Geology of the Richardson Cove and Jones Cove Quadrangles Tennessee
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Geology of the Richardson Cove and Jones Cove Quadrangles Tennessee GEOLOGICAL SURVEY PROFESSIONAL PAPER 349-A Geology of the Richardson Cove and Jones Cove Quadrangles Tennessee By WARREN HAMILTON GEOLOGY OF THE GREAT SMOKY MOUNTAINS, TENNESSEE AND NORTH CAROLINA GEOLOGICAL SURVEY PROFESSIONAL PAPER 349-A UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1961 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, 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 Description of rock units Continued Abstract.__________________________________________ A-l Ordovician system Continued Introduction.______________________________________ A-l Middle Ordovician series Continued Page Previous work__________________________________ A-2 Tellico formation.______________ A-33 Present work.__________________________________ A-3 Sedimentary history_____________________ A-34 A-3 Acknowledgments- _ _-____-__-___-_-_______-_____ Structural and metamorphic geology.________ A-35 A-3 Geography.,_ __________________________________ General features.__________-____--_---_ A-35 A-3 Description of rock units.___________________________ Metamorphism_ _______________________ A-36 A-3 General character and inferred sequence.._________ Grade.____________-___-_-____--__. A-36 A-4 Lithologic terminology._________________________ Cleavage.___________-_____-__---- A-37 A-5 Upper Precambrian rocks._______________________ A-40 A-5 Premetamorphism structural features ... Ocoee series..______________________________ Folds south of Dunn Creek fault_____ A-40 A-6 Snowbird group. _______________________ Folds north of Dunn Creek fault-____ A-40 A-6 Roaring Fork sandstone. _____-^__-_- Dunn Creek fault--.---_---_-_--_-- A-40 A-6 Pigeon siltstone___________________ A-42 A-15 Faults south of Dunn Creek fault-___ Rocks of Webb Mountain and Big Ridge __ Faults north of Dunn Creek fault__ A-42 Walden Creek group. ___________________ A-l 8 A-42 Licklog formation_________________ A-18 Postmetamorphism structural features.-.-_________ A-43 Shields formation.__________________ A-19 Great Smoky fault..__-__-___--__-_--__---_- English Mountain fault______________________ A-43 Conglomerate of Shields forma tion. ________________________ A-19 Relations of Great Smoky and English Mountain A-44 Slate of Richardson Cove_ ______ A-20 faults ----------------------------------- Structural features north of Great Smoky and Wilhite formation.. _ ________________ A-21 A-44 Dixon Mountain member. _______ A-21 English Mountain faults.__________________ Yellow Breeches member,________ A-23 Structural features between Gatlinburg and A-44 Sandsuck formation. _ _______________ A-26 Great Smoky faults.-_ -------------------- A-45 Sedimentation of Walden Creek group _ A-27 Gatlinburg fault system- _______-_-___-____-_ Cambrian(?) rocks and Cambrian system,________. A-28 Problems of structure and metamorphism _____ A-46 Lower Cambrian (?) rocks and Lower Cambrian Crustal shortening,_____________________________ A-46 series. _ __-__-_--______-____-__-__________ A-28 Ages of structural features__________---_------_-_ A-46 Chilhowee group._______________________ A-28 Surficial geology.______-________-______---_______--_ A-47 Cochran formation...-______________ A-28 Residuum_____ __________________ _______________ A-47 Missing interval-_______________________ A-30 Colluvium ______-_-_________-_______---_-_----_ A-48 Ordovician system._____________________________ A-30 Alluvium- _____________________________________ A-48 Lower Ordovician series_____________________ A-30 Stream alluvium.___________________________ A-48 Knox group____________________________ A-30 Older gravel deposits.-______________________ A-49 Jonesboro limestone.________________ A-30 Age of surficial deposits_______________-___-___-_- A-49 Middle Ordovician series___________________ A-32 Economic geology___________________________________ A-50 Lenoir limestone.____-_____--__________- A-32 Blockhouse shale_______________________ A-32 Engineering geology_________________________________ A-50 Rocks questionably assigned to Block References cited.___________________________________ A-51 house shale __________________________ A-33 Index _____________________________________________ A-53 IV CONTENTS ILLUSTRATIONS Page PLATE 1. Geologic map and structural sections of Richardson Cove and Jones Cove quadrangles, Tennessee.________ In pocket FIGURE 1. Map of Great Smoky Mountains region, Tennessee and North Carolina.___________________________________ A-2 2. Saprolite derived from Pigeon siltstone ________________________________________________________________ A-7 3. Laminated and crossbedded gray Pigeon siltstone between Mize and Dockery Branches.____________________ A-7 4. Bedding structures in specimen of greenish-gray Pigeon siltstone, Grassy Branch.__________________________ A-7 5. Laminated gray Pigeon siltstone________________________________-_____-___--___-__--_-________________ A-8 6. Photomicrograph of clastic limestone_______-____-____-___-_-____--__-----__-__-_--_--_--_-____________ A-9 7. Photomicrograph of metasiltstone with marked cleavage_________________________________________________ A-l 1 8. Ternary diagram of weight percent of alumina, potash, and soda in analyses of metapelitic rocks of Ocoee series. _ A-12 9. Ternary diagram of magnesia and iron oxides in analyses of metapelitic rocks of Ocoee series-____-__-___--____ A-l2 10. Ternary diagram of alumina, total iron and magnesia, and potash in analyses of metapelitic rocks of Ocoee series. __________________________________________________________________________________________ A 12 11. Plot of CaO against CO2 in analyses of metapelitic rocks._______-__--__-___---______-__----________-_____ A-14 12. Coarse phase of conglomerate of Shields Mountain____________________________________________________ A-19 13. Photomicrograph of metasiltstone with marked cleavage____________-_-___-_---_--___--_-___-_---________ A-22 14. Sandy limestone-conglomerate, upper division of Yellow Breeches member of Wilhite formation__ ____________ A-23 15. Platy limestone, anticlinally folded__________________________________________________________________ A-24 16. Photomicrograph of sandy limestone of Yellow Breeches member of Wilhite formation ______________________ A-25 17. Photomicrograph of sandy limestone of Yellow Breeches member of Wilhite formation.. ____________________ A-25 18. Late Paleozoic faults of Richardson Cove and Jones Cove quadrangles____________________________________ A-29 19. Photomicrograph of sandy Jonesboro limestone.._______________________________________________________ A-32 20. Schematic cross section of possible stratigraphic relationships of major rock units before deformation. __ _______ A-34 21. Metamorphic zones in pelitic rocks of the Richardson Cove and Jones Cove quadrangles_____________________ A-36 22. Photomicrograph of recrystallized feldspathic sandstone, with grains sutured together but not sheared_______ A-37 23. Photomicrograph of sheared and recrystallized feldspathic sandstone, showing great flattening of sand grains.__ A-37 24. Slaty cleavage in laminated Pigeon siltstone..________________________________________________________ A-37 25. Lower-hemisphere projection of poles of slaty cleavage and bedding in rocks south of Dunn Creek fault-______ A-39 26. Map and section of intersection of fold axes..._________________________________________________________ A-41 27. Tightly folded shale of lower member of Sandsuck formation.-_______ ____________________________________ A-42 28. Block of slate with folded slaty cleavage_____________________________________________________________ A-45 29. View south across Emerts Cove.______________________________________________________________________ A-49 30. Weathered gravel and metasiltstone___-_-______--__-___-__--_-_______-____-__----___-_--_______-____ A-49 TABLES Page TABLE 1. Stratigraphic units of Ocoee series in the Great Smoky Mountains.-________________________________________ A-5 2. Chemical analyses of metapelitic rocks of Ocoee series-__________________________________________________ A-13 3. Subzones of progressive metamorphism of Ocoee series._.-.__-__-___-_--_---_»--_-._-_-_--_____-_._-.-_-__ A-36 GEOLOGY OF THE GREAT SMOKY MOUNTAINS, TENNESSEE AND NORTH CAROLINA GEOLOGY OF RICHARDSON COVE AND JONES COVE QUADRANGLES, TENNESSEE By WAKREN HAMILTON ABSTRACT duced by prolonged weathering. Thin alluvium veneers the The Richardson Cove and Jones Cove quadrangles adjoin in flat-bottomed valleys, but most of the streams flow on or near the foothills of the Great Smoky Mountains, Sevier and Cocke bedrock. Large alluvial fans, mostly in the southeast part of Counties, eastern Tennessee. Most of their area consists of the area, overlie the weathered rock, and are being eroded forested and thoroughly dissected hills. under present conditions; these fans probably formed during The indurated rocks are of Precambrian, Cambrian, and Or Wisconsin time, when the higher parts of the area may have dovieian age and are all of sedimentary origin. The rocks form been bare of timber . four widely different groups, separated by reverse faults, oach No mineral deposits of present economic value are known in with miles of displacement. The Snowbird group of the late the area, although small quantities of iron and manganese ore Preeambrian Ocoee series underlies the southern foothills,