Is quartz (silica) a volumetrically significant mineral in potassic alteration (K-feldspar, biotite +-magnetite)?

Firstly is it a truism or a fallacy that potassic (microcline) feldspar is only formed (replacing Ca and Na and lower T K-orthoclase in orebody wall-rocks where fluids are >400deg.)? Secondly, I...

26 March 2024 8,823 0 View