| Basis for focus area |
Massive sulfide hosted in felsic, mafic and intermediate arc-volcanic and sedimentary rocks of the Chopawamsic Formation, Chopawamsic terrane. Area has historical production of sulfide, copper, and other secondary minerals. |
| Identified resources |
Historical production of lead and zinc at Valzinco. |
| Production |
Unknown. |
| Status |
Past mining; prospects and mines are abandoned. |
| Estimated resources |
Unknown. |
| Geologic maps |
Mixon and others (2000), scale 1:100,000; Marr (2002), scale 1:100,000; Spears and Murray (2013), scale 1:24,000; Spears and others (2013), scale 1:24,000; Spears (2016), scale 1:24,000; Carter and others (2019), scale 1:24,000. |
| Geophysical data |
Rank 1 aeromagnetic coverage covers the Mineral, Virginia district (Shah, 2014) and an area near Arvonia, Virginia; remaining focus area covered by Rank 4 aeromagnetic data. |
| Favorable rocks and structures |
Various mafic and felsic volcanic rocks of Ordovician Chopawamsic Formation. Zone of mineralization is about 30 miles long, extending through the Mineral and Valzinco deposits. Ore occurs as fissure and fault fillings in Precambrian and Cambrian mica schist or quartz-sericite schist. |
| Deposits |
Valzinco mine (MRDS dep_id: 10067649); (mineral district is a cluster of VMS-type ore deposits). |
| Evidence from mineral occurrences |
MRDS; Feiss and Slack (1989); Mosier and others (2009). |
| Geochemical evidence |
Valzinco mine is a past producer of chalcopyrite, galena, pyrite, pyrrhotite, and sphalerites. Ore removed during a 4-month period in the 1940s contained 7.8% Zn and 3.7% Pb. |
| Geophysical evidence |
Positive anomaly associated with mafic rocks and sulfide deposits; granitic plutons easily distinguished from country rocks. |
| Evidence from other sources |
Geologic mapping. |
| Comments |
Geologic mapping and aeromagnetic studies of the Central Virginia seismic zone is recent and includes Rank 1 aeromagnetic data. Recently completed eastern Piedmont (Virginal-North Carolina) aeromagnetic survey may also overlap part of focus area and provide advantage for exploration. |
| Cover thickness and description |
Cover less than 10 m. |
| Authors |
Arthur J. Merschat, Nora K. Foley, Bernard E. Hubbard, Gregory J. Walsh, William L. Lassetter. |
| New data needs |
Geologic mapping, geochemistry and geophysics. |
| Geologic mapping and modeling needs |
Detailed geologic mapping of various mafic and felsic metavolcanic units. |
| Geophysical survey and modeling needs |
High resolution aeromagnetic and aeroradiometric coverage. Aeromagnetic data expected to image mafic rocks and associated structures, radiometric data can help with geologic mapping in vegetated terrane; alteration may be imaged. Electromagnetic methods may help image sulfides. |
| Digital elevation data needs |
Lidar coverage is fairly complete. |
