Age and Correlation ofthe Chattanooga Shale and the Maury Formation GEOLOGICAL SURVEY PROFESSIONAL PAPER 286 Age and Correlation ofthe Chattanooga Shale and the Maury Formation By WILBERT H. HASS GEOLOGICAL SURVEY PROFESSIONAL PAPER 286 A contribution to the Devonian and Mississippian black-shale problem, based on conodont studies UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1956 UNITED STATES DEPARTMENT OF THE INTERIOR Fred A. Seaton, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25, D. C. CONTENTS Page Page Abstract.__________________________________ 1 Maury formation__________________________ 23 Introduction. ______________________________ 2 Standard section of the Maury formation . 23 Previous work.______________________________ 3 Age and characteristics.________________ 23 Chattanooga shale.__-___.-____-___________. 13 Measured sections.______________--_-_---_- 26 Standard section of the Chattanooga shale. 13 Conodont collections.______-______--__-____ L8 Hardin sandstone member_______________ 15 Literature cited__________________________ 44 Dowelltown member.___________________ 16 Index, ____________________________________ 47 Gassaway member.____-__--_-___-______ 20 ILLUSTRATIONS [PL 1, in pocket; pis. 2-5 follow index] PLATE 1. Collecting localities, Chattanooga shale and Maury formation. 2. Conodonts from the Maury formation. 3. Conodonts from the Gassaway member of the Chattanooga shale. 4. Conodonts from the Dowelltown member of the Chattanooga shale. 5. Type section of the Chattanooga shale, Cameron Hill, Chattanooga, Tenn. Page FIGURE 1. Range of significant conodont genera and species in the Chattanooga shale of the Eastern Highland Rim, in Tennessee-__._-__-______-___-___-____________-______-________-_____--___-_---._-_-__--____-______ 17 TABLES Page TABLE 1. Standard section of the Chattanooga shale_-________-_______-_____-._-_--____-,_-..--_-_--___..-__----____ 12 2. Comparison of stratigraphic limits of Campbell's type sections of his Dowelltown and Gassaway formations and the amended section adopted for this report-________._________-_-_____---______.---__-____---____-_---- 1& 3. Distribution of easily recognized conodont species of the basal sandstone of the Dowelltown member where, the Chattanooga shale section is essentially complete, and of the Trousdale shale of Pohl_______________________ 18 4. Distribution of significant conodont species present in the lower fauna of the Gassaway member________-._.___ 21 5. Distribution of significant conodont species present in the major part of the Maury formation—_____ — _______ 25 6. Conodont collections from the Chattanooga shale, Maury formation, and New Providence shale _______________ 38 7. Distribution of conodont species.-.-._______________________________________________ _______________ In pocket 8. Distribution of conodont species______-___--__-------____._____________-__-_-____--___--____.___.___ In pocket m AGE AND CORRELATION OF THE CHATTANOOGA SHALE AND THE MAURY FORMATION By WILBERT H. HASS ABSTRACT logic units: a lower one which is predominantly black shaler The Chattanooga shale and the overlying Maury formation of and an upper one which is primarily a grayish mudstone, near central Tennessee and adjacent States belong to the Devonian the top of which occurs a bentonite bed, about 0.1 foot thick. and Mississippian black-shale sequence. This sequence occurs This bentonite bed is probably present throughout at least 4,000' throughout much of the interior of the United States and a part square miles of east-central Tennessee. Along the outcrop, of Canada. northward from southern Jackson County—except in the Flynn The Chattanooga shale is herein considered to be of Late Creek structure—the Dowelltown is probably less than 10 feet Devonian age though the oldest beds of the formation could be thick. Also, it wedges out southward in the Sequatchie Valley of late Middle Devonian age. The Maury formation is herein of eastern Tennessee and has not been recognized in south-central considered to be of Mississippian (Kinderhook and possibly Tennessee or in north-central Alabama. On the west flank of Osage) age with one exception—in a part of north-central the Cincinnati anticline the Dowelltown is commonly a sandy Tennessee the basal bed of the Maury is classified as very late black shale, and is as much as 17 feet thick. At Olive Hill, Devonian. The age designations, faunal zonations, and cor­ Hardin County, where its relationships to the Hardin sandstone relations of the paper are based, for the most part, on a study member are evident, the Dowelltown is 31.8 feet thick. The of the conodonts in 325 collections from 65 measured sections; Dowelltown is assigned by the writer to the Upper Devonian conodonts in 186 collections from 27 of the measured sections Finger Lakes, Chemung, and basal Cassadaga stages of Cooper are mentioned by number. (Cooper and others, 1942); however, its basal beds may belong The Chattanooga shale has three members: the Hardin sand­ to the uppermost part of the Middle Devonian. stone, the Dowelltown, and the Gassaway (youngest). The The Gassaway member is chiefly a thin-bedded, grayish-black Hardin sandstone member grades into the overlying Dowelltown shale, though along a part of the Eastern Highland Rim, it cart member. It is a local thickening of the basal sandstone bed of be subdivided into two black-shale units and an intervening the Chattanooga shale, and is restricted to the vicinity of Wayne, thin zone consisting of gray mudstone and black shale. The Perry, Lawrence, and Hardin Counties, Tenn., and to the adjoin­ member is between 12 and 21 feet thick along the Eastern High­ ing part of Alabama. The Hardin consists chiefly of siliceous land Rim but is thinner in south-central Tennessee and north- fine-grained sand and silt, and is as much as 16 feet thick. It is central Alabama. It is absent throughout most of Lawrence herein classified as early Late Devonian though some part of the County, Tenn. and parts of the adjacent counties; on the other member could be late Middle Devonian. hand, it is at least 46.4 feet thick in south-central Kentucky. The basal sandstone bed of the Chattanooga shale commonly Phosphatic nodules occur in the youngest beds of the Gassaway ranges in thickness from a featheredge to about 0.5 foot, though, member. These nodule-bearing beds range in thickness from as stated above, to the southwest of the Nashville Basin, it a featheredge in DeKalb County, Tenn., to more than 8 feet in is thicker and is there called the Hardin sandstone member. the vicinity of Somerset, Pulaski County, Ky. This basal sandstone is a transgressive deposit, for in some areas The Gassaway member contains two distinct conodont faunas. it is a part of the Dowelltown member and elsewhere, where the The older fauna ranges throughout most of the Gassaway in­ Dowelltown is absent, it is a part of the Gassaway member. terval and its widespread occurrence indicates that during some Along the Eastern Highland Rim where it is a part of the Dowell­ part of Gassaway time, deposition of sediments took place town member, the basal sandstone contains early Late Devonian throughout most of the central Tennessee area. Beds having conodonts like those in the lowermost part of the New Albany this older fauna are correlated with the lower part of the Ohio shale of Indiana and the "conodont bed" of the Genundewa shale of Ohio and Kentucky; the Antrim shale as exposed in the limestone lentil of the Geneseo shale of New York; but where the Paxton shale pit west of Alpena, Mich.; the major part of the older beds of the Chattanooga shale are missing, as, for example, middle division of the New Albany shale of Indiana; a faunal near the crest of the Cincinnati anticline, and in south-central zone of the middle division of the Arkansas novaculite of Arkan­ Tennessee and north-central Alabama, the basal sandstone con­ sas and Oklahoma; a faunal zone of the Woodford chert of tains younger Late Devonian conodonts. Oklahoma; and a faunal zone that ranges throughout most of Good sections of the Chattanooga shale are exposed along the the Chattanooga shale of northeastern Oklahoma. All these Eastern Highland Rim of central Tennessee from southern Jack­ formations or parts of formations are classified as Late Devonian. son County south into Coffee and Bedford Counties. Through­ The Chattanooga shale and the Maury formation probably out much of that area the formation is between 25 and 35 feet are separated by an unconformity throughout much of south- thick and its subdivisions—the Gassaway and the Dowelltown central Tennessee and north-central Alabama for, there, the members—are well developed. In the above-mentioned area youngest beds of the Gassaway member have not been recog­ of the Eastern Highland Rim, the Dowelltown is between nized. These youngest beds have phosphatic nodules and 10 and 17.5 feet thick and consists of two persistent litho- conodonts like those in the upper part of the Upper Devonian 1 CHATTANOOGA SHALE AND MAURY FORMATION Ohio shale of Ohio and Kentucky, and in that part of the Sander- papers have been written on the age and correlation of son formation of Campbell (1946) which, at the type locality these beds but much of the record is incorrect because of the Sanderson, near New Albany, Ind. contains phosphatic it is based on inadequate data, for the black shales do nodules and directly underlies Campbell's Falling Run member of his Sanderson formation. The present writer classifies the not contain—except at a few widely spaced localities— Falling Run member as early Mississippian (Kinderhook) and the fossils commonly used in stratigraphic paleontology. the underlying beds of the type Sanderson as Late Devonian. Instead, the recognizable fauna and flora consist The Maury formation is a well-defined lithologic unit where­ chiefly of inarticulate brachiopods, a few arthropods, ver it underlies the Fort Payne chert but its top is indefinite fish remains, conodonts, and plant fragments and wherever it underlies beds identified in the literature as the Ridgetop shale and the New Providence shale.