The purpose of this report is to show the origin, environment of deposition, and stratigraphic relations of the Tonganoxie sandstone in northeastern Kansas. The results of detailed sedimental and stratigraphic studies bearing on these problems are presented.
The Tonganoxie sandstone is the basal unit of the Upper Pennsylvanian Virgilian Series in parts of eastern Kansas. In the area studied, it consists mainly of a basal sandstone, overlain by shale and a thin coal bed. Evidence of several sorts, outlined in this paper, indicates that in country adjacent to the Missouri River, this sandstone was deposited in a broad river valley, some 14 to 20 miles wide, which extended southwestward from northwestern Missouri across northeastern Kansas. The sandstone is nonmarine and of fluviatile origin. Also, it is judged that the river which deposited the sand and associated finer sediments was very nearly at grade. The name Tonganoxie River is proposed for this Pennsylvanian river and the name Tonganoxie Valley is assigned to the valley in which sediment belonging to the Tonganoxie sandstone of this area was deposited. These names are used in the report.
A regional disconformity occurs at the base of the Virgilian Series throughout Kansas. The Tonganoxie Valley, 80 to 95 feet deep, was formed by erosion of the underlying Pedee and Lansing groups of late Missourian age. North and south of Tonganoxie Valley, the disconformity intersects formations of the Pedee group, whereas in the Tonganoxie Valley, it cuts deeply into units of the Lansing group.
Location of the Area
Strata assigned to the Tonganoxie sandstone member of the Stranger formation, Douglas group, crop out in northeastern Kansas in a belt 0.25 to 14 miles wide, extending from northeastern Leavenworth County to southern Douglas County (Pl. 1). This area lies within Ts. 8 to 14 S. and Rs. 19 to 23 E. The towns of Leavenworth and Vinland approximately define the northern and southern limits of the area included in this study. Other towns in the area are Basehor, Hodge, and Tonganoxie.
Method of Study
The months of June and July 1949 and various subsequent weekends up to May 1950 were spent in Douglas, Leavenworth, and Wyandotte Counties examining available outcrops of the Tonganoxie sandstone. Topographic maps and aerial photographs were used for mapping. Collected samples were analyzed in the laboratory, using size analysis, heavy mineral separation, thin sections, and insoluble residues. Studies with binocular and petrographic microscopes were made where necessary. Well logs and other subsurface data were examined in an attempt to extend this study beyond the area of outcrop.
Topography of the Area
The bedrocks of northeastern Kansas, including the Tonganoxie sandstone area, comprise alternating sandstone, shale, and limestone of Pennsylvanian age. These beds dip slightly north of west, approximately 25 feet to the mile. Elevations above sea level range from 750 feet along Missouri River, at the east margin of the area studied, to 1,100 feet on the upland at the west margin of the area. Erosion has produced a series of cuestas whose east-facing fronts trend northeastward. The outcrop area is bounded at the west by a conspicuous escarpment capped by the Oread limestone. This formation rises 75 to 150 feet above the lowland east of it, which is underlain by rocks of the Douglas group. Erosion of the Oread escarpment has produced outliers which make prominent hills in the area. Blue Mound, in Douglas County, and Jarbalo Mound, in Leavenworth County, are excellent examples (Pl. 1). Throughout the area, the Haskell limestone member of the Stranger formation forms local low escarpments and outliers. These rise 10 to 30 feet above adjacent areas which are underlain by the shales and sandstones of the Stranger formation. Along Missouri River, various members of the Stanton limestone form small low east-facing escarpments. On the dip-slope plains between the Oread and Haskell escarpments and between the Haskell and Stanton escarpments, the Ireland and Tonganxoie sandstones have been eroded into low moundlike hills. Where pre-Ireland erosion has cut into the Tonganoxie sandstone and the Ireland sandstone is in contact with sandstone beds of the Tonganoxie, larger hills occur, reflecting increased thickness of sandstone. This condition exists south and west of Lansing in Leavenworth County. Glacial till has somewhat masked the escarpments in the northern part of the area.
Missouri River on the north and east and Kansas River on the south control drainage of the area. In the past, critical relief has been such that stream drainage reached grade and flood plains developed, while interfluve areas remained broad, flat, and relatively undissected. Rejuvenation has brought about minor intrenchment of all drainage. Missouri and Kansas Rivers and their main tributaries now seem to have adjusted themselves and are near or at grade, but minor tributaries still are undergoing adjustments.
Writing and field work were done under the direction of Professor H. A. Ireland, at the University of Kansas. Much assistance was given by Dr. R. C. Moore and Dr. J. M. Jewett, members of the Kansas Geological Survey, and by various staff members of the Department of Geology at the University of Kansas. Field studies were facilitated by the cooperation of various citizens of Douglas, Leavenworth, and Wyandotte Counties, who permitted gathering of data from water wells, coal mines, and outcrops. I express thanks to all of these persons.
The State Geological Survey of Kansas supplied available maps and permitted use of stratigraphic sections, well logs, aerial photographs,, and unpublished field notes. Transportation and field expenses which were furnished by the Survey made this work possible.
The geologic map was compiled from unpublished geologic maps of the State Geological Survey of Kansas and by J. M. Patterson (1933), and from field work by me.
Kansas Geological Survey, Geology
Placed on web Aug. 7, 2006; originally published Oct. 31, 1950.
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