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SPATIOTEMPORAL AND GENETIC RELATIONSHIPS OF GOLD ORE AND MERCURY-ANTIMONY MINERALIZATION AT THE HG-SB-GOLD-BEARINGCHAUVAI DEPOSIT (KIRGHIZIA): GEOLOGY, MINERALOGY OF ORES AND FEATURES OF HYDROTHERMAL-METASOMATIC PROCESSES

A. V. Malyutina, Yu. O. Redin, A. S. Gibsher, V. P. Mokrushnikov

V.S.Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk, Russia

The Chauvai Hg-Sb deposit is a striking example of combining two contrasting types of mineralization in space: mercury-antimony and gold ones. The article studies the spatial-temporal and genetic relationships of goldore and mercury-antimony mineralization based on a complex of both traditional geological and mineralogicalgeochemical methods, as well as modern instrumental methods for analyzing the mineral composition. Two types of ores with clear structural confinedness have been found at the deposit: a) mercury-antimonic (cinnabarantimonite) ores, associated with jasperoid breccias and manifested exclusively along the tectonic contact of limestone of the Alai section and terrigenous rocks of the Tolubai Formation, and b) gold- sulphide (arsenopyritepyritic) ores, localized in slightly modified carbonate-terrigenous rocks of the Tolubai Formation, overlying the plane of tectonic contact. Ore formation occurred during the following stages: in the late diagenetic, without interruption passing into the catagenetic-hydrothermal, characterized by the formation of gold mineralization, and then in the later hydrothermal-telethermal, characterized by the development of Hg-Sb mineralization. It is established that the main carrying agent of invisible gold (“invisible gold”) in ores is framboidal and idiomorphic pyrite and, especially, its high-arsenic varieties. A set of conducted studies has shown that the gold ore and mercury-antimony mineralization is broken in time and is genetically associated with various hydrothermalmetasomatic processes, and the Chauvai deposit can be classified as a Carlin-like type.

Keywords: South-Fergana belt, Chauvai deposit, gold and mercury-antimony mineralization, hydrothermal-metasomatic changes of enclosing rocks, jasperoids, Carlin-type.

DOI 10.20403/2078-0575-2021-3-61-82

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