Geologic Overview of Anatolia

The Eastern Mediterranean/Anatolian region is one of the most puzzling and highly researched topics in geosciences right now. The Anatolian block, referred to as such because it is a relatively small lithospheric fragment that moves independently from the surrounding major tectonic plates, geographically consists mostly of the Aegean Sea and the countries of Turkey, Greece, Cyprus, and Crete. This region is one of the most seismically active areas in the world due to the interactions of 3 major tectonic plates surrounding the Anatolian block. The Eurasian Plate is located north of the North Anatolian Fault, a large (~1500 km) strike-slip fault analogous to the San Andreas Fault in western North America. The Arabian Plate is underthrusting the Anatolian block in eastern Turkey, leading to the formation of high elevations and volcanism in Turkey and oil-producing basins in the Middle East. The African Plate is subducting beneath the Aegean Sea and central and western Turkey, creating the Aegean volcanic arc consisting of (from west to east) Methana, Milos, Santorini, and Nisyros.

from Bozkurt 2001

from Yolsal-Cevikbilen et al. 2012

Anatolia has been created through the amalgamation of small island-arc terranes and platform carbonates during the closure of the Paleotethys and Neotethys oceans since the Late Triassic (~230 million years ago) and is part of the Alpine-Himalayan orogenic belt which stretches from the Alps in western Europe to southeast Asia. GPS measurements show that the Anatolian block is moving counter-clockwise with respect to Eurasia, and is one of the textbook examples of the theory of “tectonic escape”.
Central Anatolian Tectonics

The tectonics of central Anatolia is generally characterized by transtensional stresses resulting in the formation of “ovas” (extensional basins bounded by oblique-slip faults). Many of the faults in the region are splays of the North Anatolian Fault that bend from E-W striking near the NAF to NE-SW as they continue southwest. Further west, conjugate faults strike NW-SE. This complex fault pattern is a result of the combination of westward extrusion of the Anatolian Plate along the Eastern and Northern Anatolian Faults, and extension from rollback of the Aegean Trench.

from Bozkurt 2001
East Anatolian Fault Zone

The sinistral East Anatolian Fault Zone is the conjugate fault to the dextral North Anatolian Fault, and the two facilitate the westward movement of the Anatolian Block. The initiation of the East Anatolian Fault is debated, but many believe that is has been active since late-Miocene to late-Pliocene.

The East Anatolian Fault Zone becomes diffuse and complex where it is thought to meet with Dead Sea Fault near Pazarcik, Kahramanmaras. Estimates of movement along the EAFZ vary, but current GPS measurements yield an ~11.2 mm/year slip rate. The EAFZ has experienced rather large (> Magnitude 5.0) earthquakes.

Central Anatolian Volcanics

The Central Anatolian volcanics intrude through the transtensional basins formed by the Central Anatolian Fault Zone. Their locations and NE-SW trending pattern does not seem to coincide with the E-W trending subduction zone located in the Mediterranean south of Central Anatolia, and has both orogenic and anorogenic geochemical characteristics (Lustrino and Wilson 2007). The orogenic igneous rocks generally predate the anorogenic rocks, which generally have a more asthenospheric geochemical signature.

Seismic investigations will probe the deeper crustal and upper mantle structures in hopes to place constraints on magma generation location and propagation through the crust.

*The information on this page is derived from research in the eastern Mediterranean, but is poorly cited.
Please consult published research for details on the regions discussed, as this page is meant to be a very brief overview.

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