Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Prolonged weathering under subtropical conditions has resulted in development of 40 m thick weathered profiles at the Ridgeway North gold deposit and the Heath Springs prospect in the Piedmont of South Carolina, developed on late Precambrian to Cambrian(?) rocks of the Carolina Slate Belt. At Ridgeway, fine-grained quartz-muscovite-pyrite phyllites contain gold grains which are predominantly {dollar}{dollar}900. At Heath Springs, the steeply-dipping zone of pyrite-rich quartz-muscovite-microcline-sillimanite granofels probably formed by metamorphism of a quartz-muscovite-pyrite phyllite, upon intrusion of the Liberty Hill Pluton.;Vertical zonation at both sites is, from bottom to top: fresh bedrock; saprolite; massive zone, and; soil, an Ultisol. Petrologic, bulk density, particle-size, clay and geochemical data all reflect this zonation. Quartz dissolution, and alteration of feldspars and micas to clay minerals (including kaolinite, illite, smectite and HIV), are the predominant changes. Mass balance calculations, assuming immobility of Ti and/or Zr, and constrained by specific gravities, indicate removal of large amounts of material during weathering, resulting in volume losses up to 30% in saprolite, and as much as 60% in soils.;Gold has been leached from soils at both sites, and from weathered zones at Ridgeway, to be redeposited in zones at depth. Iron ozide- and oxyhydrozide-rich features in soils are, however, greatly enriched in gold relative to background. Gold grains, some of which are delicate crystals, are larger and of different composition than those known from fresh rock. Grains of fineness {dollar}\sim{dollar}830 are predominant, with electrum (f 500-800) present as overgrowths. Gold of f {dollar}>{dollar} 990 occurs as small discrete grains, and veins and rims on silver-rich gold particles. Transport of gold in the weathering zone probably involved thiosulphate-, hydroxy-, chloride- and organic-complexes.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.