Chemical and Mineralogical Characteristics of the Microscopic-sized Epidotes in the Metamorphic Basement Rocks within the Late Cretaceous Hatip Ophiolitic Melange in Konya (Central Southern Turkey)

Abstract

At the base of the Neotethyan ophiolitic melange, widespread epidote crystals formed in metamafic rocks of the metamorphic basement, which were experienced a regional metamorphism in green-schist facies conditions. The epidote crystals is subhedral to euhedral, with high Al2O3 (26-30 %) and low Fe2O3 (5–8%) contents. It is predominantly zoisite (Xcz = 0.46 to 0.72) and subordinate epidote (Xep =0.27-0.53) in composition, with typical compositional zoning due to variable substitution of Fe3+ and Al3+ on octahedral sites and sector-zoning. The epidote is suggested to have a possible igneous origin, and to be crystallised from a wet (H2O>5 wt %) magma under low fO2 and intermediate pressure conditions during initial stage crystallisation on the basis of its petrographical and mineralogical characteristics.