Geologic and geochemical investigation on the Mn veins in Jonub-E Sehchangi, SW Birjand, Southern Khorasan province (east Iran)
نویسندگان
1 PhD economic geology
2 Professor, Department of Earth Sciences, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran
3 Professor, Department of Geology, University of Birjand, Birjand, Iran
4 Associate Professor, Research Institute for Fundamental Sciences, University of Tabriz, Tabriz, Iran
doi
10.22071/gsj.2018.58346چکیده
Mn-bearing veins of Jonub -ESehchangi are located 200 km southwest of Birjand, Southern Khorasan province (east of Iran). These veins are hosted by andesitic rocks of Eocene to Oligocene ages. Ore minerals identified by XRD method and mineralographic studies and are Pyrolusite, cryptomelane, psilomelane, hollandite, hematite and goethite, displaying colloform and open-space filling textures. Gypsum, halite, barite, carbonate and silica are the gangue minerals. Alteration zones, specifically argillic alteration zone, are developed along the vein within the andesitic wall rocks. Based on the mineralogical and geochemical data, the primary manganese minerals were Mn oxides and hydroxides, which have gradually been converted to psilomelane and hollandite, and finally pyrolusite. The average grade of Mn within the veins is 38.61%. Considering the average Mn/Fe ratio (about 48.55) in the Mn-bearing veins, as well as the positive correlation of Sr, U and Ba with Mn mineralization in this area show hydrothermal origin.
