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Clark Mine, Franklin Co., Kentucky, USA

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Latitude & Longitude (WGS84): 38° 16' 60'' North , 84° 45' 0'' West
Latitude & Longitude (decimal): 38.28333,-84.75000
Köppen climate type:Cfa : Humid subtropical climate

Commodities (Major) - Lead; (Minor) - Barium-Barite; (Trace) - Strontium, Zinc
Development Status: Past Producer
Host Rock Unit: Mullen Creek Complex
Host Rock: Limestone, Shale
Extends to Scott county

Mineral List

5 valid minerals.

Rock Types Recorded

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Regional Geology

This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.

Click on geological units on the map for more information. Click here to view full-screen map on

443.8 - 485.4 Ma

ID: 2965055
Garrard Siltstone and Kope and Clays Ferry Formations, undivided

Age: Ordovician (443.8 - 485.4 Ma)

Stratigraphic Name: Garrard Siltstone; Kope Formation; Clays Ferry Formation

Comments: in west-central Kentucky, collectively the thickness is 60-90 m; in north-central Kentucky, the thickness is 60-115 m; in northeastern Kentucky, the thickness is 23-145 m; in east-central Kentucky, the thickness is 35-100 m

Lithology: Major:{shale,limestone}, Minor:{siltstone}

Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. [133]

Late Ordovician - Middle Ordovician
443.8 - 470 Ma

ID: 1841865
Clays Ferry Formation

Age: Ordovician (443.8 - 470 Ma)

Description: Interbedded limestone and shale: Limestone (about 50 percent) is of two types: (1) light to medium light gray, medium to coarse grained, generally in beds less than 6 inches thick, very fossiliferous; crinoidal limestone present near base; brachiopod Sowerbyella abundant in zone from 20 to 50 feet above base; (2) medium dark gray, fine to micrograined, thin, tabular bedded, poorly fossiliferous. Shale is medium gray, weathering to brownish-yellow clay soil that contrasts with dark-brown soil of underlying unit. Upper 50 to 60 feet contains beds of limy siltstone which forms a surface residuum of large blocks where partially or totally leached. Lower contact generally sharp except locally in northern part of quadrangle. \nGeotechnical: Roads cut into the Clays Ferry on hillsides may tend to slump downhill, especially where the formation locally contains more than the typical 50 percent shale. Fill from this formation also may be less stable than that from more limy units unless adequate drainage is provided. \nHydrology: Adequate ground water should be available to wells drilled in valley bottoms, especially along larger streams. Availability of ground water is discussed by Hall and Palmquist (1960a, 1960b). The Clays Ferry Formation, because of its high clay content, is a poor aquifer. Farm ponds on the Clays Ferry are generally successful. \nLand-Use: Soil cover of 4 or more feet forms on the Calloway Creek Limestone, Clays Ferry Formation, and Tanglewood Limestone Member of the Lexington Limestone on ridgetops or in areas of low topographic relief. On steep slopes this soil may be less than 2 feet thick. Soil formed on the Clays Ferry may be reduced to near zero even on ridgetops by erosion caused by planting of crops or by overgrazing pastures. Soil formed on the Grier Limestone Member of the Lexington Limestone is about 3 feet thick on ridgetops and possibly a foot thick on steep slopes.

Comments: Ocf; Switzer Quadrangle (GQ-1266) | | Map description and column:

Lithology: Interbedded limestone | shale

Reference: KGS Databases, Maps, and Publications. Kentucky 1:24,000 Geologic Map. Kentucky Geological Survey. [22]

Data and map coding provided by, used under Creative Commons Attribution 4.0 License

This page contains all mineral locality references listed on This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.


Rocks & Minerals 81:420-440

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