The Adriatic and the Aegean Plates
Adriatic Plate
The Adriatic plate, also known as the Apulian plate, is situated in the deformation zone at the boundary between the Eurasian and the African plates. This microplate is bordered by an orogenic belt, the peri-Adriatic mountain chain that runs through Italy and Greece, in the region surrounding the Adriatic Sea (Channell and Horváth, 1976). Once part of a promontory at the edge of the African plate, it has been pushed into the Eurasian continent lithosphere by the convergence of the Eurasian and African plates during the Cenozoic (Battaglia et al., 2004).
The Adriatic plate consists of two blocks, a northern and a southern one, which have different lithospheric thicknesses and divided by an E-W trending shear (Devoti et al., 2002). The low seismic activity in the Adriatic Sea indicates that this plate is relatively rigid (Battaglia et al., 2004). It is bordered by major fault zones surrounding it to the north and the east. In the northern region, the Peri-Adriatic Line runs through the southern Alps as a major continental fault (Picha, 2002). To the east, along the Dinarides, a complex system of strike-slip and thrust faults marks the boundary with the Eurasian Plate (Picha, 2002). On the west side, the Adriatic plate subducts underneath the Apennine Mountains in Italy in a subduction zone that extends south towards the Ionian Sea and beyond (Devoti et al., 2002). These tectonic features outline the plate and are responsible for the unusually twisted shape of the plate.
The Adriatic plate consists of two blocks, a northern and a southern one, which have different lithospheric thicknesses and divided by an E-W trending shear (Devoti et al., 2002). The low seismic activity in the Adriatic Sea indicates that this plate is relatively rigid (Battaglia et al., 2004). It is bordered by major fault zones surrounding it to the north and the east. In the northern region, the Peri-Adriatic Line runs through the southern Alps as a major continental fault (Picha, 2002). To the east, along the Dinarides, a complex system of strike-slip and thrust faults marks the boundary with the Eurasian Plate (Picha, 2002). On the west side, the Adriatic plate subducts underneath the Apennine Mountains in Italy in a subduction zone that extends south towards the Ionian Sea and beyond (Devoti et al., 2002). These tectonic features outline the plate and are responsible for the unusually twisted shape of the plate.
The general direction of this plate is NNE with respect to Europe, with a small counter-clockwise rotation and an Euler pole located approximately in North Italy (Devoti et al., 2002). This direction of motion suggests that it is completely independent of both the African continent, which has a NNW direction of movement in this region, and the Eurasian plate (Battaglia et al., 2004).
The geology of the region encompassing the Adriatic and Aegean microplates is mostly comprised of Neogene and Quaternary sediments overlying carbonate platforms and an igneous rock basement (Channell and Horváth, 1976).
The geology of the region encompassing the Adriatic and Aegean microplates is mostly comprised of Neogene and Quaternary sediments overlying carbonate platforms and an igneous rock basement (Channell and Horváth, 1976).
Aegean Plate
Located between the Adriatic and the Anatolian plates, the small Aegean plate is also caught between the converging Eurasian and African plates. Its border is defined by a belt of active seismic activity surrounding the plate (Innocenti et al., 2010).
South of the plate, near the island of Crete, the active trench delineates the border with the African plate, which subducts under the Aegean microplate (Innocenti et al., 2010). This region is also where the active Hellenic margin is located, which joins the Ionian Islands to Western Anatolia (Innocenti et al., 2010). The central part of the plate is characterized by the Plio-Quaternary volcanic arc and the Pindos ophiolites (Innocenti et al., 2010). The northern extensional basins form the boundary between the Aegean microplate and the Eurasian plate (Innocenti et al., 2010).
A model done by the Berkeley Seismological Laboratory describes a plate rate of about 34mm/year for the Aegean plate relative to a fixed Nubia plate, in a SSW direction (Apel et al., 2007).
References
Apel, E., Burgmann, R. and Serpelloni, E.: Rigid Block Motion, Interseismic Strain, and Backarc Deformation in the Aegean, [online] Available from: http://seismo.berkeley.edu/annual_report/ar07_08/node5.html, 2007.
Battaglia, M., Murray, M. H., Serpelloni, E. and Burgmann, R.: The Adriatic region: An independent microplate within the Africa-Eurasia collision zone, Geophys. Res. Lett., 31(9), 2004.
Channell, J. E. T. and Horváth, F.: The African/Adriatic promontory as a palaeogeographical premise for alpine orogeny and plate movements in the Carpatho-Balkan region, Tectonophysics, 35(1–3), 71–101, 1976.
Devoti, R., Ferraro, C., Gueguen, E., Lanotte, R., Luceri, V., Nardi, A., Pacione, R., Rutigliano, P., Sciarretta, C. and Vespe, F.: Geodetic control on recent tectonic movements in the central Mediterranean area, Tectonophysics, 346(3–4), 151–167, 2002.
Innocenti, F., Agostini, S., Doglioni, C., Manetti, P. and Tonarini, S.: Geodynamic evolution of the Aegean: constraints from the Plio-Pleistocene volcanism of the Volos–Evia area, J. Geol. Soc., 167(3), 475–489, 2010.
Picha, F. J.: Late Orogenic Strike-Slip Faulting and Escape Tectonics in Frontal Dinarides-Hellenides, Croatia, Yugoslavia, Albania, and Greece, AAPG Bull., 86(9), 1659–1671, 2002.
By: Alex K.
Battaglia, M., Murray, M. H., Serpelloni, E. and Burgmann, R.: The Adriatic region: An independent microplate within the Africa-Eurasia collision zone, Geophys. Res. Lett., 31(9), 2004.
Channell, J. E. T. and Horváth, F.: The African/Adriatic promontory as a palaeogeographical premise for alpine orogeny and plate movements in the Carpatho-Balkan region, Tectonophysics, 35(1–3), 71–101, 1976.
Devoti, R., Ferraro, C., Gueguen, E., Lanotte, R., Luceri, V., Nardi, A., Pacione, R., Rutigliano, P., Sciarretta, C. and Vespe, F.: Geodetic control on recent tectonic movements in the central Mediterranean area, Tectonophysics, 346(3–4), 151–167, 2002.
Innocenti, F., Agostini, S., Doglioni, C., Manetti, P. and Tonarini, S.: Geodynamic evolution of the Aegean: constraints from the Plio-Pleistocene volcanism of the Volos–Evia area, J. Geol. Soc., 167(3), 475–489, 2010.
Picha, F. J.: Late Orogenic Strike-Slip Faulting and Escape Tectonics in Frontal Dinarides-Hellenides, Croatia, Yugoslavia, Albania, and Greece, AAPG Bull., 86(9), 1659–1671, 2002.
By: Alex K.