ABSTRACT: Late Paleozoic Tectonic Evolution of the Southern Uinta Basin: Evidence from Reflection Data
C. J. Potter, R. Tang, T. J. Hainsworth, S. Y. Johnson
Seismic reflection data from the southern part of the Uinta basin near Price, Utah, reveal a network of late Paleozoic faults that produced a 50 km wide east-west-trending trough in which Pennsylvanian-Permian clastic rocks are several thousand feet thicker than in directly adjacent areas to the north and south. Pennsylvanian rocks are locally absent along an elongate late Paleozoic uplift that bounds this trough on its south side.
The faults were active between Morrowan (Manning Canyon Shale) and Guadalupian (Kaibab Limestone) time. Fault styles include: (1) high-angle reverse and normal faults in a "block faulting" pattern similar to that observed in upper Paleozoic rocks in the Piceance basin in northwestern Colorado; and (2) thrust faults having obvious hanging-wall and footwall cutoffs and hanging-wall anticlines, features commonly seen in fold-thrust belts. Northeast-directed reverse faults dominated deformation in the eastern part of the study area, and a combination of normal, reverse, and thrust faults controlled deformation in the western part. This complex pattern records temporal variation in regional stress directions during Ancestral Rockies orogenesis. The overall pattern may be that of an eastwar -trending late Paleozoic rift system that cut from the hingeline into the craton and was later modified during shortening.
AAPG Search and Discovery Article #91002©1990 AAPG Rocky Mountain Section Meeting, Denver, Colorado, September 16-19, 1990