Przeobrażenia amfiboli w porfirach ryodacytowych z Zalasu koło Krakowa

Abstract

The study was aimed at alteration of amphibole phenocrysts in the porphyries from Zalas. The alteration processes took place at the magmatic stage: development of orthopyroxenes and biotitization, and at the postmagmatic one: chloritization followed by argillitization and formation of feldspars, carbonate minerals, quartz, ilmenite, magnetite and hematite. Post-magmatic alteration resulted from hydrothermal processes of the metasomatic character.