Development of the Permian-Triassic unconformity in southwestern Utah, southeastern Nevada and northwestern Arizona
- Stephen F. Austin State Univ., Nacogdoches, TX (United States). Dept. of Geology
Development of positive areas, that are oriented northwest-southeast in south-western Utah, southeastern Nevada, and northwestern Arizona, are indicated by the depositional patterns of the Rock Canyon Conglomerate and facies changes produced by on-lapping during the deposition of the Timpoweap, Lower Red, and Virgin Limestone Members of the Moenkopi Formation. The lack of facies change in the Kaibab Formation indicates that uplift of the positive areas did not start during the early Permian. The Fossil Mountain Member of the Kaibab Formation, is a marker of continuous shallow marine sedimentation across the area. The Harrisburg Member contains three limestone units, separated by gypsum and shale units, that represent regressions and transgressions. Where the gypsum in the Kaibab Formation thins, collapse breccia and deformed shale units are present indicating that the gypsum was deposited and then removed by dissolution. Channels cut during the late Permian and early Triassic Periods do not cut through the Harrisburg Member of the Kaibab Formation. West of St. George, Utah, where the gypsum deposits are thickest, is the location where Timpoweap, Lower Red, and Virgin Limestone members thin and are absent. Late Permian and early Triassic topography may have in part been controlled by dissolution of the gypsum deposits in the Kaibab Formation. The low angle of discordance between Permian and Triassic units indicated that the area was not subjected to major deformation during the late Permian and early Triassic, but was gently tilted and uplifted.
- OSTI ID:
- 5023854
- Report Number(s):
- CONF-9305259-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 25:5; Conference: 89. annual meeting of the Cordilleran Section and the 46th annual meeting of the Rocky Mountain Section of the Geological Society of America (GSA), Reno, NV (United States), 19-21 May 1993; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
Similar Records
Permean and Lower Triassic reservoir rocks of central Utah
Upper Valley oil field, Garfield County, Utah. [Guidebook]
Related Subjects
ARIZONA
GEOLOGIC FORMATIONS
DEPOSITION
STRATIGRAPHY
NEVADA
UTAH
CONGLOMERATES
GEOLOGIC HISTORY
GEOLOGIC STRATA
GYPSUM
LIMESTONE
PERMIAN PERIOD
TRIASSIC PERIOD
CARBONATE ROCKS
DEVELOPED COUNTRIES
GEOLOGIC AGES
GEOLOGIC STRUCTURES
GEOLOGY
MESOZOIC ERA
MINERALS
NORTH AMERICA
PALEOZOIC ERA
ROCKS
SEDIMENTARY ROCKS
SULFATE MINERALS
USA
580000* - Geosciences