Kaibab Limestone

Named as the upper formation of the Aubrey group for the Kaibab Plateau, north side of the Grand Canyon, Coconino Co, AZ in the Plateau sedimentary province. No type locality designated. Geologic map. Mapped as far west as the Grand Wash Cliffs, Mohave Co, AZ in the Plateau sedimentary province, and as far south as the Verde River in Yavapai Co, AZ in the Basin-and-Range province. Previously called Aubrey limestone. Ranges from 100 to 820 ft thick. Description of a measured section at Cataract Creek from an earlier report shows it as consisting of soft, yellow limestone at base that becomes hard, blue chert limestone in middle and upper parts and is interbedded with green, red, and white shale and snowy gypsum 180 ft thick, 100 ft above base, and coarse drab sandstone containing quartz pebbles and vegetable impressions 20 ft thick that lies 50 ft below the top. Contains abundant Pennsylvanian fauna--corals, brachiopods, mollusks, etc. Overlies Coconino sandstone (new) of Aubrey group. Underlies Moencopie formation of Shinarump group. Stratigraphic chart. Harrisburg gypsiferous member newly named as the uppermost member of the Kaibab limestone. Two measured sections, both in Washington Co, UT in the Great Basin province, described. The first measured 6 mi south of Hurricane, UT is 930 ft thick consisting mostly of cream to gray limestones separated by a slope-unit of shale, sandstone, and gypsum. The uppermost 160 ft is the Harrisburg. The second section is a composite near St. George, UT where the Kaibab is 957 ft thick, and composed of a basal yellow gypsiferous sandstone and thin-bedded arenaceous limestone unit overlain in sequence by massive, cherty gray limestone, slope-forming gypsum, red shale, and a breccia of limestone and chert, massive, fine-grained, cherty, gray limestone, and at top the Harrisburg member, a gray limestone, gypsiferous shale and gypsum. Kaibab overlies Coconino sandstone and unconformably underlies the newly named Rock Canyon conglomerate member (new) of the Moenkopi. Kaibab may be as much as 1,100 ft thick. Of Permian age. Gilluly, James, and Reeside, J.B., Jr., 1928, Sedimentary rocks of the San Rafael Swell and some adjacent areas in eastern Utah, IN Shorter contributions to general geology, 1927: U.S. Geological Survey Professional Paper, 150-D, p. D61-D110. Is present in thin patches in the San Rafael Swell. Ranges from 0-85 ft thick. Is cut out at many places by the pre-Triassic unconformity. Fossil mollusks, brachiopods, and pelecypods found. Assigned to the Permian and to the Carboniferous. [Permian removed from Carboniferous in 1941.] Gregory, H.E., and Moore, R.C., 1931, The Kaiparowits region, a geographic and geologic reconnaissance of parts of Utah and Arizona: U.S. Geological Survey Professional Paper, 164, 161 p. McKee, E.D., 1938, The environment and history of the Toroweap and Kaibab formations of northern Arizona and southern Utah: Carnegie Institution of Washington Publication, no. 492, p. . Name Kaibab stratigraphically restricted to upper part of Darton's Kaibab because original Kaibab is thought to have included two formations that have distinctive faunas and lithologies, and are separated by widespread unconformity. Name Kaibab limestone redescribed as Kaibab formation because the formation in eastern Grand Canyon is mostly sandstone and elsewhere it includes gypsum and red beds. Composed of an upper and lower red bed sequence separated by a massive limestone in its type "locality." Includes subdivisions A and B of Kaibab of earlier reports. Unconformably underlies Moenkopi formation. Unconformably overlies Toroweap formation (new name). Units formerly designated subdivisions C, D, and E of Kaibab are redesignated gamma, beta, and alpha (base to top) which characterize advancing sea (base), extended sea, and retreating sea (top). Cross sections. Areal extent map of facies. Detailed description of lithologies. Chemical analyses. Fossils (worms, sponges, crinoids, echinoi