Radiometric K/ag data as evidence of the geodynamic evolution of the Zdraljica ophiolitic complex, central Serbia

Abstract

The study presents age data and petrologic characteristics of igneous rocks of the Zdraljica ophiolitic complex (ZOC), situated in central Serbia, 150 km south of Belgrade. The complex consists predominately of a MORB/VAB-like tholeutic suite, represented mostly by gabbros and diabases. The tholeiitic suite is intruded by calc-alkaline intermediate and acid magmas of a VA-affinity, which presumably formed in a pre-collisional setting. The whole complex is intruded by peraluminous granite magmas. The crystallization age of the calc-alkaline pre-collisional quartzdiorite is 168.4?6.7 Ma and it post-dates the formation of the here exposed ocean?ic crust. Geological evidence suggest that the emplacement of the complex occurred during the Upper Jurassic. With respect to their petrology and age, the Zdraljica ophiolitic rocks are similar to the south Apuseni Mts. ophiolites, situated to the north, and to the Kursumija and Guevgeli ophiolites, situated to the south. All these ophiolites probably formed as parts of a single Jurassic belt, which can be termed the eastern branch of the Vardar Zone.U ovom radu prikazani su podaci o starosti i o najvaznijim petroloskim odlikama magmatskih stena ofiolitskog kompleksa Zdraljice koji ce nalazi u centralnoj Srbiji, 150 km juzno od Beograda. Kompleks je izgradjen pretezno od toleitskih stena MORB/VAB karaktera koje su predstavljene uglavnom gabrovima i dijabazima. Ovu toleitsku svitu intruduju kalko-alkalne intermedijarne i kisele magme VA-afiniteta, za koje se pretpostavlja da su obrazovane u pre-kolizionim uslovima. Ceo kompleks je intrudovan peraluminijskim leukokratnim granitima. Vreme kristalizacije kalko-alkalnog kvarcdiorita je 168.4 ? 6.7 Ma i ono najverovatnije ukazuje na pre-kolizioni stadijum. Geoloski dokazi ukazuju da je ofiolitski kompleks Zdraljice smesten tokom gornje jure. Prema petrologiji i starosti, ispitivani kompleks pokazuje veliku slicnost sa ofiolitima juznih Apusena na severu i sa ofiolitskim kompleksima Kursumlije i Djevdjelije na jugu. Svi ovi ofioliti su verovatno formirani kao delovi jednog jurskog pojasa koji danas pripada istocnom obodu Vardarske zone.