Triassic Fluvial Systems, Colorado Plateau
Moenkopi Formation at Lees Ferry, Arizona
Chinle Formation at Paria (ghost town), Utah
Introduction
Triassic rocks on the Colorado Plateau comprise two well-known formations, the Lower and Middle Triassic Moenkopi Formation and the Upper Triassic Chinle Formation. Both consist of several members that vary in nature and distribution. Fluvial systems range from very large, perennial systems in both formations to ephemeral, small streams and associated dunes and sabkhas. Most streams flowed northwestward to northward from highlands south and east of the present Plateau (including mountains of Pangaea, the source of some of the really large rivers). Triassic rocks form some spectacular badlands including the beautiful Painted Desert.
Triassic Fluvial System graphics
The paleogeography of Triassic fluvial rocks on the Colorado Plateau is fairly well known. The following maps show moderately detailed hypothetical paleogeography for the Moenkopi and Chinle formations. The former is based on Blakey, Basham, and Cook (1993 -- see my list of refs above) and the later is based on Blakey and Gubitosa (1983). Most of the patterns and colors should be fairly intuitive so no separate key is provided.
Triassic Outcrops
Triassic Tectonic Settings
Moenkopi Stratigraphic Columns
Triassic Fluvial Paleogeography
Moenkopi Formation
Moenkopi 1
Moenkopi 2
Moenkopi 3
Moenkopi 4
Moenkopi 5
Moenkopi 6
Moenkopi 7
Moenkopi 8
Moenkopi 9
Moenkopi 10
Chinle Formation
Chinle Shinarump
Chinle Monitor Butte
Chinle Moss Back
Chinle Petrified Forest
Chinle Owl Rock
Chinle Church Rock
Outcrop Photos of Triassic Fluvial Rocks
All photos were take by me and cannot be used for any commercial purposes withuot my permission.
Moenkopi and Chinle, Vermilion Cliffs
Moenkopi and Chinle, Paria
Moenkopi and Chinle, Orange Cliffs
Moenkopi near Winslow
Moenkopi near Cameron (type section)
Moenkopi near Cameron
Chinle (near type section) at Rock Point
Chinle at Lees Ferry
Chinle in Painted Desertl
