Tectonic evolution of Leros (Dodecanese, Greece) and correlations between the Aegean Domain and the Menderes Massif

Abstract

The history of subduction below the Aegean region and western Anatolia is hampered by a lack of comprehension of the correlations between the Cyclades and the Menderes Massif. The Dodecanese Archipelago, which is critical for this discussion, has received very little attention so far. This study is focused on the island of Leros, where two tectonometamorphic units can be observed: the upper Marina unit and the lower Temenia unit. The field study, including new field mapping and structural observations, reveals that the Temenia unit has been exhumed under the Marina unit through a top-to-the-NE ductile shearing followed by a top-to-the-SW brittle deformation cutting the Temenia–Marina contact. The description of metamorphic aragonite and blue amphibole, complemented by Raman spectroscopy on carbonaceous material (RSCM) thermometry, reveals that the Temenia unit has been buried to at least 20 km depth along a cold metamorphic gradient. In terms of lithology and palaeogeographical affinities, the cover of the Marina unit is similar to the Lycian Nappes, which rest on top of the Menderes Massif and belong to the northern margin of the Pelagonian domain. The Temenia unit can then be compared with the Lower Cycladic Blueschists Nappe, which could in turn be correlated with the cover of the Menderes Massif, which has also recorded an HP–LT metamorphic overprint. Supplementary material: Representative chemical analyses are available at https://doi.org/10.6084/m9.figshare.c.4090229