Gold occurrences in the Stanly County area were first found in 1799. Gold-bearing quartz veins, typical of those found in many parts of the Appalachians, have been studied at the Cotton Patch, Mountain Creek, Parker, Gold Hill, and Coggins mines.
The veins are sharply defined, near-vertical, and lie subparallel to schistosity in the Andesitic Tuffs Unit of the Upper Volcanic Sequence or Millingport Formation. Lower greenschist grade regional metamorphism at 483 m.y. has slightly altered the tuffs but little affected the veins. The veins are >95% milky to glassy quartz with minor chlorite, and trace amounts of magnetite, ilmenite, pyrite, and native gold. Gold fineness values and copper contents for the deposits range from 656-999 and 0-1.53 wt % respectively.
Study of the fluid inclusions reveals homogenization temperatures of 194°-219°C (uncorrected) and saltinites of 0-5.0 wt% NaCl equivalent. A presumed pressure correction of 0.5-1.0 Kbar at the time of formation correspond to an increase of 40°-84°C for the original trapping temperature.
The subparallel nature and sharp contacts of the veins, absence of metamorphic foliation in the vein minerals, and the low salinities indicate a post-peak-of metamorphism age for the veins. The volume of fluid (10¹³ liters) required to deposit the quartz but the small quantity of gold (5000 troy oz.) suggests that the veins were deposited by recirculating meteoric water which was heated at depth and which scavenged gold from a small volume (0.03 km³) of the underlying and adjacent rocks. / M.S.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/101436 |
| Date | January 1983 |
| Creators | Fitzpatrick, Thomas Frank |
| Contributors | Geology |
| Publisher | Virginia Polytechnic Institute and State University |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis, Text |
| Format | ix, 88 leaves, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | OCLC# 11100035 |
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