Mineralogical and Petrological Characteristics of the Neoproterozoic Orthoamphibolite and Orthogneisses in the Mutki Area, the Bitlis Massif, Southeast Turkey

• Published in: Acta geologica Sinica (Beijing) Vol. 84; no. 3; pp. 563 - 580
• Main Authors: KOCAK, Kerim, CERAN, F. Mehmet
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.06.2010; Geology Department, Selcuk University, Campus Konya 42075, Turkey
• Subjects: amphibolite; Bitlis Massif; Gondwana; metamorphism; petrochemistry; Turkey; 土耳其; 岩石学特征; 新元古代; 片麻岩; 矿物学; 部分熔融程度; metamorphism; Turkey; Bitlis Massif; petrochemistry; amphibolite; Gondwana
• ISSN: 1000-9515; 1755-6724
• DOI: 10.1111/j.1755-6724.2010.00189.x

The rocks form as amphibolite±garnet±epidote and orthogneisses in the Pan-African basement of the Bitlis Massif.The petrochemical data of the studied metamorphic rocks suggest different igneous protoliths ranging from calcalkaline basalt to andesite in composition. Petrochemically,the rocks can be classified as group 1（low Zr and La） and group 2（high Zr and La）, all showing various enrichments in large ion lithophiles and light rare earth elements,and a depletion in high-field strength elements,suggestive of a destructive plate margin setting.The protoliths of the all samples might have formed mostly by the partial melting of an enriched source,possibly coupled with the fractional crystallization of plagioclase,apatite,and titaniferous magnetite±olivine±clinopyroxene±amphibole in relation with subduction-related magmatism neighboring the Andeantype active margins of Gondwana.The group 2 samples could,however,be generated by a relatively lower degree of the partial melting of an inhomogeneous source with a preponderance of a high-level, fractional crystallization process in comparison to group 1.The protoliths of the samples were metamorphosed up to amphibolite facies conditions,which destroys original igneous texture and mineral assemblages.Geothermobarometric calculations show that the metamorphic rocks are finally equilibrated between 540 and 610℃and～5 kbars,following a clockwise P-T-t path.