High-pressure melanocratic rocks of Anrakhai sialic massif (Southern Kazakhstan): the features of mineral, chemical compositions and metamorphism paths

Abstract

In the structure of Anrakhai massif of Chu-Ili region (Southern Kazakhstan) metamoiphic formations of high-pressure conditions derivation (under eclogite facies field) were identified; the rocks are represented by eclogites and garnet clinopiroxenites. Investigation of mineral and chemical compositions of melanocratic high-pressure varieties as well as detailed petrographic and geological studies allowed characterizing P-T parameters of the metamorphic rocks formation (P 1,6-2,1 GPa; Г750-840°C), determining presumed protolith composition for them, that represented evidently the fragment of differentiated complex of mafic-ultramafic compositions, located within the continental crust prior metamorphism.

Keywords

• high-pressure metamoiphism
• eclogites
• garnet clinopiroxenites
• southern kazakhstan