Revised Correlations of the Ordovician (Katian, Richmondian) Waynesville Formation of. Ohio, Indiana and Kentucky. A thesis submitted to the Graduate School.
Revised Correlations of the Ordovician (Katian, Richmondian) Waynesville Formation of Ohio, Indiana and Kentucky
A thesis submitted to the Graduate School of The University of Cincinnati in partial fulfilment of the requirements of the degree of Master of Science in Department of Geology of McMicken College of Arts and Sciences by Christopher D Aucoin B.S. (Geology & Anthropology), State University of New York at the College of Oneonta, Oneonta, NY, 2012
Advisory Committee: Dr. Carlton Brett (Chair) Dr. Benjamin Dattilo (Member) Dr. Dave Meyer (Member) Dr. Arnold Miller (Member) Dr. Brenda Hunda (Member)
ABSTRACT
The Upper Ordovician Waynesville Formation of the Ohio, Kentucky and Indiana tri-state region is situated during and between two major paleoecological events:, the Richmondian Invasion, and the End Ordovician Extinction. Because of this juxtaposition, understanding the regional stratigraphy of this interval is vital to interpreting these events. Stratigraphic and paleontological work on this interval dates back to the late 1800s, and, as a result, numerous nomenclature schemes (biostratigraphical, lithostratigraphical, and state-line geology) have been developed to characterize the Waynesville Formation. The variety of schemes has inhibited the ability to make detailed bed-by-bed correlations. This study has attempted to rectify this issue by selecting the best nomenclature scheme, and create bed-by-bed correlations that cross state lines. The results of the study herein demonstrate that correlations are indeed possible from the deepest water facies to the shallowest water facies fairly readily. The study has also resulted in the discovery of a Mid-Richmondian Unconformity which has previously gone undocumented. This unconformity, which separates the Waynesville Formation from the overlying Blanchester Formation, at places cuts through the entirety of the Clarksville Member of the Waynesville. If extended further south, this unconformity likely removes the Fort Ancient Member and the underlying Arnheim Formation. The discovery of Mid-Richmondian Unconformity will have important implications for paleoecological studies of this interval.
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ACKNOWLEDGEMENTS
There a number of individuals I would like to thank for their assistance in making this project a reality. First and foremost, my advisor Dr. Carlton Brett, for introducing me to the stratigraphical side paleontology, something I value very highly now. Dr. Brett has always been available and enthusiastic to discuss my research and my thesis is all the better for it. I also owe a great deal of thanks to Dr. Benjamin Dattilo who has spent countless hours discussing my project, answering questions and reviewing manuscripts. I would also like to thank my other committee members, Dr. Arnold Miller, Dr. David Meyer, and Dr. Brenda Hunda for all their input into this project and this manuscript. I would also be amiss to not thank all my fellow graduate students, TJ Malgieri, James Thomka, Cameron Schwalbach, Allison Young, Gary Motz and Matt Vrazo, who have assisted with fieldwork and discussions of my research. There have also been a countless number of former and current undergraduate students, who have helped with fieldwork, and I cannot name them all, but among them are Alex Reis, and Ariane Castagner. Much of this work would not have been possible without the assistance of Dan Cooper who has granted me access to his various quarries in the Waynesville. This project was also funded in large part by the Dry Dredgers and its generous members. Lastly, I would like to thank my parents for their love and support throughout this entire process. I certainly would not be where I am now if it were not for them.
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CONTENTS ABSTRACT …………………………………………………………………………………….. i ACKNOWLEDGEMENT ……………………………………………………………………. iii LIST OF FIGURES ……………………………………………………………………………vii LIST OF TABLES ……………………………………………………………………………. xii LIST OF APPENDICES ……………………………………………………………………. xiii 1. INTRODUCTION: ………………………………………………………………………….. 1 1.1
Review of Stratigraphic Nomenclature ………………………………………………….. 1
2. GEOLOGICAL SETTING: ………………………………………………………………… 5 2.1
Paleogeography …………………………………………………………………………. 5
2.2
Geochronology ………………………………………………………………………….. 5
3. METHODS: ………………………………………………………………………………….. 6 4. RESULTS: …………………………………………………………………………………… 8 4.1
Lower Richmondian Stratigraphic Units in Ohio and Indiana ………………………... 16
4.1.1
Arnheim Formation: Oregonia Member ……………………………………………... 16
4.1.2
Waynesville Formation: Fort Ancient Member ……………………………………… 17
4.1.2.1
South Gate Hill Submember …………………………………………………… 17
4.1.2.2
Lower Fort Ancient Shale Submember ………………………………………… 19
4.1.2.3
Bon Well Hill Submember ……………………………………………………... 20
4.1.2.4
Upper Shale Submember: Treptoceras duseri Shale – Trilobite Shale ………... 22
4.1.3
Waynesville Formation: Clarksville Member ………………………………………... 24
4.1.3.1
Lower Clarksville Submember: Cincinnetina Epibole Beds …………………... 27
4.1.3.2
Upper Clarksville Submember: Eochonetes-Leptaena Beds …………………... 30
4.1.3.3
Oldenburg Butter Shale ………………………………………………………… 30 iv
4.1.4
Waynesville Formation: Blanchester Member …………………………………….… 30
4.1.4.1
Mid-Richmondian Unconformity ……………………………………………… 31
4.1.4.2
Lowest Glyptorthis insculpta Submember and Rafinesquina "cornflakes" Submember …………………………………………………………………….. 32
4.1.4.3
Lyrodesma -Isotelus Shale Submember ……………………………………...… 35
4.1.4.4
"Lower Disturbed Zone" ……………………………………………………….. 36
4.1.4.5
Strophomena nutans - Tetrapharella neglecta Submember …………………… 38
4.1.4.6
Upper Disturbed Submember ………………………………………………….. 38
4.1.4.7
Coral-Isotelus Submember …………………………………………………….. 39
4.1.5
Liberty Formation (Redefined) ………………………………………………………. 39
4.1.5.1
Middle and Upper Glyptorthis insculpta Submember …………………………. 39
4.1.5.2
Lower Liberty including "Crinoid Beds" ………………………………………. 42
4.1.5.3
Flexicalymene retrorsa minuens-Isotelus Bed ……………………………………
42 4.1.5.4 4.2
Upper Liberty …………………………………………………………………... 43 Lower Richmondian Interval in Kentucky …………………………………...…………45
4.2.1
Bull Fork Formation …………………………………………………………………. 45
4.2.2
Fort Ancient Equivalent ……………………………………………………………… 46
4.2.3
South Gate Hill Submember …………………………………………………………. 47
4.2.4
Coral Bearing/Cherty Lower Shale …………………………………………………... 48
4.2.5
Fisherville Coral Bed ………………………………………………………………… 49
4.2.6
Cyphotrypa Shale ………………………………………………………….…………. 50
4.2.7
Rowland Member …………………………………………………………………….. 53
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4.2.8
Marble Hill Beds ……………………………………………………………………... 55
4.2.9
Basal Liberty-Bardstown Coral Bed ………………………………………………… 58
4.3
Correlations ……………………………………………………………………………. 58
5. DISCUSSION: ........................................................................................................................ 62 5.1
Nomenclature …………………………………………………………………………... 62
5.2
Mid-Richmondian Unconformity ……………………………………….……………... 67
5.3
Implications for the Richmondian Invasion ……………………………………………. 68
5.3.1
Patterns of Incursion …………………………………………………………………. 68
5.3.2
Paleoecological Implications of the Blanchester-Marble Hill-Rowland Correlation ... 75
6. CONCLUSIONS: …………………………………………………………………………... 82 7. FUTURE RESEARCH: …………………………………………………………………… 83 REFERENCES: ………………………………………………………………………………. 85 APPENDIX: …………………………………………………………………………………… 93
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LIST OF FIGURES
Fig. 1: is a chart summarizing some, but not all, of the nomenclature used in the Cincinnati Arch region. …………………………………………………………………………………………… 4
Fig 2: Map of the Cincinnati Arch based on Holland (1993) showing key outcrop locations used in this study. 1 = Waynesville, OH; 2 = Maysville, KY; 3 = Flemingsburg, KY; 4 = Owingsville, KY; 5 = Brookville, IN; 6 = Oldenburg, IN; 7 = St Leon, IN; 8 = Madison, IN; 9 = Milton, KY; 10 = Bedford, KY; 11 = New Castle, KY; 12 = Fisherville, KY; 13 = Seatonville, KY; Star = Cincinnati. ………………………………………………………………………………………. 7
Fig. 3: Stratigraphic cross section showing the correlation of the Waynesville and Brookville Formations and their members along the western side of the Cincinnati Arch. Datum is the basal Bon Well Hill Submembers. Correlation extends from the northernmost outcrop on the left (#5 on Figure 2) to the southernmost outcrop on the right (#12 on Figure 2). Vertical scale is in meters. ………………………………………………………………………………………….... 9
Fig. 4: Stratigraphic cross section showing the correlation of the key marker beds in the Oregonia-Liberty interval along the western side of the Cincinnati Arch. Datum is the Bon Well Hill Submember. Correlation extends from the northernmost outcrop on the left (#5 on Figure 2) to the southernmost outcrop on the right (#12 on Figure 2). Vertical scale is in meters. ……… 11
Fig. 5: Stratigraphic cross section showing the correlation of the Waynesville and Brookville Formations and their members along the western side of the Cincinnati Arch. Datum is the Midvii
Richmondian Unconformity. Correlation extends from the northernmost outcrop on the left (#5 on Figure 2) to the southernmost outcrop on the right (#12 on Figure 2). Vertical scale is in meters. ………………………………………………………………………………………….. 13
Fig. 6: Stratigraphic cross section showing the correlation of the key marker beds in the Oregonia-Liberty interval along the western side of the Cincinnati Arch. Datum is the MidRichmondian Unconformity. Correlation extends from the northernmost outcrop on the left (#5 on Figure 2) to the southernmost outcrop on the right (#12 on Figure 2). Vertical scale is in meters. ………………………………………………………………………………………….. 15
Fig. 7: Photographs of the South Gate Hill Bed that marks the base of the Waynesville Formation. A) Photograph of the SGB at its type location at South Gate Hill. B) Photograph of the top surface of the SGB displaying the abundant Cincinnetina that make up the bed. Isolated crinoid ossicles can also be seen. Lens cap diameter is 67mm. ………………………………... 18
Fig. 8: Photograph from South Gate Hill showing the Basal Fort Ancient Shale, the underlying South Gate Hill Bed (SGB) and the overlying Bon Well Hill Beds (BWH). The shale rarely outcrops well and is generally covered as seen here. …………………………………………... 19
Fig. 9: Photographs of the Bon Well Hill Beds. A) Image shows the full cluster of limestone beds at their type locality near Brookville, Indiana. B) Closer view of two of the basal beds and the shale in between. C) Image of the BWH beds as seen at the South Gate Hill locality. ………... 21
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Fig. 10: Images of the Treptoceras duseri butter shale. A) Image of the butter shale at a private pit quarry. Note bluish-green coloration when fresh. B) Photograph of a Flexicalymene in situ at a private pit quarry. …………………………………………………………………………….. 23
Fig. 11: Diagram showing faunal zones correlated from the west side of the Cincinnati Arch (notes from Pope 1976) to the east side of the arch (notes from Wolford 1930). Diagram starts with the very top of the Fort Ancient Member and extends through the lowest Liberty Formation. …………………………………………………………………………………………………... 26
Fig. 12: Photograph of the Clarksville Member at Caesar Creek, OH. The Clarksville is predominately shale with regular spaced limestones. The Member is bracketed by the Cincinnetina epibole bed at its base and capped by the Glyptorthis insculpta bed of the Blanchester above. …………………………………………………………………………… 27
Fig. 13: The Cincinnetina epibole zone in Clarksville, OH. This bed marks the base of the Clarksville Member. Image A also shows Eochonetes in the bed. Lens cap is 67mm. ……….. 29
Fig. 14: Images of the pyrite bed found at the Mid-Richmondian Unconformity in Indiana. A) Fallen block showing weathered pyrite crust (orange coloration) from Hanna Creek, Indiana. B) Closer view of the pyrite crust seen in image A. C) Polished slab showing the pyrite bed from Oldenburg, Indiana. ……………………………………………………………………………. 32
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Fig. 15: Images of the Rafinesquina ‘cornflakes bed’ from Garr Hill, Indiana. The lens cap is 67mm in diameter. A) Broad view of the cornflakes bed. B) Closer look at the jumble of Rafinesquina shells in the cornflakes bed. ……………………………………………………... 34
Fig. 16: Lower Disturbed Zone at Caesar Creek. A) Fallen block of the disturbed zone. Rafinesquina on the left side of the block are flat lying and become progressively more edgewise to the right. B) Closer view of the bedding surface showing a large cephalopod in the top right as well as a pygidium of an Isotelus. C) Closer view of the edgewise Rafinesquina that represents a weaker "cornflakes" texture. …………………………………………………………………… 37
Fig. 17: Photographs of the Glyptorthis insculpta zone that marks the base of the Liberty Formation. A) Image of the Middle Glyptorthis insculpta bed from South Gate Hill. B) Image of the G. insculpta bed from the Brookville Causeway. C) Collection of G. insculpta found at South Gate Hill. ……………………………………………………………………………………….. 41
Fig. 18: Images from the Brookville Causeway showing the Eochonetes bed. A) Abundant Eochonetes. B) Closer view showing the presence of Grawinkia among the Eochonetes. C) Example of the Eochonetes beds with cornflakes texture. …………………………………….. 44
Fig. 19: Photographs of the Cyphotrypa interval in Kentucky. A) Image of the Bead Bryozoan Bed (BBB) showing hundreds of C. clarksvillensis on the surface. Photograph was taken at the ‘Fault Outcrop’ along I-64 in Kentucky. B) Closer view of the BBB at the I-64 section. C) View
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of the underside of a Cyphotrypa from Bedford, Kentucky. Note the bryozoan has produced a natural mold of the bivalve it encrusted. ……………………………………………………….. 52
Fig. 20: Image of the Rowland Member of the Drakes Formation, herein described as equivalent to the Blanchester Formation. Photograph taken from the ‘Fault Outcrop’ along I-64 in Kentucky. Green paint marks the Basal Rowland Bed at the Mid-Richmondian Unconformity in the south. ……………………………………………………………………………………….. 54
Fig. 21: Images of the Upper Marble Hill Bed near Bedford, Kentucky. A) The 2m gastropod grainstone and the overlying gastropodal shale. B) Gastropods weathering out of the Marble Hill shale. …………............................................................................................................................ 57
Fig. 22: Fourth and third order cycles for the Waynesville and Blanchester interval. Red lines represent sequence boundaries and blue lines represent maximum flooding surfaces. SGB = South Gate Hill Bed, BFAS = Basal Fort Ancient Shale, BWH = Bon Well Hill Beds, TDS = Treptoceras duseri Shale, CF = Cornflakes Beds, MGI = Middle Glyptorthis insculpta Bed … 64
Fig. 23: Stratigraphic cross section showing the position of the various third order systems tracts for the Waynesville through Blanchester interval. Red lines indicate third order sequence boundaries. ……………………………………………………………………………………... 66
Fig 24: Diagram depicting key faunal ranges in the Waynesville and Blanchester Formations. .73
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LIST OF TABLES
Table 1: Key marker beds in the Waynesville through Lower Liberty interval. ……………… 60
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LIST OF APPENDICES
Appendix A: List of Outcrop Location ………………………………………………………… 93 Appendix B: Hanna Creek, IN Stratigraphic Column …………………………………………. 95 Appendix C: Garr Hill, IN Stratigraphic Column ……………………………………………… 96 Appendix D: Bon Well Hill, IN Stratigraphic Column ………………………………………... 97 Appendix E: Russel Branch, IN Stratigraphic Column ………………………………………... 98 Appendix F: Oldenburg, IN Stratigraphic Column …………………………………………….. 99 Appendix G: South Gate Hill, IN Stratigraphic Column ……………………………………... 100 Appendix H: Hanna Creek, IN Stratigraphic Column ………………………………………... 101 Appendix I: Milton, KY Stratigraphic Column ………………………………………………. 102 Appendix J: Bedford, KY Stratigraphic Column ……………………………………………... 103 Appendix K: New Castle, KY Stratigraphic Column ………………………………………… 104 Appendix L: Seatonville, KY Stratigraphic Column …………………………………………. 105 Appendix M: Junction of AA & Rt 1449, KY Stratigraphic Column ………………………... 106
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1. INTRODUCTION: The Ordovician, Waynesville Formation of Indiana, Kentucky and Ohio, marks one of the most interesting ecological events in the early Paleozoic of Laurentia, the Richmondian Invasion. Although it begins in the underlying Arnheim Formation, the Waynesville displays a continuing of this event which saw in invasion of a variety of organisms into the region. Likewise following the Richmondian Stage (of which Waynesville is a part) is the Hirnantian Stage, which marks the End Ordovician Extinction. To better understand these various ecological events, the strata in which these events can be studied require a detailed correlation, uninhibited by state lines and nomenclature. The pages herein are a first attempt towards this goal. 1.1 Review of Stratigraphic Nomenclature The Cincinnatian Series is a treasure trove of paleontological and sedimentological potential; but, overly complex stratigraphic nomenclature has obscured some simple and highly widespread patterns. In their important but little noted paper Ross and Ross (2004, p. 246) remark: “The stratigraphic nomenclature of the Cincinnatian Series seems unduly complex, fraught with contradictions, has not consistently been applied in the field from worker to worker or by the same workers from outcrop to outcrop. In general, it is not an exercise for the faint of heart.” This bleak outlook is not overstated. Ross and Ross (2002, 2004) strove to make their own revisions. The proliferation of independently-derived Cincinnatian lithostratigraphic units developed under conflicting stratigraphic models (e.g. Foerste, 1908; Weir et al, 1984) has resulted in an accumulated complex patchwork of nomenclature (Figure 1) that hinders fine scale correlations across the Cincinnati Arch (Holland and Patzkowsky, 1996).
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The earliest workers traced widespread thin units based on "faunal zones" like brachiopod epiboles (e.g. Nickles, 1903; Foerste, 1904, 1908; Cumings and Galloway, 1912; Caster et al., 1961; Pope, 1976). The “Richmond Formation” was originally applied to Ordovician, Richmondian-aged rocks in the Ohio, Kentucky, and Indiana tri-state region (Winchell and Ulrich, 1887). At that time, the Arnheim Formation, Nickles’s (1903) Warren Formation, was included in the Lorraine (Maysvillian), and was subsequently reassigned by Foerste (1912). Nickles (1903) subdivided the Richmond into the Waynesville, Liberty, Whitewater and Madison (= Saluda; Brown, 1966) Formations. He named the Waynesville for stream cuts found near Waynesville, Ohio. Foerste (1908; attributed to Dr. G. Austin) subdivided the Waynesville into the Fort Ancient, Clarksville, and Blanchester Members. In the 1960s, stratigraphers purposely ignored fossil data in order to designate purely lithostratigraphic units which subdivided the Richmondian into a spatio-temporal patchwork. In southeastern Indiana, the Tanners Creek Formation (Fox 1962) encompasses the Arnheim through parts of the Liberty and Whitewater Formations; the Dillsboro Formation (Brown and Linebeck, 1966) includes the entire Maysvillian and much of the lower Richmondian through the lowest Whitewater Formation; and the Brookville Formation (Hay, 1981) lumps the Corryville (Mid-Maysvillian) through Liberty intervals, and splits the Waynesville Formation between the uppermost Excello Member and the overlying Waynesville Shale Member. In Kentucky, The Drakes Formation (Weir et al., 1965) applies to the upper Richmondian on the western side of the Cincinnati Arch. The Drakes includes 1) the Rowland Member, greenish-gray argillaceous micrites approximately equivalent to the Waynesville; 2) the Bardstown Member, richly fossiliferous, coral-bearing packstones and shales equivalent to the Liberty and lower Whitewater Formations; and 3) the Preachersville Member, equivalent to the 2
upper Whitewater and Saluda Formations. On the east side of the Cincinnati Arch, the Bull Fork Formation (Peck, 1966) for the interval that correlates approximately to the Arnheim through Liberty or lower Whitewater Formations. This is overlain by the Preachersville Member of the Drakes Formation (Peck, 1966). In the southeastern areas of the Cincinnati Arch, "Preachersville" includes not only the strata equivalent to upper Whitewater and Saluda but also the correlatives of the underlying Bardstown Member to the northwest (i.e., Liberty, lower Whitewater). Holland (1993; Holland and Patzkowsky, 1996) subdivided Cincinnatian strata into six third-order depositional sequences labeled C1-C6. The Waynesville through Saluda Formations are all contained within the C5 sequence. Holland and Patzkowsky’s (1996) model has served as the stratigraphic framework for chemostratigraphic (e.g. Bergstrom et al 2010), paleoecological (e.g. Holland et al. 2001; Stigall, 2010, 2014), and high resolution correlations (e.g. Brett and Algeo, 1999), among others. Holland and Patzkowsky’s (1996) model is a coarse stratigraphic framework subject to fine-scale revision. Our finer-scale analysis of the Waynesville suggests that many of the original member and formation boundaries (e.g. Nickles, 1903) correspond to significant sequence stratigraphic surfaces, and that correlations of these smaller units constrains and refines the third-order sequence stratigraphic surfaces. For example, Holland (1993) and Holland and Patzkowsky (1996, 2007), placed the Rowland Member in sequence C4 along with Oregonia and Sunset Members of the Arnheim Formation. Our correlations (in agreement with Foerste, 1909; Butts, 1915) suggest that the Rowland is a nearshore correlative of the Blanchester Member of the Waynesville Formation. In this paper we document this and other correlations of the Waynesville Formation along the western side of the Cincinnati Arch, and argue for revisions and subdivisions of the C5 sequence. 3
Figure 1 4
Figure 1 is a chart summarizing some, but not all, of the nomenclature used in the Cincinnati Arch region.
2. GEOLOGICAL SETTING 2.1 Paleogeography During the Late Ordovician (Katian, Richmondian) the Ohio, Kentucky and Indiana Tristate region was a portion of the distal Taconic foreland basin with a forebulge (Lexington Platform) to the south and a WNE-WSW trending narrow basin, possibly a backbulge basin (Sebree Trough), to the north, covered by a shallow epicontinental sea The intervening area had a ramp geometry with a shallow "lagoonal" to peritidal environments in southwestern Kentucky gradually deepening towards northeastern Ohio (Brett and Algeo, 1999; Meyer and Davis, 2008). The region was located approximately 20oS of the equator and the entire proto-North American continent of Laurentia was rotated clockwise 45o relative to present orientation (Holland, 1993; Brett and Algeo, 1999; Holland and Patzkowsky, 2007). To the east, the Taconic Orogen provided fine-grained clastic sediment, with coarser material trapped in the foreland basin to form the Queenston-Juniata Delta (Beaumont et al 1988). 2.2 Geochronology Richmondian biostratigraphy (Figure 1) of the Cincinnati Arch is poorly constrained. Graptolites are rare, but the Richmondian falls fully within the Amplexograptus manitoulinensis Zone. Likewise, abundant conodonts delineate broad zones, the Amorphognathoides grandis Zone encompasses the Maysvillian and middle Richmondian, and the A divergens Zone extends through the remainder of the Richmondian (Sweet and Bergstrom, 1984). A distinct positive δ13C excursion might be useful for global correlation of the Richmondian. δ13C values are low (near 5
0) in the Arnheim Formation, near the base of the Richmondian, but increase abruptly to near 1.5 per mil at the base of the Waynesville in the "Waynesville Excursion" (Bergström et al., 2010). This excursion can be identified throughout North America and other parts of the globe including Estonia (Bergström et al., 2010). The δ13C values gradually decrease throughout the Waynesville before reaching another interval of low, slightly fluctuating, isotopic values in the Liberty. Within the basin, the Richmondian brachiopod epiboles that were utilized by early stratigraphers (e.g., Nickles, 1903; Foerste, 1904, 1908; Austin, 1927) are more useful than graptolites, conodonts, or carbon isotopes for high resolution correlation 3. METHODS We measured over a dozen roadcuts (Figure 2) and stream outcrops to the nearest 10 cm using tape and levels. Published measurements were sufficiently detailed to be used for a number of outcrops that are currently covered. We observed lithologies, sedimentary structures, and fossils. From this we identified marker beds, lithologic stacking patterns, faunal zones and sequence stratigraphic surfaces to aid with correlation. Our epiboles and marker beds are based, in part, on previously-recognized faunal zones as utilized by past researchers (e.g. Foerste, 1908; Austin, 1927; Wolford, 1930; Pope, 1976).
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Figure 2 Figure 2: Map of the Cincinnati Arch based on Holland (1993) showing key outcrop locations used in this study. 1 = Waynesville, OH; 2 = Maysville, KY; 3 = Flemingsburg, KY; 4 = Owingsville, KY; 5 = Brookville, IN; 6 = Oldenburg, IN; 7 = St Leon, IN; 8 = Madison, IN; 9
7
= Milton, KY; 10 = Bedford, KY; 11 = New Castle, KY; 12 = Fisherville, KY; 13 = Seatonville, KY; Star = Cincinnati. 4. RESULTS We focused primarily on the western side of the Cincinnati Arch and illustrate our concepts with a stratigraphic cross section that extends from Hanna Creek near Roseburg, Indiana, in the north to Seatonville, Kentucky in the south (Figures 3 and 4). We have identified what is likely a third-order sequence boundary and unconformity surface within the Waynesville referred to here as the Mid-Richmondian Unconformity as proposed by Ross and Ross (2002). Figures 5 and 6 show the same correlations using the Mid-Richmondian Unconformity as the datum to accentuate basin geometry.
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Figure 3 9
Figure 3: Stratigraphic cross section showing the correlation of the Waynesville and Brookville Formations and their members along the western side of the Cincinnati Arch. Datum is the basal Bon Well Hill Submembers. Correlation extends from the northernmost outcrop on the left (#5 on Figure 2) to the southernmost outcrop on the right (#12 on Figure 2). Vertical scale is in meters.
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Figure 4 11
Figure 4: Stratigraphic cross section showing the correlation of the key marker beds in the Oregonia-Liberty interval along the western side of the Cincinnati Arch. Datum is the Bon Well Hill Submember. Correlation extends from the northernmost outcrop on the left (#5 on Figure 2) to the southernmost outcrop on the right (#12 on Figure 2). Vertical scale is in meters.
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Figure 5 13
Figure 5: Stratigraphic cross section showing the correlation of the Waynesville and Brookville Formations and their members along the western side of the Cincinnati Arch. Datum is the MidRichmondian Unconformity. Correlation extends from the northernmost outcrop on the left (#5 on Figure 2) to the southernmost outcrop on the right (#12 on Figure 2). Vertical scale is in meters.
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Figure 6 15
Figure 6: Stratigraphic cross section showing the correlation of the key marker beds in the Oregonia-Liberty interval along the western side of the Cincinnati Arch. Datum is the MidRichmondian Unconformity. Correlation extends from the northernmost outcrop on the left (#5 on Figure 2) to the southernmost outcrop on the right (#12 on Figure 2). Vertical scale is in meters.
4.1 Lower Richmondian Stratigraphic Units in Ohio and Indiana 4.1.1 Arnheim Formation: Oregonia Member The Arnheim Formation (Foerste, 1912) includes the Sunset and Oregonia Members. The Arnheim is identified with the C4 sequence and is correlated with the Rowland Member of the Tate Formation in Kentucky (Holland, 1993; Holland and Patzkowsky, 1996, 2007). However, it should be noted that present study indicates a correlation with the middle-upper part of the Waynesville Formation (Blanchester Member or upper C5 of Holland, and Patzkowsky, 1996) and not with the Arnheim at all. A detailed study of the Sunset Member can be seen in Malgieri et al (2014, in preparation). The base of the Oregonia Member is marked by first appearance of the strophomenid brachiopod Leptaena richmondensis and Rhynchotrema dentatum associated closely with Retrorsirostra carleyi (Foerste 1912. These two taxa are typically recognized as part of the “Richmondian” fauna (Caster et al., 1961), although, in fact, at least the genera occur lower in the succession as well. About 12 meters above the base of the Arnheim Formation at its type sections near Arnheim and Oregonia and OH is a thin interval (~ 1 m) of shale and packstone containing the brachiopod Retrorsirostra carleyi and Platystrophia ponderosa (Foerste, 1912; 16
Wolford, 1930; Caster al et., 1961; Pope, 1976). The R. carleyi epibole has been traced from near Madison, Indiana, northward to Waynesville and from there southeastward to about Maysville, Kentucky. Above the R. carleyi zone is a bed of diminutive phosphatized brachiopods, bivalves and gastropods commonly known as the “Cyclora bed” after the diminutive gastropod that can be found there (Wolford, 1930; Caster et al., 1961; Pope, 1976). Finally, the uppermost Oregonia is a distinctive 8-15' interval of knobby, irregularly bedded argillaceous limestone and calcareous mudstone containing rare Strophomena concordensis. 4.1.2 Waynesville Formation: Fort Ancient Member The type section of the Fort Ancient Member (Foerste, 1908, p. 292) is along “the stream crossed by a north and south road a little over a mile southeast of the Fort.” Foerste (1908) noted various bivalves including Anomalodonta gigantea, Modiolopsis concentrica, M. pholadiformis, Opisthoptera fissicosta and Pterinea demissa, and suggested that the Fort Ancient might be better placed as a member of the Arnheim. There is merit to this proposal in that the Fort Ancient appears more genetically related to the Arnheim than to upper Waynesville, but for the present time we retain the Fort Ancient as a member of the Waynesville. 4.1.2.1 South Gate Hill Submember We define the South Gate Hill Submember (SGB) as the basal bioturbated pack- to grainstone of the Waynesville Formation (Figure 7). It is named for excellent exposure in the large roadcut on Indiana Rte. 1 at South Gate Hill, near St. Leon, Indiana. It is recognizable in the Waynesville type area and traced southward to Arnheim, Ohio, and Maysville, Kentucky, where it is a thin, irregularly-bedded interval containing Strophomena concordensis. It is the most phosphatic bed in the Waynesville Formation and is often reddish-orange in color when 17
weathered. At some locations the SGB consists of Cincinnetina-rich grainstone and may have one or more small shale partings. Thicknesses range from a few centimeters to about a meter along the west arch. The base of this bed is sharp, possibly erosional, and marks the third-order boundary between sequences C4 and C5 (Holland, 1993; and Holland and Patzkowsky, 1996). However, the minor facies offset and faunal change suggests a smaller (fourth order) boundary.
Figure 7
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Figure 7: Photographs of the South Gate Hill Bed that marks the base of the Waynesville Formation. A) The SGB at its type location at South Gate Hill. B) Top surface of the SGB displaying the abundant Cincinnetina that make up the bed. Isolated crinoid are also visible. Lens cap 67mm. 4.1.2.2 Lower Fort Ancient Shale Submember The Lower Fort Ancient Shale submember (Figure 8) overlies the South Gate Hill Bed. At its thickest near Bon Well Hill, it is just over 6m thick. This relatively barren bluish-gray, somewhat silty, calcareous shale thins considerably to the south, reaching its minimum thickness of just under a meter at the Bedford site before expanding slightly. Bedford may represent a localized high. In outcrops near New Castle and Seatonville, Kentucky, the shale is 2-3m thick. The shale tends to be soft and fossil poor. Along the northeast side of the arch, the basal shale is significantly thicker. For Warren County, Austin (1927; also Wolford, 1930) reported an interval of 40’ (12m) that he called the Rafinesquina loxorhytis bed containing sparsely fossiliferous, “heavy shales”, and interbedded limestone.
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Figure 8 Figure 8: Photograph from South Gate Hill showing the Basal Fort Ancient Shale, the overlying South Gate Hill Submember (SGB) and the overlying Bon Well Hill Submember (BWH). The shale rarely outcrops well and is generally covered as seen here. 4.1.2.3 Bon Well Hill Submember We name the Bon Well Hill Submember (BWH; Figure 9) for the roadcut just north of Brookville Dam along highway 101 at Bon Well Hill (Figure 2, #5). These beds lie between the lower Fort Ancient shale and the Treptoceras duseri shale. At their type locality the BWH beds are a 1.5 m package of approximately ten Cincinnetina-rich packstone to grainstone beds with thin, intercalated shale. The upper contact is an orange-weathering pyrite-encrusted hardground. These beds thin to the south and become more amalgamated. On the eastern side of the arch, the Bon Well Hill Beds may contain a slightly different fauna. Austin (1927) discusses a 12’ (3.6m) bed referred to as the Anomalodonta gigantea bed containing abundant molluscan bivalves. Cincinnetina meeki are mentioned in the underlying shale package. Wolford (1930) identified a 3’ (1m) bed above the diverse molluscan bed containing Rafinesquina alternata and Cincinnetina meeki. This suggests that the Bon Well Beds were not distinguished from the Anomalodonta gigantea bed of Austin (1927). To the south, the BWH beds are probably correlative with the Fisherville Coral Beds (Browne 1964; see below).
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Figure 9 Figure 9: Photographs of the Bon Well Hill Submember. A) The full cluster of limestone beds at their type locality near Brookville, Indiana. B) Closer view of two of the basal beds and the shale in between. C) The BWH beds as seen at the South Gate Hill locality.
4.1.2.4 Upper Shale Submember: Treptoceras duseri Shale – Trilobite Shale The Treptoceras duseri Shale overlies the BWH beds on the northeastern side of the Cincinnati Arch and is equivalent to the Trilobite Shale on the western side in Indiana (Frey, 1987). This shale was first identified by Foerste (1908), who called it the Orthoceras fosteri bed (Austin, 1927). Wolford (1930) referred to this interval as the Orthoceras duseri shale. This unit is one of the “butter shale” units, an informal lithological term describing the soft mudstone (Figure 10). This butter shale, like others, is known for its abundant, well-preserved trilobites, mainly Isotelus and Flexicalymene, both frequently enrolled on the northeastern side of the arch, this shale also contains an abundance of the eponymous nautiloid Treptoceras duseri. The duseri shale is an approximately 1.5m thick, bluish-green claystone bed with calcisilitites near the base and abundant trilobites and other fossils located near the top (Frey 1987a, 1987b). At some localities the shale contains a thick grainstone at its base (Frey, 1987a, 1987b); but, at other localities such as South Gate Hill, the grainstone is absent. This unit is not obviously bedded in outcrop and it breaks conchoidally. Both the duseri and the trilobite shales contain abundant bivalves including Modiolopsis, Ambonychia, Caritodens and others (for a complete list see Frey, 1987a). Lingulids, bryozoans, monoplacophorans, conulariids and other fossils can also be found in this shale (Frey, 1987b). The eastern exposures also yield rare small tabulate corals, 22
Tetradium, the colonial rugosan Columnaria, and the stromatoporoids Labechia and Stromatocerium (Foerste, 1908; Austin, 1927; Wolford, 1930; Frey, 1987). This unit has been traced from Waynesville, Ohio, to Milton, Kentucky, a distance of over 142km.
Figure 10 Figure 10: Images of the Treptoceras duseri butter shale. A) Exposure at a private pit quarry. Note bluish-green coloration when fresh. B) Flexicalymene in situ at a private pit quarry. 23
4.1.3 Waynesville Formation: Clarksville Member Foerste (1908), based his description of this unit on the outcrops near Clarksville, Ohio, southeast of Fort Ancient, Ohio, along with exposures at Blacksmith Hollow in Oregonia, Ohio, and Stony Hollow. Originally he included the T. duseri shale (then Orthoceras fosteri) within the Clarksville. Figure 11 shows epibole correlations across the arch from Brookville, Indiana, to Waynesville, Ohio. In most locations, the T. duseri shale is topped by a bed with abundant Cincinnetina meeki (Frey, 1987) referred to in recent literature as the Onniella epibole (Frey, 1996). We use this bed to define the base of the Clarksville Member in accordance with earlier authors (but see Wolford, 1930). The Clarksville Member is thus defined as starting at the base of the Cincinnetina meeki (Jin, 2012; formerly Onniella of Frey, 1987; Dalmanella of Wolford, 1930) epibole beds and extending to the base of the lower Glyptorthis insculpta bed. Thus demarcated, the thickness of the Clarksville Member is far more variable than other members of the Waynesville Formation, ranging from ~ 0 m to about 14 m in the area of southeastern Indiana and then thinning again to about 6m near Madison, Indiana. In contrast to most other marker beds and intervals in the Waynesville Formation, the Clarksville Member shows major changes in thickness. Thus, at Caesar Creek near Waynesville, Wolford reports a total of almost 16.5' (5m) in three units between the Cincinnetina bed and the lower Glyptorthis insculpta bed, whereas at Bon Well Hill the equivalent interval is less than half this thickness at about 2.6m (8'). However, the interval appears to expand again to more than 11 m to the southwest of Brookville and at South Gate Hill some 17 km to the southeast. At Madison, Indiana, the interval apparently thins again to about 3 m (9.5'). This thickness
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variability, suggests erosion below an unconformity at the top of this unit. Figure 12 shows the entirety of the Clarksville Member as exposed at Caesar Creek (Figure 2, #1).
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Figure 11 Figure 11: Diagram showing faunal zones correlated from the west side of the Cincinnati Arch (notes from Pope 1976) to the east side of the arch (notes from Wolford 1930). Diagram starts with the very top of the Fort Ancient Member and extends through the lowest Liberty Formation.
Figure 12 Figure 12: Photograph of the Clarksville Member at Caesar Creek, OH. The Clarksville is predominately shale with regular spaced limestones. The Member is bracketed by the Cincinnetina epibole bed at its base and capped by the Glyptorthis insculpta bed of the Blanchester above.
4.1.3.1 Lower Clarksville Submember: Cincinnetina Epibole Beds The Cincinnetina meeki Bed contains an epibole, and has been termed a “zone” (Frey, 1996). The bed is a 1.5 to 2m package of closely-spaced interbedded packstone-grainstone and 27
thin shale overlying the duseri -Trilobite shales (Frey, 1996). This marks the base of the Clarksville Member of the Waynesville and is characterized by abundant Cincinnetina meeki (Figure 13), an orthid brachiopod that first appears in the Arnheim Formation (Wolford, 1930) and peaks mid-Clarksville. Frey (1996) reported that this epibole is restricted along a regional strike from southeastern Indiana to southwestern Ohio and does not appear to continue further south into Kentucky. The brachiopods Leptaena and Platystrophia clarskvillensis appear near the top of the epibole creating a unique assemblage of overlap for the three brachiopods (Pope, 1976; Frey, 1996).
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Figure 13 Figure 13: The Cincinnetina epibole zone in Clarksville, OH. This bed marks the base of the Clarksville Member. Image A also shows Eochonetes in the bed. Lens cap is 67mm.
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4.1.3.2 Upper Clarksville Submember: Eochonetes-Leptaena Beds The Eochonetes-Leptaena Beds form an interval of variable thickness overlying the Cincinnetina meeki beds. This interval includes shales and fossiliferous packstones which yield a diverse "Richmondian" fauna including the first abundant appearances of the solitary rugosans Grewingkia and Streptelasma and the brachiopods Eochonetes (Holland and Patzkowsky, 2007; formerly Plectambonites of Cumings, 1908; Sowerbyella of Caster et al., 1961; and Thaerodonta of Pope 1976) clarkvillensis, which first appears about 5' (1.5m) above the Cincinnetina beds and Leptaena cf. richmondensis, which is prolific about 2' (0.6m) higher in the type section. Cincinnetina meeki persists through this interval. 4.1.3.3 Oldenburg Butter Shale Recognized at only a few locations, including Oldenburg and St Leon, Indiana, the Oldenburg shale is a meter thick blue-green claystone unit containing articulated Isotelus and Flexicalymene in the top 30cm. This unit is much like the Trilobite Shale of Fort Ancient with its abundant bivalves, trilobites, bryozoans and the occasional brachiopods Zygospira, Platystrophia sp., lingulids, and conulariids. The Oldenburg shale exhibits conchoidal fracture and no obvious bedding in outcrop. Silty, irregular shaped calcisiltite masses can be found throughout the shale. These blocks can be upwards of 20cm long and 7cm thick.
4.1.4 Waynesville Formation: Blanchester Member The type Blanchester Member was named for exposures near Blanchester, Ohio. However, Foerste (1908) did not provide an exact location of the outcrops. Foerste also reported
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exposures of the Blanchester along Stony Hollow just northwest of Clarksville, Ohio. This member is bracketed by the lower Glyptorthis insculpta zone at its base and the base of the upper Glyptorthis insculpta zone above. The upper G. insculpta bed, as defined herein, marks the base of the overlying Liberty Formation. Foerste suggest that the boundary be placed above the upper Glyptorthis insculpta zone and much of the subsequent literature uses one placement or the other. 4.1.4.1 Mid-Richmondian Unconformity The Mid-Richmondian Unconformity (MRU) is situated just about at the midpoint of the thickest measured section of the Waynesville Formation at South Gate Hill. In the north at Hanna Creek, the unconformity surface is formed by the sharp base of a packstone to grainstone, apparently the lower Glyptorthis insculpta bed, with a 1-2mm crust of pyrite at the base (Figure 14). The Garr Hill outcrop also contains pyrite just below the unconformity, but instead of being concentrated in one bed, the pyrite is spread over an approximately 0.5m zone containing the brachiopods Cincinnetina and Leptaena. To the south, at the New Castle and Seatonville localities, the unconformity is marked by the switch to highly altered dolostone.
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Figure 14 Figure 14: Images of the pyrite bed found at the Mid-Richmondian Unconformity in Indiana. A) Fallen block showing weathered pyrite crust (orange coloration) from Hanna Creek, Indiana. B) Closer view of the pyrite crust seen in image A. C) Polished slab showing the pyrite bed from Oldenburg, Indiana.
4.1.4.2 Lowest Glyptorthis insculpta Submember and Rafinesquina "cornflakes" Submember Glyptorthis insculpta (= Hebertella insculpta, Wolford, 1930) is an orthid brachiopod known from the Waynesville and lower Liberty intervals (Caster et al., 1961). The brachiopod is 32
distinguished by a series of growth rings parallel to the shell margin that create a crosshatched pattern with the radial striae (Caster et al., 1961; Schwimmer and Sandy, 1996). There are three primary Glyptorthis insculpta-rich beds in the Waynesville-Liberty succession; the lowest bed marks the sharp contact of the Clarksville Member and Blanchester Members. The unit has a unique fauna characterized by abundant Glyptorthis insculpta with Retrorsirostra. cf. retrorsa, Holtedahlina sulcata, and the rare atrypid brachiopod Catazyga headi. This fauna has been identified in the vicinity of Madison and Brookville, Indiana, and in the type Waynesville, Ohio area. The lower Glyptorthis insculpta bed is a compact grainstone bed approximately 40 cm thick at the South Gate Hill site near St Leon, Indiana. The bed is about 30 cm (1') thick at Brookville, Indiana, and near Waynesville, OH. Wolford designated the base of this bed as the contact between the Clarksville and Blanchester members. Austin (1927) lists the thickness of the "Lower Hebertella insculpta" bed as 3' thick presumably using a more inclusive definition of the epibole. However, he refers to a "heavy, compact argillaceous layer up to 7" (17.7 cm) thick", which forms a "Cap" to the interval. Presumably this is equivalent to the 20-27 cm compact bed observed elsewhere. Wolford (1930) also described the lower Glyptorthis insculpta bed at this section as 11" (27 cm). Overlying the limestone in its type area is an interval of shale that is full of fossils with thin, irregularly bedded packstones containing abundant brachiopods of several common species, especially Rafinesquina, but also Cincinnetina meeki, Retrorsirostra and Eochonetes clarksvillensis. It is characterized by fragments of shells arranged chaotically, in places shingled or edgewise, in a muddy matrix; Wolford notes "fossils jumbled and broken" in this interval. Similarly, at the Hanna Creek and Garr Hill sections, the G. insculpta bed is overlain by a 1-2m zone of broken, chaotically oriented shells of Rafinesquina and likely other
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brachiopods. This zone is informally referred to as the Rafinesquina “cornflake beds” due to its distinctive appearance upon weathering (Figure 15). The MRU is apparently the basal contact of the lower Glyptorthis insculpta bed. The Rafinesquina ‘cornflakes bed’ is about 1.5m thick at Bon Well Hill and about 1.7m at Waynesville
Figure 15
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Figure 15: Images of the Rafinesquina ‘cornflakes bed’ from Garr Hill, Indiana. The lens cap is 67mm in diameter. A) Broad view of the cornflakes bed. B) Closer look at the jumble of Rafinesquina shells in the cornflakes bed.
4.1.4.3 Lyrodesma -Isotelus Shale Submember This is a distinctive interval of blue-gray shale with thin limestone and an abundance of bivalves of several species but especially Lyrodesma, the brachiopod Leptaena, the highest stratigraphic occurrence of Cincinnetina meeki, and the trilobite Isotelus occur above the "cornflakes bed". Wolford (1930) does not specifically identify this zone and lists only fragments of Isotelus in this general interval. Austin (1927 p. 8), but, specifically identifies the interval as the Isotelus gigas Bed and notes that this interval yields abundant, well-preserved fossils, including "entire specimens of I. gigas more abundantly than any other horizon." (Austin, 1927). The Lyrodesma-Isotelus Shale is about 3’ (1m) thick near Caesar Creek but only 1.5’ (0.5m) at Bon Well Hill, perhaps being somewhat truncated beneath the overlying edgewise brachiopod bed (Pope 1976). Schumacher and Shrake (1996) also discussed the Isotelus shale in the Caesar Creek Spillway of Ohio and correlated it for over 40 km. They reported the shale to be positioned 7m below the upper Glyptorthis insculpta zone. The top 14cm of the interval was studied to reveal a number of different taxa including the trilobites Isotelus, Flexicalymene retrorsa, the brachiopods Zygospira modesta, Leptaena richmondensis, the bivalves Caritodens demissa, Orthodesma and various crinoids including Lichenocrinus, Cincinnaticrinus,, the eurypterid Megalograptus welchi various ostracods and significantly more ichnofossils than reported by
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Brandt (1984) for other butter shales (Schumacher and Shrake, 1996). They do not report Lyrodesma despite its abundance in Indiana. 4.1.4.4 "Lower Disturbed Zone" Austin (1927) refers to a bed immediately overlying the Lyrodesma-Isotelus Shale as a 1.5' (40cm) thick interval with 6” (15cm) beds full of Rafinesquina "standing on end" and interbedded with sparsely fossiliferous shale. These edgewise brachiopod coquinas resemble the thicker basal "cornflakes" beds (Figure 16). It is not known how widely this interval is traceable beyond Waynesville. This interval is overlain by about a meter (3') of even-bedded limestones and shale yielding small Platystrophia, crinoids (Austin reports Reteocrinus neali) and rugose corals. At present it is not clear whether this zone can be found in Indiana.
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Figure 16 Figure 16: Lower Disturbed Zone at Caesar Creek. A) Fallen block of the disturbed zone. Rafinesquina on the left side of the block are flat lying and become progressively more edgewise to the right. B) Closer view of the bedding surface showing a large cephalopod in the top right as well as a pygidium of an Isotelus. C) Closer view of the edgewise Rafinesquina that represents a weaker "cornflakes" texture.
4.1.4.5 Strophomena nutans - Tetrapharella neglecta Submember This widespread unit contains a bundle of closely-stacked coquinoid packstones with abundant strophomenid brachiopods including the unique species S. nutans and Tetraphaerella neglecta as well as Strophomena planumbona and Rafinesquina spp. No thickness is given for this zone near Brookville or Madison but it is clearly recognizable. There is a discrepancy in thickness given for this bed at Bon Well Hill; Austin reports 4’ to 5' (1.2-1.5m) while Wolford gives the thickness as 2' to 10' (0.6-3m) near Waynesville. There are 3’ (0.9m) of blue-gray shale with thin limestones, referred to by Austin as the Homotrypa dawsoni beds, and this overlies the S. nutans-T. neglecta bed.
4.1.4.6 Upper Disturbed Submember In the vicinity of Caesar Creek a still higher occurrence of edgewise Rafinesquina is represented by a 2’ (0.6m) zone with two layers of coquinoid packstone separated by undisturbed shale. Notably, this horizon yields Rhynchotrema dentatum which has also been reported from
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approximately the same level at Bon Well Hill. It is followed by a richly fossiliferous succession of thin-bedded limestones and shales closely resembling those below. 4.1.4.7 Coral-Isotelus Submember A distinctive 4' – 8’ (1.2-1.4m) blocky, bluish-gray shale interval occurs above the Upper Disturbed beds, about 9-10' (2.7-3m) above the S. nutans bed and immediately below the middle Glyptorthis insculpta bed at Waynesville (Austin, 1927; Wolford, 1930). This zone is mentioned but not described in Schumacher and Shrake (1996) for the Caesar Creek Spillway in Ohio. This interval is noted for the occurrence of Tetradium and the colonial rugosans Foerstephyllum and Cyathophylloides. As with the T. duseri shales of the Waynesville, this interval also yields well- preserved Isotelus and Flexicalymene trilobites and the bivalves Ambonychia, Caritodens and others. Although this distinctive zone has not been identified as such at Bon Well Hill, colonial rugosans are reported from beds below the middle G. insculpta bed. This interval has yet to be definitely recorded at Madison. However, a shaly interval rich in Tetradium with rare colonial rugosans occurs in an analogous position, slightly below the Liberty or Bardstown Member at the top of the Rowland Member in Kentucky and it may record the same horizon. 4.1.5 Liberty Formation (Redefined) 4.1.5.1 Middle and Upper Glyptorthis insculpta Submember Two thin limestones, separated by a distinctive band of nearly barren pure shale, form the middle and upper occurrences of the restricted taxon Glyptorthis insculpta. Figure 17 shows the Middle Glyptorthis insculpta bed. This package, totaling 5’-10’ (1.5-3m), is highly consistent in
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thickenss: the lower division and barren shale are, respectively, 0.94m and .76 m at Waynesville and 1.03m and 0.76m thick at Madison, Indiana (Austin, 1927; Wolford, 1930; Pope. 1976). The lower bed is a distinctive ledge-forming limestone bundle, which locally forms waterfalls. This interval contains G. insculpta and Strophomena nutans and Tetrapharella neglecta. The upper Glyptorthis bed is a distinctive 6-10 cm limestone with a ripple-marked top that contains G. insculpta, Strophomena planumbona and Hiscobeccus capax. As previously defined (see Wolford, 1930), this interval forms the top of the Blanchester Member and of the Waynesville Formation. However, we suggest that this widespread interval should be used as the base of the Liberty Formation in analogy to the base of the Blanchester Member.
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Figure 17 Figure 17: Photographs of the Glyptorthis insculpta zone that marks the base of the Liberty Formation. A) Middle Glyptorthis insculpta bed from South Gate Hill. B) G. insculpta bed from the Brookville Causeway. C) Collection of G. insculpta found at South Gate Hill. 4.1.5.2 Lower Liberty including "Crinoid Beds" An interval of compact mudstones and ledge-forming limestones overlies the G. insculpta beds. The interval is very consistent over Ohio, Indiana, and northern Kentucky with a thickness of about 11’ (3.35m) from Waynesville to Madison. Greenish-gray shales in the lower 6’ (1.8m) yielded the most diverse crinoid fauna of the Cincinnatian (including species of Cincinnaticrinus, Paradendrocrinus, Reteocrinus, Glyptocrinus, Compsocrinus and Canistrocrinus) in creeks in Warren and Clinton County, Ohio (Austin, 1927). The upper limestones are rich in brachiopods, especially the plectambonitacean Eochonetes (Thaerodonta) clarksvillensis, as well as Rafinesquina cf. alternata, Plaesiomys subquadrata, Hiscobeccus capax, the bivalves Caritodens, Ctenodonta, and Ambonychia, solitary rugose corals Grewingkia and Streptalasma and the less common colonial corals, such as Cyathophylloides. 4.1.5.3 Flexicalymene retrorsa minuens-Isotelus Bed A very distinct interval of light-gray weathering, bluish-gray mudstone about 5-6’ (1.51.8m) thick occurs low in the Liberty Formation and provides a useful regional marker. This interval is noted for exceptionally large specimens of the trilobites Isotelus gigas and/or I. brachycephalus, the rare Chasmops breviceps, and tiny, enrolled individuals of Flexicalymene retrorsa var minuens. Hence the bed has commonly been called the "minuens shale". The shale also yields abundant bivalves (Ctenodonta, Modiolopsis, Caritodens) and the brachiopods 42
Rafinesquina, Thaerodonta, Plaesiomys, and Strophomena, sometimes as bedding planes of small or juvenile individuals. 4.1.5.4 Upper Liberty The upper liberty commences with a limestone up to 60cm thick, crowded with shells of Eochonetes (Thaerodonta) clarkesvillensis, which typically forms the caps of waterfalls and overhangs the soft blue-gray mudstone of the "minuens" beds. This is the base of a 3-5m thick succession of thin-bedded packstones and grainstones and shales with a highly diverse "Richmondian" fauna: rugose corals Grewingkia, Streptalasma, Protarea, ramose bryozoans, brachiopods, especially Strophomena, Rafinesquina, Leptaena, Eochonetes, Hiscobeccus, Hebertella, Plaesiomys and the bivalves Caritodens and Ambonychia. Flexicalymene and Isotelus fragments are relatively common (Figure 18). The upper boundary of the Liberty remains somewhat ill-defined, although in the Waynesville area the boundary is frequently placed at an unusually thick, burrowed, micritic bed informally referred to as the "Turkey Track” bed. This contact is in need of further study and refinement.
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Figure 18 Figure 18: Images from the Brookville Causeway showing the Eochonetes bed. A) Abundant Eochonetes. B) Closer view showing the presence of Grawinkia among the Eochonetes. C) Example of the Eochonetes beds with cornflakes texture.
4.2 Lower Richmondian Interval in Kentucky In contrast to the continuity of stratigraphic units in the lower Richmondian along the western side of the Cincinnati Arch from the type area of the Waynesville to Madison, units change very abruptly close to the Ohio River. To date, there have been no attempts at detailed correlation into Kentucky. At a coarse scale, these units clearly correlate to parts of the Bull Fork and Drakes Formations in Kentucky. While the Liberty Member can be traced to the Bardstown Member of the Drakes Formation, the correlation between Waynesville units and the sparselyfossiliferous peritidal facies of the Rowland Member have remained poorly defined. For example, Holland (1993) correlated the Rowland to the Oregonia Member of the Arnheim, while earlier workers correlated it to the Waynesville Formation (e.g. Butts, 1915). But the finer details have always been obscure. The situation is further complicated by the distinctive "Marble Hill” bed of the Rowland. This bed is a series of lenses of coarse, gastropod-rich grainstone (Swadley, 1979). Below we describe the units of the Marble Hill and adjacent Rowland Member in northern Kentucky. 4.2.1 Bull Fork Formation The Bull Fork Formation (Peck, 1966) is equivalent to the Arnheim through midWhitewater interval. This unit was named for Bull Fork Creek near Plumville, Kentucky, and the 45
type section was designated in roadcuts along Kentucky Route 1443 near Springdale. The Bull Fork Formation is the quintessential product of the “lithostratigraphic movement”, which saught to designate units based solely on lithology, in the absence of faunal data: “In this area, the boundaries separating the Arnheim and Waynesville, the Waynesville and Liberty, and the Liberty and Whitewater-Elkhorn have been placed at faunal breaks in the rock sequence. The faunal boundaries do not occur at recognizable lithologic breaks. The names Waynesville, Liberty, Whitewater, and Elkhorn, therefore, are inappropriate for rock-stratigraphic units in the Maysville area.” (Peck, 1966, p. B12). Another reason that traditional units were “lumped” into this thick unit is that it was created for mapping purposes. Aside from being a highly lumped unit, the Bull Fork Formation was applied to different strata in different regions of Kentucky. In the Bedford Quadrangle, Kentucky (Swadley, 1977), the Bull Fork Formation encompasses the base of the Corryville (member of the Grant Lake Formation) through the top of the Arnheim while the Rowland Member of the Drakes Formation is equivalent to the Waynesville. In the Smithfield Quadrangle, the Bull Fork Formation includes only most (but even not all) of the Arnheim Formation (Luft, 1977). In the Simpsonville and Fisherville Quadrangles, the Bull Fork was not used. Instead the majority of the Arnheim Formation was included in with the Grant Lake Formation below (Kepferle, 1976; Peterson, 1978). 4.2.2 Fort Ancient Equivalent Although the Waynesville Formation has never been correlated in any detail in northern Kentucky, our detailed work in sections from Milton to New Castle strongly suggest that the formation has its correlatives in two units, which have typically been correlated as a single 46
member, the Rowland. We recognize the Rowland sensu stricto as an interval of pale, olive-gray cream weathering argillaceous limestone and calcareous mudstone that sharply overlies a distinctive soft, yellowish, weathering shale formerly known as the Cyphotrypa shale (Butts, 1915). This Cyphotrypa shale caps a 10’-15’ (3-4.5m) interval, previously assigned to the Rowland (References). This shale-rich unit includes a) a basal skeletal grainstone that may grade into the basal Marble Hill bed; b) a lower, largely barren, shale with corals in its upper portion; c) a 1-2 m middle coral bearing limestone, and d) a variable thickness pale, greenish-gray shale with thin wackestones and black shales in its upper portion-the Cyphotrypa shale (however, thickness varies between quadrangles). Based on its facies, lithologic succession, and faunal content, we correlate this shaly interval with the Fort Ancient and possibly the lowest Clarksville Member of the Waynesville Formation. This tripartite unit can be identified as far north as Henry County in cuts along I-71 in the Smithfield Quadrangle. Here Luft (1977) reports the lower coral-bearing shale, the Fisherville Bed and the Cyphotrypa shale. Here an 8” (0.2m) bed 20’ (6m) above the top Cyphotrypa shale contains stromatoporoids measuring upwards of 3’ (0.9m) wide located (Luft 1977 This interval maintains its character southward with little thickness or facies change at least to Seatonville and Mt. Washington, Kentucky. We outline more detailed correlations of this succession below. 4.2.3 South Gate Hill Submember To the north, in Indiana, the SGB is prominent and recognizable, but to the south the bed seems to disappear or is reduced to a rather insignificant surface. In fact, many of the USGS geologists mapping in Kentucky in the 1960s and 1970s (e.g. Luft, 1977; Gibbons, 1977) place the base of what they called the Rowland at the Fisherville Coral bed, the southern equivalent of the Bon Well Hill beds as discussed below. Butts (1915) also started the Waynesville at the base 47
of the Fisherville/BWH. This may suggest that the SGB, which marks the C4-C5 boundary under the Holland (1993) model, is in fact a rather minor surface. 4.2.4 Coral Bearing/Cherty Lower Shale In the northern sections, near Milton and Bedford, the Bon Well Hill Beds overlie a relatively thick package of nearly barren shale with few interbeds, rare Cincinnetina and fragments of Flexicalymene. We tentatively identify this as the Basal Fort Ancient Shale. In Henry County, Kentucky, this shale is noted to contain occasional corals near its top (Luft 1977). We have discovered colonial corals (Columnaria; Tetradium) near the top of this shale at the New Castle locality (also in Henry County). At the New Castle site, this coral-bearing shale measures at least 1m thick with additional shale below separated by limestone beds. This suggests that in this region, the coral-bearing shale is conformable with the Fisherville Coral Bed above. The shale continues southward beneath the Fisherville bed for 90 km to the vicinity of Springfield, Kentucky. Between the Fisherville, Jeffersontown, and Springfield this unit contains thin to medium beds of calcisiltite with distinctive "amoeboid" chert nodules. We correlate this shaly interval with the lower Fort Ancient Shale, although the South Gate Hill Bed below is poorly defined as a 0.5m cluster of compact grainstones with abundant Flexicalymene cephala and pygidia. This correlation is based on tracing of markers, especially the linkage of the overlying Fisherville bed with the Bon Well Hill beds of the lower Fort Ancient Member.
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4.2.5 Fisherville Coral Bed The Fisherville Coral Bed was first identified by Foerste (1908) who named it for a series of outcrops near Fisherville, Kentucky (see Browne, 1964). This interval consists of rhythmically-interbedded dark fissile shale with carbonaceous compressions (probably noncalcified dasyclad algae) and pale-gray weathering, micritic wackestones with bivalves, gastropods and corals resembling those in the underlying shale. This bed was used by Foerste and Butts (1915) as the base of the "Waynesville Formation" in northern Kentucky extending roughly from New Castle southward to its type section and Seatonville, Kentucky, and is characterized by the corals Columnaria (Favistella alveolata) and Tetradium approximatum (Foerste 1908; Butts 1915; Browne 1964). Butts (1915) reported a thickness of 4’-6’ (1.2m1.8m) in Jefferson County, Kentucky where the type Fisherville is located. Kepferle (1976) reported a thickness of 5’ (1.5m) to 7’ (2m) in the Fisherville quadrangle. Luft (1977) reported a maximum coral head diameter of 3’ (1m) decreasing northward of Henry County, Kentucky. To the north near New Castle, Kentucky, the Fisherville Coral Bed is a 0.5m limestone overlying the coral-bearing shale, noted above; together they form a 1.5m package. The corals near New Castle reach upwards of 1.5’ (0.5m) in diameter (Gibbons 1977). To the south near Seatonville, the Fisherville bed is a series of interbedded limestones and shales approximate 0.7m thick with some of the corals reaching 0.3m in diameter. The Cyphotrypa shale overlies the coral bed. The large coral zone of the Fisherville bed consistently lies above the 4' to 10' (1.2-3m) cherty basal calcisiltite and shale of the Rowland Member and can still be recognized as far south as Mt. Washington and Seatonville on the west side of the Cincinnati Arch. We tentatively correlate the Fisherville bed with the Bon Well Hill beds of the Waynesville and the subjacent shale as the lower Fort Ancient shale. Although no corals have 49
been found in the typical BWH beds, the overlying T. duseri shale is known to contain the occasional corals Tetradium,and Columnaria and stromatoporoids Stromatocerium and Labechia (Foerste 1908; Austin 1927; Wolford 1930; Frey 1987a, 1987b). 4.2.6 Cyphotrypa Shale The "Cyphotrypa shale" is a pale olive-gray, yellowish weathering shale situated directly above the Fisherville Coral Bed (Kepferle, 1977). The upper portion of the Cyphotrypa shale is rhythmically bedded-dolowackestones with sparse gastropods, bivalves and Cyphotrypa interbedded with black, algae-bearing shale, much like the top of the Fisherville bed. The lower part of the shale is characterized by an abundance of C. clarksvillensis, a domal, slightly monticular bryozoan ranging between 8mm and 4.4cm in diameter (MacFarlan, 1931) which, in the majority of cases, encrusted on a bivalve shell (Schwalbach et al., 2014). This is evidenced by the presence of a concave-down depression on the underside of the bryozoans, which clearly show the shape of the bivalve that was encrusted (Figure 19). The Cyphotrypa shale crops out as far north as Henry County (Smithfield Quadrangle). It is 10’ (3m) thick in Jefferson County, Kentucky on the western side of the arch and disappears to the south (Butts, 1915; Browne, 1964). In Henry County, Kentucky, the Cyphotrypa interval is noted to contain abundant Modiolopsis clams (Luft, 1977). In Henry County, Kentucky, the Cyphotrypa interval contains abundant Modiolopsis clams (Luft, 1977). We have tentatively correlated the Cyphotrypa shale south to Owingsville, Kentucky, (0.7m thick) on the eastern side of the arch, where it is capped by a limestone called "Ball Bryozoan bed", which shows a bedding plane packed with Cyphotrypa (Schwalbach et al., 2014). This interval may correlate with the Cincinnetina bed at the base of Clarksville Member further north.
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At New Castle, the Cyphotrypa shale is 1.8m thick and passes upward into thin-tomedium bedded limestones and dark shales which are sharply overlain by a meter-thick argillaceous micritic limestone at the base of the Rowland Member (sensu stricto). This shale is identifiable in all quadrangles from Smithfield southwestward to Seatonville. In both Shelby and Jefferson counties, the Fisherville underlain by a thick shale and overlain by a Cyphotrypa-rich unit (Kepferle, 1976; Peterson, 1978). In Jefferson County, a skeletally supported cross-bedded limestone is found close to the base of the Rowland.
Just above the Fisherville Coral Bed at the Seatonville stream cut is a 1.5m thick shale occupying the position of the Cyphotrypa shale. Overall the Cyphotrypa shale shows a general thinning to the south, likely related to the Mid-Richmondian Unconformity. To the north the Cyphotrypa shale likely grades into the Treptoceras duseri shale, which has been reported to contain Cyphotryp clarksvillensis within it as far north as Waynesville, Ohio (Austin, 1927; Wolford, 1930; Frey, 1987a, 1987b). Cyphotrypa has been found to range throughout the Waynesville, although less commonly towards its top, so the presence of Cyphotrypa elsewhere to the north is not entirely unexpected.
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Figure 19 Figure 19: Photographs of the Cyphotrypa interval in Kentucky. A) The Bead Bryozoan Bed (BBB) showing hundreds of C. clarksvillensis on the surface at the ‘Fault Outcrop’ along I-64 in Kentucky. B) Closer view of the BBB at the I-64 section. C) Underside of a Cyphotrypa from Bedford, Kentucky. Note the bryozoan has produced a natural mold of the bivalve it encrusted.
4.2.7 Rowland Member (sensu stricto) The type section for the Rowland Member of the Drakes Formation is a roadcut along U.S. Highway 27, 1.2mi west of Rowland, Kentucky (Weir et al., 1965). At this section the Rowland is measured at 64’ (19.5m) thick, composed mostly of fossil-poor dolomitic and glauconitic limestone. The member at this southern location exhibits ripple marks and mudcracks on some bedding surfaces, indicating a peritidal depositional (Weir et al., 1965). There have been multiple interpretations of the Rowland Member to the north. The majority of authors have correlated the Rowland to the entirety of the Waynesville Formation (e.g. Kepferle, 1976; Gibbons, 1977; Luft, 1977; Peterson et al., 1971; Peterson, 1978; Swadley, 1977); others have correlated it to the Oregonia Member of the Arnheim Formation (Holland, 1993; Holland and Patzkowsky, 1996); still others have postulated that the Rowland has no downramp equivalent and suggested that the Drakes Formation, including its basal Rowland Member, is younger than the Waynesville, Liberty and Whitewater Formations (Ross and Ross, 2002, 2004). Herein, we propose that the Rowland sensu stricto (as defined in its type section) is correlative with the Blanchester Member of the Waynesville and that the Clarksville and Fort Ancient Members have been truncated under the basal Rowland bed, which is the southern extension of the MidRichmondian Unconformity. In most localities the base of the unit, as we recognize it, is a sharp 53
contact of a thick, blocky (Figure 20), locally vuggy, Skolithos-bearing, heavily bioturbated lime mudstone-wackestone. In Henry County, Kentucky, the Rowland is between 30’ (9m) and 55’ (16.7m) in thickness, but, this includes part of what we would refer to as Fort Ancient -equivalent (Luft, 1977). In Oldham County, Kentucky, the next county south, the Rowland and underlying shale thins to between 40’ (12m) and 52’ (15.8m) (Kepferle, 1977). Here the author again reports the Fisherville and Cyphotrypa shales toward the bottom of the interval. Above the Cyphotrypa shale, the rest of the unit is described as dolomitic and glauconitic. Further south in Shelby and Jefferson Counties, the Rowland is +/- 50’ (15m). Little work has done to trace beds within the Rowland. Butts (1915) noted that the beds above the Cyphotrypa shale (the Rowland sensu stricto), which he considered part of the Waynesville, were sparse in fossils containing primarily Cyphotrypa, the brachiopods Zygospira, and Hebertella, ostracods, various mollusks and the gastropod Lophospira.
Figure 20 54
Figure 20: Image of the Rowland Member of the Drakes Formation, herein described as equivalent to the Blanchester Formation. Photograph taken from the ‘Fault Outcrop’ along I-64 in Kentucky. Green paint marks the Basal Rowland Bed at the Mid-Richmondian Unconformity in the south.
4.2.8 Marble Hill Beds The Marble Hill Bed is a complex of lenticular beds in northern Kentucky situated near the base, top, and locally middle of the Rowland Member of the Waynesville Formation. It was first described by Owen (1859) who called it the Marble Hill Rock for the quarry in which it was discovered. Owen indicated that the gastropod-rich Marble Hill ranged from 6’ (1.8m) to 20’ (6m) and dominated by “an immense accumulation of spiral marine univalves, belonging to the fossil genus Murchisonia” (Owen ,1859, p. 29). Of the localities examined in this study, the Marble Hill Bed was only found at Bedford. The bulk of the upper Marble Hill at the locality is a 2m thick gastropod grainstone topped by a 0.65m gastropod-rich shale (Figure 21). The gastropods themselves are recrystallized and tend to have a grayish-green coloration with highlights of pink. Harrison et al (2010) reported that the recrystallization occurred at a fine enough scale to preserve the lamellar microstructure. Swadley (1979) reports an additional, much smaller Marble Hill Bed near the base of the Rowland, thus acting as bookends for the Rowland. This lower bed has an average thickness of 1.2m and a maximum thickness of 4m whereas the upper unit is up to 9m thick (Swadley, 1979). The lower Marble Hill unit is 1km wide and 29km long in a northeast-southwest belt. The upper Marble Hill Bed thins rapidly to the north and
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much more gradually to the south (Swadley, 1979). This upper Marble Hill Bed caps the Rowland and is overlain by the Liberty/Bardstown. On the eastern side of the arch, along Rte 32 near Flemingsburg, Kentucky, there appears to be a transitional Marble Hill facies, which may correlate with the basal Marble Hill Bed. Exact thickness of the unit at this location is unknown; but, it contains an abundance of gray moldic gastropods (up to 4cm long) as well as moldic bivalves, Flexicalymene trilobites as both molds and body fossils, and tentaculitids. Small Hebertella are also present in these blocks. These fossils are situated in a yellowish-gray weathered matrix. Approximately 24.5km to the north near Maysville, Kentucky, an additional outcrop also displays a transitional Marble Hill / Rowland facies. The upper slope of this outcrop, which overlies the Rafinesquina “cornflakes” beds, consist of beige-green colored carbonate containing Flexicalymene, Hebertella, Rafinesquina, Cornulites and abundant moldic gastropods.
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Figure 21: Images of the Upper Marble Hill Bed near Bedford, Kentucky. A) The 2m gastropod grainstone and the overlying gastropodal shale. B) Gastropods weathering out of the Marble Hill shale
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4.2.9 Basal Liberty-Bardstown Coral Bed Foerste (1908) reports that near the base of the Liberty Formation in Kentucky, a coral horizon, which he called the Bardstown Coral Reef. In the absence of Herbertella insculpta in these southern outcrops, the Bardstown Reef has been commonly referred to at the base of Liberty (Browne, 1964). Butts (1915) identified two Liberty reefs in Jefferson County, Kentucky, 10’ (3m) from the base of Liberty separated by 5’ (1.5m). Browne (1964) identified the upper of the two reefs to be the true Bardstown based on the presence of Foerstephyllum vacuum and Tetradium approximatum. The lower horizon is characterized by Columnaria (Favistella) and thus was referred to as the Columnaria zone by Butts (1915). 4.3 Correlations Figures 3 through 6 show regional cross sections through the Waynesville Formation. One of the most striking features of these cross sections is a strong, overall thinning of the Waynesville Formation from South Gate Hill both to the north and, more strikingly, to the southwest toward Madison. While a general pattern of southward thinning of the Waynesville Formation into Kentucky has long been noted (Foerste, 1903), the source of this thinning has never been explained. The present study demonstrates most individual units have consistent thickness, which emphasizes that thinning occurs at a single level, below the base of the Blanchester Member (Figures 3-6). Further consideration of the Waynesville equivalents in northern Kentucky suggests that the majority or entirety of the Rowland Member (of the Drakes Formation) and the laterally equivalent Marble Hill Beds is equivalent to the Blanchester Member of the Waynesville, while the underlying Clarkesville Member is completely removed, stacking the Blanchester Member onto a truncated and thinned remnant of the Fort Ancient
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Member, which is mapped either as the basal unit of the Rowland or the upper unit of the Bull Fork Formation. An important inference from the high-resolution correlations is the lateral continuity and persistence of stratigraphic units at meter scale. As in the lower Cincinnatian Kope Formation (e.g. Brett and Algeo, 2001), limestone marker beds intercalated with thicker shale intervals provide regional control. Moreover, a suite of consecutive faunal epiboles together with distinctive taphonomic epiboles notably the "butter shales" intervals, provides a strong degree of control on these correlations. A series of six marker horizons in the Fort Ancient to Clarksville Member can be correlated across this region. Likewise, 10 marker horizons and intervals occur in the Blanchester Member and four or five in the Liberty Member (Table 1). These markers were routinely employed by previous workers, but dismissed through most of the later 1900s when strict application of a facies model cast doubt on regional correlation of thin units. Nonetheless, the beds are so distinctive as to leave little doubt that they record unique physical and biological events that affected large parts of the basin, at least along depositional strike. Our observations confirm that these markers are through-going and that they cross subtle facies transitions. Thus these markers are not merely diachronous facies that migrated through time, but rather records of extrinsically-forced events superimposed on basin facies.
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Waynesville Formation
Blanchester Formation
Liberty Formation
Marker Bed
Description
Eochonetes grainstone which may exhibit a weak cornflakes appearances locally. Butter shale noted for large articulated Minuens Shale Isotelus and abundant diminutive Flexicalymene Mudstone package containing at least 6 “Crinoid Beds” different crinoid genera. Middle and Upper Recurrent appearance of Glyptorthis Glyptorthis insculpta insculpta Buttery shale containing articulated bivalves Coral-Isotelus Bed and trilobites and also the corals Tetradium, Foerstephyllum and Cyathophylloides Upper Disturbed Thin weak cornflakes like bed containing Bed Rhynchotrema dentatum Strophomena nutans S. nutans and Tetraphaerella neglecta Bed Epibole Weak cornflakes bed with abundant Lower Disturbed Rafinesquina, other brachiopods and some Zone Grewingkia Butter Shale rich in Lyrodesma on the west Lyrodesma-Isotelus side of the arch and rich in trilobites on the Shale east Lower Glyptorthis First appearance of G. insculpta, recurrent insculpta and Retrorsirostra c. and abundant edgewise Rafinesquina Rafinesquina. May contain pyrite crust and Cornflakes Beds ripup clasts. Butter Shale restricted to the Oldenburg, IN Oldenburg Shale area. Contains abundant bivalves, and trilobites. Abundant Eochonetes and Leptaena along Eochoneteswith Cincinnetina, Platystrophia c., and Leptaena Beds Grewingkia Peak occurrence of Cincinnetina, marks Cincinnetina base of Clarksville Member, May have Epibole Beds Eochonetes Treptoceras duseri – Butter Shale rich in Flexicalymene, Isotelus, Trilobite Shale bivalves, lingulids and Treptoceras duseri Cincinnetina grainstone overlying major Bon Well Hill Beds shale Thick shale between SGB and BWH Beds, Fort Ancient Shale relatively barren
Sequence Stratigraphic Importance
Eochonetes Bed
South Gate Hill Bed
Phosphate rich Cincinnetina grainstone Table 1 60
4th Order Sequence Boundary
Mid-Richmondian Unconformity, 3rd Order Sequence Boundary / TST
4th Order Sequence Boundary
4th Order Sequence Boundary C4/C5 3rd Order Sequence Boundary
Table 1: Key marker beds in the Waynesville through Lower Liberty interval.
Correlated intervals show remarkably persistent proportional and absolute thickness across the study area with one exception. Individual markers are only slightly thicker in the Waynesville area and thin toward Brookville, with a reversal of this pattern between Bon Well Hill and South Gate Hill, where in 17 km most units display thickening. The total proportion of thickening is approximately 10-20% in the Fort Ancient. The similarity of units in terms of thickness and facies is even greater in the Blanchester and Liberty divisions where the thickness changes are less than 3m. Lists of common and rare taxa are nearly identical across this region. This suggests during deposition of the upper units this cross section was aligned nearly parallel to depositional strike. In contrast to the detailed similarities of the Fort Ancient and Blanchester-Liberty divisions, the Clarkesville Member displays striking changes in terms of thickness and included units. As noted earlier, the Clarksville ranges from 15 to 0m with thinning both NE and SW of the thickest region in southeastern Indiana. Collectively, old and new field data provides strong evidence for a previously unrecognized regionally angular discontinuity that lies below the lower Glyptorthis insculpta beds at the base of the Blanchester and truncates beds in the Clarksville Member. Indeed, a key discovery of this study is an extra interval, including the Oldenburg shale that is only present in a narrow region around South Gate Hill to Oldenburg and is missing elsewhere, even immediately to the northeast and southwest (Figures 3-6). This strongly suggests truncation beneath an erosional surface. This unconformity is cryptic in most outcrops, but near Hannah Creek the entire Clarksville Member is absent, and the lower G. insculpta bed overlies the T. duseri Shale directly. Here it has a sharply erosive base and contains abundant rip-up clasts. Likewise near 61
Maysville, Kentucky, the Rafinesquina “cornflakes” beds, which occur just above the unconformity surface also sit right above the T. duseri Shale. To the south, near New Castle, the basal Rowland Bed, which marks the southern expression of the unconformity surface sits about a meter above the Cyphotrypa Shale, which we correlate with the T. duseri Shale to the north. Farther southward, the unconformity surface appears to merge with the regional unconformity beneath the, which progressively cuts out the Fort Ancient equivalents in the Cyphotrypa Shales and the Fisherville beds and finally truncates much or all of the Bull Fork Formation (or Arnheim equivalent). Remarkably, the Mid-Richmondian unconformity has largely escaped notice for almost two centuries of study with the notable exception of Ross and Ross (2002, 2004).
5. DISCUSSION 5.1. Nomenclature The nomenclature for the Waynesville Formation has a complex history and we favor a variation of Foerste’s use of the name Waynesville Formation and its three subdivisions: Fort Ancient, Clarksville and Blanchester. The Fort Ancient Member, like the rest of the Waynesville, consists predominantly of soft shale with the lower Fort Ancient Shale towards the bottom of the member, and the Treptoceras duseri butter shale near its top. Certain authors have reported that the duseri shale should be included in the overlying Clarksville due to the presence of the occasional Tetradium (Wolford 1930); but, we agree with the former classification. Splitting these two shales is the Bon Well Hill Submember. Sequence stratigraphically, the Fort Ancient represents two fourth-order cycles (Figure 22). The first sequence boundary coincides with the third-order sequence boundary present at the base of the South Gate Hill Bed (SGB), which itself
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represents the transgressive systems tract (TST). The top of the SGB represents a fourth-order flooding surface giving way to an expansive highstand systems tract (HST). We infer that the lowstand systems tract (LST) and falling stage systems tract (FSST) are both absent from this cycle. The second fourth-order cycle starts with the sequence boundary below the Bon Well Hill Beds. The BWH beds represent a fourth-order TST with a flooding surface at its top. The Treptoceras duseri butter shale at the top of the Fort Ancient Member represents a FSST. The cap of this shale is another fourth-order sequence boundary marked by the Cincinnetina epibole (Frey, 1996) and represents the change from Fort Ancient to Clarksville (Figure 22). In this way the former classification of the duseri shale as Fort Ancient fits with the sequence stratigraphy.
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Figure 22 Figure 22: Fourth and third order cycles for the Waynesville and Blanchester interval. Red lines represent sequence boundaries and blue lines represent maximum flooding surfaces. SGB = South Gate Hill Bed, BFAS = Basal Fort Ancient Shale, BWH = Bon Well Hill Beds, TDS = Treptoceras duseri Shale, CF = Cornflakes Beds, MGI = Middle Glyptorthis insculpta Bed
The Clarksville Member is a more difficult member to characterize but it is dominated by shale with many thin limestones scattered throughout. Its cap, the Mid-Richmondian Unconformity, cuts down into the member in many of the outcrops. Traditionally its top boundary was selected based on the first occurrence of Glyptorthis insculpta in a limestone ledge, the lowest bed of the Blanchester (Wolford, 1930). At some locations, the highest bed in the Clarksville is the Oldenburg butter shale, which is generally cut away. The Clarksville represents an expanded fourth-order cycle terminating with the third-order sequence boundary at the MRU (Figure 23).
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Figure 23
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Figure 23: Stratigraphic cross section showing the position of the various third order systems tracts for the Waynesville through Blanchester interval. Red lines indicate third order sequence boundaries. The lowest Glyptorthis insculpta zone, which traditionally delineates the lowest bed of the Blanchester, sits on the MRU. Above this zone is the Rafinesquina "cornflake bed". Together, these beds are interpreted as a condensed third-order TST. Lithologically the Blanchester member is much like the Clarksville, predominantly shales with multiple thin limestone beds. The upper limit of the Blanchester also marks the boundary between the Waynesville Formation and the overlying Liberty Formation. Traditionally, this boundary has been based on the second and third occurrences of the Glyptorthis insculpta. Some authors have placed the boundary at base of the second Glyptorthis bed (Caster et al., 1961) whereas others have chosen the top of the third bed (Wolford, 1930). The present authors choose to use the base of the Middle Glyptorthis insculpta zone to mark the base of the Liberty. The Blanchester consists of one fourth-order cycle. The cycle is expanded, beginning with the third-order sequence boundary at the MRU, and the cornflakes beds represent the fourth-order TST. An expanded HST overlies these beds, but; no FSST seems to be present. The cycle ends at the middle Glyptorthis insculpta Zone, which marks the base of the Liberty. 5.2 Mid-Richmondian Unconformity From South Gate Hill to Seatonville, the thickness of the Waynesville Formation below the Unconformity shrinks from roughly 26m to 7m. This represents at least 19m of combined erosion and condensation, which removes much or all of the Clarksville Member towards the southern margin of the study area and likely continues even further south. Our study area also
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demonstrates roughly 5m of erosion below the unconformity to the north of South Gate Hill. Further investigation is expected to reveal an even greater magnitude of erosion to the north. The cause of this erosion is likely a brief period of sea-level drawdown due to local tectonics or minor global glaciation. Based on preliminary data from Baltica (Calner et al., 2010), we support the latter explanation; the exact mechanism for this drop in sea level needs further investigation. This bimodal direction of erosion also supports basin geometry with a depocenter situated around Oldenburg or South Gate Hill for the western side of the arch. From here, shallowing upramp occurs both north and south of this location. We know that the decrease in thickness of the Waynesville below the unconformity is not a simple product of non-deposition because the Rafinesquina cornflake bed overlying the unconformity is situated on top of progressively older rock. The original sequence stratigraphic interpretation of the Cincinnatian (Holland, 1993; Holand and Patzkowsky, 1996) placed a third-order sequence boundary at the base of the Waynesville Formation below the South Gate Hill Bed. This marks the boundary of the C4 and C5 named cycles. The next third-order sequence boundary was placed at the top of the Saluda Formation (Holland, 1993; Holland and Patzkowsky, 1996). Here we suggest that the MidRichmondian Unconformity represents an additional third-order sequence boundary,which divides the C5. The MRU shows considerably more erosion than the third-order sequence boundary present at the base of the South Gate Hill Bed. 5.3 Implications for the Richmondian Invasion 5.3.1 Patterns of Incursion
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The refined stratigraphy of the Waynesville-Lower Liberty interval and the documentation of important new fourth and even third-order sequence boundaries provides a more nuanced understanding of the patterns of the Richmondian invasion documented by Patzkowsky and Holland, and permits examination of possible phases of the incursion in relation to sequence stratigraphy (cf. stratigraphic paleobiology approach of Patzkowsky and Holland, 2012). Although aspects of the biotic turnover precede the deposition of the Waynesville Formation, these are primarily confined to shallow-water facies of the upper Maysvillian Arnheim Formation (sequences C3 and C4 as redefined by Malgieri et al. in preparation). Moreover, the faunal changes seen at this level are perhaps of an intermediate scale of biotic turnover that does not represent the full on warming of the later Richmondian. The lower Waynesville, Fort Ancient Member is unusual in showing the proliferation of the normally more offshore taxon Cincinnetina meeki and/or C. jugosum; the strong reappearance of dalmanellid brachiopods-typical of the upper Edenian upper Kope (McMicken Member) and some levels in the Fairview Formation and may signal a relatively strong transgression associated with the South Gate Hill Submember. In the basal beds and/or the highest beds of the underlying Arnheim these small orthids are associated with Strophomena. In addition, a majority of the diverse suite of lower Maysvillian (lower Fairview) bryozoan species (about 33 of 56 species) recur in the Fort Ancient Member or its lateral equivalents in the upper Bull Fork Formation of Kentucky; many of these species (~12) disappear above this level (data from Ross and Ross, 2004). In these ways the basal condensed interval of the Waynesville (South Gate Hill Bed), herein identified as the lower portion of a TST, rather closely resembles the prolific Cincinnetina-Strophomenadiverse bryozoan biofacies of the lower transgressive beds of the basal Maysvillian Fairview
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Formation (Holland and Patzkowsky 2005). Intervening beds carry a sparse mixture of dalmanellids and Rafinesquina, Flexicalymene, Isotelus and a diversity of bivalves. Such biofacies closely resemble those of the subjacent middle and lower Cincinnatian as noted by Holland and Patzkowsky (2005). Both may record a minor sequence boundary at which a transgressive, condensed interval follows a modest shallowing and therefore occurs in a relatively offshore facies. In upramp sections, the Fort Ancient appears to abruptly lose its dalmanellids and instead beds are exceptionally rich in Hebertella occidentalis, and Rafinesquina; however, Vinlandostrophia ponderosa, commonly associated with abundant Hebertella in the Mayvsillian and lower Richmondian is absent. Tetradiids, colonial rugose corals, and small stromatoporoids appear in shallow water carbonates as well as unusual muddy offshore facies for the first time in the middle Fort Ancient (lower T. duseri shale and underlying carbonates and their probable upramp equivalents in the Fisherville coral beds). This represents a recurrence of shallow biofacies seen in the Mt. AuburnSunset, although with a greater dominance of corals and fewer and smaller stromatoporoids than in the upper Maysvillian-lower Richmondian beds and an incursion of these taxa into, muddy environments. Surprisingly, these corals occur in the Treptoceras duseri shale, associated with an unusual bivalve-dominated fauna including Anomalodonta, Modiolopsis concentrica, and M. pholadiformis, Opisthoptera fusicosta, and Caritodens demissa. Other fauna includes abundant Sinuites and other gastropods and nautiloids of the eponymous T. duseri, as well as the famed and abundant, well-preserved trilobites, mainly Isotelus spp. and Flexicalymene meeki. This general biofacies associated with thicker claystone intervals or "butter shale" recurs several times in the higher Waynesville and Liberty with corals mingling with diverse bivalve and Flexicalymene-Isotelus faunas in the lower and upper Blanchester and the Flexicalymene
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minuens bed of the lower Liberty, although the exact proportions and composition of bivalve taxa are somewhat variable (Rosenkranz, 1999). Most of these taxa and the general biofacies occur lower in the Maysvillian, especially in the Hill Quarry beds of the Fairmont Member and in the Miamitown Shale. The main phase of the Richmondian invasion, at least in offshore facies, appears to be associated with the Clarksville Member of the Waynesville. Although the basal beds of the Clarksville continue the prolific Cincinnetina meeki fauna of the Fort Ancient, beds about 1.5 to 2m above the base of Clarksville (= top of T. duseri shale) exhibit the first abundant appearance of much of the Richmondian fauna, including the rugose corals Grewingkia rusticum, Streptelasma sp., the plectambonitacean Eochonetes clarksvillensis, and Hiscobeccus capax, together with Strophomena planumbonum, S. sulcata, Rhynchotrema cf. perlamellosum, and Leptaena richmondensis (Foerste, 1908; Wolford, 1930). Just as important as the influx of new taxa is the decrease or, extirpation of previously dominant or abundant forms. It is particularly notable that the orthid brachiopod Vinlandostrophia ponderosa, which was prolific throughout most of the Grant Lake-Arnheim (C3-C4) succession, absent above the level of the South Gate Hill Bed; Retrorsirostra recurs at one higher horizon but is basically absent elsewhere. Perhaps more important is the major loss in biodiversity of bryozoans at about this level as documented by Ross and Ross (2002, 2004). Largely this is a loss of species diversity within genera (some 25 species, including some very common types); but, the genera Ceramoporella and Attactoporella, as well as almost all Heterotrypa, Eridotrypa, and Dekayia disappear at about the level of the base of the Clarksville Member.
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Importantly, the newly recognized mid-Richmondian unconformity, which separates the lower Waynesville from the Blanchester Member, does not appear to coincide with a major turnover of taxa. Most of the taxa that first occur abundantly in the Clarkesville Member also occur abundantly to dominantly in the higher beds of the Blanchester Member (Figure 24) and Liberty Formation and Whitewater formations. With the exception of some rare taxa and forms such as crinoids and aragonitic forms that are highly sensitive to the vagaries of taphonomy, the typical fauna appears in a relatively conformable succession below the mid-Richmondian unconformity and persists through it. As such, the "Richmondian invasion" is not an artifact of gaps associated with a sequence boundary as predicted in many events of rapid turnover (see Holland, 1995; Patzkowsky and Holland, 2012).
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Figure 24
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Figure 24: Diagram depicting key faunal ranges in the Waynesville and Blanchester Formations.
Although this main suite of Richmondian species is established in the Clarksville, there are notable epiboles associated with condensed beds at the base and top of the overlying Blanchester Member and thus above the large unconformity. Indeed, the Blanchester interval probably shows more incursion epiboles than any other interval of comparable thickness in the Cincinnatian, suggesting unstable and/or unusual conditions. The lower boundary of this interval, a thin, condensed, shell-rich bed previously referred to as the lower Glyptorthis insculpta bed, which not only shows an incursion of the eponymous species, G. insculpta, but also a recurrence of Retrorsirostra cf. carleyi and an influx of the very rare atrypid brachiopod Catazyga headi. This suggests unusual conditions associated with the basal transgression following a major eustatic drawdown and/or tectonic reorganization of the basin. Likewise, Glyptorthis insculpta occurs in two higher beds in the generally condensed interval, which we call the base of the Liberty Formation as per the original definition of this interval (Foerste, 1908). The second and third G. insculpta beds appear again to record condensed beds associated with the transgressive interval following the sub-Bardstown unconformity that we recognize herein. Assuming that we have correctly correlated the lower and upper G. insculpta beds with the lower and upper Marble Hill beds respectively, the same unusual conditions that affected the proliferation of Glyptorthis in the shallow shelf also had parallel impacts in shallow shoal settings. Both lower and upper Marble Hill beds in their type area near Madison, Indiana, are characterized by an anomalous, remarkable abundance of the gastropod Loxoplocus bowdeni, which forms the major, larger grains of this limestone, along with bellerophontids and nautiloids. As noted above, detailed studies of the Marble Hill beds led to the recognition that they represent
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a series of narrow, NE-SW trending bar-like deposits and, in the case of the lower beds, a series of perpendicular narrow shoreward extensions that might be tidal channel deposits. Moreover, there are hints of the same proliferation in a corresponding position in the upper "Bull Fork" Formation along the east side of the Cincinnati Arch near Flemingsburg, and beds nearly identical to Marble Hill also occur in the putative mid-Waynesville position above beds correlated to Arnheim, within the Leipers Formation in the Nashville Dome of Tennessee (C. Brett, personal observation. The main mass of the Blanchester Member also shows some unusual epiboles. A few meters above the lower G. insculpta bed, the mid-Blanchester Strophomena nutans Bed yields a variety of unusual strophomenids including S. nutans, S. cf. vetusta and the unique occurrence of Tetrapharella neglecta; a still higher level yields a recurrence of Rhynchotrema dentatum and a unique occurrence of Austinella scovellei, both associated with a thick edgewise coquinas of Rafinesquina. The upper mudstones of the Blanchester contain an abundance of Tetradium and Columnaria corals. This shallow zone appears to extend southward into a rubbly, nodular interval very rich in Tetradium. 5.3.2 Paleoecological Implications of the Blanchester-Marble Hill-Rowland Correlation The unusual gastropodal grainstones of the Marble Hill beds appear to represent shoal facies analogous to shoal grainstones that are more typically dominated by pelmatozoan echinoderms and/or bryozoans. This widespread proliferation of gastropods and corresponding decrease in crinoids and bryozoans in shallow wave agitated environments is very distinctive and of uncertain significance. An associated increase in micrite in shallow, inboard shelf lagoon sediments of the contemporaneous Rowland Member suggests a large increase in micriteproducing chlorophyte algae; in addition, many thin, dark shale intercalations show black 75
carbonized, branching fossils that are interpreted as a fleshy dasycladacean algae typical of very shallow, subtropical settings (S.T. LoDuca, personal communication). Expansion of green algae could have been tracked by a proliferation of herbivorous gastropods. Rowland strata are also unusual facies, typically sparsely fossiliferous, muddy micrites. They become increasingly dominated by olive to greenish-gray mudstones in upramp locations which commonly show desiccation cracks. These facies are analogous to the older Tate and Terrill Members of the Maysvillian Ashlock Formation and, in each case, these facies represent shallow water, "lagoonal" to tidal flat environments that lay inboard (upramp) from a high energy barrier, represented by the Marble Hill gastropod shoals and bars. The abundant micrite may have been produced preferentially in and adjacent to the Marble Hill shoal and came to interfinger with terrigenous sediments from a southerly source. They may have aggraded relatively rapidly and, so, represent a relatively short time interval; perhaps two 4th order cycles. However, the Rowland is more laterally extensive than the Tate and Terrill. The scarcity of fossils in these facies may be attributable to low energy turbid, low oxygen and/or slightly hypersaline conditions in these broad, sheltered, shallow water areas. One further aspect of Rowland facies that is quite anomalous, if not unique within the Cincinnatian, is the occurrence of abundant pale-gray chert nodules. These are prevalent in the basal Rowland beds up to about 1.2m thick, in the region southeast of Bardstown. This is may be another indicator of high productivity or may represent replaced evaporite nodules. Unusual for the Cincinnatian, the Rowland is typically quite sparsely fossiliferous. In many areas, the only fossils present are poorly preserved mollusks, including both bivalves and archaeogastropods and the small ball-like colonies of the domal bryozoan Cyphotrypa cf. clarksvillensis, many of which attached preferentially to the valves of modiolopsid bivalves
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(Schwalbach et al., 2014) and/or lingulid brachiopods, which are commonly preserved in situ. In more downramp localities proximal to the Marble Hill facies, the Rowland locally contains beds with abundant Grewingkia horn corals with Hebertella, Platystrophia, Loxoplocus and poorly preserved bivalves. In the Smithville Quadrangle, the middle Rowland shows very large coral colonies, exceeding a meter in diameter (Luft, 1977), which also may point to warming and/or increased influx of nutrients as causes of these ecological effects. We suggest that the Blanchester-Rowland interval records the culmination of mid-Richmondian warming. Following the rather low diversity and unusual Rowland faunas, the diverse Richmondian faunas in the Liberty are similar to those of the older Clarksville Member. These include abundant solitary and colonial rugose corals, Tetradium, and the addition of the peculiar columnar aulacerid stromatoporoid Beatricia, a low diversity of bryozoans including the late Richmondian forms Rhombotrypa and Gortanipora, and diverse brachiopods, such as dalmanellids, Eochonetes, Leptaena, Strophomena planumbona, and Hiscobecus, as well as the long ranging Rafinesquina, Zygospira, Hebertella, and varied small Platystrophia. Moreover, the strong, regional partitioning seen in the Blanchester-Marble Hill-Rowland regional cross section is greatly reduced during deposition of the Liberty and Whitewater Formation. The Liberty faunas are very similar to those of the Bardstown in Kentucky although the latter display a much higher abundance of colonial corals in two major coral biostromes (Otter Creek and mid Bardstown coral beds). The Richmondian was subdivided into three third-order sequences by Holland (1993, 1995) and Holland and Patzkowsky (1996). Sequence C4 was essentially coincident with the Arnheim/lower Bull Fork formations. The C4/C5 boundary was placed at the base of the Fort Ancient Member of the Waynesville Formation, coincident with the base of the South Gate Hill
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Bed as named herein. Sequence C5 was a very broadly defined interval ranging through the entire Waynesville, Liberty, Whitewater, Saluda and equivalent upper Bull Fork and Drakes formations of Kentucky usage or Tanners Creek in Indiana (Galloway, 1913). Finally, sequence C6 included the highest Cincinnatian units, the Hitz beds and Elkhorn Formations, exposed in southeastern Indiana. Pope and Read documented third-order sequences in the entire Chatfieldian (Lexington) to Cincinnatian interval of the Cincinnati arch. Their scheme differed substantially from that of Holland and Patzkowsky (1996) in that they divided the entire Cincinnatian into only two and a half sequences. The first (their sequence 2) comprised the upper Lexington Formation and KopeClay Ferry formations; the next ranged from the base of the Garrard Siltstone above typical Kope and continued up through the Tate peritidal facies the base of the Bellevue Formation in the Cincinnati area. Elsewhere, they set the top boundary between the Tate and overlying Rowland. In fact, the Rowland is nowhere in contact with the Tate. Pope and Read mistakenly conflated the Terrill with the Tate Member. All of the remaining Cincinnatian strata up to the base of the Silurian Brassfield were placed in Pope and Read's sequence 4. Thus, this scheme not only did not recognize as many third-order sequences as did Holland (1995), but also did not set the sequence boundaries at the same horizons. Although Pope and Read identified, correctly in our view, two sharp boundaries at places that Holland had failed to recognize, in most aspects their sequence stratigraphic framework was less resolved than that of Holland. As suggested earlier, a major advance that has been largely ignored was the detailed work of J.P. Ross and C. Ross (2002, 2004) based on a study of more than 130 measured sections and 30,000 thin sections. Ross and Ross identified a much larger number of sequence boundaries in the Chatfieldian- Cincinnatian of Kentucky, Ohio and Indiana. The new data were presented
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mainly as a series of figures with minor text in two papers dealing largely with the bryozoan faunas and published in proceedings volumes of International Bryozoan conferences. These researchers adopted a practice very similar to that of the present study in placing sequence boundaries at the sharp bases rather than the tops of condensed shell-rich limestone beds, as in the Holland scheme. Within the Richmondian part of the section the Ross's recognized three major third-order sequences as well as seven smaller ones. The first Richmondian sequence, comparable to Holland and Patzkowsky’s C4, coincided with the Arnheim Formation with its upper boundary placed at the same position (the base of Fort Ancient or South Gate Hill bed). The second was originally defined as constituting the Waynesville, Liberty and Whitewater formations (Ross and Ross, 2002). These beds were shown to be separated from a younger Drakes Formation by a large and widespread, regionally angular unconformity that Ross and Ross termed the midRichmondian or unconformity or "central Kentucky hiatus”. This was suggested to cut downward through the Whitewater, Liberty and Waynesville and locally through the Arnheim as well. Subsequently, the Whitewater was shown as being above the unconformity as a part of their Drakes-Whitewater sequence, which truncated the Liberty and Waynesville. In retrospect, this unconformity was an important discovery that could have been anticipated from the work of Weir et al. (1965). However, these workers considered most of the Cincinnatian to be conformable successions of interfingering facies instead and failed to identify regional erosion. Holland and Patzkowsky also failed to recognize this important surface, which lies within their sequence C5, also shown to be internally conformable. Our recent work in Kentucky confirms the existence of this important unconformity; indeed, we discovered this regional truncation independently of Ross and Ross, being unaware at
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the time of their important work. However, our research suggests some important differences with the interpretation of Ross and Ross (2002 and 2004). In particular, we concur with a several previous faunal and sequence studies that the Liberty and lower Whitewater are more nearly conformable with each other and that the Liberty is equivalent to the lower Bardstown member of the Drakes. Moreover, the Rowland and associated Marble Hill are herein inferred to be equivalent to the upper or Blanchester Member of the Waynesville Formation, and it is for that reason that the Blanchester is separated as a formation in its own right, being bounded by discontinuities at the base and top of the lower and upper (middle) Glyptorthis beds, respectively. Our work suggests that the lower G. insculpta bed is equivalent to the lower Marble Hill bed that locally forms the sharp base of the slightly redefined Rowland Member of the Drakes formation in the vicinity of Madison, Indiana, and adjacent Milton-Bedford, Kentucky. The most significant new finding of our work is that an unconformity occurs at the base of the Blanchester, i.e., basal contact of the lower G. insculpta bed. This disconformity locally removes major portions of the underlying Clarksville Member. Indeed, an entire succession of beds, the Oldenburg submember, up to 2m thick is not seen elsewhere in the upper part of the Clarkesville in the vicinity of St. Leon to Oldenburg in southern Indiana. Moreover, the hiatus below the Blanchester beds increases in extent both northeast and southwest of this area. We infer that this unconformity is confluent with the sharp base of the Rowland Formation (base of lower Marble Hill grainstone). This further implies that the sub-Blanchester regional discontinuity is a local manifestation of the mid-Richmondian or Central Kentucky unconformity, which, in turn, suggests that Holland's C5 sequence should be divided into two additional sequences. Moreover,
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evidence for truncation of the Rowland beneath the basal Bardstown Otter Creek bed suggests a second, higher regional unconformity that separates the Rowland from the Bardstown Member of the Drakes Formation, as also partially implied by the figures of Ross and Ross (2002, 2004). However, the latter errs in showing the Liberty Formation below both the Otter Creek bed and the Rowland. In fact, the Liberty appears to be equivalent to the lower Bardstown with the equivalent of the Otter Creek bed at its base, and both are younger than the RowlandBlanchester. The base of the Fort Ancient Member, used by Holland (1993, 1995) as the C4-C5 sequence boundary, is objectively defined at the sharp base of the phosphatic skeletal packstone herein termed South Gate Hill Bed. The amount of litho and biofacies offset at this boundary seems minor, and even Foerste (1908) suggested that this similarity might imply that the Fort Ancient was genetically more closely related to the Arnheim than to the higher parts of the Waynesville Formation. Moreover, there does not appear to be a major regional unconformity. However, there is some evidence for southward thinning and removal of beds (e.g., Retrorsirostra carelyi bed) of the upper Arnheim Formation at this boundary (Foerste, 1905). Therefore, we suggest that the lower Waynesville, i.e., Fort Ancient and Clarksville members, as previously defined, should be retained as a third-order sequence, C5. There are as many as three or four fourth-order sequences: a) lower Fort Ancient commencing with the South Gate Hill Bed as its TST; b) upper Fort Ancient, including Bon Well Hill beds (TST) and T. duseri shale; c) lower Clarksville from Cincinnetina bed (TST) through lower shaly Clarksville; and perhaps d) an upper Clarksville sequence from Leptaena beds through the Oldenburg shale. The fourth, tentative fourth-order sequence remains incompletely characterized as it is only present, and incompletely exposed, in a few outcrops in southeastern Indiana. The upper or Blanchester
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Member of the Waynesville Formation on the other hand is separated from the lower by the regional unconformity, apparently confluent with the major Central Kentucky hiatus. Therefore, we argue that the Blanchester be elevated to formation status to coincide with a new third-order sequence, herein termed C6, not equivalent with the much higher succession previously termed C6, which will require re-designation. Overall, Cincinnati Arch outcrops in Kentucky comprise an excellent cross section of the Upper Ordovician strata that record the aforementioned physical and biotic changes. A highly detailed sequence and cycle stratigraphic framework along this southward dipping ramp is required to tease apart signatures of global climatic and sea level fluctuations to improve the global standard and also to reveal the details of far-field basin tectonics. 6. CONCLUSIONS
The nomenclature for the strata along the Cincinnati Arch is convoluted, difficult to apply and requires significant revision. The Waynesville, Bull Fork, Drakes, Tanners Creek, Brookville and Dillsboro are all formation names that have been given to the interval encompassing the Waynesville Formation. Each has been used inconsistently, representing different packages of rock.
Formations created by earlier researchers (Nickles, Foerste, Wolford) were based on faunal zones and coincide with the sequence stratigraphic interpretations more closely than the over lumped units created by lithostratigraphic workers in the 1960s and 70s. Thus the early formation names are considered to be more meaningful.
The Waynesville Formation has numerous faunal zones, beds and epibole events which are traceable from the eastern side of the Cincinnati Arch to the western side, as well as from offshore to nearshore. 82
The Fisherville Coral Bed, described as the lowest part of the Rowland Member in the Kentucky Geological Survey Quadrangles, is the nearshore equivalent to the Bon Well Hill Beds. The overlying Cyphotrypa shale is the nearshore equivalent of the Treptoceras duseri "butter Shale".
The Waynesville Formation contains a Mid-Richmondian Unconformity first proposed by Ross and Ross (2002, 2004) and independently discovered by the authors of this paper. This unconformity cuts away much of the Clarksville Member and eventually cuts into the Fort Ancient Member and the underlying Arnheim Formation.
Based on the presence of the Mid-Richmondian Unconformity, we propose that the Blanchester Member of the Waynesville be elevated to the Blanchester Formation with the Waynesville Formation below containing the Fort Ancient and Clarksville Members.
The Rowland Member of the Drakes Formation is interpreted to be the shallow facies equivalent to the now named Blanchester Formation. This is in contrast to some interpretations that placed the Rowland in the C4 along with the Arnheim Formation (Holland, 1993; Holland and Patzkowsky, 1996).
Maximum thickness of strata within the Waynesville Formation is located near Oldenburg, Indiana, suggesting that the basin depocenter was situated near that location.
7. FUTURE RESEARCH This paper marks significant progress towards revision and understanding of the Waynesville-Blanchester interval, but, much work still needs to be done. In the Cincinnati Arch region itself, revised correlations still need to be completed for the eastern side of the arch to complement the work done on the western margin. Once the two complementary correlations are
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completed, cross-arch correlations can also be constructed to better determine the direction of depositional strike. The Mid-Richmondian Unconformity also remains to be investigated further, both on the Cincinnati Arch and elsewhere. Offshore-nearshore correlations presented in this paper need to be extended further in both directions through the use of outcrop and core material to better understand the full extent of the unconformity’s incision. Contemporaneous rock in Canada, western United States and parts of Europe also need to be investigated for a possible MidRichmondian Unconformity to determine to what extent this unconformity is controlled by global eustacy and, to what extent, local tectonism.
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HOLLAND, S.M., 1995, Depositional sequences, facies control and the distribution of fossils, Sequence Stratigraphy and Depositional Response to Eustatic, Tectonic and Climatic Forcing, Springer, p. 1-23. HOLLAND, S.M., MILLER, A.I., MEYER, D.L., and DATTILO, B.F., 2001, The detection and importance of subtle biofacies within a single lithofacies: the Upper Ordovician Kope Formation of the Cincnnati, Ohio region: Palaios, v. 16, p. 205-217 HOLLAND, S.M., and PATZKOWSKY, M.E., 1996, Sequence stratigraphy and long-term paleoceanographic change in the Middle and Upper Ordovician of the eastern United States: Geological Society of America Special Papers, v. 306, p. 117-129 HOLLAND, S.M., and PATZKOWSKY, M.E., 2007, Gradient ecology of a biotic invasion: biofacies of the type Cincinnatian Series (Upper Ordovician), Cincinnati, Ohio region, USA: PALAIOS, v. 22, p. 392-407, doi: 10.2110/palo.2006.p06-066r JIN, J., 2012, Cincinnetina, a new Late Ordovician Dalmanellid brachiopod from the Cincinnati type area, USA: implications for the evolution and palaeogeography of the epicontinental fauna of Laurentia: Palaeontology, v. 55, p. 205-228 KEPFERLE R. C., 1976, Geologic map of the Fisherville quadrangle, north-central Kentucky: U.S. Geological Survey Geol. Quad. Map GQ-1321 Kepferle R. C., 1977, Geologic map of the Ballardsville quadrangle, north-central Kentucky: U.S.
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POPE, J. K., 1976, Upper Ordovician (Richmondian) fossils and strata of eastern Indiana, Brookville to Richmond. POPE, M., and READ, J. F., 1997, High-resolution surface and subsurface sequence stratigraphy of Late Middle to Late Ordovician (Late Mohawkian-Cincinnatian) foreland basin rocks, Kentucky and Virginia: AAPG Bulletin, v. 81, no. 11, p. 1866-1893. ROSENCRANTZ K.J., 1999, Compositional variation in Cincinnatian mudstone communities (Upper Ordovician of Ohio, Indiana and Kentucky): implications for coordinated stasis, unpublished Master’s Thesis, University of Cincinnati. ROSS, J.R.P., and ROSS, C.A., 2002, Bryozoans in Ordovician depositional sequences, Cincinnati Arch region, USA, in Wyse Jackson, P. N., Buttler, C. J., and Spencer Jones, M. E., eds., Bryozoan Studies 2001: A.A. Balkema Publishers, Lisse, p. 261-274 ROSS, J.R.P., and ROSS, C.A., 2004, Bryozoans and stratigraphy, Upper Richmondian (Cincinnatian, Ordovician), in Wyse Jackson, P. N., Cancino, J. M., and Moyano H. G., eds., Bryozoan Studies 2004: Taylor & Francis, p. 245-256. SCHUMACHER G. A., AND SHRAKE D. L., 1996, Paleoecology and comparative taphonomy of an Isotelus (trilobite) fossil lagerstätten from the Waynesville formation (Upper Ordovician, Cincinnatian Series) of southwestern Ohio, in Brett, C. E., and Baird, G. C., eds., Paleontological Events: Columbia University Press, New York, p.131-161. SCHWALBACH C. E., BRETT, C.E., AUCOIN, C.D., and MALGIERI, T.J., 2014, Faunal epiboles in the Upper Ordovician of north-central Kentucky: implications for high resolution sequence stratigraphy: 2014 GSA Annual Meeting in Vancouver, British Columbia.
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SCHWIMMER B.A., and SANDY M.R., 1996, Phylum Brachiopoda, in Feldmann, R.M., and Hackathorn, M., eds., Fossils of Ohio: Ohio Division of Geological Survey, Columbus, p. 210-224 STIGALL, A. L., 2010, Using GIS to assess the biogeographic impact of species invasions on native brachiopods during the Richmondian Invasion in the Type-Cincinnatian (Late Ordovician, Cincinnati region): Palaeontologia Electronica, v. 13, no. 1, p. 5A. STIGALL, A. L., and BRAME, H.-M. R., 2014, Relating environmental change and species stability in Late Ordovician seas: GFF, no. ahead-of-print, p. 1-5. SWADLEY, W.C., 1977, Geologic map of the Bedford quadrangle, north-central Kentucky: U.S. Geological Survey Geol. Quad. Map GQ-1409 SWADLEY, W., 1979, The Marble Hill Bed: an offshore bar-tidal channel complex in the Upper Ordovician Drakes Formation of Kentucky, US Department of the Interior, Geological Survey. SWEET, W.C., and BERGSTRÖM, S.M., 1984, Conodont provinces and biofacies of the Late Ordovician: Geological Society of America Special Papers, v. 196, p. 69-88 WEIR, W.G., GREENE, R. C., and SIMMONS, G. C., 1965, Calloway Creek Limestone and Ashlock and Drakes Formations (Upper Ordovician) in South-Central Kentucky: Geological Survey Bulletin WEIR, W.G., PETERSON, W.L., SWADLEY, W.C. AND POJETA, J., 1984, Lithostratigraphy of Upper Ordovician strata exposed in Kentucky WINCHELL, N. H., and ULRICH E. O., 1887, The Lower Silurian deposits of the upper Mississippi province; a correlation of the strata with those in the Cincinnati, Tennessee, 91
New York, and Canadian provinces, and the stratigraphic and geographic distribution of the fossils: Minn. Geol. and Nat. History Survey Final Report, v. 3, p .83-128 WOLFORD, J.J., 1930, The Stratigraphy of the Oregonia-Ft. Ancient Region, Southwestern Ohio: The Ohio Journal of Science, v. 30 p. 301-308
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APPENDIX Appendix A: List of Outcrop Locations Name
Nearby Town
State
Easting (m)
Northing (m)
Caesar Creek
Waynesville
Ohio
16S 753039.13
4374259.84
Clarksville
Clarksville
Ohio
-
-
Clarksville
Ohio
Brookville Brookville
Indiana Indiana Indiana
Brookville
Indiana
Oldenburg
Indiana
Oldenburg
Indiana
St Leon
Indiana Indiana
Madison
Indiana
Milton Bedford
Kentucky Kentucky
New Castle
Kentucky
Fisherville
Kentucky
Seatonville
Kentucky
Maysville
Kentucky
Maysville
Kentucky
Flemingsburg
Kentucky
Owingsville
Kentucky
Owingsville
Kentucky
Camp Graham / Stony Hollow Hanna Creek Garr Hill Bon Well Hill Brookville Causeway Oldenburg Quarry Harvey’s Branch South Gate Hill Russel Branch Rt 421 Madison Milton Cut Bedford Cut I-71 Mile Marker 30 Fisherville Seatonville Stream 1449 & AA Highway Jnc AA Maysville Rt 32 Flemingsburg I-64 Fault Outcrop Dollar General Outcrop
Notes
Dam Spillway Private Property Stream Cut
16S 676342.85 16S 676431.93 16S 672984.49
4383566.53 4372310.04 4366960.34
Stream Cut Route 101 Route 101
-
-
Private Property
16S 676511.00
4356429.00
Route 1
16S 640729.84 16S 650139.42
4287444.81 4273861.01
Route 421 Route 42 I-71 N
17S 264713.76
4274168.69
17S 261623.41
4254554.36
17S 258550.58
4223563.78
93
McDonald Outcrop
Owingsville
Kentucky
17S 258635.16
94
4223765.32
Appendix B:
95
Appendix C:
96
Appendix D:
97
Appendix E:
98
Appendix F:
99
Appendix G:
100
Appendix H:
101
Appendix I:
102
Appendix J:
103
Appendix K:
104
Appendix L:
105
Appendix M:
106
