NEW DATA ON METAMORPHIC ROCKS OF THE LOK CRYSTALLINE SPUR OF THE TRANSCAUCASUS MEDIAN BLOCK

Abstract

Much of the Lok crystalline spur of the Transcaucasus median block consists of Paleozoic granite. These metamorphic rocks constitute mainly the western periphery of the spur, along the right-bank tributaries of the Moshevani (Pinazauri) River. The maximum width of the outcrop of the metamorphic rock is about 2000 m. We calculate that 50 percent of the metamorphic rock in the spur in K2O-saturated metapelite (muscovite-containing chloritoid, chlorite, garnet, biotite and andalusite schists), 22 percent is graphitic quartzite, 20 percent is CaO-rich rock (primarily amphibole schist), and 6 percent is metapsammite (epidote- or carbonate-containing schists), while marble and other varieties of rocks make up about 2 percent of the metamorphic schist. We have determined the ages of the sericite-rich fractions from the metamorphic rocks of the Lok spur. A detailed electron microprobe study was made of the rock-forming minerals in the spur. Results are presented in this paper.