Architectural-Facies Analysis of Nonmarine Depositional Systems in The Upper Triassic Chinle Formation, Southeastern Utah
Russell F. Dubiel, 1991. "Architectural-Facies Analysis of Nonmarine Depositional Systems in The Upper Triassic Chinle Formation, Southeastern Utah", The Three-Dimensional Facies Architecture of Terrigenous Clastic Sediments and its Implications for Hydrocarbon Discovery and Recovery, Andrew D. Miall, Noel Tyler
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The Upper Triassic Chinle Formation in southeastern Utah is a sequence of continental strata deposited in a back-arc cratonic basin. Archi tectural-faries analysis of exposures in sub-parallel canyons and in cliffs surrounding structural uplifts reveals an intricately interbedded fluvial-deltaic-lacustrine system characterized by: 1. mobile fluvial-channel belts consisting of stacked, high- and low-sinuosity channel complexes; 2. overbank deposits, including levees, paleosols, marshes, and small floodplain lakes interiingered with crevasse splays and lacustrine deltas; and 3. extensive lacustrine-basin, lacustrine-mudflat, and eolian sandsheet strata deposited throughout the entire study area. Stratigraphic panels of closely-spaced measured sections oriented both perpendicular and parallel to depositional dip depict the facies architecture both within the extra-channel strata and the relations of the extra-channel deposits to adjacent channel complexes.
In the Shinarump and Monitor Butte Members in the lower part of the Chinle Formation, fluvial-channel complexes interfinger with extra-channel facies. These extra-channel facies include levees, crevasse splays, and wetland complexes consisting of lacustrine deltas, lakes, and marshes. In the Moss Back and Petrified Forest Members in the middle part of the Chinle, fluvial-channel complexes interfinger with floodplain strata characterized by paleosols and crevasse splays. Locally, paleosol horizons and lake and marsh deposits serve as marker beds in three dimensions. The Owl Rock and Church Rock Members in the upper part of the Chinle are dominated by laterally extensive lacustrine-basin, lacustrine-mudflat, and minor eolian sandsheet strata that extended throughout the study area.