Ophiolites 2008 Guidebook: Link between the Mesohellenic Ophiolites and the Pelagonian Margin

Anne Rassios, Alan Smith, and Dimitrios Kostopoulos

The geology of Greece is complex. The interpretation of key ophiolitic localities of Greece has, in classic studies, aided formulation of primary models of plate tectonic theory. One of these localities, exposed along the Aliakmon River below Zavordas Monastery, was described by Jan Brunn (1908 – 2006) as the best exposure of the base of an ophiolite in the world. Zimmerman (1968) and Moores (1969) used the Aliakmon exposures to document the initial description of the structural nature and zoned metamorphism of an ophiolitic sole. Unfortunately, much of this historic section will be inundated with the construction of a hydroelectric dam. A final study to document this river section has produced new data concerning the nature of this complex suture: in short, the Aliakmon valley records the rifting of Pelagonia, early formation of the Tethys, and the destruction of the Tethys with the emplacement of the Vourinos ophiolite.

To further understand the nature of the sole zone, research extended into its “footwall unit,” the west Pelagonian margin. Virtually unstudied, this Paleozoic-Jurassic margin preserves a continuous section from the Pelagonian core complex gneiss-migmatites, through schistose metamorphics, and into slatey phyllites. Age dating and structural analyses are on-going, their results deciphering exhumation processes of the Pelagonian margin and in delineating the extent an “ophiolitic footprint” beneath the sole zone.

Other classic localities of the Pindos, Koziakas, and Vourinos ophiolites enable discrimination of structure within an obducting ophiolitic nappe: mantle layering and foliation, lower temperature ductile structures, ductile-brittle and brittle emplacement related deformation are demonstrated among our stops, as well as imprint of later Tertiary Alpine deformation. The entire lithospheric section is traversed by stops crossing the Vourinos ophiolite. In the Pindos section, emphasis on emplacement kinematics and ductile structures of the sole and mantle series demonstrate strong evidence of NE-topping directions that favor original Jurassic emplacement models over the Avdella mélange.