THE LEAD-ANTIMONY-BISMUTH MINERALIZATION IN ORES OF THE AGYLKI SKARN-SCHEELITE-SULFIDE DEPOSIT (YAKUTIYA, RUSSIA)

Abstract

The mineral composition of quartz-scheelite and quartz-sulfide (pyrrhotite, pyrrhofite-chalcopy rite with scheelite) ores of the Agylki skarn-Cu-W deposit has been studied in detail. Ores of this deposit contain tungsten and copper, as well as bismuth, antimony, lead, silver, gold, tellurium, and selenium. It was found that the formation of two bismuthinite-bismuth and galena-sulfobismuthite mineral associations during the cessation of productive tungsten quartz-scheelite and sulfide stages is responsible for the concentration of ore elements, which are spatially telescoped. The galena-sulfobismuthite association is more widespread in ores and is mainly composed of lead-antimony-bismuth sulfosalts, sulfotellurides, and native gold. Optical-microscope investigations of the minerals under consideration were, supported by examinations with help of an electron probe microanalyzer. This allowed for the identification of several previously unknown minerals at this deposit such as bismuthian jamesonite, kobellite, antimony-bearing bismuthinite, hessite, boumonite,joseite B, and intermediate members of the joseite B-tetrademite series, as well as native bismuth, galena, jamesonite, and tetradimite. The present work discusses data on mineral intergrowths, mineral chemical compositions, and some problems regarding the origin of this lead-antimony-bismuth mineralisation.