Metamorphosed ophiolitic rocks from the Serbo-Macedonian Massif, near Lake Volvi, North-east Greece

Abstract

The paper describes preliminary results from the 120sqkm Volvi mafic complex within the Greek Serbo-Macedonian Massif. We conclude from published information and isotopic ages that the central and eastern part of the Massif (basement and Triassic/Jurassic cover) were affected by an amphibolite-facies regional metamorphic and deformational event in the Late Jurassic-Early Cretaceous. Delayed uplift from this same event may explain Tertiary ages from Kerdilion migmatites. The Volvi complex may thus be A: pre-Mesozoic 'basement', or B: an in situ Mesozoic rift complex or C: a Mesozoic collisional suture remnant. Field, microprobe and XRF data appear to fit model B best. Though deformed, the complex has recognisable 100% sheeted-dyke tracts and substantial areas of undeformed gabbro at lower structural levels. Deformation began before the end of magmatic activity: late sheets of pegmatic gabbro cut deformed dykes; late dykes cut sheared gabbro. Assemblages are of high-grade amphibolite facies and give garnet-hornblende temperatures of 750~ significantly higher than inferred for staurolite-garnet schists outside the complex. Geochemically, the basaltic rocks show LIL enrichment and are intermediate between 'alkalic' and 'above-subduction-zone' in character. The complex may relate to Mesozoic rift-basins identified in E. Serbia, but is not thought to be a Palaeotethyan remnant.

Kinematics of the Southern Rhodope Core Complex (North Greece)

“…1a) corresponds to the upper part of the Serbo-Macedonian Massif. It consists of a pile of thrust units affected by HP metamorphism (Dixon and Dimitriadis 1984;Michard et al 1994) that were emplaced toward the WSW likely in Cretaceous times (Burg et al 1990(Burg et al , 1996. To the north of the SRCC, the Sideroneron Gneiss Unit (Fig.…”

Structural and geochronological evidence for Paleogene thrusting in the western Rhodopes, SW Bulgaria: Elements for a new tectonic model of the Rhodope Metamorphic Province

“…Turpaud and Reischmann [2010] showed that in the Figure 2. Tectonic map of the Rhodope Metamorphic Province modified after Burg et al [1996], Ricou et al [1998], Bonev et al [2006], and Dixon and Dimitriadis [1984]. Rectangle indicates the study area (Figure 4).…”

“…Kostopoulos et al [2000] found evidence for the former presence of diamond, and hence UHP metamorphism, in rocks of the Vertiskos Unit and the CircumRhodope Belt (see section 2.6). Metamorphic mafic and ultramafic rocks, the Volvi Ophiolites, occur in the basal part of the Vertiskos Unit, close to its boundary against the Kerdilion unit [Dixon and Dimitriadis, 1984].…”

U–Pb LA-SF-ICP-MS zircon geochronology of the Serbo-Macedonian Massif, Greece: palaeotectonic constraints for Gondwana-derived terranes in the Eastern Mediterranean

“…The rocks of the Vertiskos Terrane underwent amphibolite-facies metamorphism and a retrograde greenschist-facies overprint (e.g. Dixon and Dimitriadis 1984;Kilias et al 1999). Because all contacts are tectonic, there is no clear relationship with the surrounding country rocks.…”

“…The mafic-ultramafic rocks have generally been assigned to the so-called Therma-Volvi-Gomati (TVG) Complex (e.g. Dixon and Dimitriadis 1984) and commonly been interpreted as either a remnant of the Palaeotethys Ocean that closed in the Early Jurassic (Ş engör et al 1984) or, in contradiction, as a rift-related intrusive complex of Mesozoic age (Dixon and Dimitriadis 1984). In comparison, Brun and Sokoutis (2007) suggest that the boundary between the Kerdillion Unit and the Vertiskos Terrane is represented by the WSW-dipping Kerdillion detachment (Fig.…”