Mineral composition of Fe-oxide-Cu-Au (IOCG) ores in the basalts of manifestation Hurat (the Sette-Daban ridge, Eastern Yakutia)

Kostin A.V.

Manifestations with Fe-oxide-Cu-Au±REE ores is a new direction in mining geology of Russian North-East. One of unexplored genetic varieties of the Fe-oxide Cu-Au (IOCG) ores, associated with basalt covers was discovered during field works 2013-2015, Sette-Daban ridge. The sole of basaltic cover (manifestation Hurat) include a bedded deposit of hematite breccia with sparse sulfide mineralization. Ores are complex and economically attractive - the content of FeOtot – 15.11–43.29 %; Cu – 0.023–0.083 %; Au – 0.1–17.5 g/t and the main mineral-concentrator of gold is hematite. It has been established that clusters of Fe-oxide ores were formed by the decomposition of ilmenite into hematite, ulvospinel, pseudorutile and rutile. Native gold in ores contain admixture of iron and palladium and does not contain any silver at all. One of the important genetic characteristics of ores are constant presence of monazite-Ce, the chemical composition of which is not constant and is determined by the amount of Ce, La, Pr, Nd, Sm, Eu, Gd, Tb. Its origin is closely connected with the formation of Fe-oxide ores, where monazite is found everywhere in intergrowths with Ti-hematite and pseudorutile.

Key words: Fe-oxide-Cu-Au, basalts, copper manifestation, gold, monazite, Eastern Yakutia.

Arctic and Subarctic Natural Resources, Vol.23, No.4, 2018,  pp.30-38.