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Depositional Environments And Sandstone Diagenesis In The Tyler Formation (Pennsylvanian), Southwestern North Dakota, Stephen D. Sturm

Theses and Dissertations

The Tyler Formation, of Early Pennsylvanian age, in southwestern North Dakota may be divided into upper and lower units, reflecting both a change in lithology and depositional environments. The lower unit is dominated by varicolored, noncalcareous shales and mudstones, siltstones, thin coal beds, and medium-grained sandstones. The upper unit in the areas of the Square Butte to Fryburg fields may be divided into a lower subunit, dominated by dark gray to grayish-black, argillaceous limestones and calcareous shales, and an upper subunit dominated by grayish-red, anhydritic limestones, varicolored to reddish-brown, calcareous shales, and locally, thin anhydrite. In the area of the …