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Introduction
Purpose and Scope of the Investigation
For many years I have felt the need of having in separate covers detailed descriptions of one or more groups of Pennsylvanian rocks in Kansas. In an unpublished manuscript prepared in 1937, Abernathy described the Cherokee rocks occurring in their outcrop area in southeastern Kansas. This paper treats rocks in Kansas belonging to the next younger group, the Marmaton. Inasmuch as the Cherokee is the lowermost of the Pennsylvanian rocks in the state, Abernathy's report and this one may be regarded as the first of unit descriptions of Kansas Pennsylvanian rocks. Field data already at hand will be used in preparing reports on the two next higher groups, Bourbon and Bronson. In the files of the State Geological Survey of Kansas are many data relative to other stratigraphic units; field notes that are sufficient with little additional work for use in preparing detailed descriptions of all the outcropping Paleozoic rocks of the state. Moore (1936) classified the Pennsylvanian rocks of Kansas, but his descriptions of Marmaton rocks are somewhat less detailed than are those of other groups. Several papers give descriptions of Kansas Paleozoic rocks in smaller specific areas. A recent Geological Survey bulletin (Moore, Frye, and Jewett, 1944) contains a brief tabular description of the outcropping rocks in Kansas.
The chief purpose of this paper is to present descriptions, as detailed as is now possible, of rock strata in Kansas that have been classified as belonging to the Marmaton group, Pennsylvanian system. Based on these detailed descriptions, certain conclusions pertaining to earth history can be drawn, and several questions, as yet unanswered, are raised.
An attempt has been made to present all new available data that are pertinent to the outcropping rocks of the Marmaton group in Kansas. The nomenclature, general and specific character, thickness, distribution, and correlation are described for each unit, and correlated graphic sections of numerous outcrops are shown. It is believed that this report contains comments about these rocks of late Desmoinesian age in Kansas that are of geologic and economic interest. Important fossils of the various units are mentioned, although no attempt has been made to prepare complete faunal or floral lists or to give descriptions of specific fossils. Paleontologic studies, as well as several other types, could logically be guided by the contents of this paper.
It should be noted here that although paleontology is an extremely useful tool in the stratigraphy of Pennsylvanian rocks in the northern Mid-Continent region, guide fossils of the smaller stratigraphic units are nearly lacking or absent. The larger units, notably the series, are somewhat characterized by distinctive animal and plant remains, but, with the exception of fusulines, fossils are not unique to individual formations. Except in the zones of disconformities that mark the various series boundaries as they have been established, the upper and lower limits of the occurrence of species vary from place to place. It is true, however, that the relative abundance of particular species or assemblages as well as the biologic make-up are usable characteristics of individual units. It is believed, also, that the relative abundance and paucity of characteristic faunas and floras are significant criteria useful in interpreting the record of conditions under which the rock units were formed.
Stratigraphy is that branch of geologic science that embraces descriptions and definitions of natural divisions of sedimentary rocks and the interpretation of their significance in geologic history. As stated by Moore (1941, p. 179), it involves determination of the sequence of rocks both locally and in the general time scale, tracing their areal distribution, observation of lateral and vertical changes in their character, correlation of equivalent but possibly widely dissimilar units, and, finally, study of geologic events involved in their genesis. It is obvious that geologic history is a fundamental part of all divisions of earth science. Therefore, all branches of geology are intimately related to stratigraphy which both serves and depends upon them.
All stratigraphic information is of economic importance. The rocks described in this paper are exposed in an area of shallow oil and gas production, and oil and gas are produced from them in several eastern Kansas fields. Coal included in these rocks is mined in eastern Kansas and in western Missouri. Cement is made from some of them. Several of the sandstones are important because of their water-bearing properties. Rock wool has been made from some of the limestones and shales. Asphalt rock is mined from rocks of this group in Missouri. Included limestones have various other uses and the shales are important sources of ceramic materials. All operations that involve penetration below the soils are facilitated by stratigraphic information, and in most of them knowledge of details of stratigraphy is essential for successful operation. Specific engineering projects--dam construction for example--are continuously requiring the services of geologists well acquainted with details of local stratigraphy. The importance of stratigraphy to soil studies is widely gaining recognition.
Surface structure mapping, so extensively practiced in the earlier stages of petroleum geology, requires exact stratigraphic data. Much surface mapping was done 20 or more years ago, at a time when few details of the stratigraphy of many parts of Kansas were known. It is altogether possible that detailed surface mapping may again be an extremely efficient tool in oil discovery. Levorsen (1943) has recently written that "the basis of this work (the 'art of discovery') is a restudy first of all of surface outcrops, most of which will have to be reexamined. . ."
Stratigraphy is necessarily largely compilation of a great amount of data on thicknesses, rock materials, fossil contents, and structural relationships, but this information, which is useful per se, is also requisite in making soundly based conclusions pertaining to geologic history. The economic and academic value of such conclusions cannot be overemphasized. Stratigraphy may be looked upon as the foundation of several other types of geologic investigations.
It has been stated (Bucher, 1936) that the essence of all geologic work is:
to search for the general properties, the "specific laws" in the reality in which we deal, and ultimately for such "general laws" as can be safely formulated. . . to seek understanding of the empirical laws thus found by studying the findings of workers in the nearest level of complexity.
The field work on which this report primarily is based was in progress during parts of several field seasons covering a period from 1928 to the present. I have drawn also upon my studies of Pennsylvanian rocks in several other states. Field studies of this kind should not stop at state or other political boundaries. I have therefore spent much time tracing and studying the rock layers described in this paper beyond the boundaries of Kansas into Oklahoma and into Missouri. In order that these rocks in Kansas may be better understood and that the studies may be extended geographically, descriptions and graphic sections of some outcrops in Oklahoma and Missouri are included in this paper.
In order to appreciate as fully as possible the significance of what one sees in the strata, one should not lose sight of the theories and conclusions of the world's prominent students of earth history. Here it may be mentioned that Grabau (1931, p. 3) wrote that the present is not the key to the past and that the earth in Paleozoic time was so distinct that we cannot visualize its history in the light gained from study of later eras. This does not mean, however, that observations of present phenomena are not vital to the understanding of the processes that operated in forming Paleozoic rocks. It does mean, however, that the probabilities of Pangea and Panthalassa, of great geosynclines, of an exchange of poles and tropics, and of other unknown features must not be disregarded. It is held as true that in Paleozoic time the earth was unique in its physical conformation and organic history.
Marmaton rocks are included in one of the several groups of the Pennsylvanian system of the North American Mid-Continent region. Jongmans (1936) has made this significant statement concerning Carboniferous (Pennsylvanian and Mississippian) rocks:
There is no geologic formation of which the detailed subdivision and correlation have been the subject of longer scrutinizing than the Carboniferous, but at the same time agreement on the formation has been found more difficult to attain than on almost any other.
Previous Work
Many geologists have contributed to knowledge of the rocks of southeastern Kansas. Specific reference to several of these is omitted here because detailed citations are given subsequently.
The first annual report on the geology of Kansas was published by Mudge in 1866. In 1878 Mudge published the first geologic map of the state. G. C. Swallow, appointed State Geologist in 1865, gave his attention to the stratigraphy of eastern and central Kansas and in 1866 issued a preliminary report on the geology of Kansas (Swallow, 1866). Swallow and his assistant, Major Frederick Hawn, may be regarded as the first important stratigraphic workers in southeastern Kansas.
G. C. Broadhead should perhaps rank first among those of the pioneer students of Pennsylvanian rocks in eastern Kansas and western Missouri. His interests were largely centered in the coal-bearing rocks and his field studies were carried out in great detail. He numbered various zones from 1 to 224 and, although subsequent workers have recognized more rock units in the same section, most of his numbered beds can be identified.
During a period of 50 years Charles R. Keyes contributed many papers to Pennsylvanian stratigraphy; several of his papers contain reports on Marmaton rocks. The paleontologic works of Keyes are important among the early faunal studies of Pennsylvanian rocks.
Erasmus Haworth and his co-workers, especially John Bennett and M. Z. Kirk, made important contributions to eastern Kansas stratigraphy. In the same period J. W. Beede and Austin F. Rogers made important paleontologic studies that included Marmaton and other faunas. In 1915 Henry Hinds and Frank C. Greene published an important work on the Pennsylvanian stratigraphy of Missouri. Their report contains a chapter on invertebrate paleontology by G. H. Girty. Greene has continued his interest and activity in studies of Pennsylvanian sediments and is an authority on Marmaton and other rocks in Missouri.
A great deal of credit is due to Raymond C. Moore for the advancement of Mid-Continent stratigraphy and paleontology. His publications on Pennsylvanian rocks and fossils are numerous.
Numerous geologists who have studied oil and gas fields of eastern Kansas, eastern Oklahoma, and western Missouri have added to the knowledge of Marmaton stratigraphy. In Oklahoma the studies of Malcolm C. Oakes and Robert H. Dott have been important contributions to the stratigraphy of Marmaton and other rocks in that state. Previously D. W. Ohern (1910) studied and mapped Marmaton and other formations in northeastern Oklahoma.
Marmaton rocks in Missouri and Iowa were described by L. M. Cline (1941), and interbasinal correlations of Marmaton and other Pennsylvanian formations were indicated in a recent paper by J. M. Weller, H. R. Wanless, L. M. Cline, and D. G. Stookey (1942).
In addition to the studies made by Keyes, Beede, Rogers, and Girty, descriptions of fossils from Marmaton rocks are included in the works of several specialists in specific biologic fields. Carl O. Dunbar and George E. Condra pioneered fusuline studies. Several other paleontologists later contributed to the studies of these fossils. Dunbar and Condra's work on Pennsylvanian brachiopods includes descriptions of Marmaton forms. J. Brookes Knight's work on gastropods, A. K. Miller, Carl O. Dunbar, and George E. Condra's work on cephalopods, and Norman D. Newell's studies of Late Paleozoic pelecypods include descriptions of Marmaton fossils.
This paper is the first to describe in detail Marmaton rocks in Kansas. In a previous paper (Jewett, 1941) I offered a classification of the Marmaton group in Kansas.
Acknowledgments
I have studied Kansas rocks for several years and in doing so have been associated with many geologists, all of whom have been my teachers. I have learned from all of them. To Professor, now Major, Raymond C. Moore I am especially indebted for guidance in this and other stratigraphic studies. Thanks are extended also to John C. Frye who has critically read the manuscript and to Edith Lewis and Betty Hagerman who edited it.
General Considerations of the Marmaton Rocks in Kansas
Marmaton rocks are partly marine and partly nonmarine in origin. Like probably all known sedimentary rocks, they are of continental origin. That is, although some of them were formed in submarine environments, they were formed on the floors of shallow epicontinental seas and not in deep ocean basins. The present northern Mid-Continent outcrop area of these rocks was a part of a relatively stable platform at the time of their genesis. There were deeper basins of accumulation to the south, as shown by the vastly thicker sections of rocks of equivalent age in the Pennsylvanian basins in Oklahoma and Arkansas. Still farther south was a land that was undergoing erosion and that perhaps furnished the greater part of the rock material. The sediments that are now incorporated in these rocks, however, very probably came in part from other directions. To the north of the Kansas outcrop area were also regions that were undergoing erosion. To the east was the Ozark uplift, and, although the Ozark area was now and then the site of deposition, there is evidence that some of these sediments came from there.
Marmaton rocks crop out in Kansas in a belt ranging in width from about 10 miles to about 25 miles. The outcrop belt extends from Linn and Bourbon counties on the Kansas-Missouri boundary to Montgomery and Labette counties on the Kansas-Oklahoma boundary. The general strike is about 30° east of north and the dip is westerly. The average dip is about 20 feet to the mile. The prevalent dip locally is interrupted by minor flexures. Because of variations in thickness of individual layers, the dip measured on any one horizon is different from that measured on another. The total thickness of the rocks of the group is about 250 feet.
The Marmaton group comprises the upper and more calcareous part of the stratigraphic section assigned to the Desmoinesian series. In Kansas the Marmaton rocks are dominantly shale. Limestone is second in quantitive importance and sandstone is third. There is a minor amount of coal. The Cherokee shale, comprising the lower part of the Desmoinesian series, is chiefly shale and sandstone. Desmoinesian limestones especially differ in lithologic characteristics from those of the younger Pennsylvanian section. The most noticeable difference is the absence of certain lithologies that are common in the higher section. Flinty limestone is plentiful in higher groups, especially the Bronson and Kansas City. Marmaton limestones are only locally and very sparsely flint bearing. Massive cross-bedded "oölitic" limestone which is mostly a mass of algal pellets is characteristic of the Bronson and Kansas City groups, but is absent from Marmaton rocks. Fusulines, although present in several Desmoinesian limestones, were not important rock makers in Desmoinesian time. In the Shawnee and Wabaunsee groups there are limestones that are little more than cemented masses of fusulines. Dark, bluish-gray, impure limestone that shows little or no bedding within individual units and that also is common higher in the section is sparsely present in the Marmaton group.
Most of the limestone in these rocks is light gray and weathers into a rock of even lighter color. This more or less contrasts with most of the limestone of younger groups which develops a rusty brown coating when exposed for a few years. Brown-weathering limestone beds are not absent from the Marmaton group, however. One type of finely crystalline brownish-gray limestone characteristically weathers into a deep-brown-coated rock. The most common limestone type in the Marmaton group is light gray, rather coarsely crystalline, and has the appearance of being a breccia. Small limestone fragments of irregular outline seem to be imbedded in a matrix of slightly different color and texture. This type of limestone is also common in younger groups.
Coralline limestone, which is dominantly composed of Chaetetes but contains plentiful "Aulopora" and some algal remains, is the most distinctive rock type in the Marmaton group. The coral Chaetetes was important as a rock builder in Late Desmoinesian time as were fusulines later. Chaetetes was a colonial tabulate coral that formed large coralla resembling heads of cauliflower.
The thicker shale units that are called formations include sandstones which are classified in two general types on the basis of their relationships to the shale. One type of sandstone can be sharply differentiated from the nonarenaceous clay shale below and in lateral directions. The other type is gradational from shale through sandy shale. This difference is based more upon the kind of contact than upon the rock itself, although the first type is generally less clayey than the type with gradational contacts. Clay and sand were being deposited at about the same time and some cutting and filling took place. One sees the first type of contact in those outcrops where a sand-filled channel cuts clay shale. In general, channel filling seems to be not more than 25 feet in depth.
Shales that separate the limestone members in the limestone formations are partly if not wholly marine. They contain fossil brachiopods, bryozoans, crinoid remains, and locally mollusks and corals. Black carbonaceous shale and small amounts of coal are characteristic of some of the thinner shale units. Where fossiliferous, the black shales contain a sparse fauna in which brachiopods are the most conspicuous and conodonts -are locally present. Small dark phosphatic concretions are common in the black shales. The thin fossiliferous shales are thinner bedded than the thicker nonmarine shales. Thin coal beds in these thinner shales may have been deposited locally below sea level.
All of eastern Kansas shows evidence of the presence of a Late Tertiary (?) peneplain truncating the gently westward-dipping rocks. The peneplain dips gently to the east and is now being destroyed by erosion. The truncated edges of more resistant strata form steep east-facing escarpments ranging in height from a few feet to approximately 150 feet. The physiographic history of eastern Kansas is probably complex and certainly has not been sufficiently studied. Evidence of peneplanation is found chiefly in the nearly accordant escarpment crests, in enclosed river meanders, and in the presence on the high divides of bedded gravel deposits which in the northern part underlie glacial drift.
The outcrop area of Marmaton rocks in Kansas is drained by the Marais des Cygnes and Verdigris rivers. Most of the region is under cultivation, but the economic use of the land is largely determined by the nature of the underlying rock. The dip slopes held by some limestones and sandstones are mainly unplowed grasslands and woodlands. The presence of generally deep residual soil and other surficial deposits and the tendency of limestone blocks to slump over less resistant beds cause the study of natural outcrops to be somewhat difficult. There are, however, many artificial and some natural cuts in which the rocks are well exposed.
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Kansas Geological Survey, Geology
Placed on web Feb. 2, 2010; originally published April 1945.
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