Paleogeographic and Tectonic Controls on Some Lower and Middle Jurassic Erg Deposits, Colorado Plateau

摘要: Abstract Lower and lower middle Jurassic rocks on the Colorado Plateau are dominated by eolian deposition in large to regionally extensive ergs. Regional stratigraphic patterns were used establish five major depositional sequences that divided bounding unconformities. The their unconformities consist of following: Sequence 1: J-0 unconformity, Wingate Sandstone coeval Dinosaur Canyon Member Moenave Formation; 2: J-sub-k sandy facies Kayenta Formation Springdale Formation, silty parts Navajo overlying Sandstone; 3: J-1 Temple Cap 4: J-2 Carmel Page 5: J-s-up transition member Sandstone, upper Formation. Analysis demonstrates portions Wingate, Navajo, Sandstones flanked fluvial systems. In each fluvial-eolian system, paleocurrents opposed paleocurrents. Sand, mud, minor gravel was transported northwesterly river systems, some which may have originated Ouachita System west Texas. Northerly winds deflated plains initiate erg Sand escaped ergs blew southward onto then recycled northward. rivers northwest blown back south. Eolian frequently interrupted marine flooding accompanying rise water table. resulting surfaces (super surfaces) reflect temporary demise deposition. contrast, sequence tectonic, climatic, or eustatic events mark termination sequences.