The inherent link between precipitation mechanism and mineralogy (invisible gold, cinnabar, stibnite and fluorite) in the Southern Kyrgyzstan Hg-Sb belt

• Applicant: Professor Dr. Gregor Markl
• Subject Area: Mineralogy, Petrology and Geochemistry
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 439375585

The SW Kyrgysztan Sb-Hg belt comprises about 10 major and minor Sb-Hg deposits some of which are internationally important Sb- or Hg-deposits which show some mineralogical and geochemical peculiarities. For example, some of them have only Stibnite as main ore mineral, some only or mostly cinnabarite, and some both. If this is an effect of "telescoping" or if different precipitation mechanisms are responsible for this observation, is unclear. Some of the deposits show complex Hg-Sb-(Pb-Cu) sulfosalts, even as main ore minerals. Possibly, these complex ores are products of interaction of later hydrothermal solutions with earlier formed ores, hence products of remobilisation. Some of the ores contain significant amounts of old, others not, and, finally, the SW Kyrgyz deposits contain besides quartz also fluorite as an important gangue mineral - which is very unusual and, as far as we know, internationally unique for this type of deposit. The present proposal addresses all these peculiarities and will investigate mineral textures and mineral compositions to establish a mineral succession/sequence of hydrothermal events and their conditions of formation, will analyse fluid inclusions to unravel the composition and physico-chemical conditions of the hydrothermal solutions involved, will try to get a hold on the source and importance of fluorine for the formation of these deposits, will on a district scale (i. e., in several deposits) try to geochemically model the precipitation mechanisms and will try to derive a genetic model for this type of deposits from all these data and modelling results. The project is neatly tied to the sibling project of Prof. Wagner (Aachen).

• DFG Programme: Priority Programmes
• Subproject of: SPP 2238: Dynamics of Ore-Metals Enrichment - DOME