Garnets from lower Ordovician Telposskaya suite (Mayak mt, Subpolar Urals)

We have studied the morphological and chemical features of garnets from coarse clastic metaterrigenous rocks in Paleozoic basement of Western Subpolar Urals. The garnets are represented by rhombododecahedrons, cuboctahedra and intergrowths of crystals of different habit. The internal structure of the studied grains is homogeneous - they do not have zonality and do not contain inclusions. Regardless of the morphology, four groups of garnets are distinguished by their chemical composition: pyrope-grossular-almandine, grossular-pyrope-almandine, grossular almandine-pyrope and almandine-grossular. The absence of rounding and perfect preservation of the surface of the grains and their intergrowths indicates an insignificant distance from the source areas. The comparison of the morphological and chemical characteristics of the studied garnets with typomorphic features of garnets from various rock species suggested that the source of the garnets was metamorphic rocks of the basement, at present widespread in the southern part of the Lyapinsky anticlinorium in the axial zone of Central Ural uplift and, possibly, contact-metasomatic structures associated with introduction of granitoids.