• unlimited access with print and download
    $ 37 00
  • read full document, no print or download, expires after 72 hours
    $ 4 99
More info
Unlimited access including download and printing, plus availability for reading and annotating in your in your Udini library.
  • Access to this article in your Udini library for 72 hours from purchase.
  • The article will not be available for download or print.
  • Upgrade to the full version of this document at a reduced price.
  • Your trial access payment is credited when purchasing the full version.
Buy
Continue searching

Conodont-based correlation of major cyclothems in lower Cherokee Group (lower Desmoinesian, middle Pennsylvanian), Oklahoma to Iowa

Dissertation
Author: Thomas Robert Marshall
Abstract:
Three named major cycles of marine transgression and regression (cyclothems) in the lower Cherokee Group are recognized from the Arkoma Basin margin in east-central Oklahoma across the northern Midcontinent shelf, on the basis of distinctive conodont morphotypes. The lowest of these (McCurtain) is characterized by Idiognathodus cf. praeobliquus and absence of I. obliquus and Idiognathoides. The middle cyclothem (Doneley) is the first major cyclothem to yield I. obliquus. The uppermost (Inola) yielded abundant Idiognathodus, Neognathodus and Idioprioniodus, and sparse Gondolella, and is characterized by large numbers of Idiognathodus podolskensis. All three contain large numbers of I. amplificus. At the base of the succession, the genus Idiognathoides in three cores from northeastern Kansas to south-central Iowa confirms the presence of Atokan strata in the Forest City Basin. The McCurtain cyclothem extends from Oklahoma to the Forest City Basin in northeastern Kansas. The Doneley and Inola cyclothems extend from Oklahoma into Iowa. The Inola Limestone of Oklahoma is equivalent to the Hackberry Branch Limestone of western Missouri. The Bluejacket Coal of Oklahoma, at the base of the Inola cyclothem, is likely equivalent to Bluejacket A Coal of Kansas, Weir B or C coals in Missouri, and a middle Laddsdale coal in Iowa. The Rowe Coal of Oklahoma, Kansas, and Missouri, at the base of the Doneley cyclothem, is likely equivalent to the Cliffland Coal of Iowa. Inconsistent marine lithofacies in all three cyclothems suggest a complex depositional history on irregular surfaces.

v TABLE OF CONTENTS LIST OF TABLES ............................................................................................................ vii LIST OF FIGURES .............................................................................................................x LIST OF PLATES ........................................................................................................... xiii CHAPTER I. INTRODUCTION ............................................................................................1

Previous Work ..................................................................................................5 The Study Area .................................................................................................7 Field Methods ...................................................................................................9 Laboratory Methods ........................................................................................10 Rationale for Correlation ................................................................................12 Geologic Setting .............................................................................................12 Geologic History .............................................................................................15 Significance of This Study ..............................................................................19 II. STRATIGRAPHY ..........................................................................................20

Introduction .....................................................................................................20 Lithostratigraphy .............................................................................................23 Oklahoma ................................................................................................23 Nevada, Missouri Conference .................................................................24 Missouri ...................................................................................................24 Kansas ......................................................................................................25 Iowa .........................................................................................................26 Genetic Stratigraphy .......................................................................................27 McCurtain Cyclothem .............................................................................27 Sam Creek Cyclothem .............................................................................29 Doneley Cyclothem .................................................................................31 Inola Cyclothem ......................................................................................34 III. RECOGNITION OF CONODONT MORPHOLOGY AND TAXONOMY .................................................................................................37

Introduction .....................................................................................................37 Recognition of Conodont Morphotypes .........................................................38 Genus Idiognathoides Harris and Hollingsworth 1933 ...........................38 Genus Gondolella Stauffer and Plummer 1932 .......................................38 Genus Idiognathodus Gunnell 1931 ........................................................39 Idiognathodus obliquus Kossenko and Kozitskaya 1978 (Figure 8-11, 8-12, 8-13, & 8-14) .....................................................41 Idiognathodus podolskensis Goreva 1984 (Figure 8-1, 8-2, 8-3, 8-4, & 8-5) ......................................................42 Idiognathodus amplificus Lambert 1992 (Figure 8-6, 8-15, 8-19, & 8-20) .......................................................43 Idiognathodus praeobliquus Nemyrovska, Perret-Mirouse, and Alekseev 1999 (Figure 8-16, 8-17, 8-18, & 8-22) ............................45

vi Idiognathodus iowaensis Youngquist and Heezen 1948 ...................46 Idiognathodus mundulus Youngquist and Downs 1949 ....................46 Idiognathodus robustus Kossenko and Kozitskaya 1978 .................47 Idiognathodus gibbus Lambert 1992 (Figure 8-25) ..........................48 Idiognathodus crassadens Stamm and Wardlaw 2003 (Figure 8-10) .....................................................................................49 Genus Neognathodus Dunn 1970 ............................................................50 Neognathodus asymmetricus (Stibane 1967) (Figure 8-6) ...............50 Idiognathodus cf. asymmetricus of Boardman, Heckel, and Marshall 2004 (Figure 8-7) ...............................................................51 Neognathodus bothrops Merrill 1972 ................................................52 Neognathodus caudatus Lambert 1992 (Figure 8-20) ......................53 IV. BIOSTRATIGRAPHY AND CORRELATION OF MAJOR LOWER CHEROKEE GROUP CYCLOTHEMS ........................................................56

Inola Cyclothem ..............................................................................................57 Cyclothems Below the Inola Cyclothem ........................................................61 Atokan Interval ........................................................................................61 McCurtain Cyclothem .............................................................................62 Doneley Cyclothem .................................................................................63 Intermediate and Minor Cyclothems ..............................................................65 Between Upper Tiawah and Inola ...........................................................66 Between Inola and Doneley/Sam Creek ..................................................66 Between McCurtain and Doneley/Sam Creek .........................................67 Other Possible Controls Over Minor Cyclothems ...................................68 V. DEPOSITIONAL FACIES AND BRIEF DEPOSITIONAL HISTORY ......70

McCurtain Cyclothem ....................................................................................70 Doneley Cyclothem ........................................................................................71 Inola Cyclothem ..............................................................................................75 VI. CONCLUSIONS AND SUGGESTIONS FOR FUTURE WORK ................80

Conclusions .....................................................................................................80 Future Work ....................................................................................................83

REFERENCES ..................................................................................................................88

APPENDIX A MEASURED SECTIONS .................................................................100

APPENDIX B CONODONT INFORMATION ........................................................211

vii LIST OF TABLES Table B1. Conodont abundances of the McCurtain Shale exposure at Brushy Creek Tributary locality in Pittsburg County, Oklahoma. ................................................212 B2. Conodont abundances of the McCurtain Shale exposure at Brushy Creek Tributary locality, normalized to platform elements per kilogram. ........................212 B3. Conodont abundances at Davis Airfield section exposure near Muskogee, Muskogee County, Oklahoma, and their corresponding sample numbers. ............213 B4. Conodont abundancs at Davis Airfield section, normalized to platforms per kilogram. .................................................................................................................213 B5. Conodont abundances at Wagoner County shale pit, Oklahoma, and their corresponding sample numbers (samples not normalized). ....................................213 B6. Conodont abundances at Inola Hill section near Inola, Rogers County, Oklahoma, and their corresponding sample numbers (Idiognathodus species B, I. sp. C., I. sp. D of Boardman and others, 2004)...............................................214 B7. Conodont abundances at Inola Hill section, normalized to platform elements per kilogram (Idiognathodus species B, I. sp. C, I. sp. D of Boardman and others, 2004). ..........................................................................................................214 B8. Conodont abundances at type Doneley section Craig County, Oklahoma, and their corresponding sample numbers. .....................................................................215 B9. Conodont abundances at type Doneley section, normalized to platform elements per kilogram. ............................................................................................215 B10. Conodont abundances at Doneley roadcut on Highway 25, Craig County, Oklahoma. ...............................................................................................................215 B11. Conodont abundances in KGS Cooper CW-1 core, Labette County, Kansas, and their corresponding sampled footages (Idiognathodus species A, I. sp. B, I. sp. D of Boardman and others, 2004). .................................................................216 B12. Conodont abundances in KGS Cooper CW-1 core, normalized to platforms per kilogram (Idiognathodus species A, I. sp. B, I. sp. D of Boardman and others, 2004).. .........................................................................................................216 B13. Conodont abundances in KGS Hinthorn CW-1 core, Montgomery County, Kansas, and their corresponding sampled footages (samples not normalized). .....217 B14. Conodont abundances in the KGS P & M #7 core in Cherokee County, Kansas, and their corresponding sampled footages. ...............................................217 B15. Conodont abundances in the KGS P & M #7 core, normalized to platform elements per kilogram. ............................................................................................218

viii B16. Conodont abundances at type Hackberry Branch section, Vernon County, Missouri, and their corresponding sample numbers. ..............................................218 B17. Conodont abundances at type Hackberry Branch section, normalized to platform elements per kilogram. .............................................................................218 B18. Conodont abundances in MGS Hess CH-9H core, Bates County, Missouri, and their corresponding sampled footages..............................................................219 B19. Conodont abundances in MGS Hess CH-9H core, normalized to elements per kilogram. .................................................................................................................219 B20. Conodont abundances in KGS Rose Hill #1-6 core Miami County, Kansas, and their corresponding sampled footages..............................................................220 B21. Conodont abundances in KGS Rose Hill #1-6 core, normalized to platform elements per kilogram. ............................................................................................220 B22. Conodont abundances in KGS Spencer #2-6 core, Franklin County, Kansas, and their corresponding sampled footages..............................................................221 B23. Conodont abundances in KGS Spencer #2-6 core, normalized to platform elements per kilogram. ............................................................................................221 B24. Conodont abundances in KGS Deffenbaugh #2 core, Johnson County, Kansas, and their corresponding sampled footages. ...............................................222 B25. Conodont abundances in KGS Deffenbaugh #2 core, normalized to platform elements per kilogram. ............................................................................................222 B26. Conodont abundances in KGS Edmonds 1A core, Leavenworth County, Kansas, and their corresponding sampled footages. ...............................................223 B27. Conodont abundances in KGS Edmonds 1A core, normalized to platform elements per kilogram. ............................................................................................223 B28. Conodont abundances in KGS Hopp #1-16 core, Doniphan County, Kansas, and their corresponding sampled footages..............................................................224 B29. Conodont abundances in KGS Hopp #1-16 core, normalized to platform elements per kilogram. ............................................................................................225 B30. Conodont abundances in MGS Davis “Forest City” core, Holt County, Missouri, and their corresponding sampled footages. ............................................226 B31. Conodont abundances in the MGS Davis “Forest City” core, normalized to platform elements per kilogram. .............................................................................226 B32. Conodont abundances at type Laddsdale section in Davis County, Iowa, and their corresponding sample numbers. .....................................................................227 B33. Conodont abundances at type Laddsdale section, normalized to platform elements per kilogram. ............................................................................................227

ix B34. Conodont abundances at Lakonta strip pit section, Mahaska County, Iowa, and their corresponding sample numbers (Idiognathodus species B of Boardman and others, 2004). ..................................................................................228 B35. Conodont abundances at Lakonta strip pit section, normalized to platform elements per kilogram (Idiognathodus species B of Boardman and others, 2004). ......................................................................................................................228 B36. Conodont abundances in IGS CP-78 core, Wayne County, Iowa, and their corresponding sampled footages. ............................................................................229 B37. Conodont abundances in IGS CP-78 core, normalized to platform elements per kilogram. ...........................................................................................................229 B38. Conodont abundances in IGS CP-79 core, Lucas County, Iowa, and their corresponding sampled footages (Idiognathodus species B of Boardman and others, 2004) ...........................................................................................................230 B39. Conodont abundances in IGS CP-79 core, normalized to platform elements per kilogram (Idiognathodus species B of Boardman and others, 2004). ..............231 B40. Conodont abundances in WC-22 “Logan” core, Harrison County, Iowa, and their corresponding sampled footages. ...................................................................232 B41. Conodont abundances in WC-22 “Logan” core, normalized to platform elements per kilogram. ............................................................................................232

x LIST OF FIGURES Figure 1. Position of Cherokee Group within Carboniferous System and Pennsylvanian Subsystem. ..................................................................................................................2 2. Marine transgressive-regressive cycles (cyclothems) recognized in lower Cherokee Group in eastern Oklahoma (Marshall, 2002) with sea-level curve modified from Boardman and others (2002) by Boardman and others (2004); colored names indicate units that have been thought to be regionally extensive, MR- maximum regression, MT-maximum transgression. ........................3 3. Composite section of marine transgressive-regressive cycles (cyclothems) recognized in middle and upper Cherokee Group in eastern Oklahoma and southeastern Kansas by Marshall (2002) and Hanley (2008); bolded names indicate units that are thought to be regionally extensive. ..........................................4 4. Locations of cores and outcrops used in this study. Dots indicate location of cores and triangles of significant surface exposures; gray shaded area indicates approximate outcrop belt of Cherokee Group. Tectonic features outlined in dark blue. Line of correlation in red. .......................................................8 5. Regional tectonic setting of Midcontinent with outcrop belts of individual Pennsylvanian stages outlined (from Heckel, 2002). ...............................................13 6. Paleogeographic reconstruction of Midcontinent during Early Desmoinesian, illustrating general depositional environments during lower stands of sea level during early Cherokee time (from Rascoe and Adler, 1983). ...................................17 7. Stratigraphic classification and nomenclature of Cherokee Group used in different states of Midcontinent. Nomenclature based on Oakes (1953) for Oklahoma, Searight and others (1953), Howe (1956), and Zeller (1968) for Kansas, Searight and others (1953) and Gentile and Thompson (2004) for Missouri, and Ravn and others (1984) for Iowa with updates by Pope (2009) as reported in Pope and Marshall (2009) highlighted in red color. Carruthers Coal is correlated with Scammon Coal at base of Upper Tiawah cyclothem by Hanley (2008). A middle Laddsdale coal and Cliffland Coal are correlated with units to the south as discussed in Chapter IV. Bold names indicate units updated by author to be regionally extensive. ..........................................................21 8. Lower Cherokee conodonts. All speciments magnified 65X. .................................54 9. Correlation of lower Cherokee succession using base of Inola cyclothem as datum. Short brown lines represent coals, light blue lines are limestones, dark orange XX mark paleosols, dark yellow dots mark sandstones, purple lines mark dark phosphatic shales. Thick dark blue lines mark base of Upper Tiawah cyclothem. Thin red lines mark assumed top of Inola cyclothem. Other thick colored lines represent correlations based on good biostratigraphic data and/or position relative to Inola cyclothem above. Dashed lines are inferred correlations. Pink zones denote Atokan strata. ‘mnf’ denotes marine fossils, ‘rm’ denotes restricted marine fossils, purple

xi ‘Gz’ denotes position of Gondolella zone of Hanley (2008), purple ‘G’ denotes Gondolella found in the Inola cyclothem, purple ‘Ip’ denotes Idioprioniodus, dark blue ‘N’ denotes Neognathodus, and pink ‘I’des’ denotes Idiognathoides. Please refer to key included on figure for the symbols used on the diagram for the various species of Idiognathodus. .................58 10. Stratigraphic distribution of Idiognathodus podolskensis, I. obliquus, and I. praeobliquus in Donets Basin compared with stratigraphic distribution of I. podolskensis, I. obliquus, and I. cf. praeobliquus in Midcontinent North America. ....................................................................................................................85 A1. Location of cores and outcrops used in study with line of correlation drawn in. ............................................................................................................................103 A2. Explanation of symbols used in measured sections. ...............................................104 A3. Exposure of upper marine band of McCurtain Shale Member of McAlester Formation (McCurtain cyclothem) measured in roadcut west of bridge over Brushy Creek, two miles (3.2 km) west of Jones Academy and two miles (3.2 km) north of Haileyville, Pittsburg County, OK, SW-SW-SE-SW Sec. 19, T5N, R17E, and NW-NW-NE-NW Sec. 30, T5N, R17E, from Marshall (2002) ......................................................................................................................107 A4. Sam Creek and overlying Doneley cyclothem at Davis Airfield, 4 miles (6.4 km) south of Muskogee, Muskogee County, OK, NW-NW-SW-NW Sec. 26, T14N, R18E, measured along stream bed directly east of Highway 64, modified from Hemish, L.A., 1998, Coal Geology of Muskogee County, Oklahoma, Measured Section 74. ...........................................................................108 A5. Wagoner County shale pit exposure (Sam Creek and possibly Doneley cyclothems) measured from creek bed, up hillside, and across road to top of hill, one mile (1.6 km) north of Arkansas River, Wagoner County, OK, NE- NE-NE Sec. 1, T15N, R17E, and SW-SE-SE-SE Sec. 36, T16N, R17E, from Marshall (2002). .....................................................................................................109 A6. Exposure of Inola cyclothem, southwest slope of Inola Hill, Rogers County, Oklahoma, NE-SW-NW Sec. 10, T19N, R17E, measured with Alan Bennison, from Marshall (2002), some section based on Hemish, L.A., 1990c, Oklahoma Geology Notes, v. 50, pp. 4-23. ............................................................111 A7. Type Doneley locality (Doneley cyclothem), measured on north-facing bank of Mill Creek, Craig County, Oklahoma, SW-NW-NW Sec. 16, T26N, R20E .....112 A8. North-facing roadcut of Doneley cyclothem 1.5 miles west of Bluejacket, Craig County, Oklahoma, OK Highway 25, NW-NW-NE Sec. 30, T27N, R21E, from Hemish, 1986, Coal Geology of Craig County and eastern Nowata County, Oklahoma, Measured Section 75. ................................................113 A9. KGS Cooper CW-1 core description, Labette Co., KS, from previous description by J. Lange (2003). ..............................................................................114 A10. KGS Hinthorn CW-1 core description, Montgomery Co., KS, from previous description by J. Lange (2002). ..............................................................................123

xii A11. KGS P & M #7 core description, Cherokee Co., KS, previously described by John Harris and Michael Roberts (description taken from Harris with additional notes by author). ....................................................................................130 A12. Type Hackberry Branch Limestone, Vernon County, Missouri (Inola cyclothem), NE-NE-NW Sec. 29, T35N, R32W (formerly misidentified as Seville Limestone in Missouri), based upon R.J. Gentile’s 1964 and 2001 measured sections. ..................................................................................................138 A13. MGS Hess CH-9H core description, Bates Co., MO..............................................139 A14. KGS Rose Hill #1-6 core description, Miami Co., KS, previously described by Johnson (2003). ..................................................................................................143 A15. KGS Spencer #2-6 core description, Franklin Co., KS, previously described by Johnson (2004) (descriptions are from Johnson with additional notes from author). ....................................................................................................................150 A16. KGS Deffenbaugh Quarry #2 core description, Johnson Co., KS, previously described by W.M. Brown (2005). .........................................................................155 A17. KGS Edmonds 1A core description, Leavenworth Co., KS, previously described by L. Brady (1992). ................................................................................160 A18. KGS Hopp #1-16 core description, Doniphan Co., KS, previously described by W.M. Brown (2005). .........................................................................................167 A19. MGS FCC Davis #1 (Forest City) core description, Holt Co., MO. ......................177 A20. Inola cyclothem, type Laddsdale Coal locality (Ravn and others, 1984), northwest-facing cutbank of Soap Creek, east end of bend in creek, 0.5 miles (0.8 km) west of Salt Creek School, Davis County, IA, Center Sec. 7, T70N, R12W, modified from Ravn et al. (1984), p. 30. ....................................................188 A21. Blackoak Coal and overlying marine units in abandoned strip mine, 0.8 miles (1.3 km) southwest of Lakonta (Truax), Mahaska County, IA, SW-NW Sec. 29, T74N, R16W, measured quarter mile east of Figure A22, modified from Howes et al. (1988), p. 36. ......................................................................................189 A22. Cliffland Coal and overlying marine units (Doneley cyclothem) at west end of abandoned strip mine, 0.8 miles (1.3 km) southwest of Lakonta (Truax), Mahaska County, IA, SW-NW Sec. 29, T74N, R16W, quarter mile west of Figure A21, modified from Howes et al. (1988), p. 36. .........................................190 A23. IGS CP-78 coal project core description, Wayne Co., IA, previously described by Paul VanDorpe (modified by author). ...............................................192 A24. IGS CP-79 coal project core description, Lucas Co., IA, previously described by Paul VanDorpe (1979) (modified by author). ....................................................198 A25. IGS WC-22 (Logan) core description, Harrison Co., IA, previously described by Philip Heckel (43 to 323 feet) and Brian Witzke (323 to 628 feet) (modified by author).. .............................................................................................205

xiii LIST OF PLATES Plate B1. Lower Cherokee Correlation ..................................................................................233

1

CHAPTER I INTRODUCTION Despite being noted for its highly repetitive sequences of sandstones, shales, limestones, underclays and importantly, coals, little recent work has been done on the sequence stratigraphy and biostratigraphic correlation of the lower Desmoinesian Cherokee Group. Most previous workers in the Cherokee Group (e.g. Abernathy, 1936; Searight and others, 1953) dealt with resolving issues of stratigraphic nomenclature rather than interpretive stratigraphy. More recent interpretative stratigraphic work (see Heckel, 2002) dealt only with upper Desmoinesian through lower Virgilian strata, leaving a significant gap in the lower Desmoinesian. The Cherokee Group lies entirely within the Desmoinesian Stage in Oklahoma and within the Desmoinesian and Atokan stages in Kansas, Missouri, and Iowa; both stages are in the Middle Pennsylvanian Series, Pennsylvanian Subsystem, and Carboniferous System (Figure 1). The Cherokee Group overlies the Atoka Formation in the Arkoma Basin of east-central Oklahoma and Mississippian strata in Kansas and northward, and it is essentially conformable beneath the overlying Marmaton Group. In Oklahoma, Missouri, and Kansas, the Cherokee Group is divided into two subgroups: the Krebs and Cabaniss (Figures 2 and 3). In Oklahoma, the Cherokee Group is further divided into five formations in ascending order: Hartshorne, McAlester, Savanna, Boggy (in the Krebs Subgroup), and Senora (in the Cabaniss). The other states divide the Cherokee Group into a number of different formations, many of which are recognized only as members or beds in Oklahoma. In Iowa, the Cherokee Group is divided into the Kilbourn, Kalo, Floris, and Swede Hollow Formations.

2

Figure 1. Position of Cherokee Group within Carboniferous System and Pennsylvanian Subsystem.

3

Figure 2. Marine transgressive-regressive cycles (cyclothems) recognized in lower Cherokee Group in eastern Oklahoma (Marshall, 2002) with sea-level curve modified from Boardman and others (2002) by Boardman and others (2004); colored names indicate units that have been thought to be regionally extensive, MR- maximum regression, MT-maximum transgression.

4

Figure 3. Composite section of marine transgressive-regressive cycles (cyclothems) recognized in middle and upper Cherokee Group in eastern Oklahoma and southeastern Kansas by Marshall (2002) and Hanley (2008); bolded names indicate units that are thought to be regionally extensive.

5

Previous Work Describing a succession of coal, shale, limestone, sandstone, and fire clay near Peoria, Illinois, Udden (1912) was the first to denote the cyclical nature of the Midcontinent Pennsylvanian (Heckel, 1984, p. 535). Wanless and Weller (1932, p.1003) established the term cyclothem and attempted the first regional correlation of the cyclothems of Illinois, Iowa, western Missouri, eastern Kansas, and northeastern Oklahoma. Wanless and Shepard (1936) proposed as the drivers of cyclic deposition the growth and shrinkage of glaciers in the Southern Hemisphere resulting in eustatic sea- level changes. Moore (1936, p.24) established an “ideal cyclothem” of the Midcontinent Pennsylvanian, consisting initially of the following: “. 9. Shale (and coal). .8. Shale, typically with molluscan fauna. .7. Limestone, algal, molluscan, or with mixed molluscan and molluscoid fauna .6. Shale, molluscoids dominant. .5. Limestone, contains fusulinids, associated commonly with molluscoids. .4. Shale, molluscoids dominant. .3. Limestone, molluscan, or with mixed molluscan and molluscoid fauna. .2. Shale, typically with molluscan fauna. .1. c. Coal .1. b. Underclay .1. a. Shale, may contain land plant fossils. .0. Sandstone.”

According to Moore (1936, p.25), the nonmarine portions of the cyclothem were members .0, .1, and .9, with .9 being part of the regressive phase, while members .2 to .8 were the marine portions, with .2 being part of the transgressive phase. Ferm (1970) proposed the hypothesis of ‘delta switching’ to explain Appalachian cyclothems. Heckel (1977) developed the concept that the black phosphatic shales (core shales) were

6

deposited during the deepest marine highstands. Swade (1985) described the conodont faunas of the upper part of the Cherokee Group, but used open nomenclature. Haworth and Kirk (1894) established the name “Cherokee Shale” in southeastern Kansas. Early studies of the Cherokee Group centered on coal exploration and production (e.g., Chance, 1890, Taff, 1899, 1904; Hendricks and others, 1936; and Dane and others, 1938) in southeastern Oklahoma. Abernathy (1936, p.60) recognized a more simplified Cherokee cycle by removing the two upper limestones (.5, .7) and most of the upper shales (.4, .6, and .8) from Moore’s “ideal cyclothem”. He divided the Cherokee Group into 15 cyclothems, separated by disconformities (1936, p. 61). It should be noted that Abernathy’s cyclothem better represents a “realistic” Cherokee cyclothem than does Moore’s “ideal cyclothem”. Moore (1949) elevated the “Cherokee Shale” to “Cherokee Group”. Searight and others (1953), utilizing coal cycles, divided the Cherokee Group into 18 “formations” and also proposed dropping the term “Cherokee Group” in favor of the Krebs and Cabaniss Groups. However, according to Howe (1956), the term “Cherokee Group” was reinstated at a meeting in Lawrence, Kansas in 1955. Howe (1956) produced a seminal work describing and discussing many of the lithostratigraphic units of the Cherokee Group in Missouri, Kansas, and Oklahoma, and providing the basis for the current lithostratigraphic classification and nomenclature in Missouri. Marshall (2002) recognized and described 28 separate units of marine transgressive-regressive (T-R) cycles within the Cherokee Group from the Arkoma Basin in southeastern Oklahoma to the Northern Oklahoma Shelf in extreme northeastern

7

Oklahoma and southeastern Kansas. These repeated T-R cycles are typically genetic coal-bearing cycles or cyclothems, bounded by exposure surfaces at the tops of paleosols or at the base of incisement surfaces. Utilizing these 28 T-R cycles, Boardman and others (2002) established a modern cyclothem succession and a sea-level curve for the most complete Cherokee succession in the Midcontinent, which was updated by Boardman and others (2004) (Figure 2). The Study Area The area of study for this project extends from the Arkoma Basin in east-central Oklahoma, through the shelf area in northeastern Oklahoma and southeastern Kansas, over the Bourbon Arch in east-central Kansas and western Missouri, and through the Forest City Basin in northeastern Kansas, northwestern Missouri, and southwestern Iowa to the northern shelf area in central Iowa (Figure 4). Due to the paucity of outcrops of long sections, most work involved long cores from Kansas, Missouri, and Iowa (Figure 4). However, outcrops with stratigraphic significance were included, particularly those in the type areas of major cyclothems: Inola Hill in Rogers County, Oklahoma, the type area for the Inola Limestone Member of the Boggy Formation; the type Doneley Limestone Member of the Savanna Formation in central Craig County, Oklahoma; the type McCurtain Shale in Pittsburg County, Oklahoma; the type locality of the Hackberry Branch Limestone in southwestern Vernon County, Missouri; and the type Laddsdale coal interval in Davis County, Iowa (Figure 4).

8

Figure 4. Locations of cores and outcrops used in this study. Dots indicate location of cores and triangles of significant surface exposures; gray shaded area indicates approximate outcrop belt of Cherokee Group. Tectonic features outlined in dark blue. Line of correlation in red.

9

Field Methods Marshall (2002) studied the cyclothems in the entire Cherokee succession in northeastern Oklahoma, and the original purpose of the current work was to extend all this work northward. Initial work, however, showed that the Cherokee succession in Kansas, Missouri, and Iowa is far more complex than originally thought. Therefore, in order to ensure timely completion of research, the project was limited to the lower Cherokee (Krebs Subgroup) below the Weir-Pittsburg coal. K.D. Hanley (2008), another PhD student of P.H. Heckel, worked up the middle of the Cherokee Group from the Weir-Pittsburg coal to the Verdigris Limestone. The upper Cherokee interval from the Verdigris Limestone to the Fort Scott Limestone had already received extensive study by previous workers (see Brenner, 1989, 1995). Because of the scarcity of Cherokee surface exposures, sampling was primarily from long cores at the Missouri Geological Survey in Rolla, the Kansas Geological Survey in Lawrence, and the Iowa Geological Survey in Iowa City. To supplement core data, additional conodont materials were collected from surface exposures in Craig and Rogers counties, Oklahoma, Vernon County, Missouri, and Davis and Mahaska counties, Iowa. Because marine lithofacies are being used to correlate the cyclothems from Oklahoma to Iowa, only marine shales and limestones were sampled for detailed processing. These units were identified in cores by their marine fossil assemblages, particularly crinoids, ostracodes, foraminifers, and brachiopods. Standard sampling intervals are every six inches (15 cm) except for limestones and shales thinner than six inches (15 cm). Furthermore, if a shale or limestone exhibited significant lithologic

Full document contains 252 pages
Abstract: Three named major cycles of marine transgression and regression (cyclothems) in the lower Cherokee Group are recognized from the Arkoma Basin margin in east-central Oklahoma across the northern Midcontinent shelf, on the basis of distinctive conodont morphotypes. The lowest of these (McCurtain) is characterized by Idiognathodus cf. praeobliquus and absence of I. obliquus and Idiognathoides. The middle cyclothem (Doneley) is the first major cyclothem to yield I. obliquus. The uppermost (Inola) yielded abundant Idiognathodus, Neognathodus and Idioprioniodus, and sparse Gondolella, and is characterized by large numbers of Idiognathodus podolskensis. All three contain large numbers of I. amplificus. At the base of the succession, the genus Idiognathoides in three cores from northeastern Kansas to south-central Iowa confirms the presence of Atokan strata in the Forest City Basin. The McCurtain cyclothem extends from Oklahoma to the Forest City Basin in northeastern Kansas. The Doneley and Inola cyclothems extend from Oklahoma into Iowa. The Inola Limestone of Oklahoma is equivalent to the Hackberry Branch Limestone of western Missouri. The Bluejacket Coal of Oklahoma, at the base of the Inola cyclothem, is likely equivalent to Bluejacket A Coal of Kansas, Weir B or C coals in Missouri, and a middle Laddsdale coal in Iowa. The Rowe Coal of Oklahoma, Kansas, and Missouri, at the base of the Doneley cyclothem, is likely equivalent to the Cliffland Coal of Iowa. Inconsistent marine lithofacies in all three cyclothems suggest a complex depositional history on irregular surfaces.