Lithostratigraphy and Conodont Biostratigraphy of the Upper Boone Group and Mayes Group in the Southwestern Ozarks of Oklahoma, Missouri, Kansas, and Arkansas

Cory J. Godwin Ph.D. (2017)

Abstract

Upper Boone Group (Meramecian) and Mayes Group (latest Meramecian-Chesterian) strata exposed across the southwestern Ozarks of northeastern Oklahoma, southwestern Missouri, southeastern Kansas, and northwestern Arkansas serve as important analogs for age-equivalent rocks present in the hydrocarbon-producing subsurface of Oklahoma and Kansas to the west and southwest, and they represent important components in the geologic mosaic of the southern Mid-Continent. Through integration of standard lithostratigraphy, conodont biostratigraphy, and modern sequence stratigraphic concepts, an attempt is made to establish an outcrop-based foundation for continuing geologic research concerning this succession, as well as for its correlation into the subsurface and with other strata across the southern Mid-Continent. In terms of results, important changes in lithostratigraphic nomenclature and organization are proposed, including: (1) replacement of the term “Moorefield” by the Pryor Creek Formation (new name) in the Mayes Group of northeastern Oklahoma, (2) removal of the Tahlequah Limestone from the Mayes Group and its inclusion in the Boone Group, (3) elevation of the Moccasin Bend to formation rank, and (4) inclusion of both the Moccasin Bend Formation and Quapaw Limestone in the Boone Group of Mazzullo et al. (2013). Although most of these revisions are based on basic lithostratigraphic methods, conodont biostratigraphic data was valuable in establishing the genetic relationships between strata and correlation of time-equivalent strata across the study area. Conodont biostratigraphic data also provided the basis for establishing preliminary provincial biozones for the study interval and allowed them to be evaluated within the broader context of southern Mid-Continent geology through time-constrained inter-regional correlations. Evidence in the upper Boone Group suggests these strata record continuation of the depositional style characterizing the Osagean Boone Group and that the syndepositional tectonism was a significant factor during their deposition. In the Mayes Group, detailed stratigraphic evaluation highlights the presence of multiple orders of depositional cyclicity. The implications of both syndepositional tectonism during upper Boone Group deposition and depositional cyclicity within the Mayes Group is that reservoir architecture in the subsurface is much more complex, a result of the influence of depositional controls associated with the onset of Late Paleozoic Glaciation and early phases of Ouachita tectonism.

Chapter 2: The Proposed Pryor Creek Formation (Mayes Group) and Tahlequah Limestone (Boone Group) of Northeastern Oklahoma

Abstract

The Pryor Creek Formation is proposed to replace the obsolete term “Moorefield” for strata of the lower Mayes Group of northeastern Oklahoma. The Pryor Creek Formation is neither contiguous nor lithologically consistent with the type Moorefield Formation of northern Arkansas. Application of the term “Moorefield” in Oklahoma is therefore confusing and irrelevant to strata in Oklahoma, both at the surface and within the subsurface. Defined for exposures along the western edge of the Mississippian outcrop belt in Oklahoma, the Pryor Creek Formation more accurately represents the characteristic shaly-silty limestone and calcareous siltstone-shale of the lower Mayes Group. And, because of its location, the Pryor Creek Formation is a relevant surface analog for correlative strata in the subsurface, including the subsurface “Mayes” and Mississippian “black limestone”, with which it is contiguous.

The proposed lithostratigraphic revisions are integrated with modern stratigraphic concepts and conodont biostratigraphic data, resulting in a genetic stratigraphic framework that may be evaluated within a regional to global context through higher-resolution correlations with time-equivalent strata. Conodont data clearly show that the Pryor Creek Formation is latest Meramecian through early Chesterian in age, correlative to the upper St. Louis Limestone and Ste. Genevieve Formation of the Upper Mississippi Valley, the Ahloso Member of the Caney Shale in southern Oklahoma, and the basal Barnett Shale in Texas, to name a few. The base of the Pryor Creek Formation is a regionally-extensive, time-significant unconformity similar to those recognized below the Caney Shale of southern Oklahoma and Barnett Shale of central Texas. The boundary between the Pryor Creek Formation and overlying Hindsville Formation is conformable. Contacts between recognized lithostratigraphic divisions of the Pryor Creek Formation coincide with sub-regionally to regionally-extensive surfaces.

Conodont biostratigraphic data, together with the revised lithostratigraphic interpretation, also demonstrate that the Tahlequah Limestone (formerly “Tahlequah Member” of the “Moorefield Formation”) is separated from the proposed Pryor Creek Formation by a span of time corresponding to at least the lower St. Louis Limestone and is instead faunally and lithologically correlative to the Ritchey Formation of the Boone Group. It is therefore excluded from the proposed Pryor Creek Formation and placed within the Boone Group.

Chapter 3: Meramecian-Chesterian (Upper Visean) Conodont Biostratigraphy and Revised Lithostratigraphy along the Southwestern Flank of the Ozark Uplift, Southern Mid-Continent, U.S.A.

Abstract

Four conodont biozones, including three subzones, are interpreted within a revised lithostratigraphic framework for the upper Boone Group and Mayes Group in northeastern Oklahoma and adjacent parts of Missouri, Kansas, and Arkansas. Although revised lithostratigraphy is principally based on observed lithologic characteristics and stratigraphic relationships, conodont biostratigraphic data played an important role in correlation and final organization of units. Within the upper Boone Group, Biozone 1 (lower Meramecian) includes the Ritchey Formation and the Tahlequah Limestone and Biozone 2 (middle Meramecian) includes the Moccasin Bend Formation and Quapaw Limestone. The Mayes Group spans Biozone 3 and Biozone 4. Biozone 3 (upper Meramecian) is represented by the Bayou Manard Member of the Pryor Creek Formation (new name). Biozone 4 marks the appearance of definitive Chesterian conodont fauna. The lower two subzones within Biozone 4 correspond to the Lindsey Bridge (Biozone 4L) and Ordnance Plant (Biozone 4M) members of the Pryor Creek Formation, whereas the upper subzone consists of the Hindsville Formation (Biozone 4U). 

Documentation of conodont taxa and recognition of the proposed biozones provides relative time constraints for genetically-meaningful interpretations of regional geology and subsequent evaluation of the Mayes Group and upper Boone Group within a broader interregional context.

Chapter 4: Depositional Cyclicity within the Mayes Group (Meramecian-Chesterian) along the Western Edge of the Mississippian Outcrop Belt in Northeastern Oklahoma

Abstract

Multiple orders of depositional cyclicity in the Mayes Group of northeastern Oklahoma are delineated by refined depositional facies associations and stratigraphic surfaces. Facies associations include deep subtidal facies, shallow subtidal facies (including distal and proximal subfacies), carbonate shoal facies, and shoal crest facies. The Mayes Group records a primary transgressive-regressive depositional cycle bounded below by a major unconformity (sub-Mayes unconformity) and above by an important provincial conodont biostratigraphic boundary and widespread flooding surface at the base of the Fayetteville Shale. Within the Mayes Group, two secondary transgressive-regressive depositional cycles are separated by an interpreted unconformity. The lower Mayes cycle comprises the Bayou Manard and Lindsey Bridge members of the Pryor Creek Formation, whereas the Ordnance Plant Member is grouped with the Hindsville Formation in the upper Mayes cycle. Present in both the lower and upper Mayes cycles are high-frequency shallowing-upward cycles bounded by flooding surfaces. Evaluating the distribution of facies and stratigraphic surfaces within a framework of multiple orders of depositional cyclicity is essential to interpreting the geologic evolution of the southern mid-continent during the Meramecian and Chesterian, and impacts oil and gas production by improving our understanding of reservoir compartmentalization.

Chapter 5: Summary and Conclusions

The papers included within this dissertation represent elements of ongoing research concerning Mississippian strata of the southern mid-continent, specifically Meramecian and Chesterian (Visean) rocks exposed across the southwestern flank of the Ozark Uplift in Oklahoma, Missouri, and Arkansas. As with all scientific research, the results interpretations and conclusions presented within those three papers are in no way final, nor are they sure to be agreeable to everyone. They do, however, serve to advance our understanding of these rocks and provide a modern stratigraphic foundation for continued study.

            Although the subject of lithostratigraphy may seem elementary to some, at least in light of the more quantitative methods in the geosciences, it remains the foundation of outcrop-based (as well as subsurface) sedimentary geology and lithostratigraphic nomenclature serves as a common language with which working geologists may communicate. Lithostratigraphy and the ability of geologists to communicate through reasonable lithostratigraphic nomenclature is essential both the construction of geologic models. The proposed lithostratigraphic revisions presented in chapters II and III are aimed at making more sense out of strata of the upper Boone Group and Mayes Group, most of which have been little studied during the past six decades. Proposal of Pryor Creek Formation for lower Mayes Group strata in northeastern Oklahoma, in lieu of the term “Moorefield Formation” as defined by Huffman (1958), is done because the application of the term “Moorefield” requires constant clarification as to whether one is discussing the type Moorefield Formation of northern Arkansas or to the strata of northeastern Oklahoma. The reason this is important is that the type Moorefield Formation of northern Arkansas is shale-dominated, whereas equivalent strata in northeastern Oklahoma (i.e. Pryor Creek Formation) are limestone and calcareous siltstone-dominated. Thus, a basic lithostratigraphic differentiation is justifiable based on the lithologic difference. Although Pryor Creek Formation strata do become shalier as they are traced southward, they share a greater affinity with the Caney Shale of southern Oklahoma to which they are geographically closer and appear to be physically continuous. Of note, the Pryor Creek Formation is not currently known to be continuous with the type Moorefield Formation.

Prior to this study, the lowest stratigraphic unit of the Mayes Group was considered to be the Tahlequah Member of the “Moorefield Formation” based on the definitions of Huffman (1958). In both chapter II and chapter III, a proposal is made to remove the “Tahlequah” from the Mayes Group and include it within the Boone Group as the “Tahlequah Limestone”. This lithostratigraphic change is predicated on evaluation of conodont biostratigraphic data. Conodont fauna collected from the Tahlequah Limestone are almost identical to those of the Ritchey Formation of the Boone Group in the Tri-State Mining District of Oklahoma, Missouri, and Kansas. Furthermore, the Tahlequah Limestone is separated from the Bayou Manard Member of the Pryor Creek Formation by a major regional unconformity, herein designated the “sub-Mayes unconformity”. At this point it becomes important to understand the nature of the strata overlying the Ritchey Formation in the Oklahoma portion of the Tri-State Mining District, both in terms of their relationship to the Boone Group and Mayes Group. It also becomes important to recognize the common application of interpreted equivalency of strata of the southern mid-continent to those of the Upper Mississippi River Valley, which is both the Mississippi type area and the area in which conodont studies of Mississippian strata in North America began. For example, the Ritchey Formation and Tahlequah Limestone are considered to be equivalent to all or part of the Warsaw Formation of the Upper Mississippi Valley. In the redefinition of the Boone Group proposed by Mazzullo et al. (2013), post-Ritchey Formation strata of the Moccasin Bend Formation and Quapaw Limestone were not included. This was first and foremost a result of the incompleteness of work concerning these strata at the time of publication. It is clear from further evaluation, however, that the Moccasin Bend Formation and Quapaw Limestone represent a continuation of deposition that characterized older Boone Group strata, including the Reeds Spring Formation, Bentonville Formation, and Ritchey Formation. The Moccasin Bend Formation and Quapaw Limestone are therefore included in the Boone Group in this study, as shown in Chapter III. This also follows the results of McKnight and Fischer (1970) who included the Moccasin Bend “member” within their Boone “formation”. Excluded from the Boone “formation” of McKnight and Fischer was the Quapaw Limestone. This was done presumably because it lacked the diagenetic chert that so characterizes much of the Boone Group. Conodont recoveries demonstrate the Moccasin Bend Formation and Quapaw Limestone to be of early-late Meramecian age and equivalent to the St. Louis Limestone of the Upper Mississippi River Valley. Because strata of the southern mid-continent are so often discussed in terms of their equivalency to strata of the Upper Mississippi River Valley (i.e. Mississippian type area), we must be careful in such application. For example, the Bayou Manard Member of the Pryor Creek Formation (Mayes Group) is also equivalent to the St. Louis Limestone. Conodont data, however, show that not all southern mid-continent St. Louis-equivalent strata were created equal. The Moccasin Bend Formation and Quapaw Limestone, characterized by the co-occurrence the genera Cavusgnathus and Taphrognathus suggest these strata are equivalent to the lower St. Louis Limestone (REFERENCE). In contrast, the Bayou Manard Member yielded no specimens of Taphrognathus, but did yield the first observed occurrence of Hindeodontoides spicules. Thus, the Bayou Manard Member is equivalent to the upper St. Louis Limestone (REFERENCES). The Moccasin Bend-Quapaw section is therefore not considered correlative to the Bayou Manard Member at this time.

In chapter IV an attempt was made to define lithologic patterns observed in the Mayes Group in terms of the distribution of depositional facies and infer from that a hierarchy of depositional cyclicity. Previous workers interpreted large-scale shallowing-upward trends within the Mayes Group (Huffman, 1958; Turmelle, 1982), and these depositional trends are recognized throughout northeastern Oklahoma. The Bayou Manard and Lindsey Bridge members of the Pryor Creek Formation appear to represent a single transgressive-regressive depositional cycle, whereas the Ordnance Plant Member is grouped with the Hindsville Formation is a subsequent transgressive-regressive depositional cycle. Separating these two cycles is an unconformity between the Lindsey Bridge and Ordnance Plant members of the Pryor Creek Formation first postulated by Swinchatt (1967), but unrecognized by Huffman (1958). This interpretation also differs from that of Huffman (1958) in that he included Ordnance Plant Member within the other two members of the Pryor Creek Formation in a transgressive-regressive cycle and interpreted the Hindsville Formation by itself as the second cycle. In contrast, Turmelle (1982) interpreted the Mayes Group as a single transgressive-regressive cycle. Both Huffman (1958) and Turmelle (1982) recognized the interfingering of lithofacies typifying the various lithostratigraphic units within the Mayes Group, beyond that of the standard lithostratigraphic succession defined by Huffman. Nothing of significance was attributed to such “interfingering” except that it represented natural mosaic of depositional facies within the overall Mayes Group depositional system. Results of this investigation, however, suggest a more orderly and predictable vertical facies pattern that, along with recognition or re-interpretation of lithostratigraphic boundaries and surfaces, suggest the presence of higher-frequency depositional cycles in the Mayes Group. The implications of multiple orders of depositional cyclicity within the Mayes Group are two-fold. First, Conodont biostratigraphic data provide relative time constraints to these cycles and they are interpreted in terms of the external controlling mechanisms, including early phases of Ouachita tectonism and Late Paleozoic glaciation. Second, because these rocks serve as an analog to equivalent strata in the subsurface of Oklahoma, it may be inferred that those subsurface strata display similar depositional cyclicity, perhaps not as apparent in some instances, and that components of a given petroleum system may be compartmentalized and must be considered by exploration and production geologists.

REFERENCES CITED (Summary and Conclusions)

Huffman, G. G., 1958, Geology of the flanks of the Ozark Uplift, northeastern Oklahoma: Oklahoma Geological Survey Bulletin 77, 281 p.

Mazzullo, S.J., D.R. Boardman II, B.W. Wilhite, C.J. Godwin, and B.T. Morris, 2013, Revisions of outcrop lithostratigraphic nomenclature in the Lower to Middle Mississippian Subsystem (Kinderhookian to basal Meramecian Series) along the shelf-edge in southwest Missouri, northwest Arkansas, and northeast Oklahoma: Shale Shaker, May/June, p. 414-454.

McKnight, E. T., and R. P. Fischer, 1970, Geology and Ore Deposits of the Picher Field, Oklahoma and Kansas: United States Geological Survey Professional Paper 588, p. 165.

Turmelle, T. J., 1982, Lithostratigraphy and depositional environments of the Mayes Formation (Mississippian) in Adair County, Oklahoma: M.S. thesis, University of Oklahoma, Norman, Oklahoma, 144 p.