Development of spheroidal weathering and exfoliation (onion- skin erosion) in dioritic- quartz dioritic massifs of Ghaleh Ganj (Southeast of Kerman)

The Ghaleh Ganj dioritic- quartz dioritic massifs، as a part of intrusives in the Makran zone show spheroidal weathering and exfoliation. This phenomenon is related to the development of micro-crack systems. Furthermore، various factors such as mechanical properties of rock-forming minerals، tectonic stresses، increasing volume during mineral weathering and earth surface temperature fluctuations may be important in the formation of these features. It seems that the presence of feldspar، biotite and secondary minerals (such as clay minerals، secondary biotite and Fe- oxides) in the study area، played an important role in the development of spheroidal weathering and exfoliation. However، the modal contnents of biotite is the main controlling factor.