High-Resolution Correlation of Upper Cretaceous Stratigraphy between the Book Cliffs and the Western Henry Mountain Syncline, Utah

This study presents high-resolution correlations of the Upper Cretaceous stratigraphy between the Book Cliffs and the Western Henry Mountains Syncline in Utah. The objective of this study is to understand changes in the patterns of regional sediment dispersal during the Late Cretaceous on the western margin of the Cretaceous Western Interior Seaway. The intensely studied Book Cliffs consists of formations deposited in terrestrial, marginal marine, and open marine environments. A composite section was logged at Coal Canyon near Green River including the Blackhawk, Lower Castlegate, Buck Tongue, Sego, Neslen, Bluecastle Member, Farrer, and Tuscher Formations. The Western Henry Mountains Syncline is located in south-central Utah ~135 km S-SW of the Book Cliffs at Coal Canyon. A composite section was logged at Blind Trail and the units described are the Dakota, Tununk Shale, Ferron Sandstone, Bluegate Shale, Muley Canyon Sandstone, Masuk, and Tarantula Mesa Formations. High resolution correlation between the Book Cliffs and Henry Mountains is not straightforward because the correlative interval in the Henry Mountains succession is highly condensed (~1015m) relative to the Book Cliffs succession (>1750m). This is in part due to their proximal vs. distal locations from the Sevier thrust front and unequal rates of accommodation creation caused by differential rates of thrust loading in the west. Correlating at high-resolution from Coal Canyon to the Henry Mountains section poses similar challenges as correlating from the eastern Book Cliffs to the Wasatch Plateau because key stratigraphic surfaces cannot necessarily be carried into coeval strata up dip. Radiometric and biostratigraphic data provide age constraints on correlations between the Coal Canyon and Blind Trail sections. Correlations are based on vertical facies and depositional environmental stacking patterns and changes in sediment dispersal directions at discrete stratigraphic horizons derived from 745 paleocurrent measurements. Recognition of these patterns suggest that the Muley Canyon Fm., Muley Canyon Coal Zone at the base of the Masuk Formation, and the Masuk Formation correlate to the Star Point Sst., basal Blackhawk transgressive coal zones, and the Blackhawk Fm. respectively in the Wasatch Plateau. These interpretations provide the means to then correlate the Henry Mountains and Book Cliffs sections as well as allow pinpoints that constrain correlations both up- and down-section.  

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California