Sandstones in the Permian of Arizona, USA.
This spectacular canyon in Arizona has sheer walls of Permian-aged De Chelly Sandstone (pronounced "De Shay"). Most of the unit consists of horizontally-bedded and cross-bedded quartzose sandstones representing ancient sand sheets and desert sand dunes. A vast sand dune "sea" was present at the time - such an environment is called an "erg" (a modern example is northern Africa's Sahara Desert). The reddish-brown and orangish-brown coloration is from hematite (iron oxide, Fe2O3). Dark-colored desert varnish partially covers many cliff faces here. The canyon floor is moderately lush with greenery and has some agricultural plots.
----------------------------------
From park signage:
NAVAJO FORTRESS
By 1750, the Navajo was farmer and herdsman. Yet he remained a warrior, fighting his Indian enemies as well as the encroaching Spanish settlements. Raids and counter-raids dragged on for more than 100 years. The huge rock formation directly across from you - marking the junction of Del Muerto and Black Rock Canyons - was one of the refuges used by the Navajo against enemy attach. “Stairways” of movable, notched poles were positioned to reach otherwise inaccessible areas. Use of this refuge continued into the 1860s.
Although Navajo Fortress appears as an extension of the canyon wall, a topographical view reveals its island-like isolation. Traces of old pathways up the eastern end are still visible from the canyon floor.
----------------------------------
Stratigraphy: De Chelly Sandstone, Leonardian Stage, Lower Permian
Locality: view from Antelope House overlook (Navajo Fortress overlook), northern rim of "Canyon del Muerto" (= Canyon of the Dead), Canyon de Chelly National Monument, northeastern Arizona, USA
Tags: De Chelly Sandstone Permian Navajo Fortress Canyon National Monument Arizona
Sandstones in the Permian of Arizona, USA.
This spectacular canyon in Arizona has sheer walls of Permian-aged De Chelly Sandstone (pronounced "De Shay"). Most of the unit consists of horizontally-bedded and cross-bedded quartzose sandstones representing ancient sand sheets and desert sand dunes. A vast sand dune "sea" was present at the time - such an environment is called an "erg" (a modern example is northern Africa's Sahara Desert). The reddish-brown and orangish-brown coloration is from hematite (iron oxide, Fe2O3). Dark-colored desert varnish partially covers many cliff faces here. The canyon floor is moderately lush with greenery and has some agricultural plots.
The rimrock at the top of the section is the Shinarump Conglomerate, an Upper Triassic, fluvial, coarse-grained siliciclastic unit. It consists of quartzose sandstones, pebbly sandstones, and lithic conglomerates.
Stratigraphy: De Chelly Sandstone, Leonardian Stage, Lower Permian
Locality: view from Antelope House overlook (Navajo Fortress overlook), northern rim of "Canyon del Muerto" (= Canyon of the Dead), Canyon de Chelly National Monument, northeastern Arizona, USA
Tags: De Chelly Sandstone Permian Canyon National Monument Arizona
Sandstones in the Permian of Arizona, USA.
This spectacular canyon in Arizona has sheer walls of Permian-aged De Chelly Sandstone (pronounced "De Shay"). Most of the unit consists of horizontally-bedded and cross-bedded quartzose sandstones representing ancient sand sheets and desert sand dunes. A vast sand dune "sea" was present at the time - such an environment is called an "erg" (a modern example is northern Africa's Sahara Desert). The reddish-brown and orangish-brown coloration is from hematite (iron oxide, Fe2O3). Dark-colored desert varnish partially covers many cliff faces here. The canyon floor is moderately lush with greenery and has some agricultural plots.
The rimrock at the top of the section is the Shinarump Conglomerate, an Upper Triassic, fluvial, coarse-grained siliciclastic unit. It consists of quartzose sandstones, pebbly sandstones, and lithic conglomerates.
The shadowed cliff at right is "Navajo Fortress". It's situated at the confluence of Black Rock Canyon (= far right) and Canyon of the Dead ("Canyon del Muerto"). This view is looking upstream for both canyons.
Stratigraphy: De Chelly Sandstone, Leonardian Stage, Lower Permian
Locality: view from Antelope House overlook (Navajo Fortress overlook), northern rim of "Canyon del Muerto" (= Canyon of the Dead), Canyon de Chelly National Monument, northeastern Arizona, USA
Tags: De Chelly Sandstone Permian Canyon National Monument Arizona
Sandstones in the Permian of Arizona, USA.
This spectacular canyon in Arizona has sheer walls of Permian-aged De Chelly Sandstone (pronounced "De Shay"). Most of the unit consists of horizontally-bedded and cross-bedded quartzose sandstones representing ancient sand sheets and desert sand dunes. A vast sand dune "sea" was present at the time - such an environment is called an "erg" (a modern example is northern Africa's Sahara Desert). The reddish-brown coloration is from hematite (iron oxide, Fe2O3). Dark-colored desert varnish partially covers many cliff faces here. The canyon floor is moderately lush with greenery and has some agricultural plots.
Stratigraphy: De Chelly Sandstone, Leonardian Stage, Lower Permian
Locality: view from Antelope House overlook (Navajo Fortress overlook) (looking downstream), northern rim of "Canyon del Muerto" (= Canyon of the Dead), Canyon de Chelly National Monument, northeastern Arizona, USA
Tags: De Chelly Sandstone Permian Canyon National Monument Arizona
Sandstones in the Permian of Arizona, USA.
This spectacular canyon in Arizona has sheer walls of Permian-aged De Chelly Sandstone (pronounced "De Shay"). Most of the unit consists of horizontally-bedded and cross-bedded quartzose sandstones representing ancient sand sheets and desert sand dunes. A vast sand dune "sea" was present at the time - such an environment is called an "erg" (a modern example is northern Africa's Sahara Desert). The reddish-brown coloration is from hematite (iron oxide, Fe2O3). Dark-colored desert varnish partially covers many cliff faces here. The canyon floor is moderately lush with greenery and has some agricultural plots.
Stratigraphy: De Chelly Sandstone, Leonardian Stage, Lower Permian
Locality: view from Antelope House overlook (Navajo Fortress overlook) (looking downstream), northern rim of "Canyon del Muerto" (= Canyon of the Dead), Canyon de Chelly National Monument, northeastern Arizona, USA
Tags: De Chelly Sandstone Permian Canyon National Monument Arizona