Lithological and microstructural study of Soresat metamorphic complex (South Eastern of Shahin-Dej)

Field and microscopic studies and geochemical analyses suggest that granitoid rocks may be subdivided into three main groups. The first group of granitoid rocks is S-type syn-tectonic granitic gneiss sheets, the second group is I-type volcanic arc granite and granodiorite and the third group is S-type post-collision alkali-granite. The rocks of Soresat metamorphic complex are different kinds of schist. Andalusite, staurolite, garnet,sillimanite (fibrolite) are the main metamorphic porphyroblasts in these rocks. The protolith of Soresat metamorphic complex are a sequence including shale, siltstone and graywacke with carbonate, arkosic sandstone and pyroclastic intercalations. A prominent,regionally penetrative foliation(S2)is distinguished in studied area.S2 is generally parallel to meta-sedimentary bedding plane. Thin section studies reveal two discrete deformational events. The first deformational event (D1) is preserved as straight inclusion trails in Pre -S2 Post - S1 andalusite, staurolite porphyroblasts. The S2 is generated by the second deformational event. The retrograde metamorphic event follows the second deformational event. The proposed P-T-t path shows a clock-wise path for Soresat metamorphic complex (Pmax=3.7 Kbar, Tmax=600ºC).