Stratiform Mineralization of W-Sn (Cu-Zn-Au)In Chah-Kalap, South of Birjand

Category Economic geology & mineral exploration
Group GSI.IR
Location 21th symposium on geosciences
Holding Date 21 May 2008

     Chah-kalap W-Sn (-Cu-Zn-Au) deposit is located in 100km SSE of Birjand in Central Iran structural zone. The region is located in Lut block. It is a portion of central Iran Paleozoic platform which tolerated late Cimmerian orogenic movements (Eftekharnejad, 1992).Chah-kalap mineralization bearing volcano-sedimentary sequence of Upper Triassic-Jurassic age was metamorphosed in green schist-lower amphibolite facies. This sequence includes felsic schist, albite- serecite- chlorite- calcschist, metacarbonate, serecite- calcschist and metafelsic volcanics. Two NW-SE and NE-SW trending fault systems can be observed in Chah-kalap mining region. Based on conducted investigations, four mineralized horizons can be distinguished in Chah-kalap volcano-sedimentary rocks in albite- serecite- chlorite- calcschist, metacarbonate and serecite- calcschist host rocks. Main mineralized horizon in Chah-kalap occurred at lower contact between metacarbonate and albite- serecite-chlorite- calcschist. The N85E trending stratiform mineralization with layering and lenticular geometry has 2 kilometers length. Ore paragenesis is scheelite, ferberite, chalcopyrite, sphalerite, pyrite and pyrrhotite, which have massive, disseminated, geod like, vein and veinlet and breccia like textures. Silicification, serecitization, chloritization, carbonatization, sulfidization, biotitization and epidotization can be observed in host rocks. Mineralization occurred syngenetically with precipitation of exhalites. Diagenetic processes, which resulted in concentration of ore minerals, followed by metamorphism that led to more concentration of metallic ores. Chah-kalap mining-geological characteristics can be used as an exploratory model for reconnaissance and exploration of similar tungsten deposits in other parts of Iran especially because of vast extension of Upper Triassic-Jurassic volcano-sedimentary sequences in east of Iran and Sanandaj-Sirjan zone.