Evolution of the Northern End of Salt Valley Salt Wall, Northern Paradox Basin, SE Utah
Naqi, Mohammad; Trudgill, Bruce D.; Kluth, Charles F.
The northern Paradox Basin is characterized by a series of salt walls and minibasins that evolved by downbuilding or passive diapirism into the evaporite-rich Paradox Formation. These linear salt bodies were controlled and localized along an NW-SE trend of normal faults at the top of the Mississippian (base salt) level. The Salt Valley salt wall in the most northerly part of the Paradox Basin is located about 28 km from the basin-bounding Uncompaghre uplift and is the longest (about 40 km) and the highest (4500 m) salt wall in the northern part of the basin.
Seismic data across the northern tip of the Salt Valley salt structure reveal a symmetrical geometry of the salt wall, localized on top of normal faults. Salt withdrawal from the flanking minibasins produced salt welds that terminated further migration of salt into the salt wall. Formations thickness in Perm-Triassic strata varies significantly between the two minibasins; however Jurassic and Cretaceous successions reveal almost uniform thickness. Strike-parallel to the salt wall, the general dip direction of the bedding is toward the NW. Perpendicular to the salt wall margin, Honaker Trail and Cutler formations are almost parallel or downlapping with respect to the subsalt section while formations above the Cutler dip away from the salt body. Well developed "heel-toe" geometries for the Honaker Trail and Cutler formations are present in the western minibasin. A well-developed graben system exists on top of the salt wall with decreasing displacement toward the south.
Salt movement influenced the geometry and architecture of the sedimentary succession in the flanking minibasins. Salt might have migrated from the tip toward the center of the salt wall and that is reflected into the decrease of graben system displacement on the top of the salt structure. The symmetrical geometry of the salt wall implies that the downbuilding process might be synchronous on both flanking minibasins instead of a basinward prograding system which moved to the SW as each minibasin was filled and no more accommodation was created due to salt welding.
AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013