Writers : Shole,Ali;Rastad,Ebrahim;Babakhani,Ali Reza;Askari,Ali
Refference : The 23th Symposium on Geoscience;Tehran
Publishing Year : 1383

Abstract :

Chah-Calap W-Sn (Cu-Zn-Au) in southern Birjand occurred in upper Triassic-lower Jurassic volcanosedimentary sequence composed of metapellite, metafelsic volcanics, metacarbonate and mylonitic granite. These rocks underwent upper greenschist-lower amphibolite regional metamorphism. Major ore horizon occurred along the contact between metacarbonates and metafelsic volcanics in relation with cherty limestone facies. Geochemical investigations demonstrated anomalous contents of W, Sn, Cu, Zn, Ag, Au and Pb in all lithologies outcropping in Chah-Calap district. Anomalous concentration of mineralizing elements in an extended region reflects syngenetic exhalative-volcanogenic origin for ore mineralization in the area by the mechanism of ore deposition during exhalation of submarine volcanoes and precipitation of sediments. The granitic unit outcropping in Chah-Calap is considered to be of synorogenic S-type granite with no thermal effect on enclosing lithologies. Geochemical investigations revealed that the mineralization in Chah-Calap deposit has no relationship with granitic body. In major ore horizon Tungsten has positive correlation with Sn, Si, Mg, Ti, P, V, Y, Cr and Ni. Positive correlation of W with Si together with Mg, Ni, Cr … is due to sedimentary-exhalative origin for scheelite. REE patterns in mylonitic granite characterized by low REE distribution and partial melting and coincide with synorogenic granites. Dissimilarity of REE patterns in ore bearing calk-silicate horizon with granitic unit together with lower contents of ∑REE rejects incorporation of magmatogenic hydrothermal solutions in mineralization in Chah-Calap deposit.

Subject List : polymetal