Geochemical characterization of the Devonian-Mississippian Woodford Shale from the McAlister Cemetery Quarry, Criner Hills Uplift, Ardmore Basin, Oklahoma

Journal Pre-proof Geochemical characterization of the Devonian-Mississippian Woodford Shale from the McAlister Cemetery Quarry, Criner Hills Uplift, Ardmore Basin, Oklahoma R. Paul Philp, Clifford D. DeGarmo PII:

S0264-8172(19)30514-8

DOI:

https://doi.org/10.1016/j.marpetgeo.2019.104078

Reference:

JMPG 104078

To appear in:

Marine and Petroleum Geology

Received Date: 31 May 2019 Revised Date:

17 August 2019

Accepted Date: 8 October 2019

Please cite this article as: Philp, R.P., DeGarmo, C.D., Geochemical characterization of the Devonian-Mississippian Woodford Shale from the McAlister Cemetery Quarry, Criner Hills Uplift, Ardmore Basin, Oklahoma, Marine and Petroleum Geology (2019), doi: https://doi.org/10.1016/ j.marpetgeo.2019.104078. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier Ltd.

Geochemical Characterization of the Devonian-Mississippian Woodford Shale from the McAlister Cemetery Quarry, Criner Hills Uplift, Ardmore Basin, Oklahoma. R. Paul Philp and Clifford D. DeGarmo, School of Geology and Geophysics, University of Oklahoma, Norman, OK. 73019. [email protected] ABSTRACT It has been estimated that technically recoverable reserves from shales in the continental U.S. are believed to be approximately 24 billion barrels of oil (BBO) and 750 trillion cubic feet (Tcf) of gas. In Oklahoma the most important hydrocarbon source rock is the Woodford Shale, proposed to be the source of some 70% of the state’s liquid hydrocarbon reserves. Such a regionally widespread source rock provides potential for both academic study and industrial opportunities. In this study representative samples of the Woodford Shale from the McAlister Quarry outcrop have been characterized by a variety of geochemical techniques. TOC values range from 0.07 to 15.6 wt.% and, based on Rock-Eval Pyrolysis, most of the samples plot within the Type I/II kerogen range, with several low TOC samples plotting in the Type III kerogen range. TOC and biomarker parameters, suggests that two sections of the Upper Woodford are immature paleosols, having been subaerially exposed due to abrupt episodes of sea level fall during the Late Devonian. Evidence for these zones of paleoweathering includes highly depleted TOC, increased oxygen index (OI) values, loss of n-alkanes, decreases in the aryl isoprenoid ratio (AIR), sesquiterpenoids, cheilanthanes, hopanoids, and decreases in many of the polycyclic aromatic hydrocarbons (PAHs). The values of several paleoenvironmental proxies for samples immediately following the Frasnian-Famennian (F-F) Stage extinction boundary within the Upper Woodford suggests that a large influx of weathered terrigenous material occurred at that time. The presence of pyrogenic compounds implies that paleowildfires were widespread throughout the Middle and Late Devonian in the North American midcontinent. It is possible that these influxes of weathered terrestrial organic material stimulated algal blooms that led to the anoxic water column conditions often attributed to the F-F Stage extinction event. Investigation of the stratigraphic framework of these source rocks assists in evaluating their potential as hydrocarbon producers and/or unconventional reservoirs. Integration of geochemical data adds another powerful dimension to this approach. It has been proposed that the Woodford Shale was deposited during a 2nd order depositional sequence. The lower member represented the transgressive systems tract (TST), the Upper member the highstand systems tract (HST), and the Middle member bridging the transition between the two. Numerous 3rd order parasequences were also identified as being part of the overall 2nd order sequence and could be correlated to the Devonian sea level curve. The major objectives of the study were:

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Determination of the geochemical characteristics of the Woodford Shale at the McAlister Cemetery Quarry and integrating these data into the previously described stratigraphic framework for the Woodford Shale at this site. Evaluation of the geochemical characteristics of this core to differentiate the impact of paleoweathering vs. contemporary weathering.

While this study focuses locally on the McAlister Quarry samples, it is also of regional importance. The Woodford is a prolific source rock throughout the Anadarko Basin and has been the subject of extensive exploration and production efforts, particularly in the past decade with the development of horizontal drilling and hydrofracturing techniques. Continued investigation of the heterogeneity of the shale will greatly enhance the ability to predict more productive facies within the formation throughout the basin.

INTRODUCTION

The Woodford Shale is arguably the most important hydrocarbon source rock in Oklahoma, believed to be the source of some 70% of the state’s liquid hydrocarbon reserves (Comer and Hinch, 1987; Johnson and Cardott, 1992; Slatt and Rodriguez, 2012). Between the years of 2004 and 2011 over 1700 wells were completed in the Woodford, yielding gas, condensate, and oil and this number has increased significantly since that time (Cardott, 2012). A general map showing the major basins is included as Fig. 1. The quarry from which the samples in this study were collected is shown by the shaded circle in the middle of the map. Such a regionally widespread source rock provides potential for both academic study and industrial opportunities. The northern part of the Anadarko Basin, or STACK (Sooner Trend Anadarko (Basin) Canadian and Kingfisher (Counties)), has seen an explosion in the number of horizontal wells drilled in the past decade with most them being subjected to hydraulic fracturing. Much of the conventional oil production from the Woodford is in Southern Oklahoma where there are also numerous outcrops of the complete Woodford section, many of them below, or at the onset, of the oil generation window. The presence of these outcrops and exposures provides an

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excellent opportunity to study the Woodford in more detail and evaluate variations in the hydrocarbon potential of various facies utilizing sequence stratigraphy and characterization of the organofacies and lithofacies.

Investigation of the stratigraphic framework of these source rocks assists in evaluating their potential as hydrocarbon producers and/or unconventional reservoirs. Integration of geochemical data adds another powerful dimension to this approach. Many papers have been published that categorize changes in organic geochemical parameters throughout sequence stratigraphic packages of source rocks (e.g. Curiale et al., 1992; Horsfield et al., 1994; Algeo et al., 2004). These studies have created an initial framework for evaluation based upon properties related to source rock deposition. Notable parameters that have been evaluated in relation to sequence stratigraphy include total organic carbon (TOC), kerogen type, and biomarkers, although discussion of the latter is less prominent in the literature. Biomarkers provide a powerful tool for getting detailed information on the nature of source materials and depositional environments which can be integrated into a sequence stratigraphic framework. In many cases water depth is one of the primary factors responsible for the predominance of various oxygenation zones. Slatt and Rodriguez (2012) noted the importance of biomarkers for evaluating oxic vs. anoxic bottom-water conditions and developing a predictive model for evaluating the efficacy of gas-shale plays. The production and preservation of organic matter within a depositional setting is crucial for the development of an organic-rich source rock, but post-depositional weathering, or paleoweathering, can have a profound impact upon TOC, the molecular structure of the residual kerogen, and quantities and type of hydrocarbons that may be produced at appropriate levels of maturity. Recognition of paleoweathering within a stratigraphic sequence can be very useful in 3

terms of source rock evaluation, but there is a lack of studies on the subject (Marynowski et al., 2011a). Previous studies have illustrated that weathering has occurred in the Woodford Shale (e.g. Philp et al., 1992; Lo and Cardott, 1995). Kirkland et al. (1992) noted the impact of weathering in a geological and geochemical study of the Woodford formation at an exposure in the McAlister Cemetery Quarry in southern Oklahoma, which emphasized carbonate carbon isotope values and aliphatic hydrocarbon characteristics. The Woodford is divided into three informal log-derived members (Hester et al., 1988), and displays a broad range of TOC values, ranging from 0.1 to 17.7% (Kirkland et al., 1992). While modern weathering is known to cause TOC depletion (Wildman et al., 2004), the lower values reported here are likely caused by either depositional characteristics or paleoweathering in the uppermost formation. Serna-Bernal (2013) placed the progression of the Woodford in the McAlister Cemetery Quarry within a sequence-stratigraphic framework and proposed that the Woodford shale was deposited during a 2nd order sequence. The lower member represented the TST, the Upper member the HST, and the middle member bridging the transition between the two. Numerous 3rd order parasequences were also identified as being part of the overall 2nd order sequence and could be correlated to the Devonian sea level curve of Johnson et al. (1985). This paper presents results obtained from a study focused on applying organic geochemical techniques to the characterization of samples collected from the same section in the McAlister Quarry described by Serna-Bernal (2013). Major objectives of the study can be summarized in the following manner:

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Determination of the geochemical characteristics of the Woodford Shale at the McAlister Cemetery Quarry and integrating these data into the stratigraphic framework for the Woodford Shale at this site by described by Serna-Bernal (2013).

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Evaluation of the geochemical characteristics of this core to differentiate the impact of paleoweathering vs. contemporary weathering.

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Information for this localized study can be extrapolated regionally to provide information on the regional variability of the Woodford.

GEOLOGIC SETTING

The geological development of the various basins in Oklahoma began in the Early Paleozoic when three major provinces existed: the Oklahoma Basin, the Southern Oklahoma Aulacogen, and the Ouachita Trough (Fig. 2). According to Johnson et al. (1989) the Oklahoma Basin was a shelf-like, broad plain that developed into a sequence of thick and extensive shallow-marine carbonates, interbedded with thin marine shales and sandstones. The depocenter of the basin was the Southern Oklahoma Aulacogen, which initially developed by massive faulting, production of grabens, and outpouring of volcanic igneous rock in the form of rhyolite (Ham et al., 1964). The Ouachita Trough represents the deepest part of this area, lying to the southeast and likely under several thousand feet of water (Johnson and Cardott, 1992). The Woodford Shale The Woodford Shale has been dated based upon conodonts, but several different age ranges have been reported. Hass and Huddle (1965) proposed formation began in the Late Devonian (Frasnian) and persisted until the Early Mississippian (see stratigraphic column shown in Fig. 3). Amsden (1967) and Kirkland et al. (1992) expanded that range suggesting Woodford deposition began in the Middle Devonian (Givetian). Log data from Parish (1991) suggests a 5

range from Middle Devonian (Emsian) to Late Devonian (Famennian). Based on the measured section of Woodford Shale from the McAlister Cemetery Quarry and the Global Sea Level Curve of Johnson et al. (1985), Serna-Bernal (2013) approximated the age from Givetian to Famennian (388-359 Ma), as used in this study. Lithologically Cardott and Chaplin (1993) defined the formation as a dark-gray, marine, siliceous and carbonaceous, fissile-to-blocky shale containing abundant amounts of chert and subordinate amounts of green shale, phosphate nodules, and pyrite. The quartz-rich composition of the Woodford can be attributed to its high abundance of biogenic silica from radiolaria and sponge spicules (Kirkland et al., 1992). Serna-Bernal (2013) delineated four lithofacies present in the McAlister Cemetery Quarry section: (i) laminated, finely crystalline dolomite; (ii) laminated, siliceous shale; (iii) laminated, siliceous siltstone, and (iv) laminated chert. While the Upper member is almost exclusively chert, the entire section displays rhythmic, shale-chert cyclicity, likely caused by periodic upwelling and partially influenced by wind currents and possibly Milankovitch periodicities (Roberts and Mitterer, 1992). The Study Area The samples for this project were collected from the McAlister Cemetery Quarry, located at 34.0785° N latitude, 97.1561° W longitude (Fig. 1). The quarry is located within the Criner Hills Uplift, part of the western flank of the Ardmore Basin in southern Oklahoma. The entirety of the Woodford Shale is exposed at the quarry, from the basal contact with the Hunton Group to the unconformable contact with the Sycamore Formation. The member boundaries used in this study are those proposed by Paxton et al. (2006) and are based upon gamma ray data correlation with surrounding areas. The measured section is 122m in thickness (Serna-Bernal, 2013), striking 320-330° (azimuth) NW and dipping 35-55° NE. Much of the upper Woodford is

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exposed on the eastern wall of the quarry, which extends approximately 17m above the quarry floor at a near-vertical orientation. A total of twenty-two rock samples (See Table I; five are from the lower section, six from the middle, and eleven from the upper) were manually excavated from the quarry at an approximate depth of 1m (excluding sample 22 taken at the ground surface). An additional four samples (2, 10, 14, and 19) were provided from remnant samples of Serna-Bernal (2013), stored within the Reservoir Characterization Laboratory at the University of Oklahoma. The latter four samples represent the lower, middle, upper, and middle-upper contact of the Woodford. Additional weight was given to the upper section to more thoroughly evaluate the complex paleoweathering that has possibly occurred compared to the lower and middle. A detailed description of the analytical techniques and methods are described in the Appendix. The samples were initially characterized by Rock Eval pyrolysis and subsequently extracted, fractionated and the saturate and aromatic fractions characterized by gas chromatography (GC) and gas chromatography mass spectrometry (GCMS). RESULTS AND DISCUSSION Source Rock Characteristics Source rock samples were screened by TOC and Rock-Eval pyrolysis (Espitalie et al., 1977) and, although the thermal maturity of the Woodford is well constrained (Cardott, 2012; Curtis et al., 2012), Tmax and Rc values (calculated vitrinite reflectance from Tmax) were also determined for these samples. However, it should be noted that since the section was only 122m no significant variations in maturity were expected. Samples 2, 10, 14, and 19 from SernaBernal (2013) were used as stratigraphic references of known gamma ray and lithology to establish biomarker trends.

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Total Organic Carbon Content TOC values for the Woodford Shale from the McAlister Cemetery Quarry ranged from 0.07 to 15.6wt.% (Table 1 and Fig. 4) suggesting many of the samples are very good-to-excellent potential source rocks (Peters, 1986; Jarvie, 1991). Samples from the lower Woodford had an average TOC value of 13.8wt.%, while the middle and upper members have average values of 12.2 and 5.6wt.%, respectively. The lowest value in the section is sample 25, which was taken from the upper Woodford (97m) and was noticeably lighter in color than the more organic-rich samples from the lower and middle members, probably a result of a depositional feature or paleoweathering. From the beginning of the section to ~70m the TOC displays some variation and then increases to a maximum of 15.3 wt. % around 80m and drops to less than 2 wt. % by 90m. This extreme level of variability is seen only in the upper Woodford, where the TOC ranges from 0.07 to 15.3 wt. %. The middle and lower members display ranges of 8.62 to 15.6 and 12.2 to 15.1 wt. % TOC, respectively (Fig. 4). The carbonate content (CC) in the section ranges from 0.29 to 38.79 wt. %, with the upper, middle, and lower members averaging 5.5, 7.2, and 3.1 wt. %, respectively (Fig. 4). The highest value is represented by sample 13, which occurs just above the middle-upper boundary (~70m). The lowest value, sample 18, also occurs in the upper Woodford and is positioned at 92.3m in the section. Overall, the carbonate abundance appears to be inversely related to TOC, showing a large decrease at ~80m where the TOC is at a maximum. This inverse relationship occurs several times in the section; noteworthy examples being samples 11-15, which straddle the middle-upper member boundary. Like the TOC, the carbonate content shows the lowest variability in the lower member (1.41 to 3.3 wt. %), while the middle (0.89 to 20.48 wt. %) and upper members show significant variation (0.29 to 38.79 wt. %).

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Kerogen Type Kerogen typing was performed using the Hydrogen Index (HI) and OI, determined from the Rock Eval (RE) pyrolysis data (Table 1; Hunt, 1996). These parameters plotted on a modified van Krevelen diagram are shown in Fig. 5a (Tissot et al., 1984). The HI values vary throughout the section from 9 to 772 mg HC/g TOC. Samples 18 and 26 display the lowest values while sample 21 displays the highest. The OI values range from 4 to 156 mg CO2/g TOC, with the highest values in the upper Woodford and the lowest values in the lower Woodford. The elevated OI values could be indicative of an alternate organic matter source, or more probably some form of weathering (e.g. Fischer and Gaupp, 2005; Marynowski et al., 2011a). Katz (1983) also noted some years ago that the hydrogen and oxygen indices may also be affected by both matrix mineralogy and level of organic enrichment and care should be taken when using these data to evaluate kerogen type. The majority of samples appear to be Type I or hydrogen rich Type II kerogens (Fig. 5a). Samples with low HI and elevated OI values plot in the Type IV kerogen range and are the principle outliers of the trend. The alternative plot of S2 peak vs TOC also shows the majority of samples plotting within the Type II marine kerogen range (Fig. 5b). The six samples with the lower HI and higher OI values are those described above that may be weathered or contain alternate source materials. Delineating the occurrence of undesirable intervals within the formation is of extreme importance. The data shown above suggest that whether by sequence stratigraphic fluctuations, change in organic matter input, paleoweathering, or a combination of all three, there are intervals within the Woodford Shale that do not contain productive Type II kerogen and would certainly not be desirable targets for horizontal drilling.

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Thermal Maturity Thermal maturity data for these samples has been primarily derived from Rock-Eval Tmax values and the PI which can be used to delineate the boundaries between immature, oil generation, and gas generation windows (Fig. 6). Most of the samples plot in the “immature” range while several of the upper Woodford samples plot in the “gas” generation zone. This upper member trend is likely the result of extremely low S2 peak values (0.01 mg HC/g rock), possibly due to post-depositional weathering providing misleading data. Because the section is approximately 100m thick, large variations in maturity would not be expected in this core. Most of the samples plot in the “immature” zone based upon PI and most of the Woodford Shale outcrops in the general study area have been categorized as being “early oil generation” (early mature) by Cardott (2012), with vitrinite reflectance values in the 0.52 to 0.54%Ro range. Tmax values range from 413 to 429°C, with the minimum and maximum values represented by samples 23 and 1, respectively. Starting at the bottom of the section and progressing upward, the trend fluctuates initially then stabilizes for the upper portion of the middle member, until becoming sporadic in the upper Woodford. The Tmax variations observed in the section probably almost certainly represent variations in organic matter composition, and possibly weathering, since the depth of the section precludes maturity variations. All the Tmax values lie within the “immature” zone (~429 °C is the typical onset of oil generation). Biomarkers n-Alkanes and Isoprenoids The n-alkanes and isoprenoids pristane (Pr) and phytane (Ph), are common in sedimentary organic matter and crude oils, and can be used as a tool to characterize depositional

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environments and provide information on relative maturity (Didyk et al., 1978; Peters et al., 2005). However, these compounds, particularly the n-alkanes, are affected by weathering as well as maturation (e.g. James and Burns, 1984; Guthrie et al., 2000). All but one of the chromatograms, (sample 13), from the upper Woodford extracts are characterized by the absence of n-alkanes and the presence of an unresolved complex mixture (UCM; Fig. 7). The upper Woodford samples also show evidence of a higher relative abundance of hopanoids in the UCM than other samples in the section, probably reflecting the effects of weathering, which will be discussed in more detail below. It should be noted that during sample collection, attempts were made to dig below the contemporary weathering zone. However, the cherty and fractured nature of many of these samples appears to have promoted contemporary weathering, particularly in terms of removing the n-alkanes, which are most susceptible to biodegradation. Pristane and phytane have been widely used to assess redox conditions in samples of low maturity (Didyk et al., 1978), if one assumes they are both derived from the phytol side chain of chlorophyll (Waples, 1985). In these samples the high Pr/nC17 and Ph/nC18 ratios are almost certainly a result of the extensive contemporary weathering and preferential removal of the nalkanes (Fig. 7, Table 2). Whilst the UCM appears to be relatively abundant, this is partly due to the removal of the n-alkanes enhancing the relative concentration of the UCM (Kirkland et al., 1992). The fluctuations in the Pr/nC17 and Ph/nC18 ratios (Fig. 8) in these samples are almost certainly the result of weathering and do not reveal any significant information on variations in the depositional environment. The two uppermost samples in the upper Woodford and the lowest sample in the section show the most significant variations and will be discussed in more detail below. There are small changes in the Pr/Ph values throughout the section, but the most

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significant change is the decreasing trend through most of the upper Woodford, followed by the increase in the uppermost sample (21) where the values could be measured. These small changes may reflect variations in the relative oxicity of the depositional environment but in general conditions throughout the section would appear to be anoxic (Kaiho et al., 2013) and, as described elsewhere, euxinic conditions are implied by the presence of the arylisoprenoids and, in a number of cases, C40 carotenoids (Connock, 2015; Connock et al., 2018). Carotenoids and Aryl Isoprenoids The aromatic carotenoid isorenieratane, and its 2,3,6-trimethyl aryl isoprenoid derivatives, are commonly used as biomarkers for euxinic conditions (Summons and Powell, 1986; Requejo et al., 1992). They are primarily sourced from Chlorobiaceae, a family of phototrophic anaerobes that are responsible for producing a wide range of aromatic carotenoids (Summons and Powell, 1987; Hartgers et al., 1993; Grice et al., 1996). One typical chromatogram, shown in Fig. 9a, derived from the sum of two characteristic arylisoprenoid ions, m/z 133 and 134, shows the typical distribution for the aryl isoprenoids as well as palaeorenieratane, isorenieratane and renieratane. Variations in the concentrations of these three carotenoids in the section are shown in Fig. 9b. Renieratane, which has been attributed to both sponge symbionts and phototrophic sulfur bacteria (Schaefle et al., 1977; Liaaen-Jensen et al., 1982), and isorenieratane show very similar trends. Palaeorenieratane, also shows a similar trend although it deviates slightly and displays an increase in abundance to approximately 10.5µg/g TOC. All three compounds show two major cycles in the lower Woodford continuing through to the mid-middle member (Fig. 9b) and then remain severely depleted for the remainder of the section except for some slight variations moving into, and, in the upper Woodford (<1 µg/g TOC) around 93m. The higher concentrations of these compounds in the lower and middle

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members suggest that there were periods of significant euxinia during deposition of those intervals, but it appears that the upper Woodford was not deposited under euxinic conditions. The presence of euxinia in the middle and lower Woodford has been discussed in more detail in Connock et al. (2018). The arylisoprenoid ratio (AIR-Fig. 9b) is derived from the 2,3,6trimethylarylisoprenoids and is the ratio of the short chain (C13-C17) to long chain (C18-C22). Episodic photic zone anoxia (PZA) leads to long-chain aryl isoprenoid degradation and elevation of the AIR; periods of persistent PZA have the opposite effect, in turn, lowering the AIR (Schwark and Frimmel, 2004). The aryl isoprenoid ratio clearly shows some cyclicity in the lower 82m of the section before decreasing in the uppermost Woodford. There is a slight correlation with the concentrations of renieratane, isorenieratane, or palaeorenieratane with low values of the AIR seeming to correspond to the most abundant presence of the three carotenoids. The elevated values of the AIR in the upper-Middle and lower-Upper Woodford suggest that these periods were characterized by episodic PZA, with the lowest value in this region at sample 13 (70.7m) indicative of the middle-upper boundary. Further, detailed evaluation of water-column stratification and water-column chemistry based upon carotenoids and aryl isoprenoids can be found in Connock (2015) and Connock et al. (2018).

Tricyclic Terpanes Tricyclic terpanes have been observed in extracts and oils going back to the early 1970s when they were observed in extracts from the Green River Formation (Anders and Robinson, 1971; Gallegos, 1971). Various sources have been proposed for these compounds including prokaryotes (Ourisson et al., 1982) and the prasinophytes Leiosphaeridia (Dutta et al., 2006), as

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well as Tasmanites (e.g. Aquino Neto et al., 1992; Revill et al., 1994; Greenwood et al., 2000). Tricyclic terpanes have become of even greater interest in the Anadarko Basin due to the observation of many oils in the so-called SCOOP and STACK areas having terpane distributions dominated by tricyclic terpanes, leading to questions on their possible origins in samples totally devoid of the more ubiquitous hopanes. Chromatograms showing tricyclic terpane and hopane distributions, determined by GCMS and single ion monitoring of the ion at m/z 191 for selected samples from the McAlister Quarry are shown in Fig. 10. The concentrations of the tricyclic terpanes, C19-C29, expressed in µg/g TOC, fluctuated throughout the section at the quarry (Fig. 9b), maximizing in the lower Woodford at sample 2, middle Woodford at sample 8, the middle-upper boundary at 13, and show an overall increase throughout the upper Woodford before decreasing significantly at the uppermost sample. For all but one sample (sample 1) the C23 homolog is the dominant tricyclic terpane in the m/z 191 chromatogram as previously observed in samples elsewhere, particularly carbonate samples (e.g. Connan et al., 1980; Aquino Neto et al., 1983; Sierra et al., 1984). Several samples (1, 6, 9, 11, 12) show a predominance of the C20 tricyclic homolog over the C21 homolog, a distribution previously associated with carbonate source rocks. Serna-Bernal (2013) noted a significant presence of Tasmanites throughout the exposed section at the McAlister Cemetery Quarry, and it is possible that this group of algae is responsible for a significant contribution of tricyclic terpanes in the Woodford Shale. It is interesting that the abundance of the tricyclic terpanes in the lower and middle Woodford correlates with the abundance of the carotenoids (Fig. 9b), indicating that the euxinic conditions may have played a significant role in their preservation. Additionally, the AIR is relatively low for most of the samples with relatively abundant concentrations of tricyclic terpanes throughout the section (Fig. 9b). This observation

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reinforces the notion that persistent PZA is related to variations in the abundance of tricyclic terpanes, as Tasmanites are ubiquitous in this Woodford outcrop. Hopanoids The pentacyclic hopanoids, synthesized by most prokaryotes (Ourisson et al., 1979), are ubiquitous biomarkers in the geosphere (Ourisson and Albrecht, 1992; Fleck et al., 2002). Terpane distributions in the current sample set are dominated by the hopanes with either the C29 or C30 17α(H)-hopane being the most abundant component (Fig. 10). The C30 hopane is most abundant in the middle member at sample 8 while C29 reaches peak abundance at sample 23, in the upper Woodford based on concentrations, normalized to TOC. The C29 hopane is dominant (C29/(C29 + C30) > 0.5) in many of the m/z 191 chromatograms apart from several middle Woodford samples (Table 3). The C29/(C29 + C30) ratio is relatively stable throughout much of the section apart from the lower and uppermost intervals of the stratigraphic section (Table 3). These characteristics could be related to the onset of the 2nd order TST, during abrupt sea level rise, and the development of the HST, during terrigenous progradation, in the upper Woodford, both of which cause significant turbulence and mixing in the bottom waters. The Woodford interval in this study covers approximately 100m and significant maturity variations would not be expected and variations in commonly used maturity parameters are more likely to arise from the effects of contemporary or paleoweathering. The 22S/(22S+22R) C31 17α(H)-homohopane ratio increases with thermal maturity, crossing the oil-window threshold at approximately 0.5 (Ensminger et al., 1977; Peters et al., 2005). The value of this ratio for sample 1, that has been exposed to a small stream that runs the length of the western flank of the quarry, is anomalously low compared to the other values in the section (Table 3).

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The 17β(H),21α(H)-moretane/17α(H),21β(H)-hopane ratio generally decreases with increasing maturity (Seifert and Moldowan, 1980) but in this section the relative concentration of moretanes and hopanes remains quite constant in the Lower and Middle member of the Woodford Shale (Table 3). The Upper member shows significant variation and Marynowski et al. (2011a) previously noted an abrupt decrease in the moretane/hopane ratio in conjunction with a paleoweathered shale (Tournasian) from a quarry in Poland, possibly a similar situation to the McAlester Quarry. The gammacerane index (GI-gammacerane/gammacerane + hopane) has been used to assess water-column stratification during source rock deposition (Sinninghe Damste et al., 1995). The gammacerane index has also been used extensively in the past to indicate water column salinity but clearly in relatively sheltered environments the two factors are indirectly related (Moldowan et al., 1985). In these Woodford samples the GI is elevated in both the lowermost samples (1-2) and upper Woodford samples (Table 3). These two intervals likely experienced more water-column stratification and environmental fluctuation than the middle member due to the onset of the 2nd order sequence stratigraphic change. The middle member, which shows a great deal of variation in the aromatic carotenoids (Fig. 9b), displays the least amount of watercolumn stratification in the entire section (Table 3). Assuming the carotenoids are strong indicators of PZA, this implies the existence of euxinic conditions may not necessarily be dependent upon water-column stratification, and that anoxic waters may have been common throughout the shallow, epeiric sea that spanned the area. Steroid Hydrocarbons Steroidal hydrocarbons are derived from sterols that serve as essential lipids in all eukaryotic organisms and are abundant in oils and extracts from the Paleoproterozoic to the

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Cenozoic (Summons and Walters, 1990). The ratio of regular steranes/17α(H)-hopanes generally reflects the relative input of eukaryotes versus prokaryotes, with higher values indicating a significant benthic algae and/or planktonic organic matter input and lower values indicating a more significant prokaryotic and/or terrigenous input (Moldowan et al., 1985). The regular sterane/17α(H)-hopane ratio for the McAlister Cemetery Quarry section shows this ratio is relatively constant apart from the anomalous sample 1 and two samples (8 and 10) in the middle Woodford that have lower values possibly indicating an increased terrigenous influx or significant microbial reworking of the organic matter in samples 8 and 10 (Table 3). The upper member again shows slightly lower values for the sterane/hopane ratio throughout, except for the increase in sample 26. The slight, gradual drop in the ratio from ~60 m through much of the upper Woodford agrees with the interpreted 2nd order HST that characterizes this interval. However, the lack of such a clear trend in the lower and middle members suggests that 3rd order parasequences were the dominant influence over organic matter type in the early section. The effects of biodegradation could also diminish this ratio as steranes are preferentially degraded over the hopanes (Peters et al., 2005). C30 Steranes are generally associated with a marine source input and are present in all the samples examined with samples 2, 10, 14, and 19 having higher C30 sterane contents relative to the other samples in this study (Fig. 11; Moldowan et al., 1990). The diasterane/sterane ratio shows a significant increase in the upper Woodford from ~70 m upward, before decreasing in the uppermost sample (Table 3). Because of the lack of a clay mineralogy trend in the McAlister Cemetery Quarry section (Serna-Bernal, 2013), the increase in this ratio is more indicative of oxic conditions in the water column during this stage of the sequence (HST; Moldowan et al., 1986; Brincat and Abbott, 2001). The lower and middle members show a rhythmic cyclicity that is potentially related to parasequence alternation.

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The C29 ααα(20S/(20S + 20R)) and the C29 αββ(20S + 20R)/(ααα(20S + 20R) + αββ(20S + 20R)) sterane maturity parameters show small variations (Table 3) except sample 1, probably due to weathering as the susceptibility generally decreases from ααα 20R > ααα 20S > αββ 20R > αββ 20S (Seifert and Moldowan, 1980). The preferential degradation of the ααα 20R, has led to some 20S/20S + 20R values above the oil-window mark of 0.5 (samples 4 and 19) and made these samples appear more mature than expected based on this parameter (e.g. Philp et al., 1992). Polycyclic Aromatic Hydrocarbons (PAHs) PAHs typically result from diagenetic and catagenetic reactions (Albrecht and Ourisson, 1971; Radke, 1987) that transform olefinic and naphthenic product precursors into complex mixtures of PAHs (Hase and Hites, 1976). Several methylated naphthalenes and phenanthrenes originate from aromatized terpenoids or steroids, including 1,2,5-trimethylnaphthalene, 9methyl-phenanthrene, and 1,7-dimethylnaphthalene (Alexander et al.,1992; Grice et al., 2001). PAHs may also result from incomplete combustion of organic matter due to forest fires (Baek et al., 1991; Wilcke, 2007; Estrellan and Iino, 2010), warfare (Moriwaki et al., 2005), agriculture (Chrysikou et al., 2008), and human industrialization (Musa Bandowe et al., 2014). Several PAHs, notably benzo(a)pyrene, are highly carcinogenic (Bostrom et al., 2002), and persistent in the environment (Mastral and Callen, 2000; Choi, 2014). Very few PAHs are source specific but are very useful in assessing thermal maturity and biodegradation (e.g. Radke et al., 1986; Strachan et al., 1986; Larter et al., 2012).

Naphthalenes and Phenanthrenes Naphthalenes and phenanthrenes are relatively abundant in all extracts and representative chromatograms are shown in Fig. 12a and b. The relative abundance of 1,2,7-TMN over 1,2,5-

18

TMN indicates an early oil window oil or an immature extract (Strachan et al., 1988; Akinlua et al., 2007). High concentrations of these compounds in younger sediments (Cretaceous-Recent) have been related to aromatization of β-amyrin and oleanane-type triterpenoids in angiosperms (Strachan et al., 1988). Armstroff et al. (2006) suggested that oleanane-type lipids may have been derived from organisms that evolved before the development of angiosperms, thus a strong presence of 1,2,7-TMN and 1,2,5 TMN in these samples may be related to gymnosperm resins (van Aarssen et al., 1999), hopanoid precursors (Villar et al., 1988; Grice et al., 2001), or both. Relative concentrations of these alkylnaphthalenes generally follow the relative abundance of cadalene (Fig. 13a), reinforcing the notion that these aromatic compounds are possibly related to gymnosperms and terrigenous input to the depositional system during the alternating parasequences. The susceptibility of alkylnaphthalenes to biodegradation will typically decrease with increasing number of alkyl substituents (Volkman et al., 1984; Williams et al., 1986). The biodegradation of alkylnaphthalenes is illustrated in Fig. 13b using the dimethylnaphthalene (DBR; 1,6-dimethylnaphthalene/1,5-trimethylnaphthalene), trimethylnaphthalene (TBR; 1,3,6trimethylnaphthalene/1,2,4-trimethylnaphthalene), and tetramethylnaphthalene (TeBR; 1,3,6,7tetramethylnaphthalene/1,3,5,7-tetramethylnaphthalene) biodegradation ratios developed by Fisher et al. (1998). The DBR shows very little fluctuation apart from the large value at sample 19 but the TBR and TeBR show significant variation in all three Woodford members. According to Fisher et al. (1998) all three of these ratios should decrease with additional levels of biodegradation. Samples 4, 10, 14, and 19 would suggest that TeBR is most attuned to detect the effects of modern surface weathering in the McAlister Cemetery Quarry. The ratio decreases significantly in the upper three samples (10, 14, and 19) while showing only a slight decrease in

19

sample 2. The TBR ratio only shows a significant decrease at 4, 10, 14 and 19, whereas the DBR shows an increase for both of those samples. These four samples, which were excavated from shallower depths during collection, showed more significant deviations from the general biodegradation trend (Fig. 13a). If these four samples are excluded from the TBR and TeBR depth plots, the resulting trends likely depicts the weathering history of the section, with lower values indicating enhanced degradation. In previous studies Jiang (1998) and Jiang et al. (1998) proposed that phenanthrene was derived from combustion of ancient land vegetation. Several specific alkylphenanthrenes have been attributed to alternative sources, such as pimaric acid for 1,7-dimethylphenanthrene (Wakeham et al., 1980) and bacteria for tetramethylphenanthrenes (Killops, 1991). The phenanthrene/methylphenanthrene ratio has been utilized as a proxy for weathering and as a source parameter for PAHs (Radke, 1987; Marynowski et al., 2011b). The values for this ratio are low (0-0.5) and show little variation throughout the McAlister Cemetery Quarry section, except for a peculiar spike in abundance at sample 4 (Fig. 13c). Hydrocarbons generated from combustion sources would show much higher values for this ratio (Youngblood and Blumer, 1975; Prahl and Carpenter, 1983). The high value for the phenanthrene/methylphenanthrene ratio in sample 4 could be related to enhanced modern surface weathering at that point in the section or a change in depositional conditions at this stage during the 2nd order TST. Marynowski et al. (2011a) noted an increase in paleoweathering was also reflected by an increase in the phenanthrene/methylphenanthrene value. Variations in this parameter in the upper Woodford may indicate that processes besides paleoweathering were also active at those depths, such as differential

preservation

due

to

sequence

stratigraphic

changes.

An

increase

in

methylphenanthrene concentrations could be indicative of paleoweathering if sedimentary

20

methylation is the dominant mechanism for their generation (Alexander et al., 1995; Jiang et al., 1998). Perylene Numerous sources have been proposed for perylene (Kawamura et al., 1987) including perylene quinone pigments in modern plants (Britton, 1983), fungi (Hashimoto et al., 1994), crinoids (De Riccardis et al., 1991), and insects (Cameron et al., 1964). Itoh et al. (2012) proposed that dihydroxyperylene-3,10-quinone (DHPQ) is the parent compound of perylene and suggested that Cenococcum geophilium Fr. actively produces DHPQ in sediments. While some fungal communities in the marine environment may be contributors of perylene (Kohlmeyer and Kohlmeyer, 1979), fewer than 2% of fungi are aquatic (Ingold and Hudson, 1993), and are likely not the sole contributors of perylene in marine sediments. The correlation between the concentrations of perylene and cadalene, strongly suggest a terrestrial input, possibly from a wood-degrading fungus in this study (Fig. 13c). These two compounds probable indicate periods of 3rd order HST progradation into the depositional basin. Interestingly, both compounds (except for perylene in samples 20 and 21) show an overall decrease in concentration throughout the upper Woodford, previously interpreted to be a 2nd order HST (Serna-Bernal, 2013). Because HSTs are almost exclusively comprised of terrestrial material being transported into the basin, the loss of these two terrestrial biomarkers may be indicative of paleoweathering activity. These compounds show significant sensitivity to weathering and biodegradation, samples 2, 10, 14, and 19 tend to show a decrease in concentration when compared to the sample below it (Fig. 13c). The low abundance of these compounds in the Upper Woodford HST could be attributed to the soil erosion and paleoweathering. Pyrogenic PAHs

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Several aromatic compounds generated almost exclusively under pyrolytic conditions, notably benzo(a)pyrene, benzo(e)pyrene, and benzo(ghi)perylene, were observed throughout the McAlister Cemetery Quarry section (Simoneit, 2002; Marynowski and Simoneit, 2009). Several studies have linked the occurrence of these compounds to paleo-wildfires (e.g. Jiang, 1998; Kaiso et al., 2013). Benzo(e)pyrene has also been attributed to reworked algal kerogen (Grice et al., 2007 and 2009) but since it generally follows the same distribution as benzo(a)pyrene and benzo(ghi)perylene, it is probably derived from a combustion source at this location. The distributions of benzo(a)pyrene (B(a)P), benzo(e)pyrene (B(e)P), and benzo(ghi)perylene (B(ghi)Per), determined by GCMS and monitoring the ions at m/z=252+276, all show very similar trends throughout the stratigraphic section (Fig. 14). B(e)P is the most abundant of the three pyrogenic compounds and ranged in concentration from 0.13 to 20.02 µg/g TOC while B(ghi)Per and B(a)P ranged from 0.15 to 6.98 and 0.05 to 1.62 µg/g TOC, respectively (Fig. 15). All 3 compounds show a reasonable correlation with cadalene throughout the section, suggesting they are derived from combustion of vascular land plant material and probably reflect a 3rd order parasequence progression. Samples 2, 10, 14, and 19, which were collected slightly closer to the surface than other samples, all show a decrease in concentrations of the pyrogenic compounds but the samples stratigraphically just above them have very similar concentrations (except for sample 2) suggesting contemporary weathering processes did not have a very significant impact on the abundance of these compounds. Modern weathering vs. Paleoweathering Sea level fluctuation during the Middle Paleozoic has been discussed extensively in previous papers (e.g. Bless et al., 1993; Streel et al., 2000; Brett et al., 2011) and it is generally

22

agreed that glacial eustasy is responsible for sea level fluctuation during this time. To establish a baseline sea level reference for this study, the TOC and carbonate content (CC) of the Woodford were correlated to the gamma ray profile from the McAlister Cemetery Quarry (Serna-Bernal, 2013) using samples 2, 10, 14, and 19 as the index markers. When combined with the Devonian Sea Level Curve originally drafted by Johnson et al. (1985), there appears to be a significant relationship between TOC/CC and sea level fluctuation (Fig. 4). According to the sea level curve, such an incidence of paleosol development is only likely in the several shallowing trends following the F-F Stage extinction boundary when subaerial exposure would have taken place. In terms of distinguishing modern weathering from paleoweathering it can be inferred that the latter would only occur in the Upper Woodford member during abrupt drops in sea level. This implies that weathering signatures seen throughout the Lower and Middle members correspond to modern surface weathering. Paleoweathering, if pronounced, will result in paleosol development which would require subaerial exposure either due to tectonic uplift or sea level fall. The Devonian Sea Level Curve (Johnson et al., 1985) suggests that sea level showed no significant decreases until Upper Woodford deposition. Uplift activity in the region is restricted to the Pennsylvanian deformation of the Oklahoma Basin (Ham and Wilson, 1967; Johnson et al., 1989). The Woodford Shale is known for its remarkably high TOC values. Values less than 5 wt.% are interpreted as shales that have undergone paleoweathering resulting from postdepositional, subaerial exposure due to falling sea level fall. Modern weathering over the past ~40 years (initial quarry excavation) does not seem to have greatly affected TOC values, or for that matter the Rock Eval parameters. The OI values are still relatively low and do not show any elevated values that might be expected if there had been extensive weathering and oxidation.

23

Two samples collected closer to the surface and more susceptible to weathering (14 and 19) are among the most organic-rich in the section at 15.3 and 11.7 wt.%, respectively. Wildman et al. (2004) noted that TOC can be gradually diminished by modern weathering, but those effects would be uniform and quite likely unseen in this study. It is probable that the samples of the Lower and Middle members that are ~15 wt.% TOC, which are within the interpreted 2nd order TST (Serna-Bernal, 2013), are not primarily influenced by sequence stratigraphic changes, but by the presence of anoxic conditions that aid in preservation of organic material. Throughout the lower and middle Woodford, the AIR fluctuates significantly, indicating relatively persistent or periodic anoxic conditions (Fig. 9b). Samples 2, 10, 14, and 19, which were collected from closer to the surface of the quarry than other samples, do not show a significant drop in the AIR, supporting the interpretation that modern weathering has had little effect on this ratio. However, above the F-F Stage extinction boundary (~80 m) the ratio drops substantially to the lowest recorded values of the section (Fig. 9b). This drop would suggest that persistent anoxia exists throughout this interval, or that the entire interval above the F-F boundary is paleoweathered, or a combination of these factors. The samples with high TOC at ~92m are not within zones interpreted as paleoweathering but the AIR values are still quite low and display the signature of persistent anoxia. The moretane/hopane ratio and the TeBR biodegradation ratio, reinforce the presence of two paleoweathered zones in the Upper Woodford member. The moretane/hopane ratio appears to record slight changes due to modern surface weathering, in that the value increases slightly for samples 2, 10, and 14 (Table 3). Marynowski et al. (2011a) suggested this ratio should decrease with paleoweathering, and it does within the Woodford section that had been previously interpreted as having experienced paleoweathering. The TeBR ratio decreases for samples that

24

have experienced either modern and/or paleoweathering effects. Interestingly, sample 19 has a significantly lower value compared to the uppermost sample (26), which has been interpreted as the most paleoweathered sample in the section. The low value for sample 19 is probably due solely to contemporary weathering, as the sample is not within the lower zone of paleoweathering, has a high TOC (11.7 wt.%), and was collected at a shallower depth than other samples in this study. Paleowildfires and Terrigenous Influx Kaiho et al. (2013) noticed an abundance of weathered terrigenous organic material in association with the Frasnian-Famennian (F-F) Stage extinction boundary (372 Ma) from Late Devonian strata in Belgium. This extinction event coincides with the spread of land vegetation in lowland swamps but not in the hinterland (Algeo et al., 1995), and the anoxic conditions have been attributed to nutrient pulses that caused eutrophication and stimulation of algal blooms (Algeo and Scheckler, 1998; Murphy et al., 2000). The placement of the F-F boundary in the McAlister Cemetery Quarry was based upon the report of Sandberg et al. (1988), who suggested the boundary occurred in the middle of the cycle-IId transgression on the Devonian Sea Level Curve (Johnson et al., 1985). This location is marked in Fig. 4 at ~80 m in the stratigraphic section, using TOC and carbonate content (CC) as the correlation tool. According to Kaiho et al. (2013), a massive paleowildfire event during the Late Frasnian resulted in soil erosion and the influx of nutrients into the shallow, epicontinental seas. The paleowildfire assumption is based primarily upon the relative abundance of several aromatic compounds, the combustion proxy, soil erosion proxy, and the vascular land plant indicator, calculated for the Woodford Shale in Fig. 16 reflect very similar trends to those reported by Kaiho et al. (2013). While the correlation does not necessarily imply the same conditions, it is

25

interesting that the peak values of these ratios in the Woodford are situated just after the F-F boundary. The combustion proxy (benzo(e)pyrene + benzo(ghi)perylene/phenanthrene), modified for this study due to absence, or undetectable abundance, of coronene, remains rather steady throughout the entire Woodford before reaching a peak abundance at sample 19. Vascular land plant input, represented by cadalene/phenanthrene, reaches its maximum value at sample 16 but, unlike the combustion proxy, shows a significant fluctuation throughout the lower and middle members, probably reflecting periodic terrigenous influx. Dibenzofuran, a proxy for soil erosion (Sephton et al., 2005), shows a similar trend to the combustion and vascular plant proxies. In this core, samples 16 and 19 both show elevated values, which implies an abundant input of terrestrial organic material in the form of weathered soil detritus. The ratio displays similar variations to those of the vascular land plant proxies throughout the lower and middle members indicative of the primary source of dibenzofuran being from lichens and woody plants (Fenton et al., 2007; Nabbefield et al., 2010). While the biomarker ratios dibenzofuran/phenanthrene and cadalene/phenanthrene rely equally on the abundance of phenanthrene, it is clear they trend towards a maximum abundance just immediately above the proposed F-F boundary (Fig. 16). Despite the significant drop in phenanthrene concentration above ~82m in the section, the proxies shown in Fig. 16 are not elevated throughout the entire interval, implying that significant environmental change was present immediately above the F-F boundary. Perylene and cadalene show similar trends in concentration throughout the McAlister Cemetery Quarry section (Fig. 13c) but show significant differences when normalized to phenanthrene (Fig. 16). The peak values for these ratios occur just above the F-F boundary and correlate with both the combustion and soil erosion proxy

26

indicating at least some degree of weathered terrigenous input after the culmination of the Frasnian-Famennian Stage extinction boundary. Given the low AIR in the organic-rich zone of the Upper Woodford at ~92 m (Fig. 9b), abundant phosphate nodules, and proxy indicators suggesting weathered terrestrial influx, a combination of eutrophication caused by terrestrial nutrients (Algeo and Scheckler, 1998; Murphy et al., 2000) and phosphate upwelling (Kirkland et al., 1992) resulted in the persistent anoxia present throughout this interval. The presence of pyrogenic compounds throughout the entire Woodford Shale of this study (Fig. 15) suggests that paleowildfires may not have been restricted to the Late Frasnian. The fluctuation in concentration of dibenzofuran throughout the section indicates that soil erosion may have accompanied early paleowildfire events during deposition of the lower and middle Woodford. The seemingly abundant episode of weathered terrestrial input following the F-F Stage extinction boundary could be a larger and more widespread influx of material due to the onset of a 2nd order HST. Sequence Stratigraphic Framework Geochemical Indicators For the Woodford Shale of the McAlister Cemetery Quarry, the sequence stratigraphic progression is interpreted to be an overall 2nd order depositional sequence (388 to 359 Ma), with fourteen 3rd order parasequences throughout, based upon correlation to the Devonian sea level curve by Sernal-Bernal, (2013). The 3rd order parasequences are represented by alternating lithologies throughout the entire section, with laminated siliceous shale representing the HSTs and either dolomite, siltstone, or chert representing the TSTs. Due to the discrepancies in sampling as well as the difficulties of correlating high-resolution gamma ray to the geochemical parameters of this sample set, 3rd order parasequences could not be delineated based upon

27

organic geochemical parameters. The lack of a clearer, decreasing gamma-ray trend for the 2nd order HST is probably due to the occurrence of the brief, but pronounced, shallowing sea level intervals immediately following the F-F Stage extinction boundary and sample 19 in the upper Woodford. The overall increase in sea level from the Woodford-Hunton contact to the maximum flooding surface (MFS) correlates well with both the gamma-ray increase and carbonate content (CC) increase during that interval, although not with TOC, which is likely being influenced by preservational changes due to bottom-water oxicity. The MFS appears to correlate to the maximum value of CC at sample 13 despite the relatively lower TOC of the same (7.18 wt.%). Relatively low TOC at the MFS was possibly caused by bottom-water disturbance during the onset of the 2nd order HST. While the highest TOC value for the entire section was in the lowermiddle Woodford at sample 7 (15.6 wt.%), the peak value near the MFS/CS (condensed section) was at sample 14 (15.3 wt.%), above the CS and in the earliest portion of the HST. This may suggest that the earliest HST would, under higher maturity, be the most oil-prone interval of the section (e.g. Curiale et al., 1992; ver Straeten et al., 2011) were it not for the influence of paleoweathering just stratigraphically above sample 14. Thus, the conclusion of Robison et al. (1996) is likely a more accurate interpretation for the Woodford Shale of the McAlister Cemetery Quarry, in that the organic rich section of the 2nd order TST (ca. sample 7) would more likely be the best oil-prone interval under appropriate thermal conditions. Devonian Sea Level Several paleoclimate papers argue for the presence of low mean annual temperatures during the Middle Devonian (e.g. van Geldern et al., 2006; Joachimski et al., 2009), although most of the period was a “greenhouse” (Fischer, 1984). Elrick et al. (2009) suggested that continental glaciers may have existed during this time and could explain the apparent middle

28

Devonian sea level fluctuation attributed to long-term eccentricity Milankovitch cycles. Occurrence of late Devonian (Frasnian-Famennian) glaciation is well documented (e.g. Caputo, 1985; Frakes et al., 1992; Crowell, 1999; Isaacson et al., 1999; Caputo et al., 2008), and has been related to sharp drops in sea level noted by Johnson et al. (1985) and Sandberg et al. (2002). According to Isaacson et al. (2008), these drops in sea level were global occurrences, exposing carbonate platforms and increasing the amount of siliciclastic influx into the deep basin. Lithological indicators of these rapid cooling events include diamictites overlain by lacustrine varves with dropstones (Brezinski et al., 2008), and further evidence exists in the form of localized glacial deposits from South America (Scotese, 2001). Regarding the FrasnianFamennian Stage extinction boundary, sea level change has been proposed as a principal mechanism for its onset (e.g. Hallam and Wignall, 1999; House et al., 2000), and as discussed in the previous section, these changes may have had an influence upon the spread of epicontinental, anoxic seas. Recent geochemical evidence suggests that the expansion of anoxic and euxinic conditions correlate strongly to the F-F Stage extinction, and the availability of reactive iron may have served as the tipping point for that expansion (Formolo et al., 2014). The substantial drops in sea level that have been interpreted as causing the paleoweathered sections of the upper Woodford were almost certainly caused by episodes of glacial proliferation. Apparent 3rd order sequence stratigraphic variations seen throughout the lower and middle members, and evidenced by biomarkers, suggest that glacial flux may have occurred earlier in the Devonian than previously suggested (e.g. Fischer, 1984). Elevated TOC values, as well as the various proxies used to delineate terrigenous influx following the F-F Stage extinction boundary, support the notion of anoxia caused by eutrophication (Algeo and Scheckler, 1998; Murphy et al., 2000) as a potential kill mechanism for organisms eliminated

29

during the event. The accompanying drops in sea level would likely have been devastating to those organisms that were not initially eliminated by widespread marine anoxia across the shallow, intracratonic seas during the late Devonian. CONCLUSIONS The Woodford Shale has the geochemical characteristics of a highly productive source rock with TOC values ranging from 0.07 to 15.6 wt.%. Based on Rock-Eval pyrolysis, most of the samples plot within the Type I/II kerogen range, with several low TOC samples plotting in the Type III kerogen range. The PI suggests that some of the upper Woodford samples are more mature, but these are likely artifacts of paleoweathering activity. Biomarker analysis of the Woodford Shale reveals that modern surface weathering has caused mild degradation of hydrocarbons, particularly n-alkanes. Samples 2, 10, 14, and 19 were collected at shallower depths and displayed more pronounced weathering signatures. TOC and biomarker parameters, suggests that two sections of the upper Woodford are immature paleosols, having been subaerially exposed due to abrupt episodes of sea level fall during the Late Devonian. Evidence for these zones of paleoweathering includes highly depleted TOC, increased OI values, loss of n-alkanes, decreases in the AIR, sesquiterpenoids, cheilanthanes, hopanoids, and decreases in many of the PAHs. The values of several paleoenvironmental proxies for samples immediately following the Frasnian-Famennian (F-F) Stage extinction boundary within the upper Woodford suggests that a large influx of weathered terrigenous material occurred at that time. Furthermore, the presence of pyrogenic compounds implies that paleowildfires were widespread throughout the middle and late Devonian in the North American midcontinent. It is possible that these influxes of weathered

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terrestrial organic material stimulated algal blooms that led to the anoxic water column conditions often attributed to the F-F Stage extinction event. When placed within a sequence stratigraphic framework, the Woodford Shale represents a 2nd order depositional sequence (388-359 Ma), with an unidentifiable number of 3rd order parasequences throughout. The lower and middle Woodford comprise the 2nd order TST, with the middle-upper boundary representing the MFS and CS, while the upper member represents the 2nd order HST. The large influx of terrigenous material previously mentioned likely corresponds to 2nd order HST progradation. Smaller episodes of apparent terrigenous input throughout the lower and middle members suggest that 3rd order HST progradation was occurring, a cyclicity driven by glacial eustatic changes.

VI. REFERENCES Akinlua, A., Torto, N., Ajayi, T.R., 2007. Oils in the Northwestern Niger Delta: Aromatic hydrocarbons content and infrared spectroscopic characterization. Journal of Petroleum Geology 30 (1), 91-100. Albrecht, P., Ourisson, G., 1971. Biogenic substances in sediments and fossils. Angewandte Chemie International Edition 10, 209-225. Alexander, R., Larcher, A.V., Kagi, R.I., Price, P.L., 1992. An oil-source correlation study using age-specific plant-derived aromatic biomarkers. In: Moldowan, J.M., Albrecht, P., Philp, R.P. (Eds.), Biological Markers in Sediments and Petroleum. Prentice-Hall, Englewood Cliffs, New Jersey, 201-221. Alexander, R., Bastow, T.P., Fisher, S.J., Kagi, R.I., 1995. Geosynthesis of organic compounds: II. Methylation of phenanthrene and alkylphenanthrenes. Geochimica et Cosmochimica Acta 59, 4259-4266. Algeo, T.J., Berner, R.A., Maynard, J.B., Scheckler, S.E., 1995. Late Devonian oceanic anoxic events and biotic crises: “rooted” in the evolution of vascular land plants? GSA Today 5, 64-66. Algeo, T.J., Scheckler, S.E., 1998. Terrestrial-marine teleconnections in the Devonian; links between the evolution of land plants, weathering processes, and marine anoxic events. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences 353, 113-130. Algeo, T.J., Schwark, L., Hower, J.C., 2004. High-resolution geochemistry and sequence stratigraphy of the Hushpuckney Shale (Swope Formation, eastern Kansas): implications for 31

climate-environmental dynamics of the Late Pennsylvanian Midcontinent Seaway. Chemical Geology 206 (3-4), 259-288. Amsden, T.W., 1967. Hunton Group (Late Ordovician, Silurian, and Early Devonian) in the Anadarko Basin, Oklahoma. Oklahoma Geological Survey Bulletin 121, 1-214. Anders, D.E., Robinson, W.E., 1971. Cycloalkane constituents of the bitumen from Green River Shale. Geochimica et Cosmochimica Acta 35, 661-678. Aquino Neto, F.R., Trendel, J.M., Restle, A., Connan, J., Albrecht, P.A., 1983. Occurrence and formation of tricyclic terpanes in sediments and petroleums. In: Bjoroy, M. (Ed.), Advances in Organic Geochemistry 1981. Wiley, New York, 659-667. Aquino Neto, F.R., Triguis, J., Azevedo, D.A., Rodrigues, R., Simoneit, B.R.T., 1992. Organic geochemistry of geographically unrelated Tasmanites. Organic Geochemistry 18, 791803. Armstroff, A., Wilkes, H., Schwarzbauer, J., Littke, R., Horsfield, B., 2006. Aromatic hydrocarbon biomarkers in terrestrial organic matter of Devonian to Permian age. Palaeogeography, Palaeoclimatology, Palaeoecology 240, 253-274. Baek, S.O., Field, R.A., Goldstone, M.E., Kirk, P.W., Lester, J.N., Perry, R., 1991. A review of atmospheric polycyclic aromatic-hydrocarbons – sources, fate and behavior. Water Air Soil Pollution 60, 279-300. Bless, M.J.M., Becker, R.T., Higgs, K., Paproth, E., Streel, M., 1993. Eustatic cycles around the Devonian-Carboniferous boundary and the sedimentary and fossil record in Sauerland (Federal Republic of Germany). Ann. Soc. Geol. Belg. 116, 689-702. Bostrom, C.E., Gerde, P., Hanberg, A., Jernstrom, B., Johansson, C., Kyrklund, T., Rannug, A., Torngvist, M., Victorin, K., Westerholm, R., 2002. Cancer risk assessment, indicators, and guidelines for polycyclic aromatic hydrocarbons in the ambient air. Environmental Health Perspectives 110, 451-488. Brett, C.E., Baird, G.C., Bartholomew, A.J., DeSantis, M.K., ver Straeten, C.A., 2011. Sequence stratigraphy and a revised sea-level curve for the Middle Devonian of eastern North America. Palaeogeography, Palaeoclimatology, Palaeoecology 304, 21-53. Brezinski, D.K., Cecil, C.B., Skema, V.W., Stamm, R., 2008. Late Devonian glacial deposits from the eastern United States signal an end of the mid-Paleozoic warm period. Palaeogeography, Palaeoclimatology, Palaeoecology 268, 143-151. Brincat, D., Abbot, G., 2001. Some aspects of the molecular biogeochemistry of laminated and massive rocks from the Naples Beach Section (Santa Barbara-Ventura Basin). In: Isaacs, C.M., Rullkotter, J. (Eds.), The Monterey Formation: From Rocks to Molecules. Columbia University Press, New York, 140-149. Britton, G., 1983. The Biochemistry of Natural Pigments. Cambridge University Press. Cameron, D.W., Cromartie, R.I.T., Todd, L., 1964. Colouring matters of the Aphididae. Part XVI. Reconsideration of the structure of the Erythroaphins. Journal of Chemical Society 4850. Caputo, M.V., 1985. Late Devonian glaciation in South America. Palaeogeography, Palaeoclimatology, Palaeoecology 51, 291-317. Caputo, M.V., Goncalves de Melo, J.H., Streel, M., Isbell, J.L., 2008. Late Devonian and Early Carboniferous glacial records of South America. In: Fielding, C.R., Frank, T.D., Isbell, J.L., (Eds.), Resolving the Late Paleozoic Ice Age in Time and Space: The Geological Society of America Special Paper 441, 161-173.

32

Cardott, B.J., Chaplin, J.R., 1993. Guidebook for Selected Stops in the Western Arbuckle Mountains, Southern Oklahoma. Oklahoma Geological Survey Special Publication 93 (3), 1-55. Cardott, B.J., 2012. Thermal maturity of Woodford Shale gas and oil plays, Oklahoma, USA. International Journal of Coal Geology 103, 109-119. Choi, S.-D., 2014. Time trends in the levels and patterns of polycyclic aromatic hydrocarbons (PAHs) in pine bark, litter, and soil after a forest fire. Science of the Total Environment 470-471, 1441-1449. Chrysikou, L., Gemenetzis, P., Kouras, A., Manoli, E., Terzi, E., Samara, C., 2008. Distribution of persistent organic pollutants, polycyclic aromatic hydrocarbons and trace elements in soil and vegetation following a large scale landfill fire in northern Greece. Environment International 34, 210-225. Comer, J.B., Hinch, H.H., 1987. Recognizing and quantifying expulsion of oil from the Woodford Formation and age-equivalent rocks in Oklahoma and Arkansas. American Association of Petroleum Geologists Bulletin 71, 844-858. Connan, J., Restle, A., Albrecht, P., 1980. Biodegradation of crude oil in the Aquitaine Basin. In: Douglas, A.G., Maxwell, J.R. (Eds.), Advances in Organic Geochemistry 1979 (12). Pergamon Press, Oxford, 1-17. Connock, G.T., 2015. Paleoenvironmental Interpretation of the Woodford Shale, Wyche Farm Shale Pit, Pontotoc County, Oklahoma with a primary focus on water column chemistry and structure. M.S. Thesis, The University of Oklahoma. Connock, G.T., Thanh, X. N., and Philp, R.P. 2018. Elucidating environmental fluctuations concomitant with Woodford shale deposition: An integration of sequence stratigraphy and organic geochemistry. AAPG Bull., 102(6), 959-986. Crowell, J.C., 1999. Pre-Mesozoic ice ages: Their bearing on understanding the climate system. Geological Society of America Memoirs 192. Curiale, J.A., Cole, R.D., Witmer, R.J., 1992. Application of organic geochemistry to sequence stratigraphic analysis: Four corners platform area, New Mexico, U.S.A. Organic Geochemistry 19 (1-3), 53-65, 67-75. Curtis, M.E., Cardott, B.J., Sondergeld, C.H., Rai, C.S., 2012. Development of organic porosity in the Woodford Shale with increasing thermal maturity. Internal Journal of Coal Geology 103, 26-31. De Riccardis, F., Iorzzi, M., Minale, L., Riccio, R., De Forges, B.R., Debitus, C., 1991. The gymnochromes: novel marine brominated phenanthroperylene-quinone pigments from stalked crinoid Gymnocrinus richeri. Journal of Organic Chemistry 56, 6781-6787. Didyk, B.M., Simoneit, B.R.T., Brassell, S.C., Eglinton, G., 1978. Organic geochemical indicators of palaeoenvironmental conditions of sedimentation. Nature 272, 216-222. Dutta, S., Greenwood, P.F., Brocke, R., Schaefer, R.G., Mann, U., 2006. New insights into the relationship between Tasmanites and tricyclic terpenoids. Organic Geochemistry 37, 117-127. Elrick, M., Berkyova, S., Klapper, G., Sharp, Z., Joachimski, M., Fryda, J., 2009. Stratigraphic and oxygen isotope evidence for My-scale glaciation driving eustasy in the EarlyMiddle Devonian greenhouse world. Palaeogeography, Palaeoclimatology, Palaeoecology 276, 170-181. Ensminger, A., Albrecht, P., Ourisson, G., Tissot, B., 1977. Evolution of polycyclic alkanes under the effect of burial (Early Toarcian shales, Paris Basin). In: Campos, R., Goni, J. (Eds.), Advances in Organic Geochmistry 1975, ENADIMSA, Madrid, 45-52. 33

Espitalie, J., Madec, M., Tissot, B., 1977. Source Rock Characterization Method for Petroleum Exploration. Offshore Technology Conference 2935, 439-444. Estrellan C.R., Iino, F., 2010. Toxic emissions from open burning. Chemosphere 80, 193207. Fenton, S., Grice, K., Twitchett, R.J., Bottcher, M.E., Looy, C.V., Nabbefield, B., 2007. Changes in biomarker abundances and sulfur isotopes of pyrite across the Permian-Triassic (P/Tr) Schuchert Dal section (East Greenland). Earth and Planetary Science Letters 262, 230239. Fischer, A.G., 1984. The two Phanerozoic supercycles. In: Berggren, W.A., van Couvering, J.A., (Eds.), Catastrophes in Earth History. Princeton University Press, Princeton, NJ, 129-150. Fischer, C., Gaupp, R., 2005. Change of black shale organic material surface area during oxidative weathering: implications for rock-water surface evolution. Geochimica et Cosmochimica Acta 69, 1213-1224. Fisher, S.J., Alexander, R., Kagi, R.I., Oliver, G.A., 1998. Aromatic hydrocarbons as indicators of biodegradation in north Western Australian reservoirs. In: Purcell, P.G., Purcell, R.R. (Eds.), Sedimentary Basins of Western Australia: West Australian Basins Symposium. Petroleum Exploration Society of Australia, WA Branch, Perth, Australia, 185-194. Fleck, S., Michels, R., Ferry, S., Malartre, F., Elion, P., Landais, P., 2002. Organic geochemistry in a sequence stratigraphic framework. The siliciclastic shelf environment of Cretaceous series, SE France. Organic Geochemistry 33, 1533-1557. Formolo, M.J., Riedinger, N., Gill, B.C., 2014. Geochemical evidence for euxinia during the Late Devonian extinction events in the Michigan Basin (U.S.A.). Palaeogeography, Palaeoclimatology, Palaeoecology 414, 146-154. Frakes, L.A., Francis, J.E., Syktus, J.I., 1992. Climate Modes of the Phanerozoic. Cambridge University Press, Glasgow. Gallegos, E.J., 1971. Identification of new steranes, terpanes, and branched paraffins in Green River Shale by combined gas chromatography and mass spectrometry. Analytical Chemistry 43, 1151-1160. Greenwood, P.F., Arouri, K.R., George, S.C., 2000. Tricyclic terpenoid composition of Tasmanites kerogen as determined by pyrolysis GC-MS. Geochimica et Cosmochimica Acta 64, 1249-1263. Grice, K., Schaeffer, P., Schwark, L., Maxwell, J.R., 1996. Molecular indicators of palaeoenvironmental conditions in an immature Permian shale (Kuperschiefer, Lower Rhine Basin, north-west Germany) from free and S-bound lipids. Organic Geochemistry 25, 131-147. Grice, K., Audino, M., Boreham, C.J., Alexander, R., Kagi, R.I., 2001. Distributions and stable carbon isotopic compositions of biomarkers in torbanites from different palaeogeographical locations. Organic Geochemistry 32, 1195-1210. Grice, K., Nabbefield, B., Maslen, E., 2007. Source and significance of selected polycyclic aromatic hydrocarbons in sediments (Hovea-3 well, Perth Basin, Western Australia) spanning the Permian-Triassic boundary. Organic Geochemistry 38, 1795-1803. Grice, K., Lu, H., Atahan, P., Asif, M., Hallmann, C., Greenwood, P., Maslen, E., Tulipani, S., Williford, K., Dodson, J., 2009. New insights into the origin of perylene in geological samples. Geochimica et Cosmochimica Acta 73, 6531-6543. Guthrie, J.M., Rooney, M.A., Chung, H.M., Unomah, G., 2000. The effects of biodegradation versus recharging on the composition of oils, offshore Nigeria. Presented at the 34

Annual Meeting of the American Association of Petroleum Geologists. April 16-19, 2000, New Orleans, LA. Hallam et al -missing Ham, W.E., Denison, R.E., Merritt, C.A., 1964. Basement rocks and structural evolution of Southern Oklahoma. Oklahoma Geological Survey Bulletin 95, 1-302. Ham, W.E., Wilson, J.L., 1967. Paleozoic epeirogeny and orogeny in the central United States. American Journal of Science 265, 332-407. Hartgers, W.A., Sinninghe Damste, J.S., Requejo, A.G., et al., 1993. A molecular and carbon isotopic study towards the origin and diagenetic fate of diaromatic carotenoids. Organic Geochemistry 22, 703-725. Hase, A., Hites, R.A., 1976. On the origin of polycyclic aromatic hydrocarbons in recent sediments: biosynthesis by anaerobic bacteria. Geochimica et Cosmochimica Acta 40, 11411143. Hashimoto, T., Tahara, S., Takaoka, S., Tori, M., Asakawa, Y., 1994. Structures of a novel binaphthyl and three novel benzophenone derivatives with plant-frowth inhibitory activity from the fungus Daldinia concentrica. Chemical & Pharmaceutical Bulletin 42, 1528-1530. Hass, W.H., Huddle, J.W., 1965. Late Devonian and Early Mississippian age of the Woodford Shale in Oklahoma, as determined from conodonts. United States Geological Survey Professional Paper 525-D, 125-132. Hester, T.C., Sahl, H.L., Schmoker, J.W., 1988. Cross sections based on gamma-ray, density, and resistivity logs showing stratigraphic units of the Woodford Shale, Anadarko basin, Oklahoma. United States Geological Survey Miscellaneous Field Studies Map 2054. Horsfield, B., Curry, D.J., Bohacs, K., Littke, R., Rullkotter, J., Schenk, H.J., Radke, M., Schaefer, R.G., Carroll, A.R., Isaksen, G., Witte, E.G., 1994. Organic geochemistry of freshwater and alkaline lacustrine sediments in the Green River Formation of the Washakie Basin, Wyoming, U.S.A. Organic Geochemistry 22 (3-5), 415-440. House, M.R., Menner, V.V., Becker, R.T., Klapper, G., Ovnatanova, N.Z., Kuz’min, V., 2000. Reef episodes, anoxia and sea-level changes in the Frasnian of the southern Timan (NE Russian platform). Geological Society of London Special Publication 178, 147-176. Hunt, 1996. Petroleum Geochemistry and Geology. W.H. Freeman and Company, New York. Ingold, C.T., Hudson, H.J., 1993. The Biology of Fungi, 6th Edition. Chapman & Hall, London. Isaacson, P.E., Hladil, J., Jian-Wei, S., Kalvoda, J., Grader, G., 1999. Late Devonian (Famennian) glaciation in South America and marine offlap on other continents. Gabhad. Geol. Bundes. 54, 239-257. Isaacson, P.E., Diaz-Martinez, E., Grader, G.W., Kalvoda, J., Babek, O., Devuyst, F.X., 2008. Late Devonian-earliest Mississippian glaciation in Gondwanaland and its biogeographic consequences. Palaeogeography, Palaeoclimatology, Palaeoecology 268, 126-142. Itoh, N., Sakagami, N., Torimura, M., Watanabe, M., 2012. Perylene in lake Biwa sediments originating from Cenococcum geophilum in its catchment area. Geochimica et Cosmochimica Acta 95, 241-251. James, A.T., Burns, B.J., 1984. Microbial alteration of subsurface natural gas accumulations. American Association of Petroleum Geologists Bulletin 86, 957-960.

35

Jarvie, D.M., 1991. Total organic carbon (TOC) analysis. In: Merrill, R.K. (Ed.), Treatise on petroleum geology: Handbook of petroleum geology, source and migration processes and evaluation techniques, American Association of Petroleum Geologists, 113-118. Jiang, C., 1998. Polycyclic Aromatic Hydrocarbons and their Geochemical Significance. Application to Sediments from the Northern Carnarvon Basin. Ph.D. Thesis, Curtin University of Technology, Australia. Jiang, C., Alexander, R., Kagi, R., Murray, A.P., 1998. Polycyclic aromatic hydrocarbons in ancient sediments and their relationships to palaeoclimate. Organic Geochemistry 29, 17211735. Joachimski, M.M., Breisig, S., Buggisch, W., Mawson, R., Gereke, M., Morrow, J.R., Dat, J., Weddige, K., 2009. Devonian climate and reef evolution: insights from oxygen isotopes in apatite. Earth and Planetary Science Letters 284, 599-609. Johnson, J.G., Klapper, G., Sandberg, C.A., 1985. Devonian eustatic fluctuations in Euramerica. Geological Society of America Bulletin 96, 567-587. Johnson, K.S., Amsden, T.W., Denison, R.E., Dutton, S.P., Goldstein, A.G., Rascoe Jr., B., Sutherland, P.K., Thompson, D.M., 1989. Geology of the southern Midcontinent. Oklahoma Geological Survey Special Publication 89, 1-53. Johnson, K.S., Cardott, B.J., 1992. Geologic Framework and Hydrocarbon Source Rocks of Oklahoma. Oklahoma Geological Survey Circular 93, 21-37. Kaiho, K., Yatsu, S., Oba, M., Gorjan, P., Casier, J.-G., Ikeda, M., 2013. A forest fire and soil erosion event during the Late Devonian mass extinction. Palaeogeography, Palaeoclimatology, Palaeoecology 392, 272-280. Katz, B.J., 1983. Limitations of ‘Rock-Eval’ pyrolysis for typing organic matter. Organic Geochemistry, 4, 195-199. Kawamura, K., Ishiwatari, R., Ogura, K., 1987. Early diagenesis of organic matter in the water column and sediments: microbial degradation and resynthesis of lipids in Lake Haruna. Organic Geochemistry 4, 251-264. Killops, S.D., 1991. Novel aromatic hydrocarbons of probable bacterial origin in a Jurassic lacustrine sequence. Organic Geochemistry 17, 25-36. Kirkland, D.W., Denison, R.E., Summers, D.M., Gormly, J.R., 1992. Geology and Organic Geochemistry of the Woodford Shale in the Criner Hills and Western Arbuckle Mountains, Oklahoma. Oklahoma Geological Survey 93, 38-69. Kohlmeyer, J., Kohlmeyer, E., 1979. Marine Mycology, the Higher Fungi. Academic Press, New York. Larter, S.R., Huang, H., Adams, J., Bennet, B., Snowdon, L.R., 2012. A practical biodegradation scale for use in reservoir geochemical studies of biodegraded oils. Organic Geochemistry 45, 66-76. Liaaen-Jensen, S., Renstrom, B., Ramdahl T., Hallenstvet, M., Bergquist, P., 1982. Carotenoids of marine sponges. Biochemical Systematics and Ecology 10, 167-174. Lo, H.B., Cardott, B.J., 1995. Detection of natural weathering of Upper McAlester coal and Woodford Shale, Oklahoma, U.S.A. Organic Geochemistry 22, 73-73. Marynowski, L., Simoneit, B.R.T., 2009. Widespread Upper Triassic to Lower Jurassic wildfire records from Poland: evidence from charcoal and pyrolytic polycyclic aromatic hydrocarbons. Palaios 24, 785-798. Marynowski, L., Kurkiewicz, S., Rakocinski, M., Simoneit, B.R.T., 2011a. Effects of weathering on organic matter: I. Changes in molecular composition of extractable organic 36

compounds caused by paleoweathering of a Lower Carboniferous (Tournasian) marine black shale. Chemical Geology 285, 144-156. Marynowski, L., Szeleg, E., Jedrysek, M.O., Simoneit, B.R.T., 2011b. Effects of weathering on organic matter Part II: Fossil wood weathering and implications for organic geochemical and petrographic studies. Organic Geochemistry 42, 1076-1088. Mastral, M.A., Callen, M.S., 2000. A review on polycyclic aromatic hydrocarbons (PAH) emissions from energy generation. Environmental Science and Technology 34, 3051-3057. Moldowan, J.M., Seifert, W.K., Gallegos, E.J., 1985. Relationship between petroleum composition and depositional environment of petroleum source rocks. American Association of Petroleum Geologists Bulletin 69, 1255-1268. Moldowan, J.M., Sundararaman, P., Schoell, M., 1986. Sensitivity of biomarker properties to depositional environment and/or source input in the Lower Toarcian of S.W. Germany. Organic Geochemistry 10, 915-926. Moriwaki, H., Katahira, K., Yamamoto, O., Fukuyama, J., Kamiura, T., Yamazaki, H., Yoshikawa, S., 2005. Historical trends of polycyclic aromatic hydrocarbons in the reservoir sediment core at Osaka. Atmospheric Environment 39, 1019-1025. Murphy, A.E., Sageman, B.B., Hollander, D.J., 2000. Eutrophication by decoupling of the marine biogeochemical cycles of C, N, and P: a mechanism for the Late Devonian mass extinction. Geology 28, 427-430. Musa Bandowe, B.A., Srinivasan, P., Seelge, M., Sirocko, F., Wilcke, W., 2014. A 2600year record of past polycyclic aromatic hydrocarbons (PAHs) deposition at Holzmaar (Eifel, Germany). Palaeogeography, Palaeoclimatology, Palaeoecology 401, 111-121. Nabbefield, B., Grice, K., Summons, R.E., Hays, L.E., Cao, C., 2010. Significance of polycyclic aromatic hydrocarbons (PAHs) in Permian/Triassic boundary sections. Applied Geochemistry 25, 1374-1382. Ourisson, G., Albrecht, P., Rohmer, M., 1979. The hopanoids. Palaeochemistry and biochemistry of a group of natural products. Pure and Applied Chemistry 51, 706-729. Ourisson, G., Albrecht, P., Rohmer, M., 1982. Predictive microbial biochemistry – from molecular fossils to prokaryotic membranes. Trends in Biochemical Sciences 7, 236-239. Ourisson, G., Albrecht, P., 1992. Hopanoids: 1. Geohopanoids: The most abundant natural products on Earth? Accounts of Chemical Research 25, 398-402. Parish, D.T., 1991. Geohistory of the Ardmore Basin, Carter Country, Oklahoma. B.S. Thesis, Baylor University. Paxton, S.T., Cruse, A.M., Krystynaik, A.M., 2006. Mississippian Woodford Shale of south-central Oklahoma. American Association of Petroleum Geologists Search and Discovery Article 40211. Peters, K.E., 1986. Guidelines for evaluating petroleum source rock using programmed pyrolysis. American Association of Petroleum Geologists Bulletin 70 (3), 318-329. Peters, K.E., Walters, C.C., Moldowan, J.M., 2005. The Biomarker Guide: Biomarkers and Isotopes in Petroleum Exploration and Earth History, 2nd Edition. Cambridge University Press, New York. Philp, R.P., Chen, J., Galvez-Sinibaldi, A., Wang, H., Allen, J.D., 1992. Effects of Weathering and Maturity on the Geochemical Characteristics of the Woodford Shale. Oklahoma Geological Survey Circular 93, 106-121. Prahl, F.G., Carpenter, R., 1983. Polycyclic aromatic hydrocarbon (PAH)-phase associations in Washington coastal sediment. Geochimica et Cosmochimica Acta 47, 1013-1024. 37

Radke, M., Welte, D.H., Willsch, H., 1986. Maturity parameters based on aromatic hydrocarbons: influence of the organic matter type. Organic Geochemistry 10, 51-63. Radke, M., 1987. Organic geochemistry of aromatic hydrocarbons. In: Brooks, J., Welte, D. (Eds.). Advances in Petroleum Geochemistry 2. Academic Press, New York. Requejo, A.G., Allan, J., Creaney, S., Gray, N.R., Cole, K.S., 1992. Aryl isoprenoids and diaromatic carotenoids in Paleozoic source rocks and oils from the Western Canada and Williston Basins. Organic Geochemistry 19, 245-264. Revill, A.T., Volkman, J.T., O’Leary, T., et al. (1994). Depositional setting, hydrocarbon biomarkers and thermal maturity of tasmanite oil shales from Tasmania, Australia. Geochimica et Cosmochimica Acta 58, 3803-3822. Roberts, C.T., Mitterer, R.M., 1992. Laminated Black Shale-Bedded Chert Cyclicity in the Woodford Formation, Southern Oklahoma. Oklahoma Geological Survey Circular 93, 1992. Robison, V.D., Liro, L.M., Robison, C.R., Dawson, W.C., Russo, J.W., 1996. Integrated geochemistry, organic petrology, and sequence stratigraphy of the Triassic Shublik Formation, Tenneco Pheonix #1 well, North Slope, Alaska, U.S.A. Organic Geochemistry 24 (2), 257-272. Sandberg, C.A., Ziegler, W., Dreesen, R., Butler, J.L., 1988. Part 3: Late Frasnian mass extinction: conodont event stratigraphy, global changes, and possible causes. Courier ForschungInstitut Senckenberg 102, 263-307. Sandberg, C.A., Morrow, J.R., Ziegler, W., 2002. Late Devonian sea-level changes, catastrophic events, and mass extinctions. Geological Society of America Special Paper 356, 476-487. Schaefle, J., Ludwig, B., Albrecht, P., Ourisson, G., 1977. Hydrocarbures aromatiques d’origine geologique: II. Nouveaux carotenoi’des aromatiques fossils. Tetrahedron Letters 18, 3673-3676. Schwark, L., Frimmel, A., 2004. Chemostratigraphy of the Posidonia Black Shale, SWGermany II. Assessment of extent and persistence of photic-zone anoxia using aryl isoprenoid distribution. Chemical Geology 206, 231-248. Scotese, C.R., 2001. Atlas of Earth History. Paleomap Project, Arlington, Texas. Seifert, W.K., Moldowan, J.M., 1980. The effect of thermal stress on source-rock quality as measured by hopane stereochemistry. Physics and Chemistry of the Earth 12, 229-237. Sephton, M.A., Looy, C.V., Brinkhuis, H., Wignall, P.B., de Leeuw, J.W., Visscher, H., 2005. Catastrophic soil erosion during the end-Permian biotic crisis. Geology 33, 41-944. Serna-Bernal, A., 2013. Geological Characterization of the Woodford Shale, McAlister Cemetery Quarry, Criner Hills, Ardmore Basin, Oklahoma. M.S. Thesis, The University of Oklahoma. Sierra, M.G., Cravero, R.M., Laborde, M.A., Ruveda, E.A., 1984. Stereoselective synthesis of (+/-)-18,19-Dinor-13β(H), 14α(H)-cheilanthane: the most abundant tricyclic compound from petroleums and sediments. Journal of the Chemical Society, Chemical Communication, 417-418. Simoneit, B.R.T., 2002. Biomass burning – a review of organic tracers for smoke from incomplete combustion. Applied Geochemistry 17, 129-162. Sinninghe Damste, J.S., Kenig, F., Koopmans, M.P., et al., 1995. Evidence for gammacerane as an indicator of water-column stratification. Geochimica et Cosmochimica Acta 59, 1895-1900.

38

Slatt. R.M., Rodriguez, N.D., 2012. Comparative sequence stratigraphy and organic geochemistry of gas shales: Commonality or coincidence? Journal of Natural Gas Science and Engineering 8, 68-84. Strachan, M.G., Alexander, R., Kagi, R.I., 1986. Trimethylnaphthalenes as depositional environmental indicators. Present at the 192nd Annual American Chemical Society Meeting 1986, Anaheim, CA. Strachan, M.G., Alexander, R., Kagi, R.I., 1988. Trimethylnaphthalenes in crude oils and sediments: effects of source and maturity. Geochimica et Cosmochimica Acta 52, 1255-1264. Streel, M., Caputo, M.V., Loboziak, S., Melo, J.H., 2000. Late Frasnian-Famennian climates based palynomorph analyses and the question of Late Devonian glaciations. EarthScience Reviews 52, 121-173. Summons, R.E., Powell, T.G., 1986. Chlorobiaceae in Paleozoic seas revealed by biological markers, isotopes and geology. Nature 319, 763-765. Summons, R.E., Powell, T.G., 1987. Identification of aryl isoprenoids in source rocks and crude oils: biological markers for the green sulfur bacteria. Geochimica et Cosmochimica Acta 51, 557-566. Summons, R.E., Walter, M.R., 1990. Molecular fossils and microfossils of prokaryotes and protists from Proterozoic sediments. American Journal of Science 290A, 212-244. Tissot, B., Durand, B., Espitalie, J., Combaz, A., 1974. Influence of nature and diagenesis of organic matter in formation of petroleum. American Association of Petroleum Geologists Bulletin 58, 499-506. Tissot, B.P., Welte, D.W., 1984. Petroleum formation and occurrence (second edition). Springer-Verlag, New York. van Aarssen, B.G.K., Bastow, T.P., Alexander, R., Kagi, R.I., 1999. Distributions of methylated naphthalenes in crude oils: indicators of maturity, biodegradation and mixing. Organic Geochemistry 30, 1213-1227. van Geldern, R., Joachimski, M.M., Day, J., Jansen, U., Alvarez, F., Yolkin, E.A., Ma, X.P., 2006. Carbon oxygen and strontium isotope records of Devonian brachiopod shell calcite. Palaeogeography, Palaeoclimatology, Palaeoecology 240, 47-67. ver Straeten, C.A., Brett, C.E., Sageman, B.B., 2011. Mudrock sequence stratigraphy: A multi-proxy (sedimentological, paleobiological and geochemical) approach, Devonian Appalachian Basin. Palaeogeography, Palaeoclimatology, Palaeoecology 34 (1-2), 54-73. Villar, J.H., Puttmann, W., Wolf, M., 1988. Organic geochemistry and petrography of Tertiary coals and carbonaceous shales from Argentina. Organic Geochemistry 13, 1011-1021. Volkman, J.K., Alexander, R., Kagi, R.I., Rowland, S.F., Sheppard, P.N., 1984. Biodegradation of aromatic hydrocarbons in crude oils from the Barrow Sub-basin of Western Australia. Organic Geochemistry 6, 619-632. Wakeham, S.G., Schaffner, C., Giger, W., 1980. Polycyclic aromatic hydrocarbons in recent lake sediments – II. Compounds derived from biogenic precursors during early diagenesis. Geochimica et Cosmochimica Acta 44, 415-429. Waples, D.W., 1985. Geochemistry in petroleum exploration. International Human Resources Development Corporation. USA. Wilcke, W., 2007. Global patterns of polycyclic aromatic hydrocarbons (PAHs) in soil. Geoderma 141, 157-166.

39

Wildman, R.A., Berner, R.A., Petsch, S.T., Bolton, E.W., Eckert, J.O., Mok, U., Evans, J.B., 2004. The weathering of sedimentary organic matter as a control on atmospheric O2: I. Analysis of black shale. American Journal of Science 304, 234-249. Williams, J.A., Bjoroy, M., Dolcater, D.L., Winters, J.C., 1986. Biodegradation in South Texas Eocene oils – effects on aromatics and biomarkers. Organic Geochemistry 10, 451-461. Youngblood, W.W., Blumer, M., 1975. Polycyclic aromatic hydrocarbons in the environment: homologous series in soils and recent marine sediments. Geochimica et Cosmochimica Acta 39, 1303-1314.

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Fig. Captions Fig. 1. Geographic location of the major oil and gas producing basins in Oklahoma. Location of the McAlister Quarry is shown by the shaded circle in the approximate center of the map. Fig. 2. Three major provinces, namely the Oklahoma Basin, the Southern Oklahoma Aulacogen, and the Ouachita Trough, existed during the geological development of various basins beginning in the Early Paleozoic (from Johnson et al., 1989). Fig. 3. Stratigraphic column for the Anadarko Basin and the McAlister Quarry location. Fig. 4. TOC and carbonate content values for the Woodford Shale samples from the McAlister Cemetery Quarry plotted along with a representation of sea-level change during the deposition of the Woodford. Fig. 5(a). A pseudo van Krevelen plot of HI vs. OI for the Woodford samples showing the bulk of the samples were dominated by Type II kerogen; (b) A plot of S2 vs. TOC showing the bulk of the samples are Type II kerogen. Fig. 6. Production Index and Tmax values for the section that have been used to evaluate maturity of the samples and their oil and/or gas potential. Fig. 7. Representative saturate hydrocarbon chromatograms showing signs of contemporary weathering. Despite the removal of the n-alkanes, the more complex biomarker components were not affected by the contemporary weathering. Fig. 8. The fluctuations in the Pr/nC17 and Ph/nC18 ratios in these samples are almost certainly the result of weathering and do not reveal any significant information on variations in the depositional environment. The Pr/Ph ratio also shown in this figure does show some minor variations that may be related to variations in the depositional environment. Fig. 9(a). Extracts from this Woodford section show the abundant presence of arylisoprenoids as determined by two characteristic arylisoprenoid ions, m/z 133 and 134. In addition, three carotenoids namely palaeorenieratane, isorenieratane and renieratane were also present in these samples in varying concentrations throughout the section; (b) variations in the concentrations of these three carotenoids are shown in this Fig. along with the AIR (arylisoprenoid ratio); concentrations of tricyclic terpanes; and the C29/C29+C30 hopane ratio. Fig. 10. M/z 191 chromatograms from the GCMS analyses of the saturate fractions showing the terpane distributions, including the tricyclics, determined by GCMS for selected samples from the McAlister Quarry. Fig. 11. M/z 217 chromatograms for selected samples from the section showing the sterane distributions in these samples. Sample 1 at the base of the section was somewhat unique in the somewhat immature sterane signature. Fig. 12. The overall distributions of (a) naphthalenes and (b) phenanthrenes were relatively abundant in all extracts and representative chromatograms derived from the sum of single ion chromatograms are shown in this figure. Fig. 13(a). Variations in concentrations of 1,2,7-trimethylnaphthalene (1,2,7-TMN), 1,2,5-trimethylnaphthalene (1,2,5-TMN), and cadalene with depth through the section; (b) variations in various biodegradation ratios based on alkylated naphthalenes with depth through the section. DBR=1,6-dimethylnaphthalene/1,5-trimethylnaphthalene; TBR=1,3,6-trimethylnaphthalene/1,2,4-trimethylnaphthalene; TeBR=1,3,6,7-tetramethylnaphthalene/1,3,5,7-tetra41

methylnaphthalene; (c) the phenanthrene/methylphenanthrene ratio weathering profile plotted against section depth, along with variations in the cadalene and perylene concentrations. Fig. 14. The distributions of benzo(a)pyrene (B(a)P), benzo(e)pyrene (B(e)P), and benzo(ghi)perylene (B(ghi)Per), determined by SIM GCMS (m/z = 252, 276), all show very similar trends throughout the stratigraphic section. Fig. 15. Variations in concentration with depth of section for B(e)P, B(ghi)Per, and B(a)P plotted against the corresponding data for cadalene. Fig. 16. Variations in ratios that reflect a combustion proxy (benzo(e)pyrene + benzo(ghi)perylene/phenanthrene); a vascular land plant indicator (cadalene/phenanthrene); a soil erosion proxy (dibenzofuran/phenanthrene) and perylene/phenanthrene.

Table 1. TOC and Rock-Eval Pyrolysis data for the McAlister Cemetery Quarry Woodford Shale. Position (m) is relative to Woodford-Hunton contact. Colored zones represent Lower, Middle, and Upper members. Table 2. Various isoprenoid ratios calculated from peak areas of GC traces. Absences reflect samples that were devoid of at least one variable. Position (m) is relative to Woodford-Hunton contact. Table 3. Various tricyclic terpane, hopane, and sterane biomarker ratios in relation to stratigraphic position. Abbreviations are found in corresponding figures in the text. Position (m) is relative to Woodford-Hunton contact.

42

APPENDIX: EXPERIMENTAL METHODS Pre-extraction rock sample treatments Each rock sample (~100g) was taken from the original core plug and washed with hot water, distilled water and a 1:1 mixture of dichloromethane (DCM) and methanol to remove any possible contaminants (e.g. drilling mud). After the samples were air-dried, they were crushed by using a pestle in a porcelain mortar and ground into 60-200 mesh for screening analysis (TOC and Rock-Eval) and soxhlet extraction. Total Organic Carbon (TOC) and Rock-Eval Analysis Leco-TOC (Total Organic Carbon) analysis and Rock-Eval pyrolysis were performed on 138 rock samples either at GeoMark Research, Inc. in Humble, Texas or Weatherford Laboratories in Houston, Texas. Approximately 2 grams of crushed rock were used for determination of TOC and Rock-Eval parameters. After pre-screening based on the results of these analyses, source rock samples were chosen for further bitumen extraction and maltenes fractionation. Vitrinite Reflectance Measurements Measured vitrinite reflectance (Ro) values from all of the Woodford cores were obtained from the organic petrographic pellets (either made from a whole rock or a kerogen concentrate) prepared at the Oklahoma Geological Survey Organic Petrography Laboratories in Norman, Oklahoma, and measured at the University of Oklahoma Organic Geochemistry Laboratories by the author of this study after training by Mr. Brian Cardott. Bitumen Extraction and Fractionation The Soxhlet apparatus and cellulose thimbles were pre-extracted for 24 hours using a 1:1 mixture of dichloromethane (CH2Cl2) and methanol (CH3OH) in order to remove contaminants. Then the source rock samples (60g approximately per sample) were introduced into the preextracted thimbles to be extracted by the mixture of DCM and methanol (1:1) for 48 hours. The solvent was removed by using a rotary evaporator and the residue containing soluble bitumen was transferred into a glass centrifuge tube. The extract was separated into maltenes and asphaltenes by adding an excess (40:1) of n-pentane (C5H12) and put in a refrigerator overnight to completely precipitate the asphaltenes. After centrifuging for 5 minutes, the maltene fractions were transferred to a 250mL round bottom flask to evaporate the excess solvent until a few milliliters remained which were transferred into a pre-weighed vial. The remaining solvent was finally evaporated until dryness by a gentle nitrogen flow. The asphaltenes remaining in the centrifuge tubes were dissolved in DCM and transferred into pre-weighed vials. The solvent was evaporated and the asphaltene was weighed. The maltene fraction was diluted in a ratio of 10mg sample per 60uL n-hexane (C6H14) for maltene fractionation by alumina column chromatography. Column chromatography was performed on alumina, which was activated at 550ºC before use and packed in 100ml glass columns. Saturates, aromatics and NSO (nitrogen, sulfur, and oxygen) compounds were fractionated based on differences in polarity of different solvents mixtures and different flow rates. Columns were dry-packed with a piece of glasswool inserted at the bottom and then 7.5 g of activated alumina (A540-3) on top of the glasswool. Before loading the samples, the column was half filled with n-hexane. The column was gently tapped to remove the air bubbles, if any, in 43

the alumina. The maltene fraction (~35mg) diluted within minimum n-hexane was introduced to the top of alumina. The saturate fraction was eluted by adding ~17 ml of n-hexane to the column without disturbing the alumina surface and then drained at 1 droplet per1.5 seconds; and then the aromatic fraction was eluted with 50 ml of n-hexane and DCM (7:3) and drained at 1 droplet/second; finally NSO compounds were eluted with 50ml of DCM and methanol (98:2). Each fraction was weighed on a balance after removing the solvents under nitrogen flow very gently. Saturate and aromatic fractions were diluted into a 3 mg/ml solution for further GC and GC-MS analysis. The branched and cyclic (B&C) fraction was obtained by removing the n-alkanes from the saturate fraction following the procedures modified by Dr. Nguyen after West et al. (1990) using the molecular sieve HI-SIV 3000 purchased from Zeolyst International. The hydrophobic molecular sieve HI-SIV 3000 is activated at 550oC overnight before it is used to remove nalkanes from the saturate fraction. A glass wool-plugged Pasteur pipette was packed with ~2g of HI-SIV 3000 powder and n-pentane was applied under pressure of water-free air to compress the HI-SIV 3000 powder. This step was repeated until the uncompressible HI-SIV 3000 section occupied nearly two-third of the column. Around 10 mg of saturate fraction was dissolved in 1 ml of n-pentane and transferred to the top of the HI-SIV 3000 section and stand for 2 minutes to let the molecular sieve absorb the n-alkanes completely. The water-free air was applied on top of the pipette such that the flow rate of filtrate was about 1 drop per second. The filtrate, which contains branched and cyclic alkanes (B&C fraction), was collected in a 4 ml vial located below the tip of the pipette and n-alkanes retained in the HI-SIV 3000 section. The B&C fraction was diluted into a 3 mg/ml solution for biomarker analyses. Gas Chromatography The isolated fractions from the rock extracts, saturates and aromatics respectively, were analyzed using an Agilent 6890 series gas chromatograph with a splitless capillary injector and a 30m × 0.25mm (i.d.) J&W Scientific DB-5 122-5032 fused silica capillary column coated with a 0.25µm liquid film. The injector was set up in the splitless injection mode and the temperature was held at 300ºC. The carrier gas was helium (He) with a flow rate of 1.4 ml/min. The temperature program started with an initial temperature of 40ºC held for 1.5 minute and increased to 300ºC at a rate of 4ºC per minute followed by an isothermal period of 34 minutes for a total run time of 100.5 minutes. The flame ionization detector (FID) temperature was set at 310ºC. n-Alkanes and isoprenoids were identified in each chromatogram by comparing their relative retention times with standards. Gas Chromatography-Mass Spectrometry The GC-MS analyses of the branched and cyclic alkanes (B&C) and aromatic fractions were performed on an Agilent 7890A gas chromatography system coupled with an Agilent Technologies 5975C mass selective detector (MSD) using single ion monitoring (SIM). The GC used a 60m x 0.25mm Agilent J&W Scientific DB-5 122-5562 fused silica capillary column coated with a 0.25µm liquid film. The injected volume of branched and cyclic and aromatic fractions was 1uL per run. The injector temperature was set at 300ºC. The GC temperature program started at 40ºC with 1.5 minutes hold time and was later increased to 300ºC at a rate of 4ºC per minute and then held constant for 34 minutes for a total run time of 100.5 minutes. Samples were run in splitless mode and helium was used as the carrier gas at a flow rate of 1.4

44

ml/min. Biomarker compounds were determined from fragmentograms corresponding to each ion using relative retention times and by comparison with published data.

45

Table 1. TOC and Rock-Eval Pyrolysis data for the McAlister Cemetery Quarry Woodford Shale. Position (m) is relative to Woodford-Hunton contact. Colored zones represent Lower, Middle, and Upper members. Sample 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1

Position (m) 98.00 97.00 95.00 93.40 93.10 93.00 92.80 92.60 92.30 89.00 81.80 80.80 78.00 70.70 61.40 55.80 47.90 46.50 39.10 33.50 29.80 26.00 24.20 18.60 18.30 11.20

CC 0.60 1.05 1.87 1.15 12.45 3.21 1.58 1.90 0.29 1.58 5.91 1.88 5.16 38.79 11.29 20.48 7.16 4.81 0.89 2.45 3.65 3.30 1.75 1.41 2.69 6.12

TOC 0.11 0.07 0.09 1.43 1.20 13.00 5.28 11.70 0.12 0.10 8.14 15.10 15.30 7.18 10.60 8.62 9.66 12.90 12.80 15.60 15.20 15.10 14.80 14.10 12.20 12.80

S1 0.05 0.01 0.01 0.68 0.46 8.94 2.79 10.26 0.05 0.02 3.00 7.47 10.05 5.68 5.28 3.48 7.77 5.52 7.93 7.83 4.59 5.32 7.00 5.93 11.83 2.41

S2 0.01 0.01 0.01 3.48 3.33 100.40 33.05 76.77 0.04 0.02 49.28 110.18 85.37 51.13 70.76 53.48 66.02 91.39 89.54 97.72 85.85 95.58 98.55 95.96 80.08 76.36

S3 0.02 0.04 0.14 0.46 0.47 0.89 0.49 2.12 0.01 0.08 2.39 2.00 3.03 0.80 1.21 1.25 1.47 1.53 0.78 1.80 2.40 1.55 0.64 0.81 1.65 1.10

Tmax

%Ro

413 419 422 428 421

0.27 0.38 0.44 0.54 0.42

422 426 418 414 415 415 413 424 424 420 417 426 427 426 417 429

0.44 0.51 0.36 0.29 0.31 0.31 0.27 0.47 0.47 0.40 0.35 0.51 0.53 0.51 0.35 0.56

HI 9 15 11 243 278 772 626 656 9 21 605 730 558 712 668 620 683 708 700 626 565 633 666 681 656 597

OI 18 58 156 32 39 7 9 18 18 84 29 13 20 11 11 15 15 12 6 12 16 10 4 6 14 9

PI 0.83 0.50 0.50 0.68 0.12 0.08 0.08 0.12 0.56 0.50 0.06 0.06 0.11 0.10 0.07 0.06 0.11 0.06 0.08 0.07 0.05 0.05 0.07 0.06 0.13 0.03

Table 2. Various isoprenoid ratios calculated from peak areas of GC traces. Absences reflect samples that were devoid of at least one variable. Position (m) is relative to Woodford-Hunton cotact. Sample 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1

Pr/n-C17 Ph/n-C18 Pr/Ph

4.03

3.81

2.92

2.11

1.17 0.56 0.94

0.8 1.26 1.54 1.8 1.98 2.12 1.67 1.36 1.73 1.22 1.39 2.16 1.53 2.28 2.63 0.62

0.73 1.08 0.99 1.34 1.48 1.62 1.27 1.03 1.25 1.15 1.05 1.38 1.06 1.67 1.68 0.41

0.9 1.02 1 1.46 1.5 1.34 1.23 1.45 1.36 1.35 1.33 1.46 1.65 1.43 1.33 1.86

Table 3. Various tricyclic terpane, hopane, and sterane biomarker ratios in relation to stratigraphic position. Abbreviations are found in corresponding figures in the text above. Position (m) is relative to Woodford-Hunton contact. C29/C29 + C30 TT/H C31 22S/22S + 22R C30 M/C30 H (H)

GI

St/H

Dia/St

C29 20S/20S + 20R

C29 ββ/ββ +αα

0.18

1.20

1.04

0.19

0.43

0.57

0.50 0.47 0.51 0.51 0.55

0.73 0.63 0.50 0.59 0.22

4.31 3.84 2.53 3.33 1.19

0.18 0.22 0.33 0.26 0.26

0.57 0.56 0.49 0.59 0.54

0.41 0.39 0.34 0.36 0.51

0.69 0.68 0.66 0.68 0.56

0.86 0.69 0.87

0.51 0.53 0.52

0.41 0.21 0.26

2.40 1.16 1.41

0.30 0.30 0.41

0.55 0.39 0.42

0.36 0.39 0.35

0.65 0.68 0.65

0.68 0.78 0.77 0.69 0.87 0.52 0.68 0.77 0.58 0.87 0.57 0.80 0.83

0.52 0.51 0.51 0.51 0.51 0.52 0.52 0.52 0.52 0.52 0.52 0.51 0.36

0.16 0.18 0.17 0.20 0.16 0.15 0.16 0.16 0.16 0.23 0.16 0.30 0.24

0.71 0.86 0.82 0.98 0.82 0.81 0.88 0.81 0.93 1.15 0.86 1.65 2.01

0.90 1.04 1.08 0.40 1.04 0.44 0.92 1.08 0.88 1.01 0.80 0.52 3.95

0.14 0.11 0.13 0.40 0.12 0.27 0.14 0.12 0.19 0.32 0.19 0.41 0.09

0.40 0.35 0.37 0.45 0.37 0.46 0.41 0.36 0.44 0.57 0.44 0.42 0.13

0.56 0.53 0.55 0.62 0.53 0.61 0.57 0.55 0.57 0.41 0.56 0.59 0.21

Sample

Position (m)

26 25 24 23 22 21 20 19 18 17 16 15 14

98

0.52

0.60

0.55

93.4 93.1 93 92.8 92.6

0.84 0.81 0.76 0.80 0.56

0.67 0.71 0.94 0.78 0.63

81.8 80.8 78

0.74 0.56 0.62

70.7 61.4 55.8 47.9 46.5 39.1 33.5 29.8 26 24.2 18.6 18.3 11.2

0.47 0.48 0.48 0.52 0.46 0.46 0.48 0.48 0.47 0.56 0.47 0.67 0.41

13 12 11 10 9 8 7 6 5 4 3 2 1

Fig. 1

Fig. 2

Fig. 3

15 14

80

372372 MaMa

Upper

21

19

90

70

Middle

60 50

10

40

Lower

30

2

20

Frasnian Famennian

100

10

Sea Level

0

5

10

15

TOC (wt.%)

20 0

10

20

30

40

CC (wt.%)

Fig. 4

Kerogen Type (HI vs. OI) Hydrogen Index (S2 (mg HC/g rock) x 100/TOC)

1000

21

800

TYPE I KEROGEN

600

TYPE II KEROGEN

400

200 TYPE III KEROGEN

24

18

TYPE IV KEROGEN

0 0

50

100

150

200

Oxygen Index (S3 (mg CO2/g rock) x 100/TOC) Fig. 5a

S2 vs. TOC 120 Type I: Oil Prone Usually Lacustrine

S2 (mg HC/g TOC)

100

Type II: Oil Prone Usually Marine

80

60

Mixed Type II / III: Oil / Gas Prone

40 Type III: Gas Prone

20 Dry Gas Prone

0 0

5

10

15

20

TOC (wt.%) Fig. 5b

Production Index 100

19, 20, 21

90

17 Gas

80 70

60

60

50

50

40

40

30

30

20

20

10

10 0.0

0.2

0.4

0.6

0.8

Production Index (S1/(S1+S2))

1.0

Middle

Oil

Stratigraphic Position (m)

70

Immature

16 80

Upper

90

1 410

415

420

425

430

Lower

100

Tmax

435

Tmax °C Fig. 6

Sample 16

Sample 19

Pr

Sample 1

Ph

Sample2

Pr Ph

Fig. 7

Pr/n-C17

Ph/n-C18

Pr/Ph

100

100

90

90

80

80

70

70

70

60

60

60

50

50

50

40

40

40

30

30

30

20

20

20

10

10

100

14

10

Lower

Stratigraphic Position (m)

80

Middle

90

Upper

19

2 10 0.0 1.0 2.0 3.0 4.0 5.0

0.0

1.0

2.0

3.0

4.0

0.0

0.5

1.0

1.5

2.0 Fig. 8

C18

Sample 5

Relative Abundance

C16

C19 C20 C21

C14

C22

C15 C17

C24 C23

C25 C27 C29 C C26 30 I

II + III

Time

Fig. 9a

100

Palaerenieratane

100

100

100

90

90

90

90

Stratigraphic Position (m)

Isorenieratane

Renieratane

80

80

80

80

70

70

70

70

60

60

60

60

50

50

50

50

AIR

TT 100

100

90

90

Upper

13

80

80

70

70

60

60

50

50

40

40

40

40

40

40

30

30

30

30

30

30

20

20

20

20

20

20

10

10

10

10

10

01234

0 1 2 3 4 5

µg/g TOC

µg/g TOC

0 2 4 6 8 1012

µg/g TOC

C29/(C29 + C30)

0 1 2 3

10

0 50 100 150 200

Middle

Lower 0.3 0.5 0.6 0.8 0.9

µg/g TOC Fig. 9b

Sample 1

Sample 2

Sample 2 Sample 19

Sample 26

Fig. 10

Fig. 11

DMP MP

a TMP P

Relative Abundance

TeMP

DMN TMN

b MN

CD TeMN

NAPH

Time

Fig. 12

1,2,5-TMN

Cadalene

100

100

100

90

90

90

80

80

70

70

70

60

60

60

50

50

50

40

40

40

30

30

20

20

20

10

10

10

Upper

1,2,7-TMN

5

30

0

10

20

µg/g TOC

30

40

0

3

6

µg/g TOC

9

12

Lower

Stratigraphic Position (m)

80

Middle

13

0.0

1.0

2.0

µg/g TOC Fig. 13a

3.0

100

100

100

90

90

90

80

80

80

70

70

70

60

60

60

50

50

50

40

40

40

30

30

30

20

20

20

10

10

10

0 1 2 3 4 5 6 7

0 1 2 3 4 5 6 7

Upper

TeBR

Middle

TBR

Lower

Stratigraphic Position (m)

DBR

1.0 1.5 2.0 2.5 3.0 3.5 4.0

Fig. 13b

Perylene

Phn/MPhn

90

90

90

80

80

80

70

70

70

60

60

60

50

50

40

40

40

30

30

30

20

20

20

20

19

50

10

10

16 14

9

6

3

2 0.0

21

Middle Middle

100

Lower

100

100

Upper Upper

Cadalene

10 1.0

2.0

µg/g TOC

3.0

10 0.0 0.5 1.0 1.5 2.0 2.5

0.0

0.5

1.0

1.5

2.0

µg/g TOC Fig. 13c

Relative Abundance

Benzo(e)pyrene

Benzo(a)pyrene Benzo(ghi)perylene

Perylene

Time Fig. 14

100

Cadalene

100

100

100

90

90

90

80

80

80

70

70

60

60

60

60

50

50

50

50

40

40

40

40

30

30

30

20

20

20

10

10

10

21

90 80

14

70

13

70

10

20

2

10 0

1

µg/g TOC

2

0

10

20

µg/g TOC

6

0

2

4

6

µg/g TOC

30

8

Lower

Stratigraphic Position (m)

B(ghi)Per

Upper

B(e)P

Middle

B(a)P

0

1

2

µg/g TOC

Fig. 15

3

Per/Phn

100

100

100

90

90

90

90

80

80

80

70

70

70

70

60

60

60

60

50

50

50

50

40

40

40

40

30

30

30

30

20

20

20

20

10

10 0.00

10

10

0 10 20 30 40

0.15

0.30

Upper

DBF/Phn

Famennian 80 Frasnian

0.0

0.1

0.2

Middle

Cadalene/Phn

Lower

Stratigraphic Position (m)

Combustion Proxy 100

0

1

2

3

4

Fig. 16

Comments for Editor.

Highlights for review. I need to check this since I am not sure what you need here.