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Central Tennessee Zinc District

Producer in Smith county in Tennessee, United States with commodities Zinc, Cadmium, Germanium, Barium-Barite, Fluorine-Fluorite, Lead
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Commodities
  6. Materials information
  7. Alteration
  8. Host and associated rocks
  9. Nearby scientific data
  10. Geologic structures
  11. Economic information about the deposit and operations
  12. Mining district
  13. Production statistics
  14. Bibliographic references
  15. General comments
  16. Reporter information

Geologic information

Identification information

Deposit ID 10307223
Record type District
Current site name Central Tennessee Zinc District

Geographic coordinates

Geographic coordinates: -85.93396, 36.19709 (WGS84)

Site location context

Political divisions (FIPS codes)

Smith(county)

Tennessee(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Gordonsville(quadrangle 1:24,000 scale)

Cookeville(quadrangle 1:100,000 scale)

Corbin(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Caney(hydrologic unit)

Upper Cumberland(hydrologic accounting unit)

Cumberland(hydrologic subregion)

Ohio(hydrologic region)

Geographic areas

Country State County
United States Tennessee Smith
United States Tennessee Jackson
United States Tennessee Trousdale

Comments on the location information

  • The Central Tennessee district is an area about 120 km by 75 km located in north--central Tennessee and south-central Kentucky.

Commodities

Commodity Importance
Zinc Critical Primary
Cadmium Secondary
Germanium Critical Secondary
Barium-Barite Critical Secondary
Fluorine-Fluorite Critical Secondary
Lead Tertiary

Comments on the commodity information

  • The major commodity of the district is zinc, with cadmium and germanium as by-products. Large deposits of barite and fluorite were also discovered during zinc exploration, but are not currently mined.

Materials information

Materials Type of material
Sphalerite Ore
Barite Ore
Fluorspar Ore
Calcite Gangue
Dolomite Gangue
Quartz Gangue

Alteration

  • (Local) Dolomitization
  • (Local) Silicification

Host and associated rocks

  • Host or associated Host
    Rock type Sedimentary Rock > Carbonate
    Rock unit name Mascot Dolomite
    Rock description Mascot Dolomite
    Stratigraphic age (youngest) Early Ordovician
  • Host or associated Host
    Rock type Sedimentary Rock > Carbonate
    Rock unit name Kingsport Formation
    Rock description Kingsport Formation
    Stratigraphic age (youngest) Early Ordovician

Nearby scientific data

(1) -85.93396, 36.19709
ListMap

Economic information

Geologic structures

Type of structure Local
Structure description Nashville Dome

Comments on the geologic information

  • In the Central Tennessee district regionally extensive erosional unconformity separates predominantly shallow-water marine dolostone of the Late Cambrian - Early Ordovician Knox Group and equivalent rocks from overlying Middle Ordovician deeper water marine limestone and clastic sedimentary rocks of the Stones River Group. Green shaly dolostone of the Wells Creek Formation is found at the unconformity and fills paleotopographic lows. Rubble breccia just below the unconformity marks sites of paleosinksholes and dissolution of carbonate rocks occurred more than 500 m below the paleokarst surface. Most ore in the Central Tennessee zinc district occurs in, or immediately above, altered limestone interbeds in the lower and middle members of the Mascot Dolomite. Ore is found in extensive dissolution collapse breccias and caverns developed in soluble limestone beds (Briskey et al., 1986).
  • Throughout much of the Central Tennessee District, limestone beds of the Upper Knox Group have undergone late-stage partial to complete replacement by dolomite and chert. These dolomites and cherts can be distinguished from primary dolostone and chert that formed during early diagenesis. Dolomitization preceded ore mineralization and increased the porosity and permeability of the original limestone, forming vuggy, coarsely crystalline dolomite. Volume reduction with dolomitization may have contributed to collapse and breccia formation. Silicification was a regional process and closely associated with dissolution (Briskey et al., 1986).

Economic information about the deposit and operations

Development status Producer
Commodity type Both
Significant Yes

Mining district

District name Central Tennessee Zinc District

Production statistics

  • Year 1985
    Period 1975-1985
    Material zinc ore
    Ore mined 10000000mt
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Trace Lead Lead 0wt-pct
    Major zinc Zinc Zinc 3wt-pct

Comments on the production information

  • The last zinc mine in the district closed in 2003. Most production was from the underground Elmwood - Gordonsville mine. In 1985 production was 6000mt/day or ore averaging 3.5% Zn with cadmium and germanium as byproducts (Briskey et al., 1986).

Comments on the reserve resource information

  • In 1985 the Central Tennessee district was expected to produce over 500 Mt of ore containing about 3% Zn. Stone aggragate and agricultural lime are important coproducts in the district, adding about 25-30% to the value of the zinc ore (Briskey et al., 1986).

Reference information

General comments

Subject category Comment text
Deposit Deposits in the Central Tennessee district are the Elmwood-Gordonsville, Clinch Valley, Carthage, Gainsville, Roaring River, and Cumberland in Tennessee and Burkesville in Kentucky.
Deposit Mineralization in the Central Tennessee District occurred princiaplly by filling of open spaces in dissolution collapse breccia and by filling caverns. Both breccia and caverns formed in paleoaquifers related to paleokarst development on and below the regional unconformity at the top of the Knox Group. Most of the breccia formed as a result of the dissolution and dolomitization of soluble limestone. Broad, gently dipping local structural highs along the crest of the Nashville Dome control the distribution of ore within stratigraphic horizons. Ore bodies are confined to flanks and crests of the structural highs (Briskey et al., 1986).
Deposit Coarsely crystalline, dark-reddish brown, low-Fe sphalerite is the principal ore mineral in the Central Tennessee district. In the Elmwwod-Gordonsville area of Tennessee, reddish sphalerite commonly occurs with calcite, fluorite, barite, yellowish sphalerite, galena, and minor drusy quartz and dolomite. At Burkesville in Kentucky, quartz and dolomite are the principal gangue minerals, and calcite, fluorite, and barite are absent or rare. Sphalerite mineralized in caverns and open-spaces after dissolution, collapse, and alteration of the host rock. There is a tendency for large concentrations of fluorite and bariate to be deposited outside or above areas containing large amounts of sphalerite. When the three minerals are found together, sphalerite is always earliest in the paragentic sequence (Briskey et al., 1986).
Deposit Sphalerite in the Central Tennessee district was deposited when metalliferous basinal brines expelled from compacting sedimentary basins rose into the broad, crestal area of the Nashville Dome and coincidentally into local structural highs. In these areas, sphalerite precipted in caverns and open areas of collapse breccias, and in the primary porosity of detrital dolostone. Sphalerite may have been deposited during pH change, cooling, and/or dilution of ore fluids with meteroric waters (Briskey et al., 1986).

Reporter information

Type Date Name Affiliation Comment
Reporter 06-JAN-2004 Woodruff, Laurel G. U.S. Geological Survey Work done in Filemaker

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

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