Mineralogical petrochemical and geochemical features of near ore metasomatism in the gold ore deposit "Verkhne-Sakukanskoye" (Northern Transbaikal Region)

Abstract

Discussion in comparative aspect of the nature of geochemical fields in the mesothermal gold deposits formed in blacks and a crystal substratum is continued. The relation of near vein metasomatic and geochemical auras for a case of intervein spaces of low gold-bearing quartz veins is shown on the example of the deposit «Verkhne-Sakukanskoye» of Northern Transbaikal Region located in southwest early Proterozoic frame of the Chara ledge of the Archean base - the western fragment of the Aldan board. In the first part of the article the geological structure of the deposit, mineral structure of ores are considered. On the basis of studying of mineral composition and structure of rocks with attraction of original chemical silicate analyses and petrochemical calculations the enclosing ore containing bodies of plutonic rocks of the early Proterozoic Kodarsky complex are diagnosed as hornblende - biotite quartz diorite and quartz monzonite. In the second part of the article for the first time a mineralogical - petrochemical zonation of near vein metasomatic auras is described, their belonging to a beresite metasomatic formation, and belonging of the deposit to the gold subformation of a gold - uranium - polymetallic beresite ore formation is proved. The geochemical materials revealing distribution on near Clarke levels of contents of ore genous elements (Au, Ag, Hg, etc.) in an intervein space is given, genetic connection of near vein geochemical auras with near vein metasomatic ones in frames of mesotermal ore-forming process of late Paleozoic epoch is substantiated. The obtained results are consistent with conclusions about structure and conditions of formation of the geochemical fields, made earlier in others mesothermal gold deposits of blacks and not slate types.