Date of Award
Master of Science (MS)
F.D. Holland, Jr
Lower Mississippian rocks of the Williston Basin and Black Hills include the Bakken and Englewood formations of Kinderhockian age. The Englewood formation crops out in the northern Black Hills and can be traced with difficulty into the subsurface. The Bakken formation does not crop out in the area out in the area of this study. This study is based upon well sample and mechanical log information and measured surface sections.
The Englewood in the outcrops consists of a lower shale unit, a middle argillaceous and shaly limestone unit, and an upper delominte limestone unit. A type section, NW, SE; see. 31. T. 4N., R. 3 E., two miles southwest of Englewood, South Dakota, is proposed.
About ten miles north of the outcrop area, the Englewood consists of a lower calcareous siltstone unit, a middle silty limestone unit, and an upper calcareous siltstone unit. In northern Sutte County, South Dakota, the formation consists of an argillaceous limestone which overlies the Bakken.
The Bakken formation consists of a lower black shale unit, a middle sandstone, silty limestone, or limestone unit, and an upper black shale unit. The Bakken can be easily defined and traced where the three units are present. The Bakken can be easily defined and traced where the three units are present. This area of occurrence is designated the Central Area. Around the Central Area the stratigraphic units converge and become thin, and lower shale is not present. This area of occurrence is designated the Marginal Shelf.
The Bakken sea probably originated in the Cordilleran region, was initially restricted in circulation, later become a normal marine sea, and was then again restricted in circulation. The seaway probably occupied the Central Area with its marginal area defined by the Marginal Shelf.
Kume, Jack, "An investigation of the Bakken and Englewood formations (Kinderhookian) of North Dakota and northwestern South Dakota" (1960). Theses and Dissertations. 170.