The Illinois-Kentucky Fluorite District, Hicks Dome, and Garden of the Gods in Southeastern Illinois and Northwestern Kentucky

Outlet glacier response to forcing over hourly to interannual timescales, Jakobshavn Isbræ, Greenland

Item Type Article

Authors Podrasky, David; Truffer, Martin; Fahnestock, Mark; Amundson, Jason M.; Cassoto, Ryan; Joughin, Ian

Citation Podrasky, D., M. Truffer, M. Fahnestock, J. M. Amundson, R. Cassotto, and I. Joughin (2012), Outlet glacier response to forcing over hourly to interannual timescales, Jakobshavn Isbræ, Greenland, J. Glaciol., 58(212), 1212– 1226, doi:10.3189/2012JoG12J065.

Publisher International Glaciological Society

Journal Journal of Glaciology

Download date 01/10/2021 22:52:44

Link to Item http://hdl.handle.net/11122/11057 FLD012-02-denny 2nd pgs page 11

The Geological Society of America Field Guide 12 2008

The Illinois-Kentucky Fluorite District, Hicks Dome, and Garden of the Gods in southeastern Illinois and northwestern Kentucky

F. Brett Denny* Illinois State Geological Survey, 5776 Coal Drive, Suite 2, Carterville, Illinois 62918-3521, USA

Alan Goldstein* Indiana Department of Natural Resources, 201 West Riverside Dr., Clarksville, Indiana 47129, USA

Joseph A. Devera* Illinois State Geological Survey, 5776 Coal Drive, Suite 2, Carterville, Illinois 62918-3521, USA

David A. Williams* Kentucky Geological Survey, Kentucky Geological Survey, 1401 Corporate Ct., Henderson, Kentucky, 42420, USA

Zakaria Lasemi* Illinois State Geological Survey, 615 East Peabody Drive, Champaign, Illinois, 61820-6964, USA

W. John Nelson† Illinois State Geological Survey, 615 East Peabody Drive, Champaign, Illinois, 61820-6964, USA

ABSTRACT

Minerals have been extracted from the Illinois-Kentucky Fluorite District for over 170 years. Theories concerning the inter-relationship between the fl uorite mineralization, tectonism, and igneous activity will be discussed by several geologists during this fi eld trip. The Columbia mine (vein deposit) will be visited in Kentucky, and the only mine currently producing fl uorite in this district, the Hastie Limestone Quarry (strata-bound deposit), will be visited in Illinois. The mining history of this region will be explained at the American Fluorite Museum, where numerous mineral specimens can be examined. The Hicks Dome, a Permian crypto-volcanic feature (?) in Illinois, will also be discussed. The trip will conclude with a walking tour at the Garden of the Gods Recreational Area to view the Eagle Valley Syncline and Lower Pennsylvanian units.

Keywords: ﬂ uorite, Hicks Dome, Mississippi Valley–type deposit, Illinois-Kentucky Fluorite District, ﬂ uorspar, Permian igneous intrusion

*Field trip leaders. †Honorary ﬁ eld trip leader; retired.

Denny, F.B., Goldstein, A., Devera, J.A., Williams, D.A., Lasemi, Z., and Nelson, W.J., 2008, The Illinois-Kentucky Fluorite District, Hicks Dome, and Garden of the Gods in southeastern Illinois and northwestern Kentucky, in Maria, A.H., and Counts, R.C., eds., From the Cincinnati Arch to the Illinois Basin: Geological Field Excursions along the Ohio River Valley: Geological Society of America Field Guide 12, p. 11–24, doi: 10.1130/2008.ﬂ d012(02). For permission to copy, contact [email protected]. ©2008 The Geological Society of America. All rights reserved.

11 FLD012-02-denny 2nd pgs page 12

12 Denny et al.

REGIONAL TECTONIC SETTING cambrian crystalline basement (Potter et al., 1995). This unique structure is believed to be the product of explosive and intrusive W. John Nelson igneous activity (Brown et al., 1954; Bradbury and Baxter, 1992; The Illinois-Kentucky Fluorite District is located within one Potter et al., 1995). of the most intensely faulted areas of the North American Mid- After the Alleghenian orogeny, the stress fi eld evolved from continent (Fig. 1), with vertical offsets of hundreds of meters compression to northwest-southeast crustal extension. Fault along several fault zones. Faulting includes normal extensional blocks uplifted during the compressive phase now sank, leav- with horst and grabens several kilometers in length, high angle ing narrow slices of older rock wedged within the fault zones reverse, and strike-slip. Tectonic activity has been episodic, and (Nelson and Lumm, 1985). With roughly one mile (1.6 km) of major periods of movement have been documented in the Cam- total extension, the great array of northeast-trending horsts and brian, Pennsylvanian, Permian, and Cretaceous Periods (Nelson, grabens of the Fluorspar Area Fault Complex developed (Hook, 1991). The complex array of faults began forming at least 500 1974; Trace, 1974; Trace and Amos, 1984). It is these extensional million years ago, and in some areas earth movements are still faults that served as pathways for hydrothermal fl uids, resulting in progress (Nelson, 1995). Faults are essential to mineraliza- in the vein deposits of the district. Precise timing of tectonic and tion as pathways for hydrothermal fl uids, resulting in bedded- mineralization events remains poorly constrained. Globally, the replacement as well as vein deposits. crustal extension in the Fluorspar District is most likely related to The oldest units exposed within the fi eld trip area crop out at the breakup of Pangea during Triassic and Jurassic time. the crest of Hicks Dome. The Hicks Dome is a crypto-volcanic Earth movements continued in the western part of the dis- structure that exposes Devonian rocks on top, and Mississippian trict through Tertiary and Quaternary Periods. Resulting struc- rocks along its fl anks (Nelson, 1995). Mississippian rocks are tures are mostly narrow grabens oriented northeast along with also exposed along the crest of the Tolu Arch (Baxter and Des- cross-faults oriented north-south to northwest. The overall frac- borough, 1965). Pennsylvanian rocks are present to the north, in ture pattern suggests pull-apart grabens having a component of the Eagle Valley Syncline, and in down-thrown fault blocks along right-lateral wrenching (Nelson et al., 1999). The present-day the Reelfoot Rift and Rough Creek Graben. stress fi eld is compressive along an east-west to ENE-WSW axis. Tectonic structure in the Fluorite District is inherited from Deeply buried rift structures in the vicinity of New Madrid, Mis- rifting that took place in the Cambrian during an episode of souri, continue to move in this most active earthquake region of widespread continental break-up. A narrow fault-bounded trough the Midcontinent. developed, curving from northeast in southern Illinois to east- west in Kentucky. This trench was bounded on the northwest by FLUORITE MINERALIZATION the Lusk Creek Fault Zone, on the north by the Rough Creek Fault System, and on the south by the Tabb and Pennyrile Fault F. Brett Denny and Alan Goldstein Systems. These normal faults dipped steeply near the surface The Illinois-Kentucky Fluorite District encompasses an area and less steeply at depth. The trough became an arm of the sea of approximately 1,000 square miles (Baxter et al., 1989). The where Lower (?) and Middle Cambrian sediments accumulated mineral deposits occur in veins along fault zones and as strata- to thicknesses of more than 3 km in places (Bertagne and Leis- bound bedding-replacement deposits. Typically, veins and strata- ing, 1991; Potter et al., 1995). By the Late Cambrian, the area had bound deposits are elongate parallel with northeasterly trending stabilized, but its faults remained as permanent zones of weak- fault zones in the region (Fig. 2). Fluorite mineralization is most ness that were periodically reactivated by changes to the regional always associated with a carbonate unit in both the vein depos- stress regimen. For example, portions of the Rough Creek and its and the strata-bound deposits. The largest deposits of fl uorite Pennyrile Fault Systems underwent renewed movement during were consistently found in the Ste. Genevieve Limestone. The the Acadian orogeny in Middle to Late Devonian time (Nelson Renault Limestone above and the St. Louis Limestone below also and Marshak, 1996). hosted moderate amounts of fl uorite (Fig. 3). Fluorite gravel lag Effects of the late Paleozoic Alleghenian orogeny were far deposits were also mined at several locations. more profound. Compression along a northwest-southeast axis Fluorite veins commonly are 3–12 feet (1–4 m) in width and reactivated many Cambrian-age rift faults with reverse motion, are mineralized along strike of the fault for several hundred feet. particularly along the northern and northwestern margins of Large veins may extend vertically for over 300 ft (100 m) and the rift (Nelson and Lumm, 1987). Vertically dipping strike- have widths of up to 45 ft (15 m). Fluorite in the veins occurs in slip (?) faults of small displacement developed parallel with the fi ssures as fi lling, as replacement of vein calcite, and as replace- stress axis. Ultramafi c igneous activity, dated as Early Permian ment of the limestone wall rock. The fl uorite in the bedding- (ca. 270 Ma), accompanied these events (Zartman et al., 1967). replacement deposits is commonly banded, with alternating light The climactic event was creation of Hicks Dome. Centered in and dark bands of fl uorite. The local miners called this banded Hardin County, Illinois, Hicks Dome is a nearly circular uplift texture coon-tail ore. The strata-bound deposits are capped by 12 km in diameter, with more than 1 km of structural relief. impermeable roof material of either a shale or tight sandstone Seismic refl ection data reveal that doming is seated within Pre- (Fig. 4). These deposits are generally horizontal but may dip FLD012-02-denny 2nd pgs page 13

Illinois-Kentucky Fluorite District, Hicks Dome, and Garden of the Gods 13

o u Indiana

DuQuoinD Monocline Evansville Omaha Dome Wabash Valley Fault Zone Cottage Grove

Harrisburg Shawneetown Fault Kentucky Ste. Genevieve Eagle Valley- Rough Creek Moorman Syncline Fault System x x x Hicks x x x Dome x xx x x x x x

Cape x x xx Girardeau x Illinois x x x x x Lusk Creek Fault Zone n x x

Dixon Springs Graben x x x x x x x x xx Tabb Fault System

Rock Creek Grabe

Paducah Pennyrile Fault System Missouri Mississippi Embayment Sediments Legend high angle reverse fault fluorite mine area

normal fault x fluorite mine Reelfoot Rift N monocline igneous dome Illinois-Kentucky syncline Fluorite District 0 10 20 30 miles structure concealed Mississippi Embayment 25 50 kilometers under sediments Sediments

Figure 1. Major tectonic structures in the Illinois-Kentucky Fluorite District (adapted from Nelson, 1995). A color version of this ﬁ gure is available as item 2008108 in the GSA Data Repository at www.geosociety.org/pubs/ft2008.htm or on request from [email protected]. FLD012-02-denny 2nd pgs page 14

14 Denny et al. Cretaceous Cretaceous and Tertiary K and Tertiary Harrisburg Mvu undivided Unconformity Pt Pc Igneous diatremes Mc Pcv Permian (igneous) Pcv Igneous dike showing trend Pt Unconformity Pc Pc Carbondale Formation

Pt Pt Tradewater Formation Pennsylvanian Pt Pcv Caseyville Formation Unconformity

Mc Mc Chesterian Undifferentiated Mississippian Pcv Mvu Upper Valmeyeran Pc Mc Mvl Lower Valmeyeran Pcv Mvu e DuDu Devonian Undifferentiated Devonian s x o k Pt x x o e GooseG re CreekC Pt e r Illinois-Kentucky i Du Pcv High angle reverse fault p Mvl k c Fluorite District x m o EmpireE -R n -i Mc e Pcv v Graben x a Fluorite sub-districts x Mc Cave-in-RockC

Mc Pcv Fluorite mine Fault te Mc x x x ta x t rs r te x Pc Pcv a InterstateIn x w e x t Cave-in-Rock x x StewartS e x r la ic Mvu s x o RosiclareR Rosiclare Pt Mc Pcv xx s g in r Pcv p S x x n e x x e d or n od te x it Marion Mc m r m C x ill o - CommodoreC s x H s ia x r v e x e x y Pcv Levias-CrittendenL Springs Pcv x DyersD Hill x x ill H k re ic o L o y Salem MooreM Hill laya Lick Pt Pcv ClC Pcv x x Mexico K x TabbTabb x x Fredonia x x Mvl x TabbT Mvu abb x xxMvl

Illinois K Mvu Mc Eddyville Mvl N Princeton Mvl K 0 2 4 Miles Mc Kentucky 1 3 Mvu Calvert City 0 4 8 Kilometers Mvl K 2 6

Figure 2. Generalized geologic map of the Illinois-Kentucky Fluorite District. (compilation based on several Illinois State Geological Survey and Kentucky Geological Survey geologic maps.) A color version of this ﬁ gure is available as item 2008108 in the GSA Data Repository at www. geosociety.org/pubs/ft2008.htm or on request from [email protected]. FLD012-02-denny 2nd pgs page 15

Illinois-Kentucky Fluorite District, Hicks Dome, and Garden of the Gods 15 RANGE OF FLUORITE AGE SERIES FORMATION THICKNESS GRAPHIC MINERALIZATION ft. COLUMN Vein Strata-bound Atokan Tradewater + 200 Morrowan Caseyville 250 -350 Kinkaid 0 -200 Degonia 0 - 40 Clore 30 - 120 Pennsylvanian Palestine 40 - 80 Menard 80 - 140 Waltersburg 20 - 60 Vienna 10 - 20 Tar Springs 90 - 150 Glen Dean 40 - 90 Hardinsburg 20 - 140 30 - 150 Golconda Chesterian Cypress 25 - 150 Ridenhower 25 - 65 Bethel 40 - 100 Downeys Bluff 25 - 40 Yankeetown 30 - 45 ? Renault 15 - 35 Aux Vases 15 - 35

120 - 180 Mississippian Ste. Genevieve Upper St. Louis 350 - 400

Salem 500 +/- Valmeyeran

Ullin 125 - 360 Lower Fort Payne 225 - 640 ?

New Albany 395 +/- Group Lingle Middle Grand Tower 250 +/- Devonian Lower Clear Creek

Figure 3. Stratigraphic column with range of vein and bedding replacement deposits for the Illinois-Kentucky Fluorite District. Modiﬁ ed after Grogan and Bradbury (1968). Formation thicknesses from Trace (1954); Thurston et al. (1954); Hardin (1955); Williams and Duncan (1955); Baxter et al. (1963); and Baxter and Desborough, (1965). A color version of this ﬁ gure is available as item 2008108 in the GSA Data Repository at www.geosociety.org/pubs/ft2008.htm or on request from [email protected]. FLD012-02-denny 2nd pgs page 16

16 Denny et al.

Aux Vases SS. Bethel SS.

bedded fluorite 50 Downeys Bluff LS. Ste. Genevieve LS. 40 15 30

10 vein fluorite 20 Vertical 5 40 Vertical 0 20 10 0 10 0 10 30 50 Feet 0 horizontal 5 15 Feet Stratiform or Bedding Replacement Vein Deposit horizontal

Figure 4. Idealized bedding replacement and vein type ﬂ uorite deposit within the Illinois-Kentucky Fluorite District. A color version of this ﬁ gure is available as item 2008108 in the GSA Data Repository at www.geosociety.org/pubs/ft2008.htm or on request from [email protected].

slightly. Some bedding-replacement deposits are located near most likely expelled from alkaline igneous sources (Plumlee small faults, joints, or fractures. The largest deposits were more et al., 1995). than 4 miles (6.4 km) in length, but most were much shorter, with Several attempts have been made to date the age of the fl uo- widths approaching 200 ft (70 m). rite within the Illinois-Kentucky Fluorite District. Symons (1994) Fluorite occurs in a wide range of colors in this district with reported a late Jurassic date of fl uorite mineralization based on colorless, purple and yellow being the most common. Blue is paleomagnetic analysis. Chesley et al. (1994) reported an early widespread, but less common. One mine on Hicks dome produced Permian date based on a 147Sm/144Nd isochron for fl uorite. Ruiz et some green fl uorite, and a nearby mine yielded pinkish crystals, al. (1988), using strontium isotope data, reported an early Juras- but those should be considered anomalous. In addition to fl uo- sic date. Harder (1987, in Symons, 1994) reported an age based rite, a large quantity of zinc (sphalerite and smithsonite) has been on fi ssion-track analysis that straddles the Jurassic-Cretaceous mined within the Illinois-Kentucky Fluorite District. The larg- boundary. Brannon et al. (1997) reported a lower Jurassic age est zinc deposits in Kentucky are associated with igneous dikes. based on ore stage calcite U-Pb and Th-Pb isotopes. Some have been found to be in direct contact with dikes such as those in the Hutson and Old Jim mines (McGrain, P., in McDow- IGNEOUS ACTIVITY AND HICKS DOME ell, 2001). Other minerals that have been reported in the district

include galena (PbS), calcite (CaCO3), dolomite (Ca,Mg(CO3)2), F. Brett Denny

barite (BaSO4), pyrite (FeS2), chalcopyrite (CuFeS2), quartz Ultramaﬁ c intrusive rocks are present in southern Illinois and

(SiO2), celestite (SrSO4), cerussite (PbCO3), greenockite (CdS), western Kentucky and can be found within the Illinois-Kentucky malachite (Cu2CO3(OH)2), smithsonite (ZnCO3), witherite Fluorite District (Fig. 5). Alkaline igneous rocks that are dark

(BaCO3), strontianite (SrCO3), benstonite ((Ba,Sr)6 (Ca,Mn)6 green, porphyritic to inequigranular with a ﬁ ne-grained ground-

Mg(CO3)13), and alstonite (Ba,Ca(CO3)2) (Goldstein, 1997). mass were fi rst recognized along the Tolu Arch and Hicks Dome Researchers have utilized stable isotopes and fl uid-inclusion in the early 1900s. Johannsen (in Bain, 1905) fi rst described chemistry (analysis of halogen and noble gases trapped within these rocks as mica peridotites. The igneous bodies occur as sills, the fl uid inclusions) to determine the origin of the fl uorite dikes, and pipes and have been described and studied by English deposits within the Illinois-Kentucky Fluorite District. For and Grogan (1948), Clegg and Bradbury (1956), Koenig (1956), fl uid inclusions in the Cave-in-Rock District, homogenization Bradbury and Baxter (1992), and Denny et al. (2002). Primary temperatures between 125 and 150 °C (Spry et al., 1990), and minerals are phlogopite, pyroxenes, olivine (altered to serpen- salinities in the range of 19–21 wt% NaCl were reported (Rich- tine), apatite, calcite, garnet, perovskite, titanite, chromite, and ardson and Pinckney, 1984). Oxygen isotope data indicate that spinels. The rocks have been extensively altered, and serpentine the ore fl uids originally circulated in sedimentary formations, and chlorite are abundant. Where these rocks are highly altered, while sulfur in the fl uids was derived from both petroleum with little primary mineralogy remaining, they commonly have and basement sources (Richardson et al., 1988). Helium iso- been termed lamprophyre (Baxter et al. 1989). The composition tope data indicate that at least a portion of the helium present and texture of these rocks indicate they originated within the within the Illinois-Kentucky Fluorite District is from an upper upper mantle, ascending at supersonic velocities along cracks in mantle source and probably related to the alkaline igneous the Precambrian basement (Denny, 2005). Recent analysis of the bodies (Kendrick et al., 2002). The fl uids responsible for fl uo- ultramafi c rocks from the region indicates they may be classifi ed rite mineralization in the Illinois-Kentucky Fluorite District as alnöite (Lewis and Mitchell, 1987; Sparlin and Lewis, 1994; were quite acidic (pH < 4) and were charged with fl uorine Denny, 2005). Alnöite is an ultrabasic-lamprophyre containing FLD012-02-denny 2nd pgs page 17

Illinois-Kentucky Fluorite District, Hicks Dome, and Garden of the Gods 17 4

Igneous breccia Harrisburg and diatremes Graben Igneous dike showing trend Fault

Illinois-Kentucky High angle Fluorite District reverse fault

Radiometric age Reported age determinations of igneous of fluorite rocks in the region mineralization

Downeys Bluff Sill PERIOD 1 275 +/- 24 Ma Ma yr. 0 Zartman et al., 1967 Paleogene Grant Intrusive Breccia Hicks 2 272.7 +/- 0.7 Ma; Dome Cretaceous Reynolds et al., 1997 100

2 Davenport Mine Dike Jurassic 3 271 +/- 0.3 Ma Fifarek et al., 2001 200 Triassic Cottage Grove Dike 4 269.61 +/- 0.39 Ma Permian 300 Cave-in-Rock Denny, 2005 Pennsylvanian Missisippian Approximate age of igneous intrusions 1 Devonian Rosiclare 400

Illinois Marion

Salem 3 Mexico

Fredonia

Eddyville Princeton N Kentucky 0 2 4 Calvert City Miles 1 3 0 48 Kilometers 2 6

Figure 5. Radiometric ages for igneous rocks in southeastern Illinois and northwestern Kentucky, and reported age determinations of ﬂ uorite mineralization. A color version of this ﬁ gure is available as item 2008108 in the GSA Data Repository at www.geosociety.org/pubs/ft2008.htm or on request from [email protected]. FLD012-02-denny 2nd pgs page 18

18 Denny et al.

biotite with or without olivine, melilite, carbonate, and com- the northwesterly trend of these igneous intrusions is controlled monly perovskite. This silica-defi cient igneous rock may grade by the dominant fracture pattern within the Precambrian base- into kimberlite with an increase in forsterite and diminution of ment rocks through which the igneous bodies ascended (Denny, augite, or into carbonatite with an increase of carbonate (Wil- 2005). The dominant fracture pattern of the Precambrian rocks in liams et al., 1982). the Midcontinent is northwesterly (Marshak and Paulsen, 1997), The age of the igneous bodies throughout the Illinois-Ken- similar to the strike of the majority of the igneous dikes in the tucky Fluorite District has been determined by radiometric dating region (Denny 2005). techniques to be ca. 270 Ma (Fig. 5) or early Permian (Zartman et Mineralization within the Illinois-Kentucky Fluorite District al., 1967; Reynolds et al., 1997; Fifarek et al., 2001; and Denny, probably results from an acidic brine fl uid, charged with fl uo- 2005). Breccia (diatremes ?) at Hicks Dome (Fig. 6) were stud- rine and carbon dioxide derived from alkaline magmas (Plumlee ied by Bradbury and Baxter (1992), who proposed three clas- et al., 1995). This brine may have been concentrated within the sifi cations for these breccias based upon their clast geometry down-dropped portion of the Reelfoot Rift. As these complex fl u- and composition: (1) vent breccias, (2) carbonatitic breccias, and ids migrated through the region, they were further concentrated (3) shatter breccias. The shatter breccias are dike-like intrusive along the crest of the uplifted Tolu Arch (much like a structural bodies containing angular to sub-rounded clasts of country rock oil trap). The fl uids were then funneled along the northeasterly that were ripped up and incorporated during ascent. Carbonatitic trending fractures and fault zones possibly during periods of breccias are composed of both igneous and sedimentary clasts major regional tectonic adjustment (see “Regional Tectonic Set- set in a matrix of igneous carbonate. Bradbury and Baxter (1992) ting”). Contact between the acidic fl uids and calcium-rich car- theorized this style of breccia was a result of explosive release bonate formations resulted in precipitation and ore formation. A

of CO2-rich gas exsolving from an alkaline ultramafi c magma range of ages of emplacement of the fl uorite, reported by vari- at depth. Vent breccias are described as bodies of indeterminate ous authors from Permian through Jurassic, implies this process form, usually silicifi ed, and may contain sedimentary fragments may have been episodic over millions of years after the Permian originating from great depths. Some of these breccia pipes may igneous activity. The low temperature of crystallization of these be considered to be diatremes (breccia fi lled volcanic vents). deposits is consistent with this assumption. It is furthermore sug- The composition and texture of the ultramafi c rocks indi- gested that the deposits of the Illinois Kentucky District are sig- cate they are similar to rocks that carry diamonds. Gurney (1984) nifi cantly different from other Mississippi Valley–type deposits developed methods to evaluate the potential for diamonds within to warrant classifi cation as a fl uoritic subtype of the Mississippi an ultramafi c rock utilizing the composition of garnets. One Valley–type deposit. method utilizes a binary plot of Cr2O3 versus CaO on garnets. Garnets analyzed in an ultramafi c dike in Saline County, Illi- THE HISTORY OF THE ILLINOIS-KENTUCKY

nois, are high CaO and low Cr2O3 types, suggesting that this dike FLUORITE DISTRICT probably does not host diamonds. Certainly many more samples would need to be analyzed to estimate the diamond potential for Alan Goldstein and David A. Williams the entire igneous complex. The economic potential of an ultra- The fi rst attempt at mining ore in the Illinois-Kentucky Flu- mafi c dike in Kentucky is being explored by Marum Resources orite District was at the Columbia Mine near Marion, Kentucky, Inc. Marum drilled several boreholes into a “kimberlite” dike in in 1835. A consortium of businessmen that included President Kentucky (Lollypop Kimberlite), the deepest of which reached Andrew Jackson attempted to extract silver from galena. Unfor- 2214 ft (686 m) to test for diamonds. No diamonds were initially tunately, the concentration of silver in the galena in this district detected, but the fi nal results have not been made available1. is very low and they were not successful. A short time later the Royal mine (also called the Royal Silver mine) opened near Summary Smithland, Kentucky. Mines in the fl uorspar district produced galena as the primary ore for much of the nineteenth century, The relationship of the igneous activity and the fl uorite min- and the fl uorite was a waste product. In 1839, a well sunk in eralization of the Illinois-Kentucky Fluorite District have been southern Illinois encountered lead ore (galena). The fi rst oper- debated for many years (e.g., Weller, 1927; Bastin, 1931; Plumlee ating mine in Illinois started in 1842 near Rosiclare and pro- et al., 1995; and Kendrick et al., 2002). The trend of the mineral duced ore for eight years (Bastin, 1931). A process that utilized deposits is obviously parallel with the northeasterly trending fault fl uorite as a fl ux in the production of steel was discovered in the zones (Fig. 2). The trend of the ultramafi c dikes and the Tolu Arch 1880s, resulting in a rejuvenation of mining within the Illinois- is west of north, oblique to the northeasterly trend of the miner- Kentucky Fluorite District. alized faults and the individual mineral sub-districts. It is likely The most important area of mining at the beginning of the twentieth century was near the Ohio River near the town of Rosi- clare, Illinois. Thick veins of fl uorite were mined extensively, and 1Marum Resources INC., Suite 102, 5004 Elbow Drive SW, Calgary, Alberta Canada, T2S 2L5; 2003 Press Release (http://www.marumresources.com/ the proximity to the Ohio River made transportation to the steel id42.htm). mills relatively inexpensive. Some of the underground mines at FLD012-02-denny 2nd pgs page 19

Illinois-Kentucky Fluorite District, Hicks Dome, and Garden of the Gods 19 R6E R7E Mvu R8E R9E Shawneetown Fault Zone Pt A’ Pcv Mc T9S Pt T10S Pc Eagle Valley Syncline

Pc Pt Line of Cross Pt Section

Mc Garden of Saline County the Gods Gallatin County Hardin County Pope County Pcv A Mc

Herod Hamp Fault Pcv Fault Zone Mvu

Zone Goose Creek Fault

Hicks Dome Pt Pcv Du Mvl Lusk Creek Fault ZoneT11S T12S Mc Raum Fault Zone Mv Hobbs Creek Dixon Springs Graben Fault Zone Peters Creek Fault Zone Tolu Arch Pcv N Interstate Mc Fault Zone Igneous dikes and diatremes Permian Kentucky Illinois Carbondale Formation Rock Creek Graben Tradewater Formation Pennsylvanian Caseyville Formation Pcv Rosiclare Unconformity Chesterian Undifferentiated T13S Upper Valmeyeran Mississippian Geologic Map of Hicks Dome Area Southeastern Illinois Lower Valmeyeran 1 3 miles Devonian Undifferentiated Devonian 0 2

Figure 6. Geologic map of the Hicks Dome and Eagle Valley Syncline. Modiﬁ ed from Baxter et al. (1963); and Baxter and Desborough, (1965). A color version of this ﬁ gure is available as item 2008108 in the GSA Data Repository at www.geosociety.org/pubs/ft2008.htm or on request from [email protected]. FLD012-02-denny 2nd pgs page 20

20 Denny et al.

Rosiclare encountered signifi cant amounts of water. One mine renewed (see Appendix 1). The only production currently within which was tunneling underneath the Ohio River accidentally the Illinois-Kentucky Fluorite District is at the Hastie lime- punched into an aquifer below the riverbed. The resulting “leak” stone quarry, where the open pit mines pass through abandoned eventually fl ooded every mine along the vein. Equipment was underground fl uorite workings. Modern applications for fl uorite salvaged as large pumps slowed the infl ux of water, but ulti- include the production of hydrofl uoric acid, metal refi ning and mately the battle was lost. As a result, mine activity shifted to smelting, various chemical processes, the ceramic and glass shallow deposits near Cave-in-Rock for most of the 1920s and industries, and optics. 1930s. The famous Crystal mine and the less well known but productive Victory mine were opened in the 1930s. World War I AMERICAN FLUORITE MUSEUM AND THE HASTIE caused an increase in exploration for fl uorite because of unprec- QUARRY edented demand in the manufacturing of steel. Many small mines were opened, but no large deposits were discovered during this Zakaria Lasemi time. During World War II, the fl ooded mines in Rosiclare were The Hastie Quarry extracts Mississippian carbonate rock dewatered and underground mining was resumed. for aggregate and construction use. The quarry is located north- The 1940s brought further exploration, particularly north of west of Cave-in-Rock and is mining through an area that con- Cave-in-Rock. The most signifi cant discovery was made by the tains abandoned fl uorite workings. This quarry is the only mine Minerva Oil Company at the northeastern edge of the Cave-in- that is extracting fl uorite in the United States. Production from Rock sub-district. Named the Minerva No. 1 mine, its orebody these workings is highly variable, but this quarry offers excel- turned out to be among the largest bedding-replacement deposits lent exposures of the former underground adits in the quarry high in the world—some 20,000 ft long. Mining continued through wall. The banded nature of the bedding-replacement deposits can the 1950s until the mid 1970s when production started slowing be observed here along with volume reduction or shrinkage of down. Imports of fl uorite from South Africa and Mexico cre- the overlying roof strata. This quarry lies at the southern end of ated pricing pressures on the U.S. market. When fl uorite prices the Cave-in-Rock sub-district and quarries mainly the Ste. Gen- became depressed, zinc ores were mined. A number of mines in evieve Limestone. Kentucky were exclusive zinc producers (sphalerite and smith- The American Fluorite Museum is located at the former sonite). The Ozark-Mahoning mill in Rosiclare had modifi ca- Rosiclare Lead and Fluorspar property in Rosiclare, Illinois. The tions made specifi cally to concentrate zinc, although the last museum contains an excellent collection of minerals from this upgrade of the mill was completed a few years before mining mining district along with mine memorabilia. operations ceased. Mining within the Illinois-Kentucky Fluorite District became unprofi table in the mid 1990s as cheap Chinese GARDEN OF THE GODS fl uorite fl ooded the world market. In 1996, the last mine within the Illinois-Kentucky Fluorite District, the Minerva, closed. Joseph A. Devera Various companies built mills around the district during the The Garden of the Gods is located on the southern limb of twentieth century. Most were razed intentionally or by arson. the Eagle Valley Syncline within the confi nes of the Shawnee Two of the most recently constructed mills remain: the Ozark- National Forest, southeasternmost Saline County, Illinois (Fig. 6). Mahoning mill in Rosiclare, Illinois, and the Babb-Barnes mill Lower Pennsylvanian sandstones stand out as rounded high near Salem, Kentucky. Both are currently owned by Hastie Min- knobs and pinnacles resulting from millions of years of water and ing and Trucking. The foundations of other mills remain, includ- wind erosion. Now, only remnants of a fl uvial dominated, deltaic ing the Hutson and Lafayette in Kentucky and the Crystal, Heavy system that existed 320 million years ago create a high vista and Media, Victory, and Rosiclare Lead and Spar in Illinois. Aban- panoramic view to the north of caricatures like Camel Rock and doned mine sites are mostly rock piles with scattered concrete Monkey Face. Farther north, one can see the northern limb of the structures. Only a couple mine headframes remain. In Illinois, the Eagle Valley Syncline as a distant ridge (Fig. 7). Annabel Lee mine is still visible from Illinois Highway 1. A short The Garden of the Gods is composed of the Pounds Member headframe, a relict from the old Rosiclare Lead and Spar Com- of the Lower Pennsylvanian (Morrowan) Caseyville Formation. pany site (now the location of the American Fluorite Museum), It is a mature quartz arenite, poorly sorted, with fi ne to coarse also remains. In Kentucky, the headframe of the Babb mine sits quartz sand grains and numerous milky white, rounded quartz amidst a fl uorspar fl otation mill, while a few miles away, the Hut- pebbles. Some of the beds contain quartz pebble conglomerates. son mine’s steel and wood headframe and an ore tipple remain. In the area, both the lower Battery Rock Member and Pounds During much of its 170 year existence, the mines of the Member coalesce to form one massive cross-bedded series of Illinois-Kentucky Fluorite District produced the largest amount sandstone beds of the Caseyville Formation. The Caseyville is of fl uorite in the western hemisphere. More than 7 million tons not only thought to have been fl uvial deltaic but also estuarine of fl uorite was produced. Recently, China reduced the amount of in places as goniatites have been reported in shales that occur fl uorite for export and interest in tapping new or partially mined between the Battery Rock and Pounds Members nine miles east deposits within the Illinois-Kentucky Fluorite District has been of this area (Devera et al., 1987). FLD012-02-denny 2nd pgs page 21

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Uncon 15,000 Pt Looking west along the western end of the Eagle Valley Syncline Valley end of the Eagle along the western Looking west Mc 10,000 Mississippian Pennsylvanian Garden of the Gods Unconformity 5000 Hicks Dome approximately 4 miles (6.4 km) Gallatin County Pcv Mv Hardin Hardin County South 0 Carbondale Formation Carbondale Caseyville Formation Chesterian Undifferentiated Chesterian Tradewater Formation Tradewater Valmeyeran Undifferentiated Valmeyeran Figure 7. Cross section along the Eagle Valley Syncline. A color version of this ﬁ Syncline. A color version Valley Figure 7. Cross section along the Eagle ft2008.htm or on request from [email protected]. Sea 500 feet Level - 500 1000 - 1000