تعيين محيط تكتونيكي، پتانسيل كاني‌زايي و شرايط تبلور توده كوارتزديوريتبيوتيتدار شمال شرق دليجان با كاربرد شيمي بيوتيت

معدن آهن سرويان به­طور ژنتيكي با توده گرانيتوئيدي سرويان همراه است. هدف از اين پژوهش بررسي سنگشناسي، كانيشناسي و تعيين شرايط تشكيل كانيهاي بيوتيت توده كوارتزديوريت بيوتيتدار سرويان است و در اين تحقيق در مورد اهميت مطالعه اين كاني در تعيين محيط تكتونيكي، پتانسيل كانيزايي و شرايط تبلور اين توده بحث شده است. آناليز الكترون ميكروپروب بيوتيتهاي اين توده نشان ميدهد كه اين كانيها از نوع بيوتيتهاي منيزيمدار غني از Ti و Mg و فقير ازAl و Fe هستند. محتواي AlT بيوتيتها در حدود 37/2-52/2، با (ƩFeO)/(ƩFeO+MgO) بين 55/0 تا 58/0 و تمركز MgO در گستره 77/12-94/13 درصد وزني است. اين شرايط نشان ميدهد كه تودهي مذكور متعلق به سري ماگمايي كالكآلكالن بوده و از رده گرانيتهاي كوهزايي نوع I است كه ماگماي منشأ آن در يك محيط فرورانش، حاصل از ذوب پوسته و گوشته تشكيل شده است. بيوتيتها توده سرويان در دماي 750 درجه سانتيگراد و در شرايط فوگاسيته اكسيژن بالا و تحت فشار 0/6-1/1 كيلوبار متبلور شدهاند. در نتيجه چگونگي تشكيل بيوتيتها تاييد ميكند كه توده سرويان در تشكيل تهنشستهاي آهن اسكارني منطقه مشاركت داشته است.

The composition of skarn's mineralizing fluids is closely related to the physicochemical conditions prevailing during the cooling and crystallization of magma. Biotite is an effective indicator for determining the physio-chemical conditions prevailing during the cooling and crystallization of magma. In this study, the biotite composition of Sarvian biotite quartz diorite from Urmia-Dokhtar magmatic arc was investigated to estimate the magma crystallization conditions and also to determine the petrological and metallogenic characteristics of the granitoid rocks. Materials and methods The study area is located 15 km northeast of Delijan city and in Markazi province (Figure 1). Miocene Sarvian quartzdiorite rocks are classified into three subgroups: quartzdiorite, micro quartzdiorite and biotite quartzdiorite. In this study, 21 spots of Sarvian biotite quartzdiorite were analyzed at the Iran Mineral Processing Research Center (Table 1). Results and discussion The biotites of Sarvian granitoid are crystallized at a temperature of about 750 ° C, oxygen fugacity is between 10-11 and 10-13 and the pressure is about 0.6-1.1 kbar. The mentioned crystallization conditions indicate that the biotite quartzdiorite rocks of Sarvian crystallized at high temperature, shallowly and under high oxygen fugacity conditions. In addition, it shows that Sarvian biotite quartzdiorite has a high chance of mineral exploration. Placement of Sarvian biotite quartzdiorite rocks in Cretaceous limestones and Eocene pyroclastics, crystallization at a pressure of about 1 kbar and the mentioned crystallization conditions, indicate the formation of skarns in the region. The formation of skarn iron ores in the area is a confirmatory examination that has been performed on the studies. Conclusion Emplacement of Sarvian biotite quartzdiorite rocks are at shallow depth and crystallization at high temperature conditions. High magnesium calc-alkaline magmatic series, high oxygen fugacity and type I orogenic granites from subduction of the oceanic crust below the continental plate leads to magma which is the result of melting and mixing of crust and mantle. So it has created suitable conditions for the formation of metal skarns.