Recent studies in eastern Kansas, carried beyond the State's boundaries into Nebraska and Oklahoma, show rather pronounced facies changes in the Red Eagle formation, of Early Permian (Wolfcampian) age. Because of these conditions it is believed advisable to define more strictly the boundaries of the formation and its members. The position of the Red Eagle formation in the Lower Permian succession of the northern mid-continent region is shown below.
|Partial classification of Lower Permian rocks in Kansas|
|Council Grove group|
|Blue Rapids shale|
|Easly Creek shale|
|Red Eagle limestone|
|Virgilian Series (Pennsylvanian)|
The Council Grove group, which has an average thickness of about 320 feet, includes principally shales and limestones; these are described by Moore and others (1951) and earlier authors (Condra, 1927; Bass, 1929; Jewett, 1941). The thickness of the Red Eagle formation along its line of outcrop ranges from about 10 to 35 feet. The included rocks are believed to be entirely of marine origin, comprising limestone and shale, most of which contain marine fossils. In Kansas the rocks included in the formation crop out from Brown, Marshall, and Nemaha Counties, along the Kansas-Nebraska boundary, to Cowley County, on the Kansas-Oklahoma boundary. Northward from Kansas River, in an area including Pottawatomie, Jackson, Brown, Marshall, and Nemaha Counties, these rocks crop out on the east and west sides of both the Nemaha anticline and the Brownville syncline (which lies east of the anticline). Along most of their line of outcrop, they dip gently north of west and hence farther west they are buried under younger strata. In the subsurface of eastern Colorado they lose identity in clastic deposits of the Fountain formation. In northeastern Nebraska, as well as in much of northern Kansas, these Paleozoic rocks are concealed except locally by Pleistocene glacial deposits; in eastern Nebraska they are overlapped by Cretaceous sediments. In Oklahoma the Red Eagle limestone is identified as far southward as the Canadian River Valley, about 120 miles from the Kansas-Oklahoma line. Farther south equivalent beds are clastic deposits included in the Pontotoc group, which overlaps older formations in the Arbuckle Mountains.
Purpose of this paper
This report is presented to show stratigraphy of the Red Eagle formation and to define its members along its line of outcrop in Kansas. Usable criteria for placement of member boundaries where the lithology of the members differs from that in its type area are described. Confusion as to member boundaries apparent in previous reports is noted and our interpretation of members and their boundaries is shown graphically and discussed in detail.
All geologists to whose writings reference is made in this paper have contributed to solution of problems of the Red Eagle formation; expression of indebtedness to them is appropriate. The conclusions given in this paper, however, are the responsibility of its writers. We are indebted to Dr. George J. Verville for checking the thin sections prepared for this report and identifying some of the fossil material.
Kansas Geological Survey, Geology
Placed on web July 14, 2006; originally published Dec. 31, 1952.
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