SYNTACTIC INTERGROWTHS OF FINELY DIVIDED GRAPHITE AND MUSCOVITE FROM ZONES OF HYDROTHERMAL–METASOMATIC ROCK CARBONIZATION

Abstract

Carbonization, a recently established new type of hydrothermal metasomatic alteration, leads to enrichment of elastic rocks in carbonaceous matter on the flanks of mineralized (primarily gold) zones, as well as in the selvages of ore-bearing quartz, quartz-carbonate and quartz-feldspar veins and in fractured fault zones in mineralized areas. The authors established that finely divided graphite in clastic rocks from zones of hydrothermal metasomatic carbonization forms syntactic intergrowths with layer silicates in accordance-with the parallel basal plane law. By means of high-voltage electron-diffraction analysis, they have also shown that films of graphite no thicker than about 12 A are amorphous, whereas thicker films exhibit two-dimensional structural ordering, which can be explained by the long-range orienting effect of the hexagonal basal pinacoid of mica when these two minerals cocrystallize.