BEDROCK GEOLOGY OF PITTSBURG QUADRANGLE Illinois Department of Natural Resources Illinois Geologic Quadrangle Map ILLINOIS STATE GEOLOGICAL SURVEY WILLIAMSON AND FRANKLIN COUNTIES, ILLINOIS IGQ Pittsburg-BG William W. Shilts, Chief W. John Nelson 2007

Thompsonville -75 Gª3480 3502ª oil field 35409 -150 3494 G G 3499 3480 Gª3250 9 ' ª G9 G G' Gª 3472 9 3485 -50 3142 3681 &b Gª3504 Gª3485 ª3450 3193ª

&sp G -125 C C 574 ª3155 k" k" 644 k" G G 3180 C 724 3470 C ' ª k" 552 C k" 522 h3115 ª 672 2995 Corinth North k" Johnston City -25 oil field -100 Gª2997 Northeast oil field EXPLANATION G G 3023 G 3000 ' h k G 3208 2893 ª sm G G G 2950 Surface mine G ' ' G 3075 ' 2889k ª G 3232 2905 2885 -75 e" ª G 2998 G 2994 G 2994 672 ª k ª G k3212 &b Bond Formation Missourian

C 500 k" 0 Ck" 510 2136 Shelburn and Patoka C w G 2985 G C k" k" 595 Pennsylvanian &sp Formations undivided k 2965k C Madison Coal Co. k" p w, Womac Coal Member Hole #25 554 -50

) p, Piasa Limestone Member 25 G 3016

) ª &sp

G 3136 &sp h ) Desmoinesian 50 k Carbondale Formation

&c 75 ) h, Herrin Coal Member G 2950

G 700 100 ) ª G -25 e" ª3247

ª3127 ) 125 k"468 k"

) 604

0

150 ) ) 500

445 k" · k"

472

175 ) k" &sp )G ) G C 25 G 3160

k2719 200 k" 433 C 522

ª2968) 75 k" C C 578 k

) k" 527 k" C 385 ) k" · 25

k" k" C 519

393 ) G

) ) G 459 k 50 3155 ) iÜ

) G 2748 G )

' Ck" C 535

) Symbols k2696 · k" ) 242 )

G G 500

G 2758 275 G ) 50

'G *' 225 ª * 75 G 3138 ) 3040 Abandoned drift mine 2672* 2869 ) ª

G 2065 ) e"

G ) G &sp 534

* G 2317 250 ) G

G C O 3165

' ' '· 75 ½ Abandoned shaft mine * ) i ' 2743 2720 2075 C C

225 Ck"240 k" k" 610 G G G G G 307 ) G '2730 290 T T G 3055 550

' ' ' G e"

k 2898 2317 2289 G ) k ¾ Abandoned slope mine

k ª3065

2772 )

2800 200 G 2800 · A G

G 2653 C G G

Johnston City ' k" ª k ) i 100 G Strike and dip of bedding; number indicates degree of dip. 2719 w 20 248 ) 890 3186ª

275 o East oil field E 250 ) If no number, symbol indicates direction of dip only.

·

· G 2757 300 A� G 3170 G

' ) 125 e" h G 3033

o50) ª 3160ª

175 G G 3118 100 · G 2775 2800 G 2841 ) Horizontal bedding i H G 3216 G

k"373 k k ª G 3146 C 287 ) C k C 482

279 e" G k" k" 3142k

225 · k" C 491 557k" C h ) k" · k" Vertical joint 300 C 114 537 230 · Ä

· G 3070 G 2803 k" &sp p ) G R G G 3136

150 h k350 125 '3118 ) k 325 e · 2860 G G 2644 Bedrock outcrop

o G 2750 G 4041 G 2917 G 479 k j ) e" G G G 3090 G 2745 g ' k

· k" C O V ª3100 ' ' h · ) 3155

175 k 75 · 133 3155 · G 2641 Pittsburg North 3125 G ' G 2895 493

· oil field k e ) e" j Drill Holes 375 400 Gª 3134

175 · E from which subsurface data were obtained G 2745 G 2650 )

252 k" ' ª · G'3550

C C )

· · ·

k" J C

o N e" 2 465 · 44 Stratigraphic boring

150 281 G 0 G G 2800 k" 150 0 325 ) · G

1 2928k *Ü k e"

2

2835 J 5 N 449 k3130 ) Corinth oil field

G e" Water well

J G G

G 2904 N 496 G 3055 G G G G G 3114

e" k2678 ) · · G 4785 j ' ' ' ' k

k ª 3155 k 3059

) 317 3014 3022 3036 3120

e" J ) ) k N e" Coal boring

G G G · J 175 G G G G 3042

· ) N 3125 k ) ª ' ' ' ) 2843 G 2740 2950h 3088 3120 k

200 AF G 1375 3050

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N G Oil well

&sp J ª 2919 G

N 3150

) J G G G 3029 G G G G 325 N 3125

225 G

) · h ' ' ' ) k 2766ª 2915h k k 3005 k

) 2915 3033 3018 e" 445

225 J

N 250 Dry hole

J ) G G G N ª · LU G 2960 ) 275 2980 G G G 3080 · G

275 ª ' k ' 3087 '

) 2903 125 k ) 2971 ª j ) Ce" 300 2908 &sp Dry hole - show of oil

· G 3025 G 2910

J k 393 ) G 3032

) N G · ' ) k ª ' T 3107 ) i Dry hole - show of gas G ) · 300 ' G' ½ 2900 2912

) k" · Dry hole - show of oil and gas

273 150 ) 402 G 3005 h k" G G 3077 ) G NJ ' 250 N k J N S Y S T E M ª ) 2779 N N k NJ N J o 175 J J 2655 J N 200 426 305 Gas well

200 N N J e" e" * ) J J G

298 NJ N N e40 e" N J

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e" ) 495 G 2780 458 390 e" Gas well - show of oil

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175 ) G 2612 ) 319

) G 2625 N J

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) ) 300 k e" k )

200 ) Oil well - abandoned

) ) G 225 ) 200 9 ) )

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) ) 2689 N 490 ) J e" ) e" 435

225 ) ) Numbers indicate total depth of boring in feet.

) 275 G 2826 350 ) 225

) ) ) CSG 459

) k

) NJ 375 Boring with samples (S), geophysical log (G), or core (C); )

k 25 o

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) )

) ) ) k" 400 ) 250 Dot indicates location accurate within 100 feet.

) ) o )

) 323 ) 50

e" 250 5 )

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) 30

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p )

) ) ) GS G G )

250 2898 ) G 3096 Line Symbols

248 ª k 2780ª k)

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2845 ) k" Ä dashed where inferred, dotted where concealed

½ )

½ 223 Corinth South 17 o ½ )

½ e" 147 o G 225 gas field k" ) 400 ) ª p 20 Contact or coal subcrop 2774 2823 G A G 351 275 GS* ª2830 e" e"128 g 2829 Fault, direction of throw unknown &sp e G 2944 G 6600 e" &sp 200 k k Pittsburg 195 224 e" G 7100 Normal fault: bar and ball on downthrown side gas field G 2720 h G k 350 · i Fault, type unknown: ticks on downthrown side 1984 325 G 2817 G 2972 300 k 325 ª ) ) ) G 2570 High-angle reverse fault: sawteeth on upthrown block * G

ª2897 300 Strike-slip fault p

G ½

ª2580 o 425 Elevation of top of Herrin Coal; contour interval 25 feet

kG 325 ½ ½ 2555 265 ½ H e" 504 Anticline observed in outcrop k" o

C e" G

360 3 k" 70 o � Line of cross section G 2790 A A k &sp 23 Crab Orchard e" Note: This is a subcrop map, showing bedrock surface with all gas field 293 e" Quaternary deposits removed. Geology shown as it was prior to ½ 209 250 350 G 2250 surface mining. Faults are shown where they intersect Herrin Coal. &sp Gk gª 2259 2810 Well and boring records are on file at the ISGS Geological G 2820 Records Unit and are available from the ISGS Web site. g 275

S 73 p 300 375 k" Ä h 325 G 2692 k Gh2816 350 &c

e" 60 375 Gk2838 Gk2750 sm Á sm h sm

Base map compiled by Illinois State Geological Survey from digital data provided by the SCALE 1:24,000 Geology based on field work and data analysis by W.J. Nelson, 2001–2003. United States Geological Survey. Topography by photogrammertric methods from aerial 1 1/ 2 0 1 MILE photographs taken 1959. Field checked 1963. Digital cartography and graphics by J. Domier, S. Geegan, T. Goeppinger, and L. Verhelst, 1000 0 1000 2000 3000 4000 5000 6000 7000 FEET Illinois State Geological Survey. North American Datum of 1927 (NAD 27) 1 .5 0 1 KILOMETER Projection: Transverse Mercator The Illinois State Geological Survey, the Illinois Department of Natural Resources, and the 10,000-foot ticks: Illinois State Plane Coordinate system, east zone (Transverse Mercator) State of Illinois make no guarantee, expressed or implied, regarding the correctness of the 1,000-meter ticks: Universal Transverse Mercator grid system, zone 16 interpretations presented in this document and accept no liability for the consequences BASE MAP CONTOUR INTERVAL 10 FEET of decisions made by others on the basis of the information presented here. The geologic NATIONAL GEODETIC VERTICAL DATUM OF 1929 interpretations are based on data that may vary with respect to accuracy of geographic Recommended citation: location, the type and quantity of data available at each location, and the scientific and Nelson, W.J., 2007, Bedrock Geology of Pittsburg Quadrangle, Williamson and Franklin technical qualifications of the data sources. Maps or cross sections in this document are Counties, Illinois: Illinois State Geological Survey, Illinois Geologic Quadrangle Map, Released by the authority of the State of Illinois: 2007 not meant to be enlarged. IGQ Pittsburg-BG, 2 sheets, 1:24,000.

1 1 /2 ° ADJOINING ROAD CLASSIFICATION 123 QUADRANGLES M A TR 1 West Frankfort G Primary highway, Light-duty road, hard or

N UE NOR UE

E hard surface improved surface

2 Thompsonville TI

3 Akin C Secondary highway, 45

N TH 4 Johnston City O hard surface Unimproved road

R

5 Harco T

For more information contact: H 6 Marion Illinois State Geological Survey 678 7 Crab Orchard 615 East Peabody Drive 8 Carrier Mills APPROXIMATE MEAN Champaign, Illinois 61820-6964 DECLINATION, 2007 (217) 244-2414 http://www.isgs.uiuc.edu

IGQ Pittsburg-BG Sheet 1 of 2 MEMBER McLeansboro Group Carbondale Formation Introduction The Springfield Coal varies from 3 to 5.5 feet thick in the Pittsburg Quadrangle TION THICKNESS or GRAPHIC COLUMN and probably has a low (less than 2%) sulfur content in most of the area. Only OUP or (FEET) Bond Formation 30 Herrin Coal Member Bright-banded bituminous coal containing This map depicts the bedrock formations of the Pittsburg Quadrangle as they

UNIT small areas of Springfield Coal have been mined underground in Secs. 11 and BED SERIES

SYSTEM several shale and pyrite partings, of which the “blue band” is thickest and would appear if all Quaternary surficial materials were removed. The entire GR 12, T9S, R3E and Sec. 3, T9S, R4E. Faults and oil test holes (dry or producing)

FORMA 1 Mt. Carmel Sandstone Member Light to medium gray, weathering most continuous. The “blue band” is generally less than 0.2 feet thick and map area is blanketed with Quaternary sediments, which include glacial drift, are the principal obstacles to mining. Judging by conditions in nearby mines, orange; fine- to medium-grained lithic arenite with abundant mica and lies 1 to 2 feet above the base of the seam. The Herrin has been mined wind-blown silt (loess), and stream sediments. Rock outcroppings are confined carbonaceous debris. On outcrops, the sandstone is soft, friable, and the Springfield Coal here should offer consistent thickness without serious extensively underground in the western part of the map area. The coal to streams and road cuts, mostly in the southeastern and west-central portions rolls, splits, or other geologic interruptions. The gray silty shale is moderately “mealy” and either cross-bedded or massive. It apparently fills channels is generally underlain by several feet of gray, massive, slickensided, and that cut out underlying units. of the map area, where surficial deposits are thinnest. My own observations competent as mine roof. Several nearby mines have encountered difficulties rooted mudstone (underclay). were supplemented by field notes of previous Illinois State Geological Survey 2 Carthage Limestone Member Light gray, “dense,” massive, 31 Higginsville Limestone Member Light gray to brownish gray, from in situ stress, which promotes strongly preferential roof failure in mine Mt. Carmel 80 1 argillaceous, especially at base. Known only from core of Madison Coal micritic, nodular bedding with streaks of greenish gray shale; lower part (ISGS) geologists; these notes are on file at the ISGS library and include infor- openings oriented north-south to north-northwest. Turning the main entries at Bond Sandstone Co. Hole No. 21 in Sec. 5, T8S, R4E, where the limestone is about 7 feet contains marine fossils. In places, the limestone grades to mudstone mation on rock exposures that no longer exist. However, the information that 45° to the principal stress axis (in this area, approximately N 80° E) minimizes thick. containing scattered carbonate nodules. can be gleaned from the small, scattered outcrops is meager. stress-related roof falls. 32 Clastic interval Gray shale, siltstone, and fine-grained sandstone Shelburn and Patoka Formations, undivided that may either fine upward or coarsen upward. Shale contains linguloid Drill-hole records, on file at the ISGS, provide far more useful geologic Coal seams other than the Herrin and Springfield offer marginal prospects for 7 2 brachiopods and pectenoid pelecypods. information than do outcrops. The Pittsburg Quadrangle has been thoroughly underground mining. The Davis and Dekoven Coals have maximum thick- Carthage Ls. 3 Clastic interval Black, highly fissile shale 2 to 3 feet thick directly 33 Briar Hill Coal Member Generally shaly; in places consists of explored by drilling for coal, oil, and gas. Coal test boreholes provide accurate nesses of 5 and 4 feet, respectively. The Murphysboro Coal can be as thick as 6 underlies the Carthage Limestone. The remainder of the interval is mostly several thin coal layers or laminae separated by carbonaceous shale. drillers’ logs and, in many cases, core descriptions made by ISGS geologists. In feet but is highly lenticular. Other coal beds are 3 feet or thinner throughout the gray shale, silty shale, and siltstone forming an upward-coarsening More persistent to southeast. sequence. Siderite nodules and plant fragments are common. Sandstone addition to publically available records, confidential coal test information was map area. 34 St. David Limestone Member Dark gray to nearly black, provided by coal companies. Such wells are not plotted on the map, but their is present in some wells; it fills channels and forms an upward-fining fossiliferous lime mudstone and wackestone that is argillaceous and logs were used to map coal structure. Most oil and gas test holes have elec- 3 sequence. A coal bed a few inches thick occurs locally in the upper part grades laterally to calcareous shale. This unit disappears eastward, Coal Bed Methane of the interval. The logs of several cored coal test boreholes indicate a where the Dykersburg Shale becomes thickest. tric logs and/or other geophysical logs or sample studies made by geologists. Methane is being produced from wells drilled into virgin coal within a few thin unit of dark gray, argillaceous limestone or calcareous shale 20 to 30 35 Turner Mine Shale Member Black, highly carbonaceous, thinly Together, these logs provide a detailed, accurate record of the stratigraphic miles east and southeast of the Pittsburg Quadrangle. These wells represent the 0–2 feet above the Macoupin Limestone. fissile or “slaty,” pyritic; exhibits very high gamma-ray readings. This column and ample information for mapping geologic structure. first commercial production of coal bed methane in Illinois. Wells to date have 4 Macoupin Limestone Member Dark gray, very argillaceous lime unit also disappears eastward, where the Dykersburg Shale becomes been completed to produce from only one or two coal seams apiece, with the mudstone containing poorly preserved fossils, including worm tubes and thickest. A third valuable source of information is underground coal mines. Faults are Herrin, Springfield, Dekoven, and Davis Coals targeted. Considering the entire Macoupin Ls. the nautiloid cephalopod Pseudorthoceras sp. The limestone may be 0.5–2.0 4 36 Dykersburg Shale Member Medium gray, silty, indistinctly bedded commonly (albeit inconsistently) depicted on mine maps prepared by the engi- stratigraphic column through the upper Tradewater Formation, total coal bed both overlain and underlain by black, highly fissile shale that contains shale that contains siderite nodules, plant fossils, and pyrite crystals. It neers and surveyors who worked for the coal companies. ISGS conodonts. Exposures in railroad cuts and surface mines in Secs. 11 and thickness in the Pittsburg Quadrangle averages about 25 feet. Faults enhance 25–50 5 generally coarsens upward, grading to siltstone in the upper part where geologists mapped faults extensively in active mines during the period 1975 methane production because fractures allow gas to flow more readily. Several 14, T8S, R4E are described in ISGS field notes. thick. The Dykersburg is thickest to the southeast. Womac Coal 5 Clastic interval Massive gray, calcareous claystone that contains to 1985. Many details of structure in these mines are published (Nelson and coal bed methane wells in Saline County appear to have been deliberately 0–3.0 6 37 Springfield Coal Member Bright-banded bituminous coal, Krausse 1981). Maps of the Zeigler, Orient, and other abandoned coal mines root casts directly underlies the Macoupin Limestone or associated black containing pyrite laminae, lenses, and cleat facings, but lacking drilled into or along faults. show the locations of faults and, in many cases, include surveyed elevations of shale. Below this is an interval of gray shale, silty shale, siltstone, and fine continuous mudstone partings. Underground mining has taken place in sandstone that generally coarsens upward. Abundant and well-preserved the southeast corner of the map area. the Herrin Coal. Gas from abandoned underground mines also has been tapped in several areas

MISSOURIAN fossil plants were collected from gray shale overlying the Womac Coal in 38 Clastic interval Generally a gray, rooted massive mudstone of Williamson County. surface mines, located in the N½ of Sec. 14, T8S, R4E. (underclay) directly underlies the Springfield Coal. This interval is Stratigraphy 7 80–95 6 Womac Coal Member Widespread in the map area, but generally locally underlain by nodules and lenses of silty or sandy limestone. The Oil and Gas thin, lenticular, and shaly. Where it was mined in Sec. 14, T8S, R4E, the remainder of the interval coarsens upward from gray shale at the base to McLeansboro Group Six oil fields and two gas fields have been developed within the quadrangle. coal was as thick as 3.0 feet and had a sulfur content less than 1%. The gray siltstone or fine-grained, shaly sandstone in the upper part. Pennsylvanian strata overlying the Herrin Coal in this map area are assigned Altogether they have yielded more than 2 million barrels of oil and several thick coal was shaly near the base, grading downward to hard, black, 39 Hanover Limestone Member Dark gray, argillaceous, fossiliferous to the McLeansboro Group. According to the Tri-State Committee (2001), the hundred million cubic feet of gas. Cramer Ls. thinly fissile shale that contained fossil plants. lime mudstone to wackestone. McLeansboro constitutes the Shelburn (oldest), Patoka, Bond, and Mattoon 7 Clastic interval Grading from medium gray siltstone or fine-grained, Chapel Coal 40 Excello Shale Member Black, highly carbonaceous, thinly fissile (not shown) Formations throughout the Illinois Basin (Illinois, Indiana, and 8 shaly sandstone in the upper part through silty shale to dark gray clay The largest oil field in Williamson County is Johnston City East, partially 9 shale that yields very high gamma-ray readings. western Kentucky). These formations are essentially similar in overall lithol- shale in the lower part. In a few wells, a thin layer of black, calcareous, in the map area in Secs. 15 and 16, T8S, R3E. Discovered in 1959, the field McLeansboro Group 41 Houchin Creek Coal Member Bright-banded bituminous coal. ogy; their boundaries are based on widely traceable limestone members. The 550 maximum 10 fossiliferous shale is about 20 feet above the base. 42 Clastic interval Similar in lithology to Interval 21, above; but thinner. comprises 20 wells. As of the end of 2004, cumulative output was 1,228,600 Shelburn-Patoka contact is defined as the top of the West Franklin Limestone 8 Cramer Limestone Member and underlying shale The limestone Siderite nodules and fossil plants occur in the lower part. barrels from the 14 producing wells. The Aux Vases Formation is the chief atoka, undivided is medium to dark gray, argillaceous and fossiliferous. It forms either a 43 Survant Coal Member Banded bituminous coal. In most of the map Member or its equivalent, the top of the Exline (Scottville) Limestone (Tri- reservoir, followed by the Cypress Formation. Four wells produce from the Ste. single bed or two thin beds separated by a few feet of shale. Below the area, the Survant comprises two benches of coal that are separated by 8 State Committee 2001, p. 16). Genevieve Limestone and one from the Bethel Sandstone. Some gas has been Tr ivoli Sandstone 11 limestone may be either black, thinly fissile shale or gray, silty shale. to 20 feet of shale, siltstone, and sandstone.

n and P recovered from the Tar Springs Formation and shows of gas are reported in the 9 Chapel Coal Member Lenticular and shaly, grading to carbonaceous Neither the West Franklin nor Exline (Scottville) Limestone exist in William- ur 44 Clastic interval Either coarsening or fining upward. Where the Hardinsburg Formation. These formations are not shown. shale. In this map area, the coal is more commonly absent than present. 120–140 interval coarsens upward, sandstone in the upper part gradually changes son County. I constructed a cross section from the northeast corner of Wil- 10 Clastic interval Gray shale, siltstone, and fine-grained sandstone. downward to siltstone, silty shale, and dark gray clay shale. Where the liamson County into White County, where the West Franklin Limestone is well Shelb Most wells were completed by sand fracturing and produce through perforated These rocks form either an upward-coarsening or an upward-fining interval fines upward, it is largely sandstone that has an erosional lower developed (the cross section is presently unpublished but will be included in sequence. The latter is composed largely of sandstone having an casing. Water flooding was undertaken beginning in 1966 in two separate units. contact, cutting downward nearly to the Colchester Coal. the county bulletin in preparation). The section shows that the upper bench of erosional lower contact. 45 Mecca Quarry Shale Member Black, highly carbonaceous, thinly The field occupies the Pittsburg Anticline, which parallels the master fault 12 11 Trivoli Sandstone Member Light gray to brown, fine- to medium- the West Franklin pinches out about 12 miles northeast of Williamson County. of the Cottage Grove Fault System. Two separate domes are separated by dry fissile shale that exhibits very high gamma-ray readings. This limestone terminates within shale a short distance above the Lake Creek grained, micaceous lithic arenite with plentiful carbonaceous debris and 46 Colchester Coal Member Banded bituminous coal. holes. Pay zones are lenticular oolite shoal or bar deposits in the Ste. Genevieve Coal Member. a clay matrix, commonly iron-stained and containing interbeds, laminae, 47 Clastic interval Either a massive, rooted gray mudstone (underclay) and offshore sand bar or tidal sand ridges in the Aux Vases, Bethel, and Cy- Lake Creek Coal 0–0.5 13 and partings of shale. Cross-bedding, prominent in most outcrops, dips or a thin limestone directly underlies the Colchester Coal. The remainder press. Hence, the field combines structural and stratigraphic trapping. mostly south or southeast. A basal conglomerate is locally present, and of the interval generally consists of shaly sandstone in the upper part and Because there is no lithologic change nor mappable bed to mark the 35–45 14 the lower contact is erosional. The Trivoli fills channels locally eroded as gray siltstone or silty shale in the lower part. Shelburn-Patoka contact in the Pittsburg Quadrangle, these formations are The Pittsburg North oil field lies along the southeastern continuation of the deep as the Lake Creek Coal. The best exposure is in the railroad cut in 48 Dekoven Coal Member Bright-banded bituminous coal. In most of mapped as “undivided.” Pittsburg Anticline and contains five oil wells interspersed with dry holes. Attila Shale 2–6 15 Sec. 36, T8S, R4E. the map area, two coal benches are separated by shale; the upper bench 0.7–1.2 16 12 Clastic interval Most cores show a sequence that coarsens upward Four wells were still pumping at the end of 2004, when cumulative production Pond Creek Coal is thicker. The contact between the Patoka and Bond Formations is defined as the base of reached 120,000 barrels. Lenticular sandstone bodies in the Aux Vases Forma- from dark gray, well-laminated, sideritic clay-shale at the base through 49 Clastic interval A gray, massive, rooted mudstone (underclay) the Carthage Limestone. The Carthage was identified in a single well near the 20–25 17 medium gray silty shale and siltstone to light gray, very fine- to fine- tion were the pay in three wells; one produced from the Bethel (incorrectly directly underlies the Dekoven Coal. The remainder of the interval northeast corner of the Pittsburg Quadrangle. In nearby wells, the Carthage ap- grained, thin-bedded and shaly sandstone at the top. Calcareous shale called Benoist by oil companies) Sandstone. In addition, gas has been produced De Graff Coal contains varying proportions of gray shale, siltstone, and sandstone. parently was eroded and replaced by the overlying Mt. Carmel Sandstone. The Piasa Ls. 0–0.7 18 or, locally, impure limestone containing marine fossils is found locally Black, fissile shale directly overlies the Davis Coal in some boreholes. from sandstone in the Hardinsburg Formation. 2–4 19 Patoka-Bond contact has been extrapolated at the projected horizon of the base Danville Coal near the base. In the railroad cut mentioned above, this interval has an 50 Davis Coal Member Bright-banded bituminous coal. 0.5–2.5 20 erosional lower contact and fines upward from sandstone at the base to of the Carthage Limestone. Two deep tests were drilled in the Pittsburg North oil field. The C.E. Brehm shale at the top. 21 No. 1 Shannaford in Sec. 24 bottomed at 4,785 feet in Lower Devonian strata; 13 Lake Creek Coal Member Thin, shaly, and discontinuous, grading Tradewater Formation 30–40 Attila Shale Member the C.E. Brehm No. 1 Harris in Sec. 25 reached a total depth of 8,500 feet in Allenby Coal 22 laterally to carbonaceous shale. Overlying the coal (or its position) is 51 Clastic interval Gray, massive, rooted mudstone (underclay) directly The black shale unit that overlies the Pond Creek Coal Member (McLeansboro the Lower Ordovician Knox Group. The latter is the deepest borehole in Wil- black, hard, calcareous shale that contains small limestone nodules or Group) is herein designated as the Attila Shale Member. The unit is named for Bankston Fork Ls. underlies the Davis Coal. The remainder of the interval includes gray liamson County. The only show of oil reported was in the Mississippian Salem 2–10 23 concretions. sandstone, siltstone, and shale and tends to coarsen upward. In some the unincorporated village of Attila in Sec. 4, T9S, R4E. The type section is in Anvil Rock Ss. 14 Clastic interval Directly underlying the coal is greenish gray, Limestone in the Shannaford hole. These formations are not shown. and Lawson Sh. boreholes, channel-filling sandstone may cut out the Carrier Mills Shale. the bed and bank of Rock Creek approximately 1,600 feet from the north line massive claystone (underclay) that has hackly fracture, abundant Conant Ls. 50–70 24 52 Carrier Mills Shale Member Black, highly carbonaceous, thinly and 1,200 feet from the west line of Sec. 9, same township. At this locality, the slickensides and fossil root casts. Limestone nodules or a discontinuous, The Corinth oil field, mostly in Sec. 21, T8S, R4E, contains 22 wells and is Jamestown Coal fissile shale. A thin band of coal (not shown) may occur at the base. very argillaceous limestone underlie the mudstone. The remainder of Attila Shale is a black, hard, thinly fissile, well-jointed shale 2.7 feet thick. It the second largest field in the county, having a cumulative output of 622,800 Brereton Ls. 0–2 25 Gamma-ray readings are very high. This is the oldest “hot” Pennsylvanian 0–1 26 the interval coarsens upward, grading from siltstone or very fine-grained directly overlies the Pond Creek Coal Member, but locally a lens of dark gray barrels at the end of 2004. Eleven wells were still pumping at that time, with Anna Shale 4–20 27 shale in the area. The Carrier Mills rests directly on the Stonefort sandstone in the upper part through silty shale to clay shale in the lower shale up to 2 feet thick separates the coal from the Attila Shale. In turn, the At- Energy Shale 2–5 28 Limestone in places, but more commonly, an interval of green to gray nearly all production coming from the Aux Vases. Three or four wells have 0–29 29 part. Dark gray shale and light gray siltstone or sandstone commonly tila is overlain by about 10 feet of dark gray, slightly silty shale. Herrin Coal 5.3–8.9 30 shale or mudstone separates the two members. also recovered oil from the Ste. Genevieve Limestone. The best initial produc- 3–8 are interlaminated; the interval displays planar, ripple, flaser, and cross- 53 Stonefort Limestone Member Gray to greenish gray, argillaceous, tion was 197 barrels of oil per day. Most wells underwent acidizing and sand Higginsville Ls. 0–8 31 lamination. The Attila is readily recognized on coal test drilling records and most geo- 15–40 probably micritic. The limestone appears to be absent in most of the map fracturing to enhance oil flow. Water flooding commenced in 1971 and contin- 32 15 Attila Shale Member Hard, thinly fissile or “slaty,” calcareous, well Briar Hill Coal 0–1.2 33 area. physical logs throughout northern Williamson and adjacent counties. The shale ues today. The Corinth field lies north of the master fault of the Cottage Grove jointed, exhibits very high gamma-ray readings. In some cores, medium 0–3 34 54 Clastic interval Mudstone, shale and siltstone; locally sandstone, produces very high (“hot”) readings on gamma-ray logs. On resistivity logs, Fault System, on a structural terrace that lacks significant closure. The trap gray shale as thick as 10 feet intervenes between the black shale and the generally coarsening upward. the shale produces a sharp and distinctive inflection. The Attila is a typical 0–5 35 appears to be primarily stratigraphic within a lens-shaped sandstone deposit. St. David Ls. Pond Creek Coal. The gray shale is silty and contains siderite nodules 55 Mt. Rorah Coal Member Banded bituminous coal, lenticular, absent Pennsylvanian black “slaty” shale comparable to the Anna, Excello, and Mecca Turner Mine Sh. and pectenoid pelecypods. in most of map area. Quarry Shale Members in the Carbondale Formation. Part of the Thompsonville oil field is at the northeast corner of the quadrangle. Dykersburg Shale 16 Pond Creek Coal Member Bright-banded, locally shaly coal that is 56 Clastic interval Composed largely of shale and siltstone, but 11–80 36 thin but persistent. Discovered in 1940, the field contains 44 wells, of which 8 are currently pump- Springfield Coal contains sandstone in some boreholes. These rocks may either coarsen 17 Clastic interval Directly beneath the coal is greenish gray to or fine upward; fining upward is more common. Geologic Structure ing. Total production is 444,000 barrels from reservoirs in the Ste. Genevieve olive-gray mudstone (underclay) that has hackly fracture, abundant and St. Louis Limestones (Mississippian; not shown). The traps are stratigraph- 57 Murphysboro Coal Member Present only locally, mainly to The Pittsburg Quadrangle is situated near the southern margin of the Illinois slickensides, and fossil root casts. The remainder of the interval either ic. southeast. May consist of two coal layers separated by shale or Basin. Bedrock strata dip north-northeast into the basin at an average rate of 3.3–5.5 37 coarsens upward or fines upward. Where it coarsens upward, the interval mudstone. about 60 feet per mile, which equals about 1 foot in 85 or 0.7° of dip. Structure grades from siltstone or very fine-grained sandstone in the upper part 58 Granger Sandstone Member Light gray to buff, very fine- to The Johnston City Northeast oil field in Secs. 3 and 4, T8S, R3E contains four through silty shale to dark gray clay shale in the lower part. Shale at the of the Herrin Coal, shown by contour lines on the map, closely mirrors struc- coarse-grained lithic arenite to sublitharenite, with abundant mica and wells, all completed in the Aux Vases. One came in at 780 barrels of oil per

ANIAN 38 base may be black, calcareous, and contain marine fossils. Where the carbonaceous debris. Core samples show cross-bedding and cross- ture of the Mississippian Kinkaid Limestone. V 55–75 day, but production rapidly declined until the field was revitalized by injecting interval fines upward, gray plant-bearing silty shale and siltstone in the lamination along with wavy and planar lamination. The sandstone water into the formation. As of 2004, total production was 309,000 barrels. Hanover Ls. upper part grade downward to sandstone. In the southern part of the map generally fines upward from an erosional lower contact, but as many as The Cottage Grove Fault System crosses the central part of the map area. The 0–2 39 area, these strata fill channels or incised valleys eroded as deeply as the There is no structural trap; a lenticular reservoir rock limits production. Excello Shale three superimposed upward-fining sequences may be present. system is approximately 80 miles long, extending from Gallatin County on the 3–5 40 Bankston Fork Limestone (Unit 23). Houchin Creek Coal 1–3 41 59 Shaly interval Dominantly shale and siltstone, with minor sandstone east to Randolph County on the west. The fault system is mapped in detail from PENNSYL 18 De Graff Coal Member Shaly coal. Thin mudstone (underclay) The Corinth North and Corinth East oil fields both consist of single wells and thin, lenticular coal. Several fining- and coarsening-upward drilling information and encounters in underground mines. beneath the coal contains fossil root casts. sequences are present but not readily correlated from well to well. As that were drilled in 1957 and plugged in 1960. Corinth East yielded 10,600 19 Piasa Limestone Member Light gray to buff and greenish gray, 325–375 many as four thin coal beds are present in this interval. Thin limestone barrels, while Corinth North produced 3,700. Corinth North, in Sec. 6, T8S, 50–60 42 The principal fault, known as the master fault, is near the northeast edge of argillaceous, probably lime mudstone to packstone. Fossils, which may also be present; it was identified on density logs of a couple of wells. R4E, tapped the Aux Vases Formation; whereas Corinth East in Sec. 23, T8S,

Carbondale the system in the Pittsburg Quadrangle. Its strike trend varies from N 30° W are most common near the base, include echinoderm fragments, 60 Unnamed sandstones At stratigraphic position of “golden R4E, pumped from the “McClosky,” an oolitic limestone zone in the Fredonia brachiopods, and fusulinids. Underlying the limestone is shale that is to N 70° W within the quadrangle. It is generally a high-angle reverse fault or sandstone” of Nelson et al. (1991) and Bethlehem sandstone lentil of Member of the Ste. Genevieve. Both formerly producing wells are surrounded dark gray and fissile to black and “slaty.” narrow zone of such faults, with overall displacement down to the northeast. 0.8–2.5 Jacobson (1992). Sandstones are similar lithologically to the Granger by dry holes. Survant Coal 20 Danville Coal Member Bright-banded, bituminous. The maximum throw approaches 300 feet in Secs. 13 and 24, T8S, R3E. At 8–20 43 Sandstone but are discontinuous, commonly forming upward-fining 0–1.5 21 Clastic interval Directly below the coal is gray mudstone the point where the cross section encounters the master fault, a parallel normal sequences and having erosional lower contacts. Sandstone grades The Pittsburg gas field at the western edge of the map area in Sec. 4, T9S, R3E, (underclay) that is slickensided and contains fossil root casts. This unit is laterally to shale and siltstone. A thin coal bed occurs locally just above fault and reverse fault outline a narrow slice downdropped 80 to100 feet. This comprised four wells completed in sandstone of the Tar Springs Formation. It underlain by thin but persistent sandstone that is very fine-to fine-grained the Murray Bluff Sandstone. situation was observed where entries of the Orient No. 4 Mine were driven

DESMOINESIAN and argillaceous. produced approximately 170 million cubic feet of gas before being abandoned. 50–70 44 61 Murray Bluff Sandstone Member Light gray, very fine- to medium- across the master fault (Nelson and Krausse 1981). 22 Allenby Coal Member From one to three thin, shaly, lenticular coal The Corinth South gas field includes two wells in Sec. 33, T8S, R4E. These grained, sublitharenite with less mica and carbonaceous debris than beds that grade laterally to carbonaceous shale and are separated by younger sandstones. Wavy and ripple lamination observed in core. The were drilled in 1970 and converted to gas storage in 1972 after producing 147 2–3 45 massive to blocky, rooted mudstone. Below the coal (or its position) is A second set of high-angle reverse faults lies about 2 miles southwest of the Mecca Quarry Sh. 0.3–1.0 46 sandstone typically exhibits either “blocky” or upward-fining profile on million cubic feet of gas from the Hardinsburg Formation. The Crab Orchard greenish gray mudstone (underclay) containing limestone nodules and master fault and parallels the latter. The fault geometry depicted on cross sec- Colchester wireline logs. This unit may comprise two or more stacked sandstones gas field comprises two wells in Secs. 5 and 8, T9S, R4E. Production figures fossil root casts. tion A–A' below is based on exposures in the Orient No. 4 Mine. At this point, Coal and is difficult to differentiate from adjacent sandstones. are not available. 23 Bankston Fork Limestone Member Light gray to buff and yellowish 62 Lower Tradewater strata Sandstone, siltstone, shale, thin local three steep reverse faults outline upthrown keystone blocks. This southern fault 40–60 47 gray, commonly described as cream-colored, dense lime mudstone to zone may be actually a southern branch of the master fault. coal. The succession is highly variable vertically and laterally. Sandstone Acknowledgments crinoidal wackestone that varies from massive to nodular-bedded with generally prevails; it is light gray, very fine- to medium-grained (rarely Dekoven Coal wavy streaks of shale. Glauconite and fusulinids reportedly are present. coarse), sublitharenite to borderline quartz arenite with a small amount of Between the two sets of reverse faults is an elongate anticline, the Pittsburg 24 Anvil Rock Sandstone Members and Lawson Shale Lateral I extend gratitude to the numerous landowners who granted me property access 1–5 mica and plenty of iron oxide. Shale and siltstone are generally medium Anticline. This fold provides structural traps for the Johnston City East and for outcrop study. Special thanks are given to Freeman United Coal Mining 1–7 48 equivalents. In most boreholes, the interval tends to coarsen upward, to very dark gray, sideritic, micaceous, and commonly are interlaminated. 0–2 Pittsburg North oil fields. Numerous small, northwest-trending normal faults Company and Zeigler Coal company for access to their mines and to propri- Davis Coal 7–20 49 containing very fine to fine-grained sandstone in the upper part, grading Filling sandstone, as thick as 100 feet, near the middle of the interval is 2–4 50 cross the crest of the anticline. downward through siltstone and silty shale to dark gray clay shale in the thought to be the Grindstaff Sandstone Member. The most widespread, etary maps and borehole data. lower part. The sandstone is shaly, carbonaceous, and displays flaser thick shale interval occurs at the base of the Tradewater. The core of this As shown by the cross section, the Pittsburg Anticline could be described as bedding, ripple lamination, and burrows. Thin, shaly coal or carbonaceous interval from Madison Coal Co. Hole No. 25 (Sec. 12, T8S, R3E) shows References 25–60 51 upthrown, arched strata between two branches of the Cottage Grove Fault shale containing plant remains (Cordaites) occurs in the upper part of the it to be thoroughly burrowed, containing a variety of trace fossils. Coal interval in many cores. This carbonaceous zone lacks an underclay. In is highly lenticular; the most common location is near the middle of the System. It has the geometry of a “positive flower structure,” associated with Duchek, A.B., J.H. McBride, W.J. Nelson, and H.E. Leetaru, 2004, The Cottage 2–5 52 some wells, the sandstone fills channels that are eroded down to the top succession. strike-slip faults having an element of compression. Although the amount of Grove Fault System (Illinois Basin): Late Paleozoic transpression along a 0–2 53 Carrier Mills Sh. of the Brereton Limestone. horizontal displacement has not been measured, the Cottage Grove has been Precambrian crustal boundary: Geological Society of America Bulletin, v. Stonefort Ls. 10–18 54 25 Conant Limestone Member Dark gray, argillaceous, with scattered Caseyville Formation interpreted as a right-lateral wrench fault (northeast block moved southeast). 116, no. 11/12, p. 1465–1484. 1–3 55 brachiopods and other fossils (not identified); grades laterally to dark gray Seismic reflection profiles reveal that the master fault enters the Precambrian Nelson, W.J., and H.-F. Krausse, 1981, The Cottage Grove Fault System in Mt. Rorah Coal or black, calcareous shale. 63 Caseyville Formation Roughly half sandstone, half shale basement and that the entire system has the earmarks of compressional strike- southern Illinois: Illinois State Geological Survey, Circular 522, 65 p., 1 26 Jamestown Coal Member Thin and shaly but widespread and siltstone, rare coal. The sandstone is white to light gray, very slip. The Cottage Grove may follow an ancient plate boundary (Nelson and 25–35 56 throughout the map area. Locally the coal is underlain by mudstone plate. fine to coarse grained quartz arenite. Mica, clay matrix, and other (underclay) that contains stigmarian root casts. Although not shown here, Krausse 1981, Duchek et al. 2004). impurities are inconspicuous or absent. Small quartz pebbles are Nelson, W.J., et al., 1991, Geology of the Eddyville, Stonefront, and Creal Murphysboro Coal 0–6 57 in the northern part of the map area, as much as 10 feet of dark gray Springs quadrangles, Southern Illinois: Illinois State Geological Survey to black, hard, calcareous shale that contains marine fossils is found common, lenses of conglomerate are present. Shale and siltstone Economic Geology Bulletin 96, 85 p., 1 plate. between the Jamestown and the Brereton. are medium gray to nearly black, micaceous, carbonaceous, and 27 Brereton Limestone Member Generally dark gray, micritic laminated. The Madison #25 core shows ripple lamination and ripple Coal Jacobson, R.J., 1992, Geology of the Goreville Quadrangle, Johnson and Wil- limestone (fossiliferous lime mudstone to wackestone) that is argillaceous cross-lamination, small load casts, and burrows. Thin, local coal beds Coal mining was an important industry in the Pittsburg area through most of liamson counties, Illinois: Illinois State Geological Survey, Bulletin 97, 32 and may either be massive or have nodular bedding outlined by ragged are identified on wireline logs. The Caseyville comprises a series of the twentieth century. Numerous underground mines were active in the Her- p. dark gray shale laminae and partings. Fossils mentioned in core logs upward-coarsening sequences that change laterally to upward-fining rin Coal. The largest were the Orient No. 4, Zeigler No. 4, and Old Ben No. 9 58 include echinoderm fragments, brachiopods, and fusulinids. channel-fill or incised-valley sequences. Sandstone units thicker Tri-State Committee on Correlation of the Pennsylvanian System in the Illinois

20–100 mines. The Herrin Coal has been mined out from most of the western half of Basin, 2001, Toward a more uniform stratigraphic nomenclature for rock 28 Anna Shale Member Black, highly carbonaceous, thinly fissile or than 100 feet are common; 220 feet of continuous sandstone in one the quadrangle. Extensive reserves, accessible by underground mining, remain units (formations and groups) of the Pennsylvanian System in the Illinois “slaty,” contains phosphatic lenses and pyrite. Fossils include pectenoid well represents multiple “stacked” channel sequences. Well-to-well in the eastern area. The coal in this area is 5 to 7 feet thick and has a high (3 to Basin: Illinois Basin Consortium Study 5, published jointly by Illinois, Granger pelecypods, orbiculoid brachiopods, and gastropods. Gamma-ray correlation of specific sand bodies or sequences is challenging. 5%) sulfur content. readings are very high. The lower contact is erosional. Indiana, and Kentucky Geological Surveys, 26 p. Sandstone The lower contact is a striking erosional unconformity that has 29 Energy Shale Member Light to medium gray, silty, indistinctly approximately 220 feet of relief within the map area. bedded shale (or mudstone) that contains siderite nodules and fossil plants. 35–50 59

Southwest 35–45 60 A Northeast ater w 550–650 Elevation A� (feet) ade Murray Bluff Tr Sandstone 800 800

61 50–100 Cottage Grove Fault System

600 Pittsburg Anticline master 600

fault hole ill dr Qu Womac Coal

ill hole

dr Qu Qu &sp Qu Cahokia Formation 40–50

OKAN Chapel Coal 400 400 AT &sp Shelburn and Patoka Formations Piasa Limestone &sp Grindstaff &sp &sp (above Piasa Limestone) Sandstone Shelburn and Patoka Formations &sp Herrin Coal &sp (below Piasa Limestone)

62 200 Piasa Limestone 200 Spr 15–100 ingfield Coal &c Carbondale Formation 0 &sp Houchin Creek Coal &c Herrin Coal &c &t Tradewater Formation Survant Coal Springfield Coal 0 Colchester Coal 0 eet

50 Davis Coal &c

45–90 &t AN 1 inch = 50 f &t OW -200 -200 63 Faults shown at lower angles than true for illustrative purpose. Horizontal scale: 1 inch = 2,000 feet

100 MORR Caseyville Pounds Ss. Vertical scale: 1 inch = 200 feet Vertical exaggeration: 10�

IGQ Pittsburg-BG Sheet 2 of 2