Influence of Lateral Shear on the Formation of Enceladus' South Polar Terrain

Abstract Structural mapping indicates that Enceladus' South Polar Terrain (SPT) has experienced a regional‐scale right‐lateral shear, but the precise role of the regional shear in SPT's evolution is still under debate. Here we investigate the effects of lateral shear with a three‐dimensional visco‐elasto‐plastic model. By presetting a circular thinned lid around the south pole, we have obtained numerical results in good agreement with the general tectonic pattern of today's SPT, which explain the formation mechanism for some of the peculiar structures in the SPT. Our results suggest an inward cascading procedure in initiating the Tiger Stripes, wherein the fracturing starts at the rim of the thinned lid. Furthermore, we put forward the potential existence of ancient Riedel shear zones that pass through the tips of the Tiger Stripes, which may correspond to the strips with low albedo in infrared band in the albedo maps of the SPT.