Pacific Coastal & Marine Science Center
Bedform Sedimentology Site: “Bedforms and Cross-Bedding in Animation”
FIG. 23. Structure inferred to have formed by a dune that fluctuated in asymmetry and migration speed; eolian deposits in the Cedar Mesa Sandstone Member (Permian) of the Cutler Formation, southeast Utah.
RECOGNITION: Cyclic foresets, such as those in this example, clearly indicate cyclic depositional processes. The bedding in this set of cyclic foresets has a characteristic that suggests that the cyclicity was caused by fluctuating flow: wedges of sediment deposited along the lee slope (light-colored bottomset and foreset beds). Deposition of these basal wedges suggests that the cyclicity was produced by fluctuations in asymmetry and migration speed, as simulated in Figure 22A.