PORFIROWA MINERALIZACJA Mo–Cu–W W UTWORACH PREKAMBRYJSKO-PALEOZOICZNYCH – ANALIZA PROGNOSTYCZNA STREFY KONTAKTU BLOKÓW GÓRNOŚLĄSKIEGO I MAŁOPOLSKIEGO

Abstract

PORPHYRY Mo–Cu–W MINERALIZATION WITHIN PRECAMBRIAN–PALEOZOIC ROCKS – PROSPECTIVITY ANALYSIS OF THE BORDER ZONE OF THE UPPER SILESIA AND MA£OPOLSKA BLOCKSAbstract. Porphyry Mo–Cu–W mineralization is associated with the boundary zone of the Upper Silesia and Małopolska blocks. It is encountered within Ediacarian and Silurian metasediments, as well as in Ordovician, Silurian and Devonian carbonates and siliciclastics, intruded by granitoids and porphyry dikes. Ore mineralization is represented by chalkopyrite, molibdenite and scheelite forming veinlets, impregnationsand disseminations. Investigation of 66kmof cores from 284 prospective drill holes (done till 1992) provided new data representing the distribution of mineralization on a regional scale. Based on the contours of metal average contents, five prospective areas (Nowa Wieś Żarecka–Myszków–Mrzygłód, excluding Myszków deposit, Żarki–Kotowice, Zawiercie, Pilica and Dolina Będkowska) with porphyry Mo–Cu–W mineralization have been delineated on the Małopolska Block and Mysłów area on the Upper Silesia Block. Formation of ore mineralization was preceded by contact-metasomatic metamorphism (predominantly by biotitisation of granitoids cover extending to 1500 m away from intrusion). Ores are spatially and genetically associated with zones of hydrothermal alteration (feldspathization, silification, epidotization, carbonatization, chloritization, sericitization) developing in and around granitoid and porphyry intrusions. Close spatialand genetic association between mineralization (supported by Re–Os 303–295 Ma ages of molibdenite), Variscan magmatism, alteration, and active Cracow–Lubliniec disslocation system clearly indicates postmagmatic, hydrothermal origin of mineralization. New exploration targets can be found at the border zone of Małopolska and Upper Silesia Block.