Adriatic plate

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Borderline Apulian plate

In plate tectonics, the Adriatic Plate (also: Apulian Plate , Adriasporn and Adriatic Indenter ) is a continent (in the geological sense) whose collision with the Eurasia continent led to the formation of the Alps , Apennines and Dinarides . Due to the long subduction under the Eurasian plate, which began 100 - 120 Ma before today, a large part of the former actual continent "Greater Adria" has been subducted up to 1500 km deep in the upper mantle under the earth's crust . Its edges are severely deformed due to the convergence with the Eurasian plate. Even for geologists, the "continent of Adriatic" was not completely clear up until a few years ago due to the strong thrusts, fractures and bends. It is part of the complicated mosaic of the two microplates in the Mediterranean with active, albeit limited subduction. The Adriatic Plate is a converging continental plate that subducts under the Eurasian Plate in the Southern Dinarides ( Montenegro ) , but changes its subduction polarity in the Alpine-Apennine and Alpine-Dinaride connections and the upper one in the Eastern Alps, in the Apennines and the lower plate forms the Dinarides. Another subduction takes place on the west side of the Adriatic Plate in the Apennines. Due to the opposite movement to the west, the Apennines expands, it becomes lower and shrinks. The Dinarides, on the other hand, are narrowed and grow in height.

The continuous counter-clockwise rotation of the Adriatic against the European part of the Eurasian Plate, which is shown on the earth's surface by tectonic lineaments , is still the trigger for numerous earthquakes such as the Friuli earthquake in 1976 or the earthquake in Montenegro in 1979 (M w 7 , 2), which also triggered a tsunami that carried away houses 15 km along the Montenegrin coast, as well as the earthquake near Zagreb in 2020 (M w 5.4).

expansion

The Adriatic Plate comprises the northern part of the Italian peninsula including the northern Adriatic Sea with the Slovenian-Croatian peninsula of Istria, the western part of the Dinaric Mountains, a large part of the Eastern Alps and the Southern Alps . In the Alps, parts of the Adriatic Plate are pushed over onto the European crust in the form of tectonic blankets and, as the Eastern Alps, form the largest part of the earth's surface in the Eastern Alps.

meaning

As part of the research into the Alps, numerous models were developed to explain the complex tectonic structure of the Alps using the model of plate tectonics. One of the concepts developed as part of this research is that of a microcontinent centered around today's Adriatic that collided with the Eurasian plate. As far as we know today, this Adriatic plate was not an independent plate, but a spur-like part of the larger Apulian plate protruding northwards. The name is still used in the context of regional geological considerations, often as a synonym for the Apulian plate.

Emergence

The southern part of the Apulian Plate was at the beginning of the Triassic on the northern edge of the African Plate . The northern part was separated from the southern part by the so-called Meliata Ocean , on the southern edge of the European continent. From the Upper Triassic onwards , the southern part of the Apulian Plate separated from the African Plate, and with the opening of the Piedmont-Ligurian Ocean (alpine Tethys ) from the Jura , the northern part of the later Apulian Plate also separated from Europe. After the separation, a differentiated rotation of the individual parts took place: paleomagnetic measurements suggest that the Southern Alps rotated counterclockwise, while the Eastern Alps rotated clockwise and the Grauwackenzone with the Northern Limestone Alps drifted northwards towards the European plate .

In the Upper Cretaceous the Meliata Ocean had completely closed in the first phase of the alpine mountain formation, in which the blankets of the Northern Limestone Alps were stacked on top of one another. Only now did a contiguous Apulian continental plate exist, the northern edge of which formed the spur of the Adriatic plate. Due to the continuing closure of the Tethys, the Apulian plate was partly pushed over to the edge of the Eurasian plate (Alps), partly subducted under it (Dinarides) in the Tertiary .

The contact of the Adriatic with the European plate

The contact between the Adriatic plate and the European one, which exists today after the formation of the Alps , is interpreted as a subduction skontakt or as a suture zone (earth seam) with subsequent leaf shifts . Detailed seismic profiles of the Earth's crust have shown that both views have their place: in fact, was subducted beneath the Adriatic part of the European plate, a large role in the formation of contact of the plates in the Periadriatic seam and the Save-line play beyond steep Back thrusts , which pushed both European crust material and nappes over it upwards and south over the Adriatic plate, and at which far-reaching lateral shifts took place at the same time.

See also

literature

Web links

  • Movement of the "Greater Adria" continent in the last 240 million years, video by Douwe van Hinsbergen 2019 (YouTube)
  • Tectonics of the Mediterranean, lecture by Laurent Jolivet 2017 (EGUGIFT 2017) (YouTube)

Individual evidence

  1. ↑ The Alps mineralienatlas.de
  2. ↑ Douwe JJ van Hinsbergen, Trond H. Torsvikb, Stefan M. Schmid, Liviu C. Maţeneo, Marco Maffione, Reinoud LM Vissers, Derya Gürera, Wim Spakmana 2019: Orogenic architecture of the Mediterranean region and kinematic reconstruction of its tectonic evolution since the Triassic. Gondwana Research, Available online 3 September 2019, In ​​Press, Journal Pre-proof Orogenic architecture of the Mediterranean region and kinematic reconstruction of its tectonic evolution since the Triassic (Elsevier: PDF)
  3. ^ Uni Bonn, Nikolaus Froitzheim: Geology of the Alps (also as PDF)
  4. ↑ a b Sid Perkins (2019): Geologists uncover history of lost continent buried beneath Europe , In: Science online.
  5. ↑ Eline Le Breton, Mark R. Handy, Giancarlo Molli, and Kamil Ustaszewski (2017): Post-20 Ma Motion of the Adriatic Plate: New Constraints From Surrounding Orogens and Implications for Crust-Mantle Decoupling. Tectonics, 36, 3135-3154. (PDF)
  6. ↑ Claudia Faccenna et al. (2014), Mantle dynamics in the Mediterranean (PDF 28 MB) , Rev. Geophys., 52, 283–332, doi: 10.1002 / 2013RG000444
  7. ↑ Spiegel, April 23, 1979: Yugoslavia: Flat as biscuits - tourism was hard hit by the earthquake in Montenegro - poorly built large hotels collapsed
  8. ↑ Vanja Kastelic Michele MC Carafa 2012: Fault slip rates for the active External Dinarides thrust ‐ and ‐ fold belt. Tectonics, 31 (PDF)
  9. ↑ Christoforos Benetatos, Anastasia A. Kiratzi (2006): Finite-fault slip models for the 15 April 1979 (MW 7.1) Montenegro earthquake and its strongest aftershock of 24 May 1979 (MW 6.2). July 2006 Tectonophysics 421 (1): 129-143 (PDF: Researchgate)
  10. ↑ a b Schmid et al., P. 95 f.
  11. ↑ Hermann J. Mauritsch, Wolfgang Frisch : Palaeomagnetic results from the Eastern Alps and Their comparison with data from the Southern Alps and the Carpathians . In: Communications from the Austrian Geological Society . tape 73 , 1980, ISSN  0251-7493 , pp. 5–13 ( digitized version [PDF; 540 kB ]).