Investigation of alteration zones, geochemistry and petrogenesis of the Chahshaljami prospect, Easthern Iran

Abstract

Chahshalghami mineral index is located 190 km to the south of Birjand in the Lut Block volcanic-plutonic belt. Intrusive rocks of Chahshalghami include quartz monzonite, monzonite, granodiorite and diorite and classified as volcanic arc granites, high-K calc alkaline to shoshonite rocks. Processing Aster Satellite image has detected alteration minerals such as alunite, jarusite, chlorite, dickite, sericite, montmorillonite, quartz and iron oxide. Silicic, sulfide and stockwork zones show anomalies of Au, Cu, As, Bi, Mo, Sb, Pb and Zn. Microcrystalline and disseminated pyrite is associated with silicic alteration and many veins include molibdenite, chalcopyrite, sphalerite, galena and enargite. Intrusive rocks have similar trend on Harker diagrams for several major oxides, suggesting a common source and evolution of their magmas. Primitive mantle normalized trace element spider diagram display strong enrichment in LILE such as Rb, Sr, Ba, Zr, Cs and depletion in some high field strength elements (HFSE) e.g. Nb, P and Y. On chondrite normalized plots, display significant LREE enrichments and high degrees of La/Yb > 21.4-33.7 for intrusive rocks and the lack of Eu anomaly is evident. Sr/Y and La/Yb are respectively 31.6-72.2, 21.5-33.5 and cover characteristics of adakites and Sr-Nd isotope studies show that the source is related to the mantle melts contaminated by the lower crust.