Day 2, Stop 2
Carmel Formation Stop
38o 17.066' N
111o 08.996' W
Just off Highway 24 is a prominent angular unconformity. An angular unconformity occurs when older sediments that generally dip at a steep angle are eroded and then overlain by younger sediments that dip at a lesser angle (typically horizontal) atop the older rocks (Boggs, 2006). In this figure, the Pleistocene terrace deposits overlie the Jurassic Carmel Formation. The Carmel Formation, composed of interbedded sandstone, siltstone, limestone, and gypsum, dips ~ 10° to the east (Mathis, 2000). The Pleistocene terrace forms the horizontal bed above the Carmel. A significant amount of time (~ 165 million years) is lost/missing in between the older tilted layers and the younger horizontal layers.
Salt Wash, Tidwell, Summerville
Salt Wash Member fluvial channel sandstone overlie the thin Tidwell Member (~3 m thick). The Tidwell Member is not always present in this area. Where the member is present in the Capitol Reef area, it is interpreted as a gypsiferous, hyper-saline lagoon (Turner and Petersen, 1998) evidenced by crinkly bedding.
Tidwell Member crinkly bedding.
The unit is ~3 m thick. The bedding has been disrupted due to dissolution of evaporite minerals.
The Morrison formation Salt Wash Member representes channel deposits, and the overlying Brushy Basin Member contains floodplain and paleosol deposits.