Quartz concentrates provide a general sample medium with low background concentration of minor and trace elements. They can be obtained from most rock types by hot nitric acid or aqua regia leach, sometimes supplemented by sulphuric acid leach. The concentrates consist of a mixture of primary quartz, secondary quartz resulting from wallrock alteration and insoluble minerals such as sericite and alkali feldspar. Multi-element analysis enables detection of even the weakest mineralization and wallrock alteration, as expressed mainly by Ba, Ca, Ge, K, Li, Mn, Na, Rb and Sr, in addition to Au, Pb, and Zn. Both wallrock alteration patterns and secondary dispersion trails remain preserved in the quartz concentrates, even in deeply weathered terrain. Results of 14 case histories of various types of gold and base metal deposits are compared.
- quartz concentrate
- acid-insoluble residue
- wallrock alteration
- secondary dispersion
- © 2005 AAG/The Geological Society of London