Mantle‐derived and crustal melts dichotomy in northern Greece: spatiotemporal and geodynamic implications

Abstract

Two distinct groups of subduction-related (orogenic) granitoid rocks, one Jurassic and the other Tertiary, occur in the area between the Vardar (Axios) Zone and the Rhodope Massif in northern Greece. The two groups of granitoids differ in many respects. The first group shows evolved geochemical characters, it is not associated with mafic facies, and evidence of magmatic interaction between mantle-and crustal-derived melts is lacking. The second group has less evolved geochemical characters, it is associated with larger amount of mafic facies, and magmatic interaction processes between mantle-derived and crustal melts are ubiquitous as evidenced by mafic microgranular enclaves and synplutonic dykes showing different enrichment in K 2 O, Ti, and incompatible elements. This kind of magmatism can be attributed to the complex geodynamic evolution of the area. In particular, we suggest that two successive subduction events related to the closure of the Vardar and the Pindos oceans, respectively, occurred in the investigated area from Late Jurassic to Tertiary. We relate the genesis of Jurassic granitoids to the first subduction event, whereas Tertiary granitoids are associated with the second subduction. Fluids released by the two subducted slabs induced metasomatic processes generating a 'leopard skin' mantle wedge able to produce mafic melts ranging from typical calc-alkaline to ultra-potassic. Such melts interacted in various amounts with crustal calc-alkaline anatectic melts to generate the wide spectrum of Tertiary granitoids occurring in the study area.

The space and time complexity of chaotic mixing of silicate melts: Implications for igneous petrology

“…Mafic end-members are typically used to infer the degree of heterogeneity of the mantle from which they were generated by partial melting (e.g. Perugini et al, 2004b). Similarly, felsic end-members are used to constrain crustal source rocks (e.g.…”

Extremely Re-Rich Molybdenite from Porphyry Cu-Mo-Au Prospects in Northeastern Greece: Mode of Occurrence, Causes of Enrichment, and Implications for Gold Exploration

“…The upwelling asthenosphere provided the heat for hydrous melting of a heterogeneously enriched subcontinental mantle, resulted in the weakening of the crust, and may have produced the accelerated generation of the metamorphic core complexes in the Rhodope Massif [32,34,35]. The plutonic rocks (mostly granite to monzonite), and calc-alkaline to shoshonitic and ultra-K volcanic associations have geochemical and isotope affinities with supra-subduction rocks [31,36,37]. The second phase of core complex related extension in the Rhodope Massif was coeval with the accretion and subduction of a continental block composed of several microcontinents (Gavrovo-Tripolitsa, Olympos, Ionian, Apulian), and the subsequent subduction of the Mediterranean Sea [32].…”

RHENIUM-RICH MOLYBDENITE AND RHENIITE IN THE PAGONI RACHI Mo-Cu-Te-Ag-Au PROSPECT, NORTHERN GREECE: IMPLICATIONS FOR THE Re GEOCHEMISTRY OF PORPHYRY-STYLE Cu-Mo AND Mo MINERALIZATION

“…The latter stage started with block faulting, formation of sedimentary basins, and widespread generation of acid-intermediate and basic magmas of OligoceneMiocene age (Del Moro et al 1988, Pe-Piper et al 1998, 2004, Pe-Piper & Piper 2002, Marchev et al 1998, 2004. Associated plutonic, subvolcanic and volcanic rocks include basic to intermediate mantle-derived members and show calc-alkaline, high-K calc-alkaline, and shoshonitic to ultrapotassic (lamprophyric) affinities , Perugini et al 2004. Felsic igneous rocks in the Rhodope province are considered to be products of crustal anatexis of amphibolitic-gneissic protoliths (Pecskay et al 2003).…”

“…According to Pe-Piper & Piper (2002), it has been debated whether the Paleogene magmatism of northern Greece and Bulgaria was a consequence of subduction (Fytikas et al 1984, Del Moro et al 1988, Barr et al 1999, Perugini et al 2004, collision (Yanev et al 1998, Yanev 2003, or postcollisional extension , Marchev et al 2004. Marchev et al (2004Marchev et al ( , 2006 and Marchev (2007) suggested that the enrichment process in the eastern Rhodopes magmas is unrelated to slabreleased hydrous fluids or contamination by sediment subduction, and that some form of convective removal of the lithosphere, mantle diapirism and underplating of asthenospheric magmas at the crust-mantle boundary could be appropriate processes to explain the magmatic and extensional events in the Rhodope region.…”

“…Furthermore, some calc-alkaline volcanic rocks in southeastern Rhodope have been linked to subduction of the Intra-Pontide Ocean (Pe-Piper & Piper 2002, Pe-Piper 2004. A subduction-related origin is also favored by Perugini et al (2004), whereas the same mantle wedge beneath the Serbomacedonian and Rhodope continents were metasomatized, during two subduction events related to the closure of the Vardar and the Pindos oceans between the Late Jurassic and the Tertiary. These processes produced a mantle wedge able to produce a wide spectrum of mafic melts ranging from calc-alkaline to ultra-potassic.…”