Stratigraphy and Depositional Environments of the Mesaverde Group in the Northern Bighorn Basin of Wyoming
Using single stratigraphic methods in the geological analysis of incompletely or poorly exposed sedimentary successions can lead to non-unique interpretations and increased potential for error. In this study of the Mesaverde outcrops (Eagle Formation, the Claggett Tongue of the Cody Shale, and the Judith River Formation) in the northern Bighorn Basin of Wyoming, which has limited and variable quality exposures, an integrated method utilizing sedimentological, ichnological, and palynological data was used in order to overcome these limitations. Ten facies are identified within the exposures examined. These facies are arranged so as to depict a broadly distal to proximal gradient recording the progradation of fluvial-dominated deltas into a shallow marine environment. The utilization of a Zobaa Ternary Plot and Calgary and Brown factor analysis (CABFAC) for palynofacies analysis in the study allows for corroboration of the lithological interpretation, which has not been possible in previous studies of correlative outcrops. It also enables the identification of environmental trends not seen in the lithological analysis, thus allowing for a more robust stratigraphic analysis. The methods used in this study not only decrease the inherent error in paleoenvironmental analysis of poorly exposed areas and thereby decrease variability in paleoenvironmental interpretations, but also allow identification of changes that are not evident from a single method approach. The result of utilizing this approach in areas of limited or poor quality exposure is a more comprehensive and well-informed regional stratigraphic framework.
G. Adams et al., "Stratigraphy and Depositional Environments of the Mesaverde Group in the Northern Bighorn Basin of Wyoming," Palaeogeography, Palaeoclimatology, Palaeoecology, vol. 485, pp. 486-503, Elsevier B.V., Nov 2017.
The definitive version is available at https://doi.org/10.1016/j.palaeo.2017.07.005
Geosciences and Geological and Petroleum Engineering
Keywords and Phrases
Integrated methodology; Multivariate statistical analysis; Paleoenvironmental interpretation; Palynofacies; Sedimentology
International Standard Serial Number (ISSN)
Article - Journal
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