We have been working in an area of dolomite karst in Tasmania, and have
found areas of extensive silicification. This includes zones of vuggy quartz
with crystals to several cm. Sulphide and gold mineralisation occurs where
this has been overprinted by alteration from igneous intrusions.
The question is, can such mega-quartz form from low-T groundwaters? Fluid
inclusion work suggests T< 50 oC, but I am not aware of such coarse grained
low-T quartz elsewhere.
Regards
Ralph Bottrill
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