Petrology of Metamorphic Rocks From the Kabul Block, Afghanistan

Metamorphic rocks make up the largest volume of the Earth. This book mainly focuses on the petrology of metamorphic rocks of Kabul block, Afghanistan. This study provides significant issues that the Kabul block Metamorphic rocks is Paleoproterozoic medium-pressure type metamorphic terrane composed of pelitic gneiss having a voluminous amount of the Archean detrital zircons and amphibolite showing MORB-like affinity. Geochronology of metasedimentary rocks represents 3600-2000 Ma ages from detrital zircon cores and metamorphic rims or grains. The metamorphic zircons occasionally contain sillimanite inclusions. The results suggest that 1850 Ma age indicates the prograde to peak metamorphic conditions prior to the formation of kyanite occurring in the matrix. The oldest ages are as old as Eoarchean approximately 3600 Ma which is probably the oldest age record in Afghanistan.