MINERALIZACJA KRUSZCOWA NA TLE WIELOETAPOWYCH INTRUZJI PORFIROWYCH W REJONIE MYSZKOWA

Abstract

ORE MINERALIZATION AND MULTIPHASE PORPHYRY INTRUSIONS IN THE MYSZKÓW AREAAbstract. The three main types of porphyries, differing in lithology and sequence, have been distinguished on the basis of data from four neighbouring boreholes located in the area of the Myszków Mo-W-Cu deposit. The age of the oldest type is close to that of the main granitoid stock, the others are younger. All the porphyry types and individual intrusions have been analyzed in terms of variability of metal contents (Mo, W, Cu and Pb additionally). Because of considerable variability of ore mineralization, statistically distinct differences are observed among them. As regards multiphase development of hydrothermal mineralization in the Myszków deposit, it is clear that the majority of porphyry intrusions are older than the main ore-bearing stages (Mo-W mineralization). Only quartz-free porphyries contain no quartz-feldspar veinlets with molybdenite and scheelite, but they include disseminated chalcopyrite (younger Cu mineralization). Thus, the ores were formed at the time of intense and multi-stage development of porphyry intrusions. However, the older strongly fractured (a magmo-tectonic joint) granitoid stock with immediate wall-rocks was the main collector of ore solutions.