Microstructures of the deformed granites of eastern Kuala Lumpur - Implications for mechanisms and temperatures of deformation

Abstract

A wide variety of deformed granites, including fault breccia, cataclasite and mylonites have been generated by several episodes of faulting in the eastern part of Kuala Lumpur. The different fault rocks were formed at different ambient conditions. The microstructural variation of the constituent minerals accompanying deformation in these deformed granites are investigated. The fault breccia and cataclasites exhibit mainly brittle microstructures, while brittle and plastic microstructures co-exist in the mylonites. Generally, the minerals responded to deformation by microcracking. Polygonal subgrains were subsequently formed and this was then followed by recrystallization. The microstructural characteristics are used to suggest the mechanisms and temperatures of deformation.