رخداد تورمالین در معدن طلا- مس کوه زر (باغو) جنوب استان سمنان

The qolqoleh gold deposit located 50 km northwestof the sanandaj-sirjan metamorphic-magmatic zone. the area was affected by ne-sw trending shear zone. on the basis of the field prospecting, granitic intrusive rocks, meta-limestone, chlorite- sericite schist and metavolcanic units are altered. the intrusive body ranges in composition from granitic through granodiorite to diorite. the petrographic studies display that the altered intrusive rocks composed of quartz, k-feldspar, muscovite, biotite, sericite, microcline, chlorite, iron oxide and calcite. propylitic, phyllic, carbonatization and silicic zones are the main types of alteration in the area. from the viewpoint of tectonic environment, the intrusive bodies are emplaced in a post- collision volcanic arc setting. the rare earth elements pattern in the metavolcanic of the shear zone indicates that ree are enriches in the shear zone compared to the hanging wall (chlorite-sericite schist) and foot wall (metalimestone) units. it seems that, lree enrichment can be related to the circulation of so4-2, co2 -bearing fluids as well as regional metamorphic in the qolqoleh shear zone. the presence of positive and negative eu anomaly in the metavolcanic rocks is due to the low and advance alteration respectively. the negative anomaly is related to plagioclase alteration in these rocks. the lack of eu anomaly in the hanging wall and foot wall indicate that these rocks are unaltered.