FIND OF NEPHRITE IN THE IYA-TAGUL ULTRAMAFIC BELT (EAST SAYANS)

Abstract

Nephrite is a relatively rare product of crustal transformation of ultramafic rocks. Therefore, the finding of new nephrite-bearing provinces is of definite interest. Among the three ultramafic belts identified by G.V. Pinus in the East Sayans, only the East Sayan belt was known to host nephrite deposits. In the 1987 field season the authors investigated the ultramafic rocks of the Iya-Tagul belt and found a bedrock deposit of nephrite in a pluton in the basin of the Bol'shaya Yangoza, (a right tributary of the Agul). This is the first deposit of nephrite in the ultramafic rocks of the Iya-Tagul belt. The nephrite potential of the region has not yet been established. Judging from the distribution of nephrite in the ultrmafic rocks of the Sayan-Baikal mining district, this deposit may not be unique, and other bodies may exist in this.