New ore-magmatic ring-type structure in the Muzkol-Rangkul anticlinorium, Central Pamir

Abstract

Background. The minerogenic specialization of the Muzkol-Rangkul anticlinorium consists in industrial gemstone deposits of ruby, cordierite, almandine, aquamarine, topaz, tourmaline, scapolite, etc. Large ore objects in this area are unknown. Until recently, the area has had a negative assessment in terms of rare, rare earth, and noble metals.Aim. To justify the identification of a previously unknown magnetic ring-type structure and to study the associated ore geochemical anomalies.Materials and methods. Rock and mineral samples collected at the Chernogorskoye deposit in 2016 and 2018 were examined. The mineral composition were determined using a Polam-R211 petrographic microscope and confirmed by XRD analysis using a DRON-3M diffractometer (analyst A.V. Fedorov, Sergo Russian State University for Geological Prospecting). The chemical composition of mineral samples was studied by X-ray microanalysis using a Cameca SX 100 instrument (analyst N.N. Kononkova, Vernadsky Institute of Geochemistry and Analytical Chemistry). The chemical compositions of rock samples was determined using an X-ray fluorescence spectrometer AXIOS Advanced (analyst T.G. Kuzminа, Vernadsky Institute of Geochemistry and Analytical Chemistry).Results. A ring-type intrusion composed of hornblende peridotites, hornblendites, and gabbroids was identified in the Muzkol-Rangkul anticlinorium, in the area of the Chernogorskoye gem scapolite deposit. The gabbroids here contact the metamorphic rocks of the Sarydzhilga formation along the ring fault. The geochemical anomalies of Co, Ni, W, Nb, Ti, and REE were revealed in the contour of the ring structure and along its periphery.Conclusion. The ring-type intrusion identified by the authors is a source of geochemical anomalies.