180 Quaternary Geology/Geomorphology (Posters) II

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

Paper number: 180-6
Program: Technical Sessions
Time: 1:30 PM – 5:30 PM

Authors

Abstract

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.