Date of Award


Document Type


Degree Name

Master of Arts (MA)



First Advisor

W.L. Moore


The thickness and areal extent of the commonly defined Paleozoic rock units in eastern North Dakota has been determined by a study of mechanical well logs. Isopachous wops of these units reveal several positive areas which persisted and influenced sedimentation and unit thickness throughout most of the Paleozoic Era. Precambrian topographic highs of either erosional or structural origin produced those influences in early Paleozoic time, whereas later effects resulted from periodic structural rejuvenation of the original highs. The activity of those highs appears to be related to the location of the basin depocenter. The most prominent highs were in Cavalier, Foster, and Stutsman Counties. A less persistent, but more important high from the standpoint of exploration, was at times present in Burleigh, Sheridan, and Wells Counties.

Except for thickness variations, the effects of these highs on sedimentation were generally relatively minor. However, in the basal part of the Bottineau interval of Mississippian age a distinct change in facies from carbonated to shale is affected over the high in Burleigh and Sheridan Counties. This shale facies is herein named the Carrington Shale facies after the town of Carrington, North Dakota, which is near the type section in the Pure Oil Company’s J. M. Carr No. 1 well (Sec. 15, T. 146 N., R. 66 W. ,Foster County). This shale presents two types of potential stratigraphic traps. The fist type is the updip facies change from carbonate to shale in the basal part of the Bottineau interval. The second is the seal effected where the shale overlies the truncated Birdbear and Duperow Formations of Devonian age.

Ballard (2974104 kB)

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