ABSTRACT

The western Cold Turkey Creek field area, Bowman County, North Dakota, has several attributes characteristic of other Williston Basin structures which have been interpreted to be meteorite impact features, including rapid changes in stratigraphic section thickness over very small distances, abrupt lithology changes, small size of structure area, and apparently complicated structure.

Long term study of surface geomorphology, geophysical logs, extensive seismic coverage, and cuttings demonstrate that the feature is long-lived, related to basin-wide fault patterns, and that individual stratigraphic units can be correlated across the feature. Use of expert-system correlation techniques and the invention of continuous artificial dipmeter reconstruction has materially assisted the interpretation of a detailed geologic history for the field. The Cold Turkey Creek structure is interpreted to be the result of interaction between small, well-defined basement-cored blocks, that move separately in response to major orogenic movements along the cratonic plate margins and within the craton. Correlated episodes of fault movement between blocks are identified by unconformities, thickness changes, and lithologic variation. Theories of two-stage salt dissolution and meteorite impact origin for the feature have been geologically evaluated and discarded. The suggested interpretation is congruent with structural history elsewhere in the basin, including the Nesson anticline.