University of Kentucky UKnowledge Kentucky Geological Survey Map and Chart Kentucky Geological Survey 1992 Geologic Highway Cross Sections: Interstate Highway 75 Conway, Kentucky, to Jellico, Tennessee Donald R. Chesnut Jr. University of Kentucky, [email protected] Right click to open a feedback form in a new tab to let us know how this document benefits oy u. Follow this and additional works at: https://uknowledge.uky.edu/kgs_mc Part of the Geology Commons Repository Citation Chesnut, Donald R. Jr., "Geologic Highway Cross Sections: Interstate Highway 75 Conway, Kentucky, to Jellico, Tennessee" (1992). Kentucky Geological Survey Map and Chart. 214. https://uknowledge.uky.edu/kgs_mc/214 This Map and Chart is brought to you for free and open access by the Kentucky Geological Survey at UKnowledge. It has been accepted for inclusion in Kentucky Geological Survey Map and Chart by an authorized administrator of UKnowledge. For more information, please contact [email protected]. https://doi.org/10.13023/kgs.mc03.11 Highway roadcuts along Interstate· Highway 75 from The Breathitt Formation, which unconformably over­ KENTUCKY GEOLOGICAL SURVEY WILLIAMSBURG WOFFORD ttOFroHD I vor Conway, Kentucky, to Jellico, Tennessee, expose Missis­ lies the Mississippian rocks, consists of sandstone, silt­ B QUADRANGLE QUADRANGLE QUADK4NCLE QUADRANGLE c UNIVERSITY OF KENTUCKY sippian and Pennsylvanian rocks in south-central Ken­ stone, shale, and coal. The Breathitt Formation in the area Donald C. Haney, State Geologist and Director tucky (Fig. 1). The roadcut exposures offer easy access of tt}ese exposures is Early and Middle Pennsylvanian in ----· Jellico coal bed age (approximately 310 to 320 million years old). It con­ and stratigraphic variety for educational purposes, and are __ Jellic:ocaal bed - - - - - ------ ideal for high school, university, and professional geology tains several unnamed shale layers that were deposited as \ '.,00 - MAP AND CHART SERIES 3 field trips. Several national and international field trips, and muds, silts, and sands in extensive, shallow marine or Series XI, 1992 many out-of-State university field trips have examined brackish seas. Traces of marine and brackish-water inver­ --- BJ.,..('"*''" co.al Nd these exposures. In addition, scientific studies involving tebrate fossils can be found in some of these strata. Many 1200 - elastic and carbonate sedimentology, coal geology, pa­ of the sandstones observed along the highway represent GEOLOGIC HIGHWAY CROSS SECTIONS: leontology, biostratigraphy, and karst (cave) development sands that were deposited in the channels of rivers flowing have been undertaken along this road. from the ancient Appalachian Mountains. These channel sandstones may appear as broad lenses of rock, or as a 1100 - -- INTERSTATE HIGHWAY 75 These rocks, however, are highly variable and difficult rock layer that cuts through underlying strata. Fossil tree - to differentiate stratigraphically. The sandstones and CONWAY, KENTUCKY, TO JELLICO, TENNESSEE limbs and logs can be found in the basal parts of some of shales of different stratigraphic levels are commonly quite Reference datum these sandstone layers. These fossil tree limbs represent ,.. similar, making correlation or identification of stratigraphic Donald R. Chesnut, Jr. units very ·difficult. Moreover, these sedimentary rocks are logjams that formed in the ancient rivers. Thin shale beds highly variable laterally (for example, a sandstone may overlying these sandstones were commonly deposited as Breathitt Formalion grade laterally into a shale in a short distance), further com­ muds in abandoned channels or as flood sediments in le­ 900 - In cooperation with the Kentucky Department of Transportation plicating stratigraphic identification. In order to aid scientif­ vee oroverbank deposits associated with the rivers. These ic and educational studies of these coal-bearing rocks, this shales may contain plant fossils such as ferns, seed ferns, and horsetails. Coal beds were deposited largely as peats stratigraphic identification of the rocks exposed along Inter­ 000 - state Highway75 was undertaken. resulting in the six cross in coastal peat swamps. Some locally occurring coal beds were deposited in abandoned (oxbow) channels or as Ancient slump structure sections on these sheets. indicated by contorted beds in Locations of the cross sections along Interstate High­ transported peat mats and peat debris. Pennsylvanian rocks above way 75 are shown on the reference map (Fig. 1). Letters (A, More detailed geologic descriptions and illustrations c D the undeformed Mississ ippian have been published for the roadcut exposures marked by Slade Formation. B, C, etc.) on the map indicate where the cross sections be­ - an encircled letter. The publications containing these de­ ""' WHrtLEY I LAUREL CORBfN I ULY gin and end. The cross sections are a side-view represen­ (;QIJNJ'J' (,'(JUN'J'J' QUADRANGLE QUADRANGLE tation of the rocks that are exposed in the roadcuts. Hills scriptions are listed under SOURCES FOR STOP DE­ SCRIPTIONS. and valleys (topography) are represented by jagged up­ 140) - Jellico coal bed Poppin Roel< Member and-down lines; the elevation of the highway is indicated by the smoothly curved, heavier line. Because of vertical W _ _ - Blu" Gem coal bed exaggeration on the cross sections (the vertical component ! 1300 - ===;==" is drawn approximately 25 times greater than the horizon­ ,-= ,_..._ tal), the topography appears to be much steeper than it ac­ - - - a- - tually is. Roadcut exposures, th erefore, are shown as hills occurring above the level of the road. Mile markers (small !200 - green signs spaced 1 mile apart on the highway shoulder) are illustrated on the sections as small rectangles with numbers inside. Numbers on the left margins of cross sec­ 1100 - tions refer to elevations above sea level. Creeks, rivers, Photograph of roadcut at milepost 61. bridges, intersections, and similar features are plotted on REFERENCES CITED the sections to help the viewer locate the highway roadcuts. Cobb, J.C., Chesnut, D.R., Hester, N. C., and Hower, J.C., 1981, ""' ~--'======'--'=======---=======--=======---=====::::.--===~·~,O~•~"'~''~"~"m'-----:::=--~~__11~-~======--=====_...,..--- ===-.....:===-==-----=====~~------_;.==::::.--=======--==-.,~~-~======:.....__:=:=::=:.__:=:=:==--- The sedimentary rocks observed in the roadcut expo­ Coal and coal-bearing rocks of eastern Kentucky (Guide­ - ---- sure are iillustrated on the sections, and the major rock book and roadlog for Coal Division of Geological Society of Ancient slump structure types pre,sent are identified in the Explanation. Thick­ America Field Trip No. 14): Kentucky Geological Survey, ser. nesses fo1r many of the rock units were determined from 11, 169 p. 900 - cores drilled by the Kentucky Department ofTransportation Dever, G. R., Jr., Hester, N. C., Ettensohn, F. R., and Moody, J. R., precedin91 construction of the highway. Actual shapes of 1979, Stop 3: Nev,man Limestone (Mississippian) of east­ J'oppin R<,tk Member the rock layers were determined by field examination. central Kentucky and Lower Pennsylvanian slump struc­ ture, in Ettensohn, F. R., and Dever, G. R., eds., ULY I LONDON WNDON I BERNSTADT The shales and sandstones of the Borden Formation D QUA,DRA.NGLE QU,tJJR,tNGLE QUAJJRANGLE QUA.DJ«NGLE E were depcnsited as subaqueous (underwater) delta depos­ Carboniferous geology from the Appalachian Basin to the Il­ linois Basin through eastern Ohio and Kentucky (Ninth Inter· 1400 - its during tthe Early Mississippian Period (350 to 360 million national Congress of Carboniferous Stratigraphy and years ago,). In some areas marine invertebrate fossils can Geology, Field Trip No. 4): Lexington, University of Ken­ ~ ~ be found iin the shales. The Slade Formation, which was tucky, p.175-181, ~ ~ formerly dlivided into the Newman Limestone and the Ren­ ~ ~ Q fro Memb,er (Ettensohn and others, 1984), was deposited ~ ~ ~ 'v as calcareous (limy) sands and muds in a shallow marine SOURCES FOR STOP DESCRIPTIONS Geologic relationships shown at environm,ent similar to the shallow seas around the Baha­ milepost 61 in cross section f.G. Detailed descriptions of individual roadcut exposures ~] mas. Marine fossils are common in these limestones. The Corbin SsndBW""' Note difference between (those indicated by an encircled letter on the cross sec­ vertical and horizontal scales. Paragon !Formation, which was formerly referred to as the tions) can be found in the following stop descriptions. Bib­ Corbin Sandstone Pennington Formation, (Ettensohn and others, 1984), was 1100 - Graphic representation of geologic relationships shown in photograph at milepost 61. deposited as muds and sands in subtidal and intertidal en­ liographic references are given in REFERENCES CITED. vironments. The Paragon Formation was truncated by ero­ Locality Reference u,m81Ped' sand..-rone snd ffl11Je, Bre111blttForm•ti"" sion during the Early Pennsylvanian Period (about 320 Refcrer,;;c dstum million years ago), and this truncation is represented in the @ Cobb and others (1981), Stop 1, p. 6-10. ""' rock record as an unconformity. ® Dever and others (1979), Stop 3, p. 175-181 . &,.. Rn,,k Rookcutle Sand11tone ,00 - {·•p/<16··• otber Mndaionu -- tl,ittFornu1tlon MADISON Age _,,,.-- L~•~snd _,,dalone, Brea --- - -- _ ----- Lithology Stratigraphic Un its ~ unn..,,,ed•= - ---------__ / ,.,....- - - ation) BOO - ,., stion i Pe1111int1on Form Blue GelP coal bed Jellico co8 1 _ ----- - - ----por111f"" F~, Ro,,t Melllb<lr,