Geochemistray and tectonic setting of Halab Mafic Gabbroic body (West of Zanjan)

In the west of Zanjan، east of Halab، Gabbroic bodies with tholeiitic nature injected into the Eocene rocks. The main minerals are plagioclase، pyroxene ± olivive and epidots، chlorite، termolite-actinolite and the opaque minerals are accessory minerals. The rocks studied have SiO2:45. 1-47 wt% and are classified as gabbro. The normalized trace element patterns show enrichment in LREE and depletion in HREE. The positive anomalies of K، Th، Rb and the negative anomalies of HFSE (Zr، Nb and Ti) indicate the rocks contamination with continental crust. On the tectonic setting diagrams the studied rocks are plotted in the continental intraplate field. Based on all these data، it seems that، the studied gabbroic rocks are formed by the initial stages of the magmatism related to an Eocene pull apart basin and formed due to partial melting of upper asthenosphere risen under continental lithosphere and contaminated with crustal rocks during the Eocene.