Abstract:
Quartz and calcite are the commonest vein minerals associated with sulphide mineralization in Cardiganshire. Fifty samples of quartz were analysed for Al, Ti, Fe `"913, Mn, Li, Na, K, Ca, Mg, Sr, Pb, Zn, Cu, Ag, Cd, Co and Ni. Chromium, Ft and Cr` were determined in only a few samples. All these elements show different ranges of variation. Cobalt, however, is characteristically constant, and occurs in unusually high amounts. The absolute Cation ratio of alkalis, Ca, and Mg in quartz approaches that of Red Sea brines. Quartz also seems to be very rich in Fluorine and Chlorine. The ratio of Zn/Pb/Cu in quartz can be used for geo-chemical prospecting, but does reflect the true contents of the proportions of these elements as sulphides. Sixteen samples of Calcite were analysed for, Fe+S, Mn, Mg, Sr, Na, K, Zn, Pb, Cu, Ag, Co, Ni, Cr, F 1-1 and Cl . All these elements vary a lot except manganese which is practically constant. The ratio of Zn/Pb/Cu can be used as a geochemical tracer, but as in the case of quartz, it does not reflect the true proportion of these elements as sulphides. The partition coefficients of the different trace metals in quartz and calcite reflect the paragenetic sequence and temperature of deposition of these minerals. The ratio of Na, K, both in quartz and calcite, seems to be temperature controlled. The mineralization in Cardiganshire seems to have been caused by Na-K-Cl type brines highly enriched in fluorine and lithium, suggesting a probable contribution from juvenile waters.
Page(s):
15-72
DOI:
DOI not available
Published:
Journal: Bulletin of centre of excellence in geology, Volume: 7-8, Issue: 1, Year: 1975