Conglomerate & sandstone in the Permo-Triassic of Arizona, USA.
This outcrop is in Arizona's Canyon de Chelly National Monument. The thinner-bedded rocks in the uppper half of the photo are part of the Upper Triassic Shinarump Conglomerate. The underlying thicker-bedded rocks are part of an ancient sand dune deposit called the De Chelly Sandstone (pronounced "De Shay") (Lower Permian). The Shinarump-De Chelly contact is an unconformity. Unconformities are erosion surfaces representing missing time. Bedding geometries in the two units are parallel, making the erosion surface a disconformity. The De Chelly Sandstone here has many tilted layers - those are cross-beds, which formed in a one-directional wind current. However, the horizontal bedding in the De Chelly is parallel with bedding in the overlying Shinarump.
Stratigraphy: Shinarump Conglomerate Member, lower Chinle Formation, Norian Stage, Upper Triassic disconformably overlying De Chelly Sandstone, Leonardian Stage, Lower Permian
Locality: view from Sliding House overlook, southern rim of Canyon de Chelly, Canyon de Chelly National Monument, northeastern Arizona, USA
Loading contexts...
