Sammendrag
Mobility of sand by fluidization, so-called sand tectonics, can drive surface movements and thereby have a significant impact on depositional environments. Deformation related to sand mobilization is a typical understudied component in geology, yet important because it has implications for sediment distribution and sand body geometry. Previous studies imply regional, large-scale impacts as triggering events. This study consider the potential of local, smaller-scale drivers for sand mobilization. Improving the understanding of sand tectonic related processes is therefore necessary to better comprehend their dynamics and impact on sedimentary systems. Three outcrops in the Middle Jurassic Entrada Sandstone and Upper Curtis Formation in Utah (USA) have been used to characterize the structural and sedimentary response to the underlying mobilization of sand. Data show that mild sand mobilization results in meter-scale, gentle sags and up-warps, which can be linked to distinct depositional environments and erosional processes. With an increased localization of deformation, faults nucleate and small fault-bound grabens develop. Overall, growth sequences attest to fault movement events, demonstrating the structural control on the basin. Many of the faults in upper parts of the grabens are however removed by erosion and overlain by late basin fill. The results from this study may provide important input on deformation in near surface settings, applicable to both CO2 storage operations and the petroleum industry.