George Mountain quadrangle at 1:24,000 scale. The quadrangle straddles the Sevier fault zone and includes the easternmost part of the Markagunt Plateau and the west edge of the Paunsaugunt Plateau. Here, the fault zone places Claron and younger volcaniclastic strata down on the west against Upper Cretaceous strata, exhibiting about 4500 feet (1370 m) of tectonic offset at this latitude. Strata of both plateaus are tilted gently east. Together with the Sevier fault zone, the Sand Pass fault forms a horst that exposes Upper Cretaceous strata below the Sunset Cliffs at the west edge of the Paunsaugunt Plateau.The rocks in the George Mountain quadrangle, from youngest to oldest, consist of: (1) Holocene and Pleistocene surficial deposits, including basin-fill deposits west of the Sevier fault zone and the eastern extent of the late Pleistocene Henrie Knolls basaltic lava flow; (2) the volcaniclastic Limerock Canyon Formation (Miocene), which may have been preserved in a subtle synclinal basin in front of the Rubys Inn thrust fault zone; (3) the Eocene and Paleocene Claron Formation, made up of stream- and lake-deposited sedimentary rocks that are the colorful reason for establishing nearby Bryce Canyon National Park; and (4) Upper Cretaceous coastal plain strata, the westward equivalent of better exposed and better studied dinosaur-bearing strata of the Kaiparowits Basin to the east. |