The Geology of the Sequatchie Valley Overthrust Block, Sequatchie Valley, Tennessee
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University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Doctoral Dissertations Graduate School 6-1960 The Geology of the Sequatchie Valley Overthrust Block, Sequatchie Valley, Tennessee Robert Calvin Milici University of Tennessee - Knoxville Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss Part of the Geology Commons Recommended Citation Milici, Robert Calvin, "The Geology of the Sequatchie Valley Overthrust Block, Sequatchie Valley, Tennessee. " PhD diss., University of Tennessee, 1960. https://trace.tennessee.edu/utk_graddiss/3232 This Dissertation is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a dissertation written by Robert Calvin Milici entitled "The Geology of the Sequatchie Valley Overthrust Block, Sequatchie Valley, Tennessee." I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Doctor of Philosophy, with a major in Geology. George D. Swingle, Major Professor We have read this dissertation and recommend its acceptance: Paris B. Stockdale, C.E. McLaughlin, Geo. K. Schweitzer, W.O. Harms, Harry J. Klepser Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) May 30, 1960 To the Graduate Council: . I am submitting herewith a thesis written by Robert Calvin Milici entitled �The Geology of the Sequatchie Valley overthrust Block, Sequatchie Valley, Tennessee. " I recommend that it be accepted in partial fulfillment of the requirements for the degree of Doctor of Philosophy, with a major in Geology. We have read this thesis and recommend its acceptance: , ?II Accepted far the Council: �· De School THE GEOLOGY OF THE SEQUATCHIE VALLEY OVERTHRUST BLOCK SEQUATCHIE VALLEY, TENNESSEE A Dissertation Presented to the Graduate Council of the University of Tennessee In Partial Fulfillment ot the Requirements for the Degree Doctor of Philosophy by Robert Calvin Milici June 1960 'Jr':J2�· .. ,, ACKNOWLEDGEMENTS /Jj I , � � This investigation was pursued under the auspices of the Tennessee Division of Geology, w. D. Hardeman, State Geologist, and under the direction of Professor G. D. Swin gle, of the University of Tennessee. The writer is indebted to several persons for assistance at various times during the course of this investigatioh. Dr. C. W. Wilson, Jr. of Vanderbil.t University accomp anied the writer in the field at the commencement of work on the problem , pointing out lithologic units which he had recognized in Sequatchie Valley several years before. Members of the staff of the Tennessee Division of Geology contributed a good deal of time and effort in assisting the writer in this study. Dr. R. G. Stearns spent several days in the fie ld with the writer. Messers s. W. Maher and H. A. Tiedemann assisted the writer in preparation of the illustrations and text. Mr. C. P. Finlayson assisted the writer in measuring Middle and Upper Ordovician strati graphic sections in Sequatchie Valley, Tennessee. Mr. Helmuth Wedow of the United States Geological Survey supplie d the writer with measurements of several Rich- mond and Silurian stratigraphic sect ion s in Sequatchie Valley. Mr. J. M. Kellberg of TVA Geological branch gave the writer stratigraphic data obtained from drill holes in the TVA Widows Creek and Sequatchie No. 2 steam plant si tes. " ·q, ! -�' 4. :\..,.·-· !I· ·-' -�4• . TABLE OF CONTENTS CHAPTER PAGE I. INTR ODUCTI ON • . • • • • • 1 Location and extent • • • • • 1 . Topographic expr ession of the stnuc tur e . 1 Purpose or investigat ion • . 3 Pr evious inves tigations . •• . ·. 4 Inve stigat ions pri or to 1926 . 4 Invest igat ions art er 1926 . 5 Pr esent investigat ion . 1 . Introduc tion • • • • • • • • • • • • • . 1 Ge ologic mapping . • • • • . • • • • • 7 . Stratigraphic se ctions . 9 II. STRATIGRAPHY • • . • • • • • . 10 Introducti on • . 10 Topographi c expression of formations • . 1.5 Or dovician forma tions • • • • • • • • . 1.7 Introduction . 17 Itnox group . 2]� Stones Riv er group • • . 24 Nashville group • • • . 31 Eden group . 34 . Maysvill e group . 35 R ichmond group • • • • • • • • • • • • • • • 35 iv CHAPrER PAGE Silurian formations ••. 36 Rockwood formation. • • • • • • • • • • • • • 36 Devonian-Mississippian formations • • • • • • 38 Chattanooga shale • • • • • • • • • • • • • 38 Miss iss ippian formations • • • • • • • • . 40 Maury formation . • • 40 Fort Payne chert . • • • • • • . 40 Warsaw lime stone • . • • • . 42 St. Louis limestone . 42: St e. Genevieve-Gasper lime stone • • 43) Big Clifty formation • • • • • • • • • • 44 Glen Dean lime stone • • • • • • • • • • • • 45 Pennington formation • • • • • • • • • • • • 45 Pennsylvanian formations • . 46 Introduc tion • • • • • . 46 Gizzard group . 46 Crab Orchard Mountains group . 49 III. STRUCTURAL GEOLOGY • • • • • • 51 Introduction • • • . • • . 51 The Sequatchie anticline • . 5Z The Sequatchie Valley fault . 52 Introduction . 52 Structural units . 53 The northe astern section • . • • 56 v CHAPTER PAGE The central section • • • . 62 The southwestern section • • • • • . 63 Tectonic implications • • • • • . 66 Behavior of the fault at depth • • • • • • 66 Regional implications • . 68 Introduction . 68 The Sequatchie Valley structure • . 70 Relationship to the Cumberland Plateau overthrust • • • • • • • • • • • 71 Relationship of Cumberland Plateau st ructures to structures of the Valley and Ridge. • •. 75 IV. SUMMARY AND CONCLUSIONS • • • • • • . 78 Summary • • • • • • • . 78 Structural conclusions . 79 SELECTED REFERENCES • • • • • • • . 80 LIST OF FIGURES FIGURE PAGE 1. Loc ation and extent of Sequatchie Valley • • . 2 2. Topogr aphic expre ssion of rormations in the northern porti on or Sequatchie Valley 16 3. Gener al stratigraph ic sections of th e Knox group in the Sequ atchie V alley , Tennes see * • • 1.8 4. Locations of me asured stratigraphic sections in Sequatchie Valley, Tennessee . • • . 20 5. Strat igraphi c sections of Middle and Upper Ordovic ian formations in Sequatchie Valley 22 6. Loc ation of Ordovici an sinkhole occurrenc es at the top of the Knox group • • • • . • 25 7. General ized stratigraphic sections of Silurian rocks in Sequatchie Valley . 3'9 8. Th ickness or the Chattanooga shale in Sequatchie Valley and Gr assy Cove , Tennessee . 9. Generalized stratigraphic section of Mi ssissippi an and Pennsylvani an formati ons in Sequatchie Valley Tenne ssee . • . • . 50 10. Illus trati on of the Sequatchie Val ley fault tr ace 55 11. Cross-secti ons illustrating thr ee possibilitie s for the behavior of the fault at depth . 67 12. Regional stru ctural features • . 69 13. Major faults of the Cumberland Plate au , Tennes see 74 vii FIGURE PAGE 14. Ma jor structural features at th e northern end of Sequatchie Valley, Tennessee • • • • • . 76 15. Cross-sections of the Cumberland Plateau and Sequatchie Valley, Tennessee • . 77 LIST OF PLATES PLATES PAGE 1. Geologic map of Sequatchie Valley, northeastern section • • • • • • • • • • In pocket 2. Geologic map of Sequatchie Valley, central section • • • • • • • • • • • • • In pocket 3. Geologic map of Sequatchie Valley, southwestern section ••••••••• • • In pocket Geologic cr oss sections • • • • • • • • • • In pocket CHAPI'ER I. INTRODUCTION LOCATION AND EXTENT The Sequatchie anticline, a major structure of the Cumberland Plat eau, parall els the regional strike of the Appalachians for a distance of over 200 mile s (Fig. 1 ) . It extends "southwes tward from the south side of the Emory River in Morgan County, Tennesse e, nearly to the forks of the Black Warrior River in Walker and Jefferson Count ies, • tt: Alabama • • (Rodgers , 1950, p. 672 ). The present study is conc erned with the overthrust block of the Sequatchie Valley fault which extends approx imately 80 miles from the Tennessee-Alabama stat� line northe ast to the Crab Orchard Mountains , Cumberland County, �ennessee. The width of the portion of the overthrus t block mapped averages four mi les; hence the are a mapped approximates 300 to 350 square miles. TOPOGRAPHIC EXPRESS ION OF THE STRUCTURE Rodgers (1950, pp . 672-674) gave the following descrip� tion of the Sequatchie antic line: At its north end it is a low, nearly symmetrical arch in the Pennsylvanian rocks of the Cumberland Plateau, the uparched Pennsylvanian sandstone and conglomerate beds forming a prominent line of hills (the Crab Orchard Mountains ) . Traced southwe st, the fold rises so that the Pennsylvanian rocks are breached, 2 ·-·-·- .. -· -·- · NASHVILLE BASIN I ; ...... .,· , . i c � • ·-·L·-·-· ______ ___ _ �nn_._______ . .It!; Ala. � �� � \ \ MILES Figure 1. Location and extent of Sequatchie Valley 3 and the underlying Mississippian limestone is exposed in a series of topographic lows , the largest of which is Grassy Cove. A little southwest of Grassy Cove , the anticline rises sharply, exposing Ordovician carbonate rocks, which are the surface rocks along its crest for most of its length. Here th e fold is markedly asymmet rical, its northwest flank being much the steeper, and only a little farther southwest that flank is broken by a thrust fault,