Study of the major and rare earth elemens behavior during hydrothermal alteration in the Yanigh area (SW Hashtroud, East -Azarbaijan)
Subject Areas :
Keywords: Argillic alteration Hydrothermal Geochemistry Hashtroud Yanigh,
Abstract :
The study area is located about 27 Km southwest of Hashtroud City around the Yanigh village. This district is a part of western Alborz-Azarbaijan structural zone. In the study area, volcanic rocks with andesite to basaltic andesite composition have shown relatively intense argillic alteration. Geochemical studies and mass change calculations on the major and minor elements in the altered zone show that Fe, Mg, Ca and Mn are depleted, Na and K slightly enriched and Al and Si strongly enriched in altered rocks relative to the initial rocks. The HFSEs, LILEs and LREEs show enrichment but the TTEs and HREEs and Y show depletion during alteration. Eu/Eu* ratio in the altered rocks is more than unaltered rock and the majority of samples show positive Ce anomalies. In addition, fractionation factors, (La/Yb)n and (La/Sm)n in the altered rocks is more than, and (Gd/Yb)n is lower than unaltered rock.