Facies and Architectural Analysis of the Lower Campanian Muley Canyon Sandstone, Henry Mountain Basin, Southeastern Utah
Strike-parallel exposures of the upper Cretaceous (lower Campanian) Muley Canyon Sandstone, extensive over some 40 miles, offer an excellent opportunity to examine sub-seismic scale lithologic heterogeneity, facies patterns, and architecture at the seismic scale. Moreover, detailed sequence stratigraphic models have been developed for correlative strata to the north in the Book Cliffs region (Star Point Formation, Panther Tongue), but such models have not been tested further to the south in the Henry Mountains Syncline. New measured sections of the Muley Canyon Sandstone at Blind Trail along with an architectural photomontage extending for several miles reveal four laterally extensive stratigraphic packages bounded by key surfaces. From stratigraphic base to top, these packages are termed here units 1 - 4. Based on detailed facies analysis, we interpret units 1 and 3 as shoreface deposits and units 2 and 4 as tidally-influenced channel bodies. Each channel body unit is marked by a major erosional surface at its base and an extensive flooding surface at its top. Architectural examination of the Muley Canyon Sandstone from various parts of the basin suggests that the two identified flooding surfaces are of regional extent. The geographic extent of the two major erosional surfaces has yet to be determined. Based on current observations, we present two alternate sequence stratigraphic models of interpretation for the Muley Canyon Sandstone that will be tested with further field research. If major erosional surfaces prove to be local in extent, the succession can be said to consist of two parasequences. However, if major erosional surfaces prove to be regional in extent, then the succession can be defined as a stack of two sequences separated by low-relief, relatively planar erosional surfaces on a regional scale. The low-relief, low-gradient character of major erosional surfaces is consistent with those found in other Cretaceous stratigraphic units in the Henry Mountains region.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009