Abstract

Mineralization in the form of small veinlets or disseminated sulphides is common to many regions of granitization. Zones of intense mineralization owe their localization to fracturing, shearing, or to rocks favorable to replacement. The large quartz veins of Cornucopia have been controlled by post-granitization shearing; the magnetite deposits of eastern Okanogan County, Washington, were formed by the replacement of limestone lenses adjacent to an area of syenitization.The process of granitization envisages the transformation into granitic rocks of the material originally deposited in a geosynclinal prism. Such a process would bring about a regional redistribution of certain chemical elements. It should be emphasized that kaolinitic material so abundant in a sedimentary series contains about 14 percent water. The change of kaolinitic material to feldspars must drive off this water. Water so released by granitization can easily become the source of hydrotherrnal solutions that produce mineralization.In some ore deposits the metallization is a direct concentration of metallic elements brought about by granitization, in others the source of these elements is probably from beneath a geosynclinal prism.

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