Pennsylvanian and Early Permian paleogeography of northwestern Colorado and northeastern Utah
- Geological Survey, Denver, CO (United States)
Northwestern CO and northeastern UT include parts of four major sedimentary provinces active during the late Paleozoic ancestral Rocky Mountain orogeny: the Eagle basin (Eb), the northern Paradox basin (Pb), the southern Wyoming shelf (Ws), and the southeastern Oquirrh basin (Ob). Depositional patterns in these provinces were controlled by eustatic and climatic fluctuations, tectonism, and sediment supply. In general, regressive deposits consist of fluvial, deltaic, and eolian sandstone, and transgressive deposits consist of marine limestone and clastic rocks. Morrowan and lower Atokan strata in most of the region consist of fine-grained clastic rock and more abundant limestone. Significant Morrowan and early Atokan highlands include the Front Range and Sawatch uplifts; the Uncompahgre uplift began its rapid rise in the late Atokan to Desmoinesian. Late Atokan to Desmoinesian tectonic activity resulted in restricted circulation and low clastic sediment supply to the central Eb and Pb, leading to evaporite deposition during regression. During the Missourian and Virgilian, clastic sediments prograded into the central Eb and northern Pb, ending evaporite deposition. During regressions, fluvial and eolian deposition dominated in the Eb, and sabkha and (or) shallow marine-deposition dominated in the northern Pb. The Ws continued to serve as a throughway for clastic sediment moving to the deepening Ob. Deposition of limestone during transgressions was limited to the western part of the study region and a small area in the eastern Eb. Regionally, the rates and magnitude of subsidence were greatest in the Ob, intermediate and very similar in the Eb and northern Pb, and lowest in the Ws. In all four sedimentary provinces, rates of subsidence were lowest in the Early Pennsylvania, highest in the Middle Pennsylvanian, and intermediate in the Late Pennsylvanian and Early Permian.
- OSTI ID:
- 5126966
- Report Number(s):
- CONF-9305259--
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Journal Name: Geological Society of America, Abstracts with Programs; (United States) Vol. 25:5; ISSN GAAPBC; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
580000* -- Geosciences
CARBONATE ROCKS
CARBONIFEROUS PERIOD
COLORADO
DEPOSITION
DEVELOPED COUNTRIES
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
GEOLOGY
LIMESTONE
NORTH AMERICA
PALEOZOIC ERA
PARADOX BASIN
PERMIAN PERIOD
ROCKS
SANDSTONES
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
STRATIGRAPHY
USA
UTAH