LITHOSPHERIC THERMAL AND DENSITY STRUCTURE OF THE JUNCTION E-ANATOLIA, CAUCASUS AND NW ZAGROS

3D joint inversion of free-air gravity, geoid and topography data is applied to obtain lithospheric structure of Anatolia, Caucasus and NW Zagros Mountains and adjacent areas (31E to 49E and 36N to 45N). The method allows integration of a priori knowledge from other Earth Sciences fields like crustal thicknesses from seismic profiles and near surface density data specially in the area with thick sediments. The algorithm delivers three parameters: the crustal thickness (Moho depth), lithospheric thicknesses and the average crustal density.

The resulting model shows an important crustal root (up to 55 km) under the Caucasus and relatively tick Moho for the eastern part of Anatolia and NW Zagros (42-48 km). We find a thin crust (ca. 25 km) under the southern part of the Black Sea thickening northward.

E-Anatolia, NW Zagros and the western part of Caucasus are underlain by a thin lithosphere (ca. 90-110 km). In E-Anatolia and NW Iran, this corresponds to an area of Miocene to Recent volcanism. The lithosphere thickens rapidly northward until the Eurasian plate where it reaches more than 220 km. The southern limit of the cratonic lithosphere of the Russian Platform is very sharp and is located along the northern shore of the Black Sea, north of the western Caucasus but underneath the eastern Caucasus, continuing into the South-Caspian Sea. Under the western part of Anatolia, we find a lithospheric thickness of 130-150 km.