Tectono-stratigraphy and evolution of the Mesozoic Pindos Ophiolite and related units, northwestern Greece

The NW Pindos Mts expose Mesozoic and Tertiary thrust sheets, which include the Jurassic Pindos ophiolite of ultramafic and mafic oceanic crustal rocks. The tectono-stratigraphy of these units is outlined and discussed. Studies of immobile trace elements indicate that Triassic and Jurassic extrusives of the volcanic-sedimentary melange formed mainly at within-plate and/or mid-ocean ridge settings. By contrast, structurally overlying ophiolitic extrusives include boninitic volcanic rocks and island arc tholeiites of supra-subduction origin. Initial ophiolite displacement (approx 165 m.y.) is recorded in metamorphic sole formation, including basal peridotite mylonite amphibolites and greenschists; the sole rocks have MORB and within-plate basalt chemical affinities. The authors favour a model in which the Pindos ophiolite formed above a mid-Jurassic westerly-dipping intra-oceanic subduction zone, accompanied by accretion to form melange, followed by collision and emplacement with the Pelagonian margin. Final suturing of the Pindos ocean, however, did not take place until early Tertiary times.