RHAETIAN DIAMOND PLACERS IN SIBERIA
S.A. Grakhanova, Yu.A. Malanina, V.I. Pavlova, V.P. Afanas’evb, N.P. Pokhilenkob, A.V. Gerasimchukc, and A.N. Lipashovac
a Nizhnelenskoe Joint-Stock Company, Yakutsk
b Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
c ALROSA Enterprise, 6 ul. Lenina, Mirnyi, 678170, Russia
Keywords: Diamond, deposit, placer, Upper Triassic, northern Yakutia
Pages: 127-135
Abstract
Large diamond placers have been discovered in a Rhaetian basal horizon (Upper Triassic) in the north of the Sakha Republic (Yakutia) in the drainage areas of the Eekit, Nikabyt, Kelimyar, and Bur Rivers. The found diamonds and kimberlite indicator minerals are completely similar in typomorphic features to those from Carnian basal horizons but, in contrast to them, are well sorted, and pyropes show features of mechanical wear. Analysis of the geologic evolution of the study area, morphology of diamonds and indicator minerals, and composition of the latter showed that the Rhaetian sediments resulted from the erosion of Carnian placers.
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