Investigating the Interaction of Sevier and Laramide Structural Development in the Rocky Mountains with
3D Seismic
Mapping
Three 3-D seismic
reflection volumes have been procured by
BYU in the western Green River Basin (GRB), the southwestern Powder River Basin
(PRB), and the southern Uinta Basin (UB). State-of-the-art 3D visualization and
attribute
analyses furnish precise and detailed images of the interaction of
Sevier (Mesozoic) and Laramide (Late
Cretaceous-Cenozoic) deformation episodes and structural styles.
The position of the GRB volume between the Sevier frontal thrust and Wind
River thrust, where they begin to approach each other, provides an opportunity
to investigate close interactions between Sevier and Laramide
deformation. Alternatively, the PRB and UB volumes both represent regions that
are proximal to areas of mainly Laramide deformation.
We have prepared structure maps of prominent seismic
horizons as well as
seismic
attribute
extractions in order to map and characterize varying
deformation styles within each of and between the three
seismic
volumes.
The GRB volume shows the most complex structural variation, including both “thin-skinned” and “thick-skinned” deformation. Small-scale compressional structures in places show dual vergence, suggesting either a component of strike-slip or the interaction of two deformation episodes (Sevier and Laramide). A complex pattern of deeper high-angle faulting appears to penetrate the entire sequence and the top of basement and is accompanied by monoclinal and anticlinal flexure. The PRB and UB volumes show predominantly “thick-skinned” deformation with high-angle faults and/or strike-slip faults cutting through large-scale asymmetric compressional structures. The synoptic view provided from the three volumes allows a more generalized characterization of Laramide vs. Sevier subsurface deformation in the Rocky Mountain region.