Abstract

We present field, chemical and U-Pb age data for metamafic-ultramafic bodies of the Triassic rift-related Therma-Volvi-Gomati (TVG) complex of the Serbo-Macedonian Massif (SMM) in the northern Aegean region. The TVG rocks record igneous textures overprinted by Alpine metamorphism and deformation. The high-Ti Volvi body transformed into amphibolites which also rim a low-Ti Gomati and Nea Roda bodies. The compositions are compatible with N- and E-MORB and weak OIB signatures of high-Ti rocks, while the low-Ti rocks are depleted with respect to MORB suggesting melt extraction from a mantle source. U-Pb geochronology reveals Triassic crystallization of the Volvi body at 240 Ma. Ordovician to Carboniferous xenocrystic zircons were found in Stratoni body of the TVG complex, which were sampled from the SMM basement. The Triassic Arnea rift-related metagranite intrudes the Volvi body. Comparison of the compositions of the Volvi body and the Arnea metagranite from the SMM, with Triassic metagranite of the Rhodope Massif (RM) supports the presence of a regional bimodal rift suite. The location of the TVG complex at the SMM-RM margin of Eurasia confirms its origin as a Middle Triassic rift suite, and its nature as a continental margin ophiolite representing an ocean-continent transition of the propagating Neotethys.

Supplementary material: Whole-rock chemical analyses and U-Pb geochronology analytical results data tables are available at https://doi.org/10.6084/m9.figshare.c.4087022

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