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Gossan Lead |
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Virginia, USA |
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Cu Zn S
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Super Porphyry Cu and Au
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IOCG Deposits - 70 papers
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The Gossan Lead District is a 28 km long north-east trending belt of discontinuous massive sulphide deposits in the Blue Ridge province of south-west Virginia, USA.
The deposits are hosted by the Neoproterozoic Ashe Formation meta-sediments which include occassional conformable lenses of amphibolite and actinolite-chlorite schist. The meta-sediments are composed of metapelite, quartz-feldspar granofels (meta-greywackes), with minor quartzite and carbonaceous schist.
The deposits are composed of stratabound lenses and layers of massive pyrrhotite, with minor chalcopyrite, sphalerite and pyrite, rare arsenopyrite and galena. The main exploitation of sulphide ore was in the Iron Ridge and Betty Baker segments at the SW and NE extremities of the belt. The other sulphide bodies that have been mined are Gossan Howard, Bumbarger and Huey.
The mineralisation of the district is apparently confined to a single horizon which has been subsequently extensively folded and brecciated. Fold repetition and tectonic thickening has produced ore pods up to a maximum thickness of 40 m as at Bumbarger. The ore contains abundant coarse angular clasts of wall rocks around which the massive sulphides have flowed.
The deposits were mined from the early1850's for supergene copper, and for gossan iron from 1880 to 1908. The exact size of the deposits is not known. The combined estimate production and reserves of sulphides to a depth of 150 to 300 m is 20 Mt, although the possible sulphides to a depth of 500 m may be as high as 100 Mt.
For more detail consult the reference(s) listed below.
The most recent source geological information used to prepare this decription was dated: 1986.
This description is a summary from published sources, the chief of which are listed below.
© Copyright Porter GeoConsultancy Pty Ltd. Unauthorised copying, reproduction, storage or dissemination prohibited.
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Selected References:
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Gair J E, Slack J F 1984 - Deformation, geochemistry, and origin of massive Sulfide deposits, Gossan Lead district, Virginia: in Econ. Geol. v79 pp 1483-1520
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Stephens M B, Swinden H S, Slack J F 1984 - Correlation of massive Sulfide deposits in the Appalachian-Caledonian orogen on the basis of Paleotectonic setting: in Econ. Geol. v79 pp 1442-1478
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Porter GeoConsultancy Pty Ltd (PorterGeo) provides access to this database at no charge. It is largely based on scientific papers and reports in the public domain, and was current when the sources consulted were published. While PorterGeo endeavour to ensure the information was accurate at the time of compilation and subsequent updating, PorterGeo, its employees and servants: i). do not warrant, or make any representation regarding the use, or results of the use of the information contained herein as to its correctness, accuracy, currency, or otherwise; and ii). expressly disclaim all liability or responsibility to any person using the information or conclusions contained herein.
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