Iberian Plate

The Iberian Plate with the microcontinent Iberia encompassed not only the Iberian Peninsula but also Corsica, Sardinia, the Balearic Islands, and the Briançonnais zone of the Penninic nappes of the Alps. Nowadays, the Iberian plate is a part of the Eurasian plate.[2][3]

Astrobleme Europe
Euramerica (Late Triassic, Norian, 220 Ma, in French). Translation: Laurentia, Greenland, Fennoscandian Shield, Saharan Shield, Iberian plate, Irish plate, Scottish plate, Massif Central, Armorican Massif, L' Ardenne, Bohemian terrane, Rochechouart crater ('Impact') and Tethys Ocean.
Hercynian structures Europe-en
Most important structures and zones of the Hercynian orogeny in Europe.[1]

Neoproterozoic

The Iberian plate came into existence during the Cadomian Orogeny of the late Neoproterozoic, about 650–550 Ma, on the margin of the Gondwana continent, involving the collisions and accretion of the island arcs of the Central Iberian Plate, Ossa-Morena Plate, South Portuguese Plate. The three plates have never separated substantially from each other since that time (López-Guijarro et al. 2008).

Mesozoic

In the Mesozoic, Late Jurassic Africa started moving east, and the Alpine Tethys opened. Subsidence related to this caused deep deposits of sediments on the east and some sediment remnants in pop downs in central parts of Spain. Two stages of rifting occurred in the east, one from Later Permian to Triassic, and the second from Late Jurassic to early Cretaceous.

On the south side deposits of carbonates and clastic sediments formed a shelf in shallow water during late Triassic and Liassic times. This was rifted in Toarcian times (Early Jurassic 190 Ma). Active rifting was complete by 160 Ma. After this thermal subsidence occurred till the end of Cretaceous. During this time rifting separated North America from Africa forming a transform zone (Andeweg 2002). In the late Triassic and early Jurassic there were two stages of rifting involving extension and subsidence on the western margin of Iberia. It also extended the western margin. The Iberian Abyssal Plain, off the west coast of Portugal and Spain, formed 126 Ma. This separated Newfoundland's Grand Banks, with Galicia Bank and Flemish Cap being split at 118 Ma. By Early Cretaceous, 110 Ma rifting occurs on west and north west edges.

During the time of the supercontinent Pangea, the Iberian plate was joined to Armorica (Northern France). During the break-up of Pangea, in the early Cretaceous, the Bay of Biscay started opening around 126 Ma and completed by 85 Ma. This created the Biscay Abyssal Plain, and parted the Iberian plate from the Trevelyan Escarpment. During this time Iberia rotated anticlockwise relative to Eurasia. This caused the subduction of the Ligurian Basin onto the eastern side. This formed the Betic nappe stack. After 85 Ma the Atlantic Ocean opening started between Ireland and Greenland. This left the Bay of Biscay as a failed rift (Andeweg 2002).

Cenozoic

The rotation of the Iberia and its relation to the formation of the Pyrenees has been difficult to decipher with certainty. Detailed aeromagnetic measurements from the sea floor offshore of the Grand Banks of Newfoundland to show that Iberia moved as part of the African plate from late Cretaceous to mid-Eocene time, with a plate boundary extending westward from the Bay of Biscay. When motion along this boundary ceased, a boundary linking extension in the King's Trough to compression along the Pyrenees came into existence.[4][5]

Since the late Oligocene, the Iberian plate has been moving as part of the Eurasian plate, with the boundary between Eurasia and Africa situated along the Azores–Gibraltar fracture zone.[5][6][7][8][9][10][11][12][13][14]

Continued rotation of the Iberian plate in the early Miocene once again separated the Iberian plate from Eurasia opening the Betic Corridor a strait of water connecting the Mediterranean Sea with the Atlantic Ocean.[15][16] As the Iberian plate rotated, it closed the Betic Corridor approximately 5.96 million years ago during the Messinian period of the Miocene, precipitating the Messinian Salinity Crisis, a period when the Mediterranean Sea evaporated partly or completely (Krijgsman et al. 1996).

Iberian geology

The core of the Iberian Peninsula consists of a Hercynian cratonic block known as the Iberian Massif. On the northeast this is bounded by The Pyrenean fold belt, and on the southeast it is bounded by the Betic Foldchain. These twofold chains are part of the Alpine belt. To the west, the peninsula is delimited by the continental boundary formed by the magma poor opening of the Atlantic Ocean. The Hercynian Foldbelt is mostly buried by Mesozoic and Tertiary cover rocks to the east, but nevertheless outcrops through the Iberian Chain and the Catalan Coastal Ranges.

See also

Bibliography

Notes

  1. ^ Map is based on Franke (1992, 2000), Matte (2001), von Raumer et al. (2003) and Walter (2003)
  2. ^ Schmid, Stefan M. "Description of the Western and Central Alps". Geologisch-Paläontologisches Institut, University of Basel. Archived from the original on 2005-12-19.
  3. ^ Le Bayon & Ballèvre 2006.
  4. ^ Andeweg 2002.
  5. ^ a b Srivastava et al.
  6. ^ Le Pichon & Sibuet 1971.
  7. ^ Le Pichon, Sibuet & Francheteau 1971.
  8. ^ Sclater, Hellinger & Tapscott 1977.
  9. ^ Grimaud, S.; Boillot, G.; Collette, B.J.; Mauffret, A.; Miles; P.R.; Roberts, D.B. (January 1982). "Western extension of the Iberian-European plate-boundary during early Cenozoic (Pyrenean) convergence: a new model". Marine Geology. 45 (1–2): 63–77. Bibcode:1982MGeol..45...63G. doi:10.1016/0025-3227(82)90180-3.
  10. ^ JL Olivet; JM Auzende; P Beuzart (September 1983). "Western extension of the Iberian-European plate boundary during the Early Cenozoic (Pyrenean) convergence: A new model — Comment". Marine Geology. 53 (3): 237–238. Bibcode:1983MGeol..53..237O. doi:10.1016/0025-3227(83)90078-6.
  11. ^ S. Grimaud; G. Boillot; B.J. Collette; A. Mauffret; P.R. Miles; D.B. Roberts (September 1983). "Western extension of the Iberian-European plate boundary during the Early Cenozoic (Pyrenean) convergence: A new model — Reply". Marine Geology. 53 (3): 238–239. Bibcode:1983MGeol..53..238G. doi:10.1016/0025-3227(83)90079-8.
  12. ^ Olivet et al. 1984.
  13. ^ Schouten, Srivastava & Klitgord 1984.
  14. ^ Savostovin et al. 1986.
  15. ^ Martín et al. 2009.
  16. ^ Seber et al. 1996.

References

Adriatic Plate

The Adriatic or Apulian Plate is a small tectonic plate carrying primarily continental crust that broke away from the African plate along a large transform fault in the Cretaceous period. The name Adriatic Plate is usually used when referring to the northern part of the plate. This part of the plate was deformed during the Alpine orogeny, when the Adriatic/Apulian Plate collided with the Eurasian plate.

The Adriatic/Apulian Plate is thought to still move independently of the Eurasian Plate in NNE direction with a small component of counter-clockwise rotation. The fault zone that separates the two is the Periadriatic Seam that runs through the Alps. Studies indicate that in addition to deforming, the Eurasian continental crust has actually subducted to some extent below the Adriatic/Apulian Plate, an unusual circumstance in plate tectonics. Oceanic crust of the African Plate is also subducting under the Adriatic/Apulian Plate off the western and southern coasts of the Italian Peninsula, creating a berm of assorted debris which rises from the seafloor and continues onshore. This subduction is also responsible for the volcanics of southern Italy.

The eastern Italian Peninsula, the coastal part of Slovenia, Istria, Malta and the Adriatic Sea are on the Adriatic/Apulian Plate. Mesozoic sedimentary rocks deposited on the plate include the limestones that form the Southern Calcareous Alps.

Aegean Sea Plate

The Aegean Sea Plate (also called the Hellenic Plate or Aegean Plate) is a small tectonic plate located in the eastern Mediterranean Sea under southern Greece and far western Turkey. Its southern edge is a subduction zone south of Crete, where the African Plate is being swept under the Aegean Sea Plate. To the north is the Eurasian Plate, which is a divergent boundary responsible for the formation of the Gulf of Corinth.

Anatolian Plate

The Anatolian Plate or the Turkish Plate is a continental tectonic plate comprising most of the Anatolia (Asia Minor) peninsula (and the country of Turkey).

To the east, the East Anatolian Fault, a left lateral transform fault, forms a boundary with the Arabian Plate. To the south and southwest is a convergent boundary with the African Plate. This convergence manifests in compressive features within the oceanic crust beneath the Mediterranean as well as within the continental crust of Anatolia itself, and also by what are generally considered to be subduction zones along the Hellenic and Cyprus arcs.

The northern edge is a transform boundary with the Eurasian Plate, forming the North Anatolian Fault Zone (NAFZ).

Research indicates that the Anatolian Plate is rotating counterclockwise as it is being pushed west by the Arabian Plate, impeded from any northerly movement by the Eurasian Plate. In some references, the Anatolian Plate is referred to as a "block" of continental crust still coupled to the Eurasian Plate. But studies of the North Anatolian Fault indicate that Anatolia is de-coupled from the Eurasian Plate. It is now being squeezed by the Arabian Plate from the east and forced toward the west as the Eurasian Plate to its north is blocking motion in that direction. The African Plate is subducting beneath the Anatolian Plate along the Cyprus and Hellenic Arcs offshore in the Mediterranean Sea.

Armorican terrane

The Armorican terrane, Armorican terrane assemblage, or simply Armorica, was a microcontinent or group of continental fragments that rifted away from Gondwana towards the end of the Silurian and collided with Laurussia towards the end of the Carboniferous during the Variscan orogeny. The name is taken from Armorica, the Gaulish name for a large part of northwestern France that includes Brittany, as this matches closely to the present location of the rock units that form the main part of this terrane.

Baltic Plate

The Baltic Plate was an ancient tectonic plate that existed from the Cambrian Period to the Carboniferous Period. The Baltic Plate collided against Siberia, to form the Ural Mountains about 280 million years ago. The Baltic Plate, however, fused onto the Eurasian Plate when the Baltic Plate collided against Siberia when the Ural Mountains were completely formed. The Baltic Plate contained Baltica and the Baltic Shield which is now located in Norway, Sweden and Finland.

Betic corridor

The Betic Corridor, or North-Betic Strait, was a strait of water connecting the Mediterranean Sea with the Atlantic Ocean that once separated the Iberian plate from the Eurasian plate through the Betic Cordillera. Its closure approximately 5.96 million years ago during the Messinian period of the Miocene epoch, precipitated the Messinian Salinity Crisis, a period when the Mediterranean Sea evaporated partly or completely.

Ebro Basin

The Ebro Basin was a foreland basin that formed to the south of the Pyrenees during the Paleogene. It was also limited to the southeast by the Catalan Coastal Ranges. It began as a fully marine basin with connections to both the Atlantic Ocean and the Mediterranean Sea, before becoming an endorheic basin during the Late Eocene. In the Miocene the basin was captured by a precursor to the Ebro river and the new drainage system that developed eroded away much of the basin fill, except for resistant lithologies, such as the conglomerates at Montserrat.

Geography of Portugal

Portugal is a coastal nation in southwestern Europe, located at the western end of the Iberian Peninsula, bordering Spain (on its northern and eastern frontiers: a total of 1,214 kilometres (754 mi)). The Portuguese territory also includes a series of archipelagos in the Atlantic Ocean (the Açores and Madeira), which are strategic islands along the North Atlantic. The extreme south is not too far from the Strait of Gibraltar, leading to the Mediterranean Sea. In total, the country occupies an area of 92,090 square kilometres (35,560 sq mi) of which 91,470 square kilometres (35,320 sq mi) is land and 620 square kilometres (240 sq mi) water.Despite these definitions, the Portugal-Spain border remains an unresolved territorial dispute between the two countries. Portugal does not recognise the border between Caia and Ribeira de Cuncos River deltas, since the beginning of the 1801 occupation of Olivenza by Spain. This territory, though under de facto Spanish occupation, remains a de jure part of Portugal, consequently no border is henceforth recognised in this area.

Geology of Andorra

Andorra is located in the Axial Zone of the central Pyrenees mountain range in south western Europe, which means that it has intensely folded and thrusted rocks formed when the Iberian peninsula was rotated onto the European continent.

Geology of Guernsey

Guernsey has a geological history stretching further back into the past than most of Europe. The majority of rock exposures on the Island may be found along the coastlines, with inland exposures scarce and usually highly weathered. There is a broad geological division between the north and south of the Island. The Southern Metamorphic Complex is elevated above the geologically younger, lower lying Northern Igneous Complex. Guernsey has experienced a complex geological evolution (especially the rocks of the southern complex) with multiple phases of intrusion and deformation recognisable.

Geology of Svalbard

The geology of Svalbard encompasses the geological description of rock types found in Svalbard, and the associated tectonics and sedimentological history of soils and rocks. The geological exploration of Svalbard is an ongoing activity, and recent understandings may differ from earlier interpretations.

Gothian orogeny

The Gothian orogeny (Swedish: Gotiska orogenesen) or Kongsberg orogeny was an orogeny in western Fennoscandia that occurred between 1750 and 1500 million years ago. It precedes the younger Sveconorwegian orogeny that has overprinted much of it. The Gothian orogeny formed along a subduction zone and resulted in the formation of calc-alkaline igneous rocks 1700 to 1550 million years ago, including some of the younger members of the Transscandinavian Igneous Belt.The deformation associated with the orogeny can be seen in metatonalite, paragneiss and biotite orthogneisses in southeast Norway. These rocks were all subject to amphibolite facies metamorphism.

Hallandian-Danopolonian event

The Hallandian-Danopolonian event was an orogeny and thermal event that affected Baltica in the Mesoproterozoic. The event metamorphosed pre-existing rocks and generated magmas that crystallized into granite. The Hallandian-Danopolonian event has been suggested to be responsible for forming an east-west alignment of sedimentary basins hosting Jotnian sediments spanning from eastern Norway, to Lake Ladoga in Russia. The alignment of subsidence is thought to correspond to an ancient back-arc basin parallel to a subduction zone further south.

List of tectonic plates

This is a list of tectonic plates on the Earth's surface. Tectonic plates are pieces of Earth's crust and uppermost mantle, together referred to as the lithosphere. The plates are around 100 km (62 mi) thick and consist of two principal types of material: oceanic crust (also called sima from silicon and magnesium) and continental crust (sial from silicon and aluminium). The composition of the two types of crust differs markedly, with mafic basaltic rocks dominating oceanic crust, while continental crust consists principally of lower-density felsic granitic rocks.

Mezen Basin

The Mezen Basin is a sedimentary basin located in northwestern Russia. It list southeast of the White Sea and bounds the Timanide Orogen to the north and west. The basin is classified as a pericratonic and epicratonic foreland basin within the East European Craton. The Mezen Basin contains the following pre-Vendian sediments: the Ust-Nafta Group with a maximum thickness of 1200 meters, on top of this is rests the Safonovo Group made up of carbonates and siliciclastic sediments reminiscent of flysch. The Safonovo Group upward end is a unconformity that separates it from the poorly sorted sandstones of the Uftuga Formation.

Pic de Bugarach

The Pic de Bugarach or Pech de Bugarach (puèg de Bugarag in Occitan, i.e. "Peak of Bugarag") is the highest summit (1230 m) in the Corbières mountains in the French Midi.

The western part of the mountain is located on the territory of the commune of Bugarach. Its eastern part is on the territory of Camps-sur-l'Agly.

The geology of the Pic de Bugarach is striking. Its top layer is an overthrust from the Iberian plate and is older than the bottom ones. This has given rise to its description as an "upside-down mountain".It is possible to climb up the Bugarach: a classical route called "Voie de la fenêtre" because of a big hole in a cliff, climbs the South face. One may go down via the easiest route, North, and join the "Col de Linas". Climbing still requires a good physical condition, and the mountain has claimed the life of at least one unprepared tourist.

Piemont-Liguria Ocean

The Piemont-Liguria basin or the Piemont-Liguria Ocean (sometimes only one of the two names is used, for example: Piemonte Ocean) was a former piece of oceanic crust that is seen as part of the Tethys Ocean. Together with some other oceanic basins that existed between the continents Europe and Africa, the Piemont-Liguria Ocean is called the Western or Alpine Tethys Ocean.

Tisza Plate

The Tisza Plate is a tectonic block, or microplate, in present-day Europe. The two major crustal blocks of the Pannonian Basin, Pelso and Tisza, underwent a complex process of rotation and extension of variable magnitude during the Cenozoic era. The northward push of the Adriatic Block initiated the eastward displacement and rotation of both the Alcapa (or Pelso) and Tisza blocks. The Zágráb-Hernád line is the former plate margin between the Pelso of African origin and the Tisza Plate of Eurasian origin.

Volgo–Uralia

Volgo–Uralia is a crustal segment that together with the Sarmatian Craton and the Fennoscandian Craton makes up the East European Craton. Volgo–Uralia is the easternmost of the three segments and borders the Sarmatian Craton to the southwest along the Pachelma aulacogen and the Fennoscandian Craton to the northwest along the Volhyn–Central Russian aulacogen.

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