University of Isfahan Petrological Journal 2228-5210 7 27 2016 09 22 Petrography and Geochemistry of tourmaline nodules from Aderba leucogranite (northeast of Golpaygan) Petrography and Geochemistry of tourmaline nodules from Aderba leucogranite (northeast of Golpaygan) 191 205 21029 10.22108/ijp.2016.21029 FA Akramosadat Mirlohi Department of Geology, Faculty of Sciences, University of Isfahan, Isfahan, Iran Mahmoud Khalili Department of Geology, Faculty of Sciences, University of Isfahan, Isfahan, Iran Journal Article 2016 01 10 The Aderba leucogranite in the Golpayegan metamorphic core complex (GMC), a part of Sanandaj-Sirjan zone, host lentiform small (2*4 cm)(Type 1) and large (7*14 cm)(Type 2)tourmaline nodules. In terms of mineralogical features, the core of these two types tourmaline nodules is different. The Type 1 composed of small blue-green tourmaline, quartz, K-feldspar (microcline) and apatite while the Type 2 is characterized by tourmaline coarse crystals accompanied by quartz. Based on major and trace elements data the tourmalines under discussion are classified as alkaline, schorl (Type 1) and schorl-dravite (Type 2). The mean REE values displays a negative slope and a negative (Type 1) and positive (Type 2) Eu anomalies. The overall petrographic observations and geochemical results indicate that the Type 1 is likely influenced by two mechanisms of liquid immiscibility in the evolved melt followed by biotite breakdown in the final stages of tourmaline crystallization to complete consumption of B (closed system). For nodules, Type 2, breakdown of biotite in equilibrium with the external fluid (open system) is proposed. The Aderba leucogranite in the Golpayegan metamorphic core complex (GMC), a part of Sanandaj-Sirjan zone, host lentiform small (2*4 cm)(Type 1) and large (7*14 cm)(Type 2)tourmaline nodules. In terms of mineralogical features, the core of these two types tourmaline nodules is different. The Type 1 composed of small blue-green tourmaline, quartz, K-feldspar (microcline) and apatite while the Type 2 is characterized by tourmaline coarse crystals accompanied by quartz. Based on major and trace elements data the tourmalines under discussion are classified as alkaline, schorl (Type 1) and schorl-dravite (Type 2). The mean REE values displays a negative slope and a negative (Type 1) and positive (Type 2) Eu anomalies. The overall petrographic observations and geochemical results indicate that the Type 1 is likely influenced by two mechanisms of liquid immiscibility in the evolved melt followed by biotite breakdown in the final stages of tourmaline crystallization to complete consumption of B (closed system). For nodules, Type 2, breakdown of biotite in equilibrium with the external fluid (open system) is proposed. https://ijp.ui.ac.ir/article_21029_beeb8623c6ef25abde909aa46454c882.pdf