GEOMORPHIC AND GPR EVIDENCE FOR STRUCTURAL INFLUENCE ON DUNEFIELD FORMATION, CORAL PINK SAND DUNES, UTAH

The Coral Pink Sand Dunes (CPSD) is an active dunefield (14.6 km2) located immediately north of the Utah-Arizona border in Kane County, Utah. The elongate dunefield (11 km x 1.2 km) has sharp boundaries with the surrounding non-aeolian terrain and includes bedforms ranging from fully-active barchanoid ridges to partially-stabilized parabolic dunes to vegetated sand sheets.

Geomorphic evidence and preliminary ground-penetrating radar (GPR) surveys suggest a combination of factors has influenced the aeolian deposition at this location. First, the eastern margin of the active southern half of the dunefield lies along a plateau-edge faultline scarp (50-180 m) formed by the Sevier Normal Fault. This west-facing scarp has acted to funnel and impede local winds, thereby inducing dunefield formation.

Second, the western margin of the dunefield coincides with a diffuse east-facing scarp such that the center of the dunefield is up to 10 m lower than the alluvial basin floor to the west. Data from a GPR transect reveals an abrupt change in the subsurface radar facies consistent with the presence of a buried fault scarp. Therefore, the CPSD may be located within a small north-south-trending graben whose western margin is formed by a previously unmapped fault that is antithetic to the main trace of the Sevier normal fault.