Geological setting of the cambrian VHMS deposits of Kyzyl tashtyg, east tuva, siberia

摘要

Kyzyl Tashtyg VHMS deposit is located in southern Siberia in the Republic of Tuva one of the federated states of Russia. The deposit is hosted within a sequence of bimodal basaltic and rhyodacitic volcanics and intrusives associated with minor sedimentary horizons. Distinctive footwall feeder zones devleoped in rhyodacitic rocks pass up to massive pyritic sulphides which contain chalcopyrite and sphalerite. These pass both upwards and laterally to baritic mineralisation with sphalerite and galena. Three horizons of mineralisation are known with the presence of reworked clasts in the sediments providing evidence of seafloor reworking. The deposit appears to have formed in an arc setting with formation conditions compatible with deepwater seafloor hydrothermal activity although strontium isotopes suggest a strong igneous component to the ore fluids, relatively undiluted by seawater sources.