Splint coals of the Central Appalachians: Petrographic and geochemical facies of the Peach Orchard No. 3 split coal bed, southern Magoffin County, Kentucky

International Journal of Coal Geology 85 (2011) 268–275

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International Journal of Coal Geology j o u r n a l h o m e p a g e : w w w. e l s e v i e r. c o m / l o c a t e / i j c o a l g e o

Splint coals of the Central Appalachians: Petrographic and geochemical facies of the Peach Orchard No. 3 split coal bed, southern Magoffin County, Kentucky James C. Hower a,⁎, Leslie F. Ruppert b,1 a b

University of Kentucky, Center for Applied Energy Research, 2540 Research Park Drive, Lexington, KY 40511, United States U.S. Geological Survey, National Center, MS 956, Reston, VA 20192, United States

a r t i c l e

i n f o

Article history: Received 27 September 2010 Received in revised form 6 December 2010 Accepted 13 December 2010 Available online 5 January 2011 Keywords: Coal Kentucky Petrology Geochemistry Facies Coal to liquids Durain

a b s t r a c t The Bolsovian (Middle Pennsylvanian) Peach Orchard coal bed is one of the splint coals of the Central Appalachians. Splint coal is a name for the dull, inertinite-rich lithologies typical of coals of the region. The No. 3 Split was sampled at five locations in Magoffin County, Kentucky and analyzed for petrography and major and minor elements. The No. 3 Split coals contain semifusinite-rich lithologies, up to 48% (mineral-free basis) in one case. The nature of the semifusinite varies with position in the coal bed, containing more mineral matter of detrital origin in the uppermost durain. The maceral assemblage of these terminal durains is dominated by detrital fusinite and semifusinite, suggesting reworking of the maceral assemblage coincident with the deposition of the detrital minerals. However, a durain in the middle of the coal bed, while lithologically similar to the uppermost durains, has a degraded, macrinite-rich, texture. The inertinite macerals in the middle durain have less distinct edges than semifusinites in the uppermost terminal durains, suggesting degradation as a possible path to inertinite formation. The uppermost durain has higher ash and semifusinite contents at the eastern sites than at the western sites. The difference in the microscopic petrology indicates that megascopic petrology alone can be a deceptive indicator of depositional environments and that close attention must be paid to the individual macerals and their implications for the depositional setting, especially within the inertinite group. © 2011 Elsevier B.V. All rights reserved.

1. Introduction Studies of Bolsovian (Middle Pennsylvanian) coals in the Central Appalachians have always emphasized the abundance of dull lithologies (durain, dull clarain, and bone) in the coals, traditionally referred to as splint coals, a Scottish miner's term synonymous with durain (Thiessen, 1930; Thiessen et al., 1931; Thiessen and Sprunk, 1936; Greb et al., 2002b). Hower et al. (1994, 1996) described dull lithologies in the No. 5 Block and Stockton coals, which overlie the Coalburg (Peach Orchard) coal zone (Fig. 1). All three coals or coal zones are considered to be splint coals in northeastern Kentucky and central West Virginia. Among the latter coals, the No. 5 Block coal bed is particularly notable for lithologies composed of mixtures of detrital inertinites and detrital silicates, giving the coal a distinctive “salt and pepper” megascopic appearance (Hower et al., 1994; Richardson, 2010). The Peach Orchard coal zone, correlative with the Coalburg coal bed to the east in Eastern Kentucky and West Virginia and the Hazard No. 7 and Hazard No. 8 coals to the south in central Eastern Kentucky ⁎ Corresponding author. Tel.: + 1 859 257 0261; fax: +1 859 257 0360. E-mail addresses: [email protected] (J.C. Hower), [email protected] (L.F. Ruppert). 1 Tel.: + 1 703 648 6431; fax: +1 703 648 6419. 0166-5162/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.coal.2010.12.012

(see Ruppert et al., 2010), consists of Pennsylvanian Bolsovian-age coals in the Breathitt Group (Fig. 1) (Chesnut, 1996; Greb et al., 2002a) (note: the U.S. Geological Survey recognizes the Kentucky Geological Survey's Breathitt Group as the Breathitt Formation). The most prominent coal bed within the Peach Orchard zone in southern Magoffin County (Fig. 1) is the Peach Orchard No. 3 Split. Up to five coal splits at a single mine site were sampled in the course of our study. The split nature of the coal zone, also noted in mapping studies of the 7 1/2-minute quadrangles in the study area (Danilchik, 1977; Spengler, 1977, 1978), complicates correlations with specific coals in other parts of eastern Kentucky. The position of the Peach Orchard No. 3 Split in the lower half of the sequence of splits suggests that it may be correlative, at least in part, with the Hazard No. 7 coal bed. Discussion of the Hazard No. 7 and Hazard No. 8 coal beds to the south of the study area can be found in Hower et al. (1992). Gavett (1984) and Esterle et al. (1992) studied the Mudseam coal bed, the Hazard No. 7 correlative, to the east in Elliott County. The Peach Orchard coal zone in southern Magoffin County, Kentucky, drew the attention of University of Kentucky Center for Applied Energy Research (CAER) scientists in the late 1980's in the course of studies of the liquefaction potential of eastern United States bituminous coals. A semifusinite-rich lithotype in the Peach Orchard proved to have a greater conversion to liquids potential than was predicted solely on the basis of a traditional assessment of reactive

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complicated, with the No. 2, No. 3, No. 3 1/2, No. 4, and No. 4 rider Split coal beds exposed in the mine highwall. Only the lithologic description of the No. 3 Split from site 4 is plotted on Fig. 3 and this report is focused only on the No. 3 Split coal bed. Within the less-than 3 × 1-km area containing sites 2 through 5, the top of the coal is dominated by dull lithotypes. The top of Section 5, sample 2174, is a high ash content (37.01 weight percent (wt.%)) bone lithotype A similar lithology was noted by Spengler (1977) in his descriptions of the coal bed from the Salyersville South 7 1/2-minute quadrangle (Fig. 2). The basal lithotype is also dull, with over 30 wt.% ash content at sites 2 and 3 (Table 1). Site 1, 8.2 km from site 2, bears some resemblance to the other four sites, but it does not contain the prominent dull zone at the top of the coal. 3.2. Microscopic petrology

Fig. 1. Generalized stratigraphic section of study area (after Danilchik, 1977; Spengler, 1977, 1978).

macerals, indicating that the semifusinite was reactive under liquefaction conditions (Hower et al., 1993). Because of the usual petrography, the area was revisited (our site 1, below) for a study of triboelectrostatic separation of macerals, which used a differential charge to separate macerals in the coal (Hower et al., 1997). In this study, we investigate the petrography and geochemistry of the Peach Orchard No. 3 Split, one of the splint coals, in a small area in Magoffin County, Kentucky (Fig. 2). The size of the area, with mine sites separated by no more than 1.9 km for four of the five sites investigated, provides lateral control for the study of the depositional systems responsible for such high-inertinite coals. 2. Procedure Coal channel and lithotype/bench (subsections of whole channel) samples were collected from active surface mines from five sites in southern Magoffin County, Kentucky (Fig. 2). Coal description followed lithotype nomenclature adapted and modified from the Stopes–Heerlen terminology (Hower et al., 1990). Proximate and ultimate analyses of the coal were conducted at the CAER following ASTM standard procedures. Major oxides and minor elements were determined on a Phillips AXS2 x-ray fluorescence unit at the CAER following procedures outlined by Hower and Bland (1989). Petrographic analyses were performed at the CAER on epoxybound particulate pellets, polished to a 0.05-μm alumina final polish, and examined using reflected white-light, oil-immersion optics at a final magnification of 500x. Maceral analyses are reported on a mineral-free basis. 3. Results 3.1. Megascopic petrology Generalized seam descriptions of the Peach Orchard No. 3 Split are shown on Fig. 3. The sample sites are keyed to the regional map (Fig. 2) and to the data tables (Tables 1, 2); all represent surface mine exposures of the coal. As noted above, certain collected sections contained more than just the No. 3 Split coal bed. Site 4 was the most 2 Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Maceral analyses, along with the ash yield and sulfur content, of the samples are shown on Table 1. All coals are high volatile B/A bituminous rank, with vitrinite maximum reflectances ranging from about 0.68–0.80 %. The semifusinite content is greater than 47 volume percent (vol.%) for samples 2145 (bench 1 at site 4) and 2174 (bench 1 at site 5), Semifusinite contents for samples 2155 and 2181 (bench 1 at site 3 and bench 1 at site 1, respectively) exceed 20 vol.%. The Split 2 coal bed, where sampled at sites 4 and 5, is a highvitrinite bright lithotype with vitrinite content ranging from 83.9– 92.3 vol.%. The sulfur content of Split 2 at site 5 is 4.61 wt.% (dry basis) the highest of any coal sample in this study. The No. 3 Split basal lithotype at sites 2-5 is consistently dull, with no site having more than 51.9 vol.% vitrinite. Total fusinite + semifusinite of the basal lithotype exceeds 40 vol.% at site 3 and is not less than 28 vol.% at any of the No. 3 Split coal bed sites. The middle lithologies of the No. 3 Split sites 2–5 are a mixture of bright and dull lithotypes, none as high in semifusinite (up to 47.1 vol.%) as the uppermost lithotype (discussed below), with total vitrinite contents up to 87.5 vol.%. The middle lithologies at site 1 deviate from those at sites 2–5. Site 1 vitrinite content ranges from 14.9–72.5 vol.%, with the lowest vitrinite in a 63 vol.% macrinite lithotype (sample 2183). The upper lithotype ranges from 16.0 vol.% semifusinite and 6.50 wt.% ash (dry basis) at site 2 to 47.9 vol.% semifusinite and 37.01 wt.% ash yield at site 5. The lithology at site 5, described as a bone coal, may be equivalent to the carbonaceous shale noted by Spengler (1977). Site 4 has 27.05 wt.% ash and N60 vol.% fusinite+ semifusinite. The upper lithotype at site 1, with N28 vol.% fusinite + semifusinite (and 6.57% vol. ash, dry basis), resembles the site 2–5 lithologies. 3.3. Geochemistry With a few notable exceptions, the major element chemistry of the Peach Orchard No. 3 Split lithotypes is dominated by the aluminosilicate chemistry typical of clay- and silt-rich detrital influences (Table 2). The ratio of K2O to Al2O3 generally is highest at the upper and lower margins of the coal bed, suggesting that these lithologies contain more illite than kaolinite. Note that the upper and lower margins of the coal at sites 2–5 tend to have higher ash yields than the middle lithotypes. TiO2 is generally higher in the dull lithotypes, a feature noted in many other studies of eastern Kentucky coals (for example, Hower and Bland's (1989) study of the Pond Creek coal bed). TiO2 is relatively abundant in the high-ash lithotypes, reinforcing the important contributions of detrital TiO2 minerals in the sediment mix (as previously noted by Hower and Pollock, 1988; Hower and Bland, 1989). Unlike other coals in which a TiO2 and Zr were found to be associated with detrital minerals (Hower et al, 1992, 1994, 1996, 2005, 2007), Zr (41–550 ppm, ash basis) is not notably high in the site 2–5 sections. However, Zr does exceed 1000 ppm (ash basis) in the lower five (of seven) benches from the site 1 section.

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Fig. 2. Generalized locations of the five Peach Orchard No. 3 Split coal mine sites in the Seitz and Salyersville South Quadrangles, Magoffin County, eastern Kentucky. The Guage and Tiptop Quadrangles, Breathitt County, are also shown.

The lower three benches at site 1 (samples 2185–2187) have the highest Sr values (3790–7360 ppm, ash basis) of any samples in the study. P2O5 is also relatively high (0.58–1.07 wt.%, ash basis) in the same benches, suggesting, although not proving, a phosphate association for the Sr. Bench 2 of 5 (sample 2146) at site 4 has a comparable P2O5 concentration (1.33 wt.%, ash basis), but has lower levels of Sr (319 ppm, ash basis) than the lower three benches at site 1.

The most striking deviation from clay-dominated alumino-silicate chemistry is observed in benches 3 (sample 2147) and 4 (sample 2148) at site 3, The total sulfur (up to 1.61 wt.%, ash basis), pyritic sulfur (up to 0.51 wt.%, ash basis), and Fe2O3 (up to 19.31 wt.%, ash basis) contents of both samples are above the average of other analyzed samples of the Peach Orchard No. 3 Splint coals (Table 2; for example, the range of 0.46–0.87 wt.% total S). In these two lithotypes,

Fig. 3. Generalized coal lithology of the Peach Orchard No. 3 Split. Gray pattern represents bone, durain, and dull clarain. White represents clarain, bright clarain, and vitrain.

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Table 1 Thickness, ash yield, total sulfur, and maceral content of benches of the Peach Orchard splint coals. The overlying No. 4 rider, No. 4, and No. 3.5 Splits at site 4 and the underlying No. 2 Split coals were present and analyzed at sites 4 and 5. . Abbreviations: Vit (%) — vitrinite (percent); Fus (%) — fusinite (percent); Sfus (%) — semifusinite (percent); Mic (%) — micrinite (percent); Mac (%) — macrinite (percent); Ex (%) — sporinite and cutinite (percent); Res (%) — resinite (percent). All macerals are reported on a mineral-free basis and represent volume percent. Site

Sample

Split

Bench

Thickness (cm)

Ash (dry)

S (t) (dry)

Vit

Fus

Sfus

Fus + Sfus

Mic

Mac

Ex

Res

1

2181 2182 2183 2184 2185 2186 2187 2161 2162 2163 2164 2165 2166 2155 2156 2157 2158 2150 2151 2152 2145 2146 2147 2148 2153 2149 2174 2176 2177 2178 2179

3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 4 rider 4 3 1/2 3 3 3 3 3 2 3 3 3 3 2

1/7 2/7 3/7 4/7 5/7 6/7 7/7 1/6 2/6 3/6 4/6 5/6 6/6 1/4 2/4 3/4 4/4

12.50 14.00 8.00 10.01 12.70 10.80 19.51 28.65 7.32 11.58 23.16 8.84 10.06 39.62 23.16 31.09 17.37 11.18 47.50 23.88 8.23 21.95 10.67 13.11 12.80 26.67 37.01 18.01 19.99 16.00 32.99

6.57 5.32 25.81 5.16 3.29 3.95 10.23 6.50 6.14 3.50 3.67 4.69 30.09 19.65 7.98 4.52 37.69 34.00 5.37 22.28 27.05 4.23 4.35 4.15 17.43 8.87 49.59 6.70 4.72 10.63 12.83

0.83 0.71 0.38 0.69 0.77 1.02 0.74 0.90 0.84 0.77 1.18 0.98 0.66 0.59 0.83 1.09 0.55 0.50 0.75 2.26 0.46 0.87 1.61 1.12 0.86 1.70 0.41 0.84 1.05 1.72 4.61

53.9 55.9 14.9 59.6 65.9 72.5 46.4 51.1 72.0 49.4 77.4 52.3 47.3 35.4 61.8 71.8 39.3 56.2 75.6 61.4 23.3 59.7 68.5 87.5 51.9 92.3 30.9 57.6 78.7 48.2 83.9

6.9 8.5 3.1 10.4 11.8 9.6 11.8 14.8 8.2 21.6 11.1 15.0 20.7 8.9 19.1 7.4 14.7 7.0 6.1 10.4 13.5 10.5 10.1 2.5 8.1 1.4 5.0 11.6 6.2 12.2 5.5

21.2 18.1 5.3 13.1 9.8 8.1 16.5 16.0 7.1 11.1 2.8 15.8 14.4 31.4 5.0 7.0 27.8 16.6 6.0 14.4 47.1 11.5 9.0 3.5 22.1 1.0 47.9 10.8 5.3 16.2 1.5

28.1 26.6 8.4 23.5 21.6 17.7 28.3 30.8 15.3 32.7 13.9 30.8 35.1 40.3 24.1 14.4 42.5 23.6 12.1 24.8 60.6 22.0 19.1 6.0 30.2 2.4 52.9 22.4 11.5 28.4 7.0

5.0 3.7 0.2 1.8 1.7 1.3 5.0 6.7 3.4 2.9 2.2 5.7 4.1 5.4 3.0 3.3 1.7 3.4 2.3 1.9 4.9 3.1 1.9 2.6 4.1 0.9 3.0 3.7 2.1 7.9 2.3

0.5 0.6 63.2 0.7 0.3 0.0 0.0 0.4 0.3 1.0 0.0 0.7 0.8 1.0 0.3 0.1 2.0 0.1 0.4 0.1 0.3 0.1 0.0 0.1 t 0.0 0.4 0.0 0.1 t 0.1

12.4 13.0 12.9 14.3 10.4 8.1 20.0 10.8 8.8 13.7 6.2 10.4 11.1 14.4 9.5 9.7 13.7 16.1 9.4 11.0 9.9 13.1 9.7 3.4 11.0 4.2 10.1 16.1 7.6 15.1 5.7

0.1 0.2 0.4 0.1 0.1 0.4 0.3 0.2 0.2 0.3 0.2 0.1 1.6 3.5 1.3 0.7 0.8 0.6 0.2 0.9 1.0 2.0 0.8 0.4 2.8 0.2 0.1 0.6 0.0 0.4 1.0

2

3

4

5

1/5 2/5 3/5 4/5 5/5 1/4 2/4 3/4 4/4

both relatively low ash compared to other lithotypes, sulfide chemistry played a more significant role in the overall geochemical pattern. Both lithotypes are also higher in vitrinite content (up to 87.5 vol.%) than most of the Peach Orchard No. 3 Split lithotypes (Table 2). 4. Discussion 4.1. Petrology As in the other splint coals in the region, the nature of the highinertinite durains in the Peach Orchard No. 3 Split holds clues for the nature of the depositional environment. Examples of distinct, wellpreserved inertinite and of degraded inertinites are shown on Figs. 4 and 5, respectively. Even this distinction is not exact, however. Fig. 4b shows a mix of semifusinite and other macerals. The large semifusinite areas on the left and right are not as structured as the semifusinite in the middle of the image. Such loss/absence of structure places the macerals close to identification as macrinite. In contrast, particularly on Fig. 5b, we see a macrinite groundmass largely missing the distinct structure of the inertinite macerals in Fig. 4a. The semifusinite content is generally highest in the upper and lower benches of the Peach Orchard No. 3 Split coals. The presence of such large amounts of semifusinite, over 47 vol.% (volume, mineralfree basis) in the top bench at sites 4 and 5, has important implications for the depositional setting. Moore et al. (1996) noted settings where fungal oxidation was responsible for enhanced amounts of inertinite macerals. In particular, the inertinite maceral macrinite is considered to be a product of fungal and, perhaps, bacterial degradation (Duparque and Delattre, 1953a, b; Stach, 1956; Hower et al., 2009; Belkin et al., 2009, 2010; O'Keefe and Hower, 2011). Scott and colleagues (Scott, 2000, 2002; Jones et al., 1993; Scott and Jones, 1994;

Scott et al., 2000; Scott and Glasspool, 2005, 2007; McParland et al., 2007) argue that virtually all fusinite and semifusinite can be attributed to a fire origin. Within this discussion, though, a distinction must be drawn between the latter fire-derived inertinite macerals and the agents (funginite) and products (macrinite) of degradation. The durain at site 1, bench 3 (sample 2183, Table 1) of 7 contains 63 vol.% macrinite, and maceral boundaries are less distinct (Fig. 5) than in the uppermost durains at other sites (described below), giving the impression of degradation. An origin of degradation does not imply that the maceral could not have been ultimately fixed as an inertinite by fire (Scott, 2000, 2002; Jones et al., 1993; Scott and Jones, 1994; Scott et al., 2000; Scott and Glasspool, 2005, 2007; McParland et al., 2007; Hudspith et al., 2010), but we are suggesting that there were multiple and successive paths to the inertinite-rich maceral assemblage that we see in the coal. Further, the paths are not reversible or intersecting; funginite or macrinite does not become fusinite or semifusinite by virtue of a later-induced process or simply by the level of reflectance. Degradation with no or incomplete fireinduced fusinization may account for the semi-reactive nature of the inertinite in liquefaction conditions. Note that Hower et al. (1993) considered much of what we recounted as macrinite to be a degraded semifusinite. Our re-evaluation of the maceral distribution does not impact their findings, because their liquefaction studies were on a lithotype still considered to have abundant semifusinite. In the Peach Orchard No. 3 Split, the high semifusinite lithologies are also the higher mineral matter lithologies, up to 49.59 wt.% ash in the 47.9 vol.% semifusinite upper bench at site 5. While there is a compositional resemblance to the argillaceous durains in the No. 5 Block coal bed in Martin County, Kentucky (to the east) (Hower et al., 1994), the megascopic appearance of the Peach Orchard No. 3 Split terminal durains is more uniform, indicating a finer mixing of macerals and minerals (Fig 5). Microscopically, the uppermost durain,

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Table 2 Thickness, ash, total sulfur, forms of sulfur, major oxides (ash basis), and minor elements. Minor elements shown on both a whole coal and an ash basis. The overlying No. 4 rider, No. 4, and No. 3.5 Splits coals at site 4 and the underlying No. 2 Split coals were present and analyzed at sites 4 and 5. Abbreviations: % S(t) — percent total sulfur; % Spy — percent pyritic sulfur; % Ssulf — percent sulfate sulfur; % Sorg — percent organic sulfur; ppm — parts per million. Ash basis Site

Sample

Split

Bench

Thickness (cm)

Ash (dry)

S (t) (dry)

Spy (dry)

Ssulf (dry)

Sorg (dry)

SO3

MgO

Na2O

Fe2O3

TiO2

SiO2

CaO

K2O

P2O5

Al2O3

K2O/ Al2O3

1

2181 2182 2183 2184 2185 2186 2187 2161 2162 2163 2164 2165 2166 2155 2156 2157 2158 2150 2151 2152 2145 2146 2147 2148 2153 2149 2174 2176 2177 2178 2179

3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 4 rider 4 3.5 3 3 3 3 3 2 3 3 3 3 2

1/7 2/7 3/7 4/7 5/7 6/7 7/7 1/6 2/6 3/6 4/6 5/6 6/6 1/4 2/4 3/4 4/4

12.50 14.00 8.00 10.01 12.70 10.80 19.51 28.65 7.32 11.58 23.16 8.84 10.06 39.62 23.16 31.09 17.37 11.18 47.50 23.88 8.23 21.95 10.67 13.11 12.80 26.67 37.01 18.01 19.99 16.00 32.99

6.57 5.32 25.81 5.16 3.29 3.95 10.23 6.50 6.14 3.50 3.67 4.69 30.09 19.65 7.98 4.52 37.69 34.00 5.37 22.28 27.05 4.23 4.35 4.15 17.43 8.87 49.59 6.70 4.72 10.63 12.83

0.83 0.71 0.38 0.69 0.77 1.02 0.74 0.90 0.84 0.77 1.18 0.98 0.66 0.59 0.83 1.09 0.55 0.50 0.75 2.26 0.46 0.87 1.61 1.12 0.86 1.70 0.41 0.84 1.05 1.72 4.61

na na na na na na na 0.20 0.08 0.06 0.22 0.13 0.14 na 0.02 0.06 0.03 0.05 0.07 1.17 0.04 0.10 0.51 0.11 0.10 0.47 0.23 0.03 0.07 0.47 3.29

na na na na na na na 0.00 0.00 0.00 0.00 0.00 0.00 na 0.00 0.00 0.00 0.06 0.02 0.12 0.02 0.01 0.02 0.01 0.02 0.04 0.01 0.00 0.00 0.00 0.00

na na na na na na na 0.70 0.76 0.70 0.96 0.85 0.52 na 0.81 1.03 0.52 0.38 0.66 0.97 0.39 0.76 1.08 1.00 0.73 1.19 0.18 0.81 0.98 1.25 1.32

0.31 0.48 0.00 0.60 1.07 0.95 0.15 0.32 0.30 0.80 0.91 0.43 0.01 0.02 0.33 0.26 0.00 0.28 3.52 0.13 0.00 0.90 0.80 0.80 0.00 0.27 0.00 0.90 0.74 0.07 0.23

0.39 0.16 0.00 0.11 0.36 0.29 0.42 0.37 0.73 0.62 0.73 0.60 0.69 0.84 0.57 0.38 0.52 0.92 1.83 0.80 0.78 0.54 0.37 0.58 0.66 0.43 0.81 0.77 0.52 0.37 0.26

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.20 0.23 0.32 0.38 0.35 0.31 0.49 0.30 0.31 0.23 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.24 0.40 0.42 0.29 0.30

1.98 1.97 0.40 1.87 4.20 5.98 1.85 5.65 3.86 3.85 8.45 5.23 2.32 1.96 1.51 2.85 1.45 2.25 3.57 12.83 2.09 5.30 19.31 6.78 2.86 13.87 3.15 4.60 5.35 8.43 37.10

1.95 2.07 3.13 3.00 1.52 1.26 2.56 2.34 1.97 1.85 1.11 1.13 2.75 2.2 2.35 1.78 2.68 1.48 0.74 1.45 2.37 2.14 1.35 0.87 2.62 0.77 1.66 1.53 1.04 1.95 0.72

58.02 58.84 74.70 60.46 50.54 46.75 51.83 56.13 55.73 52.92 45.77 51.15 59.83 59.43 59.66 50.52 60.75 61.12 47.38 54.53 62.94 52.48 41.62 48.63 56.65 45.29 64.36 55.80 50.58 50.62 35.35

0.98 1.42 0.40 1.49 2.56 3.07 1.21 1.12 1.27 2.27 2.56 1.59 0.57 0.31 1.11 1.22 0.57 0.17 6.49 0.16 0.01 1.50 1.42 1.45 0.02 0.29 0.34 1.99 1.84 0.68 0.74

1.22 0.53 0.13 0.39 0.60 0.46 2.44 0.67 1.90 1.25 1.49 1.34 2.70 2.38 2.02 0.93 1.85 2.92 1.87 2.36 2.03 1.50 0.76 1.07 2.58 1.45 2.18 2.08 1.60 1.82 1.34

0.13 0.16 0.13 0.20 0.78 1.07 0.58 0.14 0.15 0.18 0.17 0.15 0.10 0.13 0.13 0.17 0.12 0.10 0.12 0.08 0.11 1.33 0.10 0.11 0.10 0.08 0.14 0.14 0.16 0.16 0.08

34.16 33.41 21.19 29.93 36.45 39.20 37.14 31.24 31.91 34.02 36.41 36.17 30.14 31.63 30.88 39.72 31.11 29.20 32.68 26.62 27.88 31.00 32.29 37.83 32.52 35.79 24.43 29.98 35.99 33.82 22.74

0.036 0.016 0.006 0.013 0.016 0.012 0.066 0.021 0.060 0.037 0.041 0.037 0.090 0.075 0.065 0.023 0.059 0.100 0.057 0.089 0.073 0.048 0.024 0.028 0.079 0.041 0.089 0.069 0.044 0.054 0.059

2

3

4

5

1/5 2/5 3/5 4/5 5/5 1/4 2/4 3/4 4/4

Ash basis Site

Sample

Split

Bench

Thickness (cm)

Ash (dry)

Mo

Zn

Cu

Ni

Co

Cr

Ba

V

Mn

Rb

Sr

Zr

1

2181 2182 2183 2184 2185 2186 2187 2161 2162 2163 2164 2165 2166 2155 2156 2157 2158 2150 2151 2152 2145 2146 2147 2148 2153 2149 2174 2176 2177 2178 2179

3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 4 rider 4 3.5 3 3 3 3 3 2 3 3 3 3 2

1/7 2/7 3/7 4/7 5/7 6/7 7/7 1/6 2/6 3/6 4/6 5/6 6/6 1/4 2/4 3/4 4/4

12.50 14.00 8.00 10.01 12.70 10.80 19.51 28.65 7.32 11.58 23.16 8.84 10.06 39.62 23.16 31.09 17.37 11.18 47.50 23.88 8.23 21.95 10.67 13.11 12.80 26.67 37.01 18.01 19.99 16.00 32.99

6.57 5.32 25.81 5.16 3.29 3.95 10.23 6.50 6.14 3.50 3.67 4.69 30.09 19.65 7.98 4.52 37.69 34.00 5.37 22.28 27.05 4.23 4.35 4.15 17.43 8.87 49.59 6.70 4.72 10.63 12.83

38 51 18 32 68 73 32 11 28 53 80 61 11 44 41 86 26 14 44 16 5 44 45 85 7 25 15 38 77 28 0

170 87 9 87 1200 473 140 66 140 92 124 155 45 110 41 114 65 72 570 43 110 136 83 167 53 132 166 100 122 118 169

243 269 74 227 477 660 383 186 96 194 342 294 66 95 106 280 74 7 121 0 89 183 485 242 168 346 120 215 272 436 560

279 216 20 177 349 393 209 157 103 118 176 131 44 72 64 120 41 72 234 114 52 148 182 178 71 272 81 190 209 225 510

19 22 dl 23 66 76 29 40 25 26 35 30 14 18 17 24 11 14 74 32 15 38 41 40 17 54 25 45 40 37 41

255 207 206 202 141 181 241 208 161 166 188 184 224 196 196 246 260 130 173 137 206 172 140 147 256 366 431 419 385 510 306

650 540 351 540 910 750 880 581 790 895 846 684 801 619 772 619 615 4530 1280 370 540 790 550 600 800 590 1060 2070 1640 1020 580

477 294 109 203 267 388 326 306 270 293 385 351 284 196 275 395 295 224 520 298 157 253 279 287 272 650 338 530 610 610 413

89 65 32 80 168 181 0 75 dl 199 276 193 125 183 188 145 dl 146 289 155 252 163 138 45 197 97 421 1150 650 266 144

155 71 dl 20 53 28 316 35 97 59 72 71 146 128 82 46 90 102 63 102 63 40 25 30 87 45 204 179 146 157 75

1260 1480 580 2480 7360 5990 3790 453 582 893 1037 652 176 239 384 623 133 88 311 142 53 319 520 303 86 165 241 1060 1240 590 324

770 730 1350 1350 1190 1080 1180 362 322 306 246 219 334 385 295 261 289 126 94 177 202 214 209 41 200 84 550 550 412 520 192

2

3

4

5

1/5 2/5 3/5 4/5 5/5 1/4 2/4 3/4 4/4

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273

Table 2 (continued) Whole coal Site

Sample

Split

Bench

Thickness (cm)

Ash (dry)

Mo

1

2181 2182 2183 2184 2185 2186 2187 2161 2162 2163 2164 2165 2166 2155 2156 2157 2158 2150 2151 2152 2145 2146 2147 2148 2153 2149 2174 2176 2177 2178 2179

3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 4 rider 4 3.5 3 3 3 3 3 2 3 3 3 3 2

1/7 2/7 3/7 4/7 5/7 6/7 7/7 1/6 2/6 3/6 4/6 5/6 6/6 1/4 2/4 3/4 4/4

12.50 14.00 8.00 10.01 12.70 10.80 19.51 28.65 7.32 11.58 23.16 8.84 10.06 39.62 23.16 31.09 17.37 11.18 47.50 23.88 8.23 21.95 10.67 13.11 12.80 26.67 37.01 18.01 19.99 16.00 32.99

6.57 5.32 25.81 5.16 3.29 3.95 10.23 6.50 6.14 3.50 3.67 4.69 30.09 19.65 7.98 4.52 37.69 34.00 5.37 22.28 27.05 4.23 4.35 4.15 17.43 8.87 49.59 6.70 4.72 10.63 12.83

2 3 5 2 2 3 3 1 2 2 3 3 3 9 3 4 10 5 2 4 1 2 2 4 1 2 7 3 4 3 0

2

3

4

5

1/5 2/5 3/5 4/5 5/5 1/4 2/4 3/4 4/4

Zn 11 5 2 4 39 19 14 4 9 3 5 7 14 22 3 5 24 24 31 10 30 6 4 7 9 12 82 7 6 13 22

Cu 16 14 19 12 16 26 39 12 6 7 13 14 20 19 8 13 28 2 6 0 24 8 21 10 29 31 60 14 13 46 72

Ni 18 11 5 9 11 16 21 10 6 4 6 6 13 14 5 5 15 24 13 25 14 6 8 7 12 24 40 13 10 24 65

Co

Cr

Ba

V

1 1 0 1 2 3 3 3 2 1 1 1 4 4 1 1 4 5 4 7 4 2 2 2 3 5 12 3 2 4 5

17 11 53 10 5 7 25 14 10 6 7 9 67 39 16 11 98 44 9 31 56 7 6 6 45 32 214 28 18 54 39

43 29 91 28 30 30 90 38 49 31 31 32 241 122 62 28 232 1540 69 82 146 33 24 25 139 52 526 139 77 108 74

31 16 28 10 9 15 33 20 17 10 14 16 85 39 22 18 111 76 28 66 42 11 12 12 47 58 168 36 29 65 53

Mn 6 3 8 4 6 7 0 5 0 7 10 9 38 36 15 7 dl 50 16 35 68 7 6 2 34 9 209 77 31 28 18

Rb 10 4 dl 1 2 1 32 2 6 2 3 3 44 25 7 2 34 35 3 23 17 2 1 1 15 4 101 12 7 17 10

Sr 83 79 150 128 242 237 388 29 36 31 38 31 53 47 31 28 50 30 17 32 14 13 23 13 15 15 120 71 59 63 42

Zr 51 39 348 70 39 43 121 24 20 11 9 10 101 76 24 12 109 43 5 39 55 9 9 2 35 7 273 37 19 55 25

or bone in the case of site 5, is dominated by detrital semifusinite and fusinite, suggesting that there was some amount of reworking of the maceral assemblage. Banded vitrite and duroclarite assemblages are also present in the lithotype.

pointed out by Wüst et al. (2001) and Moore and Shearer (2003), and others, coal facies models should be used with caution and parameters should generally not be extrapolated beyond the situations or ages for which they were first developed.

4.2. Geochemistry

4.3.1. Eastern sites (3, 4, 5) The higher ash yield in the upper or terminal lithotype at sites 3, 4, and 5, along with the presence of detrital semifusinite and fusinite (Table 1), suggests a relatively high energy environment, with reworking of macerals deposited at those sites. In studies of the argillaceous durains in the No. 5 Block coal bed, Hower et al. (1994) suggested that sediment-carrying surficial waters also may have acted to oxidize the peat, creating inertinite or inertinite maceral precursors. They also raise the possibility of detrital inertinite, such as suggested by the maceral texture of the Peach Orchard No. 3 Split terminal durains (Fig. 5).

The majority of basal and terminal Peach Orchard No. 3 Split coal lithotypes are high in ash content (66.50–49.59 wt.%) composed primarily of alumino-silicates, suggesting high detrital inputs. Middle lithologies are generally lower in ash content (4.15– 25.81 wt.%), but, they too are dominated by alumino-silicates, indicators of fluvial input. The relatively high total sulfur contents of benches 3 and 4 at site 3, bench 3 at site 4, and the basal bench of site 5 may indicate a saline incursion into the Peach Orchard No. 3 Splint peats, but additional geochemical analyses will be needed to verify this. 4.3. Coal facies Coal facies have both a lateral and a vertical component. Greb et al. (2002a) and Staub (2002) demonstrated that Central Appalachian coals, as with many coals elsewhere, do not represent simple, continuous depositional systems. The bench/lithotype structure that we see in the coals represents distinct peat depositional environments. In previous studies of eastern Kentucky coals, we had, at least, limited botanical information to supplement the petrographic and geochemical interpretations (Eble et al., 1994; Hubbard et al., 2002; Hower et al., 2005, 2007; summaries of coal facies studies in eastern United States by Hower and Eble, 2004). Other eastern Kentucky studies relied strictly on a combination of geochemistry and petrology, with limited attempts at determining depositional environments (Sakulpitakphon et al., 2004; Mardon and Hower, 2004). As

4.3.2. Western sites (1, 2) Although site 2 is separated from sites 3 and 4 by only about a kilometer, the nature of the uppermost lithotype changes considerably. The sum of the contents of fusinite and semifusinite does exceed 30 vol.%, (Table 1) but it is significantly less than at the sites to the east-northeast (3, 4, and 5, with up to 40.3 vol.%, 60.6 vol.%, and 52.9 vol.%, respectively). In addition, the ash yield of 6.50 wt.%, as well as the sum of the fusinite and semifusinite contents, makes the site 2 upper lithotype more similar to the upper lithotype at site 1, 8.2 km to the northwest, than to the other three sites. Site 2 also contains a dull clarain lithotype, a lithology missing at sites 3, 4, and 5, in the same position as the site 1 durain (sample number 2183). There is a megascopic similarity of the site 1 durain, bench 3, to durains in the other splint coals both in this study and at other eastern Kentucky sites (Hower et al., 1994, 1996). Lithologies with high sums of fusinite + semifusinite may have been periodically exposed and/or

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Fig. 4. a/Fusinite (f), semifusinite (sf), sporinite (s) in a mixed assemblage. Note lack of distinct maceral boundaries within the inertinite macerals. b/Semifusinite (sf) and sporinite (s). The semifusinite in the middle of the photograph is slightly more distinct than the labeled semifusinite in on the left and right of the image.

oxidized by fire. The high ash contents of the basal and terminal lithotypes,and the high ash yield (nearly 26%) and a high macrinite content (63 vol.%) at site 1, bench 3, suggest a planar peat environment with periodic flooding with an influx of clastic sediments. This interpretation is supported by relatively high Zr and TiO2 contents, which suggest the presence of detrital zircon, anatase, or rutile, respectively. The megascopic similarity is, therefore, superficial and degradation is a more likely pathway for the development of the lithotype in the No. 3 splint coal at site 1. Although there are differences in the uppermost, terminal durains, moving east-west, the similarities in geochemistry and petrology of the middle benches do suggest some depositional connection between all of the Peach Orchard No. 3 Split coals examined in this study. 5. Conclusions The Bolsovian (Middle Pennsylvanian) Peach Orchard No. 3 Split coal is notable for its high inertinite content. While such assemblages are found in other splint coals in the Central Appalachians, the study coal has some of the highest inertinite levels found in the region (up to 73.6 vol.%). The semifusinite content is generally highest in the upper

Fig. 5. a/Macrinite and vitrinite (v), with sporinite (sp), in a clarodurite microlithotype. b/Macrinite.

and lower benches of the studied coals. The high-semifusinite lithologies also have the highest mineral contents, up to nearly 50 wt.% ash yield in the 47.9 vol.% semifusinite upper lithotype at site 5. The maceral assemblage of the latter durain/bone is dominated by detrital fusinite and semifusinite, suggesting reworking of the maceral assemblage coincident with the deposition of the detrital minerals. Not all high-inertinite lithologies have the same depositional signature. For example, the inertinite macerals in the 63 vol.% macrinite durain in the middle of the site 1 profile have less distinct edges than semifusinites in the terminal durains, suggesting degradation as a path to inertinite formation, although the possibility of partial fixation by fire cannot be eliminated. On the basis of coal petrology and the relative amounts of mineral matter, it is suggested that the termination of the peat at the eastern sites (3, 4 and 5) occurred in different depositional environment than at the western sites (1 and 2). Even though site 2 is separated from sites 3 and 4 by only a kilometer, the nature of the terminal durain changes from the high-ash, high-semifusinite lithotype in the east (sites 3–5) to a relatively low-ash lithotype with significantly less semifusinite in the west (sites 1 and 2). The petrographic changes over such a short distance reinforce the impression that Central Appalachian coals show considerable vertical and lateral (temporal and spatial) changes in lithology, as indicated by other researchers (Greb et al., 2002a, b; and Staub, 2002). High sulfur contents may

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