Insights into the geotectonic evolution of the southern Rhodope as inferred from a combined AMS, microtextural and paleomagnetic study of the Tertiary Symvolon and Vrondou plutons

The present study focuses on the Tertiary granitoids of the Rhodope Massif, Northern Greece, namely the Early Miocene Symvolon pluton and the composite Miocene–Oligocene Vrondou pluton. In this paper we provide new anisotropy of magnetic susceptibility (AMS) data from Symvolon pluton, discussed along with previously published ones from Vrondou, as well as new paleomagnetic data from samples widely distributed over both studied regions, combined with macroscopic observations and microtextural examinations. The magnetic fabric study pointed out anisotropic bodies with strong preferred orientations of the magnetic grains; however, the paleomagnetic vectors, corrected for anisotropy effect, remain unchanged. Two groups of magnetic lineations were identified: a prevailing NE-SW-trending linear fabric, visible mainly in the Early Miocene plutons, and a second NW-SE-trending fabric, clearly imprinted in the Mid-Oligocene eastern part of the Vrondou pluton. Macro- and microtextural study revealed the presence of magmatic textures, mainly in eastern Vrondou, and sub-solidus plastic deformation textures in Symvolon and western Vrondou. Paleomagnetic results displayed a complex pattern with prevailing clockwise rotations reinforcing the existing pattern for N. Greece and supporting the capacity of granitic bodies to reliably record the Earth's magnetic field independently of their anisotropy. ► We studied the Symvolon and Vrondou granitoids using anisotropy of magnetic susceptibility and palaeomagnetism ► The plutons have high anisotropy and well-defined magnetic fabric ► Magnetic lineations are NE-SW trending in Symvolon and W.Vrondou, and NW-SE in E.Vrondou ► Clockwise rotations prevail ► An emplacement model is proposed