The Aegean Sea Plate (also called the Hellenic Plate or Aegean Plate) is a small

tectonic plate Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large te ...

located in the eastern

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ea ...

under southern

Greece Greece,, or , romanized: ', officially the Hellenic Republic, is a country in Southeast Europe. It is situated on the southern tip of the Balkans, and is located at the crossroads of Europe, Asia, and Africa. Greece shares land borders with ...

and western

Turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a list of transcontinental countries, transcontinental country located mainly on the Anatolia, Anatolian Peninsula in Western Asia, with ...

. Its southern edge is the

Hellenic subduction zone The Hellenic subduction zone (HSZ) is the convergent boundary between the African Plate and the Aegean Sea Plate, where oceanic crust of the African is being subducted north–northeastwards beneath the Aegean. The southernmost and shallowest par ...

south of

Crete Crete ( el, Κρήτη, translit=, Modern: , Ancient: ) is the largest and most populous of the Greek islands, the 88th largest island in the world and the fifth largest island in the Mediterranean Sea, after Sicily, Sardinia, Cyprus, and ...

, where the

African Plate The African Plate is a major tectonic plate that includes much of the continent of Africa (except for its easternmost part) and the adjacent oceanic crust to the west and south. It is bounded by the North American Plate and South American Plat ...

is being swept under the Aegean Sea Plate. Its northern margin is a

divergent boundary In plate tectonics, a divergent boundary or divergent plate boundary (also known as a constructive boundary or an extensional boundary) is a linear feature that exists between two tectonic plates that are moving away from each other. Divergent b ...

with the

Eurasian Plate The Eurasian Plate is a tectonic plate that includes most of the continent of Eurasia (a landmass consisting of the traditional continents of Europe and Asia), with the notable exceptions of the Indian subcontinent, the Arabian subcontinent and ...

. The seafloor in this region is about 350 m below sea level, while the adjacent

Black Sea The Black Sea is a marginal mediterranean sea of the Atlantic Ocean lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Roma ...

and

are 1300–1500 m deep. For this reason it is considered a high plateau between the seas. Evidence suggests the Aegean Plate contains thinned

continental crust Continental crust is the layer of igneous, sedimentary, and metamorphic rocks that forms the geological continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called ''sial'' be ...

, rather than

oceanic crust Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramafic cumu ...

. Since its creation the crust has been thinned through various processes, including

post-orogenic collapse In geology, orogenic collapse is the thinning and lateral spread of thickened crust. It is a broad term referring to processes which distribute material from regions of high gravitational potential energy to regions of low gravitational potential ...

and crustal extension. This extension is responsible for the formation of the

Gulf of Corinth The Gulf of Corinth or the Corinthian Gulf ( el, Κορινθιακός Kόλπος, ''Korinthiakόs Kόlpos'', ) is a deep inlet of the Ionian Sea, separating the Peloponnese from western mainland Greece. It is bounded in the east by the Isth ...

. Previous observations of the region's motion described the crust under the Aegean Sea as a part of the Anatolian Plate, and the different directions of motion were explained as the plate rotating counterclockwise. Further measurements found that motion of the Aegean region differed from the previous model, so the two plates are now considered distinct from each other.

Development

The Aegean Sea area is thought to be an actively extending

back-arc region The back-arc region is the area behind a volcanic arc. In island volcanic arcs, it consists of back-arc basins of oceanic crust with abyssal depths, which may be separated by remnant arcs, similar to island arcs. In continental arcs, the back- ...

due to

slab rollback Oceanic trenches are prominent long, narrow topographic depressions of the ocean floor. They are typically wide and below the level of the surrounding oceanic floor, but can be thousands of kilometers in length. There are about of oceanic tren ...

on the Hellenic subduction zone. This has resulted in extensive normal faulting and

rifting In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben ...

, as well as the formation of a

back-arc basin A back-arc basin is a type of geologic basin, found at some convergent plate boundaries. Presently all back-arc basins are submarine features associated with island arcs and subduction zones, with many found in the western Pacific Ocean. Most of ...

. This environment has created a number of

horst and graben In geology, horst and graben (or range and valley) refers to topography consisting of alternating raised and lowered fault blocks known as horsts and grabens. The features are created by normal faulting and rifting caused by crustal extension ...

features on the seafloor, similar to

basin and range topography Basin and range topography is characterized by alternating parallel mountain ranges and valleys. It is a result of crustal extension due to mantle upwelling, gravitational collapse, crustal thickening, or relaxation of confining stresses. The e ...

. Many of the Aegean Islands are peaks from these features reaching above sea level. The southern part of the plate is 20-22 km thick, while the northern part of the plate is 32-40 km thick, which suggests that the extensional environment has only recently begun affecting the northern region. Prior to the extensional environment, the region underwent the Aegean Orogeny (), followed by

crustal thinning Extensional tectonics is concerned with the structures formed by, and the tectonic processes associated with, the stretching of a planetary body's crust or lithosphere. Deformation styles The types of structure and the geometries formed depend on ...

due to

. This period enabled

metamorphism Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of chem ...

and then exhumation of many types of metamorphic rock found on the Aegean islands.

Seismic activity

The Aegean Sea and surrounding area is seismically active because of the Hellenic subduction zone, as well as the extension of the Aegean Plate. The African plate is subducting under the Aegean Plate at a rate of about 40 mm/year, causing shallow earthquakes near the fault and deeper earthquakes near the Greek volcanic arc. Some seismic activity is a result of the extension of the plate, which creates east-west trending faults that can slip and cause earthquakes.

References

External links

{{Authority control Tectonic plates Aegean Sea Geology of Greece Geology of Turkey

Development

Seismic activity

References

Further reading

External links