Petrology and metamorphism of amphibolites Milovanović Dragan., Eric Suzana., Seke Lajos. Petrology and metamorphism of amphibolites with corundum from Prijepolje , Dinaridic ophiolite Belt (Southwestern Serbia)

Geographic position of Serbia on Balkan Peninsula T H K A R P A A B A L K E S O N I D A L P S D I N A R I D E S A P E N I N E S

The Mesozoic ophiolites in Serbia TISSIA Belgrade Vardar zone Jadar block Vardar zone Amphibolites with corundum Dinaride ophiolite belt Drina Ivanjica terran Vardar zone

The Mesozoic ophiolites in Serbia TISSIA Pillow lavas Belgrade Vardar zone Triassic limestone Jadar block Triassic limestone Zlatibor peridotites Vardar zone Amphibolites with corundum Amphibolites with corundum Dinaride ophiolite belt Drina Ivanjica terran Peridotites Vardar zone Ophiolitic melange

The field trip observations Amphibolite with corundum occur as lens, up to 100 m. thick tectonic contact with surroundig rocks, peridotites and mafic granulites Amphibilite with corundum Peridotites with Gr-Cpi veins Mafic granulites Fault Fault 500 m

Mineral composition The field trip observations Amphibolite with corundum occur as lens, up to 100 m. thick tectonic contact with surroundig rocks, peridotites and mafic granulites

Mineral composition Plagioclase with 92.9-98.9% An (average 95.18) Piroxene Plagioclase Amphibole

Rock composition Mineral composition Corundum contain 0.085-0.161% Cr2O3 Corundum

Rock composition

8-12 kB, 820-10500C Degrees of metamorphism 1000 T (0C) 800 600 400 4 8 12 16 P (kbar) Qtz-absent Qtz-present W&N 91 S&D 94 Hbl Pl Qtz Grt Cpx L Opx V Hbl+Qtz= Opx+Cpx+Pl+V P&B 95 R 93 C 88 E&T 86 W&W 94 N&C 00b N&C 00a P 68, J 78 and WW 93 B&L 91 CWT 67 B 69 S 81 R 91 Experimental constraints Amphibole - plagioclase geothermometer (Blundy and Holland, 1990) 8-12 kB, 820-10500C Al content in Ho ( Hammerstorm and Zen, 1986) 6-12 kB

Degrees of metamorphism The genesis of Corundum: As a residue after partial melting as one of the liquides phases, with clinopyroxene and spinel or clinopyroxene and garnet for gabbroic anorthosite (Raheim&Green, 1974) Metamorphic origin by reaction spinel+anorthite = corundum+diopside in rocks with sufficiently high Al2O3 content, e.g. a troctolitic protholith This reaction needs spinel as one of the reactants, which may be formed by the raction olivine + plagioclase = orthopyroxene + clinopyroxene + spinel. (Kushiro&Yoder,1966) The maximum P-T condition still remains open. The most common mineral assemblage in the upper amphibolite facies for metabasites is Hbl+Pl±Qtz, with or without either Cpx or garnet. Replacement of Hbl+Pl±Qtz by combinations of Cpx, Pl + corundum is the main task of this study.

Protolith Subduction ? Eu and Sr positive anomalies reflect plagioclase accumulation, protolith have a cumulus origin (olivine gabbro ?) High Cr content (783-1090 ppm) imply formation from not evolved liquids. Whole-rock and mineral chemical compositions of AmC have cumulus origin, with a primary (?) mineral assemblage controlled by crystalization of olivine, plagioclase and clinopyroxene, as residue from primitive mantle (MORB source mantle ?).

Protolith Eu and Sr positive anomalies reflect plagioclase accumulation, protolith have a cumulus origin (olivine gabbro ?) High Cr content (783-1090 ppm) imply formation from not evolved liquids. Whole-rock and mineral chemical compositions of AmC have cumulus origin, with a primary (?) mineral assemblage controlled by crystalization of olivine, plagioclase and clinopyroxene, as residue from primitive mantle (MORB source mantle ?).

Conclusions: Whole rock compositions, with positive Eu and Sr anomalies indicate that protoliths of Amc have a basic composition, olivine gabbro cumulates (?) After cooling at shallow levels olivin gabbro cumulates , together with surrounding peridotites undergone subduction and metamorphose under amphibole-granulite-eclogite facies, most probably related with Jurassic subduction during formation of Dinaridic ophiolite belt. During uplift and tectonical emplacement (closing of ocean space) the AmC was dismembered, forming fragments which were included in the ophiolite melange. The absence of thermal relaxation features in Amc require rapid exhumation. Amphibilite with corundum Peridotites with Gr-Cpi veins Mafic granulites

Ophiolites in Serbia and surrounding countries Conclusions: Ophiolites in Serbia and surrounding countries Dinaridic Vardar zone ophiolite belt Degrees of metamorphism of AmC and relation with ultramafic rocks is one of the important questions in genesis and emplacement of Dinaridic ophiolite belt.