Kibbey Formation of Montana: ABSTRACT

Abstract

Laboratory and filed studies of the Kibbey Formation indicate that Kibbey rocks were deposited largely in shallow, marine, oxidizing water in the Big Snowy sea which extended across central Montana during Late Mississippian time. The Siouxia (Transcontinental) arch east of the depositional site supplied most of the detritus for the Kibbey rocks. The climate was semi-arid. Tentatively stable tectonic conditions with moderate to low relief prevailed in the source area throughout Kibbey deposition. The present northern limit of Kibbey rocks is a result of post-Kibbey erosion; the southern limit, although locally determined by erosion, is essentially the depositional limit. Sandstone beds of the Kibbey produce oil in Mussel-shell and McCone Counties, and produced for a short time in Roosevelt County, Montana. Kibbey rocks at all three productive localities appear to have been deposited under very similar environment conditions and in essentially the same position with respect to the axis of the Big Snowy sea. End_of_Article - Last_Page 1571------------