About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 40 (1956)

Issue: 2. (February)

First Page: 416

Last Page: 416

Title: Stratigraphy of Jurassic Type Localities of Northern United States and Correlation with Adjoining Areas: ABSTRACT

Author(s): James A. Peterson

Article Type: Meeting abstract

Abstract:

On the basis of faunal and lithologic correlations, Jurassic units can be traced northward from their type areas of the northern United States Rocky Mountains into southern Canada. The five-unit classification of the marine Jurassic in the Black Hills is useful in the subsurface for only a limited distance from the type area. The most useful nomenclature for subsurface work in the northern Rocky Mountains of the United States is probably that of the Ellis group of Montana. The Swift, Rierdon, and Piper units of the Ellis group can be correlated throughout most of the Western Interior United States. Within the central part of the Williston basin, however, these units are not yet recognizable on a lithologic basis alone, but micropaleontologic work indicates that these unit may be distinguishable paleontologically.

The major tectonic elements affecting the marine Jurassic sedimentary pattern in the northern United States were the Belt island of western Montana, the Williston basin of North and South Dakota, eastern Montana, and southern Saskatchewan, and the Twin Creek trough of southeastern Idaho, central and northern Utah, and western Wyoming. Isopach maps indicate that several minor "positive" and "negative" elements were also present within the shelf area of Montana, Wyoming, western Colorado, and eastern Utah.

End_of_Article - Last_Page 416------------

Copyright 1997 American Association of Petroleum Geologists