Acta Musei Moraviae

Mylonitisation and chemical composition of metagranites, the borehole Do-7, Oskava block, Silesicum

Mylonitisation and changes in chemical composition of metagranites were studied in the bore hole D0-7 situated in the Oskava block (southern Silesicum). Relatively undeformed domains are prevailing, mylonites and ultramylonites are exposed only in narrow shear zones with a thickness varying from millimetres to tens of metres. Brittle deformation of feldspars and brittle – ductile deformation of quartz point to low grade conditions of mylonitisation. Chemical changes in metagranites are influenced by the primary composition of primary rocks and hydrotermal alteration.