Characterization of amphiboles from the Kola super-deep borehole, Russia by Raman and infrared spectroscopy

Abstract

We present here for the first time, the Raman and infrared spectroscopic investigation of amphiboles from the World's deepest borehole, the Kola super-deep borehole, at the depth of 11.66 km. The Kola Super-deep borehole (SG-3) (henceforth referred as KSDB) is located in the northwest of the Kola Peninsula in the northern frame of the Pechenga structure, Russia. It was drilled in the north-eastern part of the Baltic Shield (69о5’N, 30о44’E) and reached a depth of 12.262 km. It has been drilled in the northern limb of the Pechenga geosyncline composed of rhythmically inter-bedded volcanogenic and tuffaceous-sedimentary strata extending to the NW at 300°–310° and dipping to SW at angles of 30°–50°. The SG-3 geological section is represented by two complexes – Proterozoic and Archaean. Amphibolite facies is dominant in the depth region from 6000 m to 12,000 m to the deepest.The Raman spectra of the sample reveal abundant presence of plagioclase and amphiboles. The most distinct Raman peak in this study indicates the tremolite-ferro-actinolite rich enrichment of the borehole samples at this depth corroborating earlier conventional petrographic studies.