NEW TYPE OF DIKE IN GRANITOID PLUTONS

Abstract

In the southern part of the Kayrakty pluton, USSR we identified a series of granosyenite porphyry dikes and traced them for 15 km. Individual dikes range in thickness from 10 to 15 m and are 3 to 4 km long. Ore-bearing quartz veins spatially tend to be in or near them. The granosyenite porphyry matrix is aphanitic and fine grain. The phenocryst concentration is variable, ranging from 20 to 55 percent and increasing toward the center of the dikes. All this suggests that the dikes studied represent a genetically independent rock group, formed upon slight intrachamber differentiation, from the same magma source as rocks of the Kayrakty pluton.