plate tectonics

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World map with a simplified representation of the lithospheric plates
The kinematics of the plates. The directions and speeds of the drift shown were determined from raw GPS data.

Plate tectonics is originally the name for a theory of geosciences about the large-scale tectonic processes in the outer shell of the earth, the lithosphere ( earth's crust and upper mantle ), which today is one of the fundamental theories about the endogenous dynamics of the earth . It says that the outer shell of the earth is divided into lithospheric plates (colloquially known as continental plates ), which lie on top of the rest of the Earth's upper mantle and wander around it (→  continental drift ).

Primarily, the term plate tectonics no longer refers to the theory, but to the phenomenon as such, which is now largely directly or indirectly proven. The same can be understood as an expression of the mantle convection occurring on the earth's surface in the earth's interior, but has other causes.

The processes and phenomena associated with plate tectonics include the formation of fold mountains ( orogenesis ) as a result of the pressure of colliding continents and the most common forms of volcanism and earthquakes .

Relief map of the earth's surface with the lithospheric plates and information on geodynamics

overview

The lithospheric plates

The fragmented structure of the lithosphere is fundamental to plate tectonics . It is divided into seven large lithospheric plates , also known as tectonic plates or (especially by non-geologists) as continental plates :

There are also a number of smaller plates such as the Nazca plate , the Indian plate , the Philippine plate , the Arabian plate , the Caribbean plate , the coconut plate , the Scotia plate and other microplates , although little is known about their delimitation or whose existence is currently only suspected.

The movements of the plates

The plate boundaries are usually represented either by mid-ocean ridges or deep-sea channels on the earth's surface . At the ridge, the neighboring plates drift apart ( diverging plate boundary ), as a result of which basaltic magma rises from the upper mantle and new oceanic lithosphere is formed. This process is also known as ocean floor spreading or sea floor spreading . It is accompanied by intense, mostly submarine volcanism.

At other plate boundaries, on the other hand, oceanic lithosphere dips below an adjacent (oceanic or continental) plate deep into the earth's mantle ( subduction ). The deep-sea channels are located at these converging plate boundaries . Drainage processes in the submerged plate also lead to pronounced volcanism in the plate that remains above.

The actual continental blocks or continental floes made of predominantly granitic material - together with the surrounding ocean floors and the lithospheric mantle below - are pushed away from the spreading zones and towards the subduction zones as if on a slow conveyor belt. Only a collision of two continental blocks can stop this movement.

Since the continental crust is specifically lighter than the oceanic crust, it does not dip in a subduction zone together with the oceanic plate, but instead bulges to form a mountain range (orogeny). This leads to complex deformation processes . A continent-continent collision takes place between the Indian and Eurasian plates, which also led to mountain formation ( Himalaya ).

In addition, two panels can also slide horizontally past each other ( conservative panel boundary ). In this case, the plate boundary is referred to as transform fault (transform fault).

The bearing on which the lithospheric plates slide is located in the border area between the rigid lithosphere and the extremely viscous flowing asthenosphere (English: Lithosphere-Asthenosphere Boundary , LAB). The results of seismic investigations of the ocean floor in the western Pacific suggest that a low-viscosity layer exists in the area of ​​the LAB between 50 and 100 km depth, which allows the mechanical decoupling of the lithosphere from the asthenosphere. The reason for the low viscosity is assumed that the jacket is either partially melted in this area or has a high proportion of volatile substances (mainly water).

Whereas previously the friction of the convective envelope (ger .: convective drag ) was considered at the base of the lithosphere as the main driving force of plate tectonics, rather the self-emanating from the plates forces are now seen as the key. The so-called ridge push is based on the young, warm crust of the mid-ocean ridge, which "floats" on the mantle and therefore towers upwards, which creates a pressure directed horizontally away from the spreading zones. The slab pull is the pull that old, cold lithosphere creates when it dips into the convective mantle at subduction zones. As a result of rock transformations of subducted oceanic crust in greater mantle depths, the density of the crustal rock increases and remains higher than the density of the surrounding mantle material. As a result, the tension on the not yet subducted part of the corresponding lithospheric plate can be maintained.

History of the theory of plate tectonics

Continental drift

The paleobiogeographical distribution areas of Cynognathus , Mesosaurus , Glossopteris and Lystrosaurus (shown here very schematically and not identical to the actual distribution areas reconstructed on the basis of the fossil sites ) belong to the evidence for the earlier existence of Gondwana , the southern part of the Wegener's Pangea, and thus also for the continental drift.

After some researchers had already expressed similar thoughts, it was above all Alfred Wegener who in his book The Origin of the Continents and Oceans , published in 1915, concluded from the sometimes very precise fit of the coastlines on both sides of the Atlantic that today's continents are part of a large one Must have been the primary continent that had broken apart in the geological past. The fit is even more precise if one does not consider the coastlines but the shelf edges , that is, the submarine boundaries of the continents. Wegener called this supercontinent Pangea and the process of breaking up and scattering its fragments continental drift . Although Wegener collected much more evidence for his theory, he could not name any convincing causes for the continental drift. A promising hypothesis came from Arthur Holmes (1928) who suggested that heat flows in the Earth's interior could generate enough force to move the Earth's plates. At this point, however, his hypothesis could not prevail.

From 1960: ocean floors, subduction, earth measurements

The paradigm shift to mobilism therefore only began around 1960, primarily through the work of Harry Hammond Hess , Robert S. Dietz , Bruce C. Heezen , Marie Tharp , John Tuzo Wilson and Samuel Warren Carey , when fundamentally new knowledge about geology was achieved that attained ocean floors .

Pattern of the oceanic crust magnetized with alternating polarity. a) 5 million years ago, b) 2–3 million years ago, c) today
  • It was recognized, for example, that the mid-ocean ridges are volcanically active and that large amounts of basaltic lava emerge from long fractures , mostly in the form of pillow lava .
  • In paleomagnetic measurements of these basalts it was discovered that the repeated reversal of the polarity of the earth’s magnetic field over the course of earth’s history had created a mirror-symmetrical “striped pattern” on both sides of the mid-Atlantic ridge.
  • It was also recognized that the sedimentary rocks that cover the deep-sea floors also get thicker and older as the distance from the mid-ocean ridges increases.

The most plausible explanation for these phenomena was that the constant emergence of basaltic magma at the elongated mid-ocean fracture zones is part of a process by which the ocean floor is pushed apart in opposite directions, so that it continues to expand over time ( seafloor spreading ).

Since there is no evidence that the radius of the earth increases continuously in the course of its existence, as it is e.g. B. was requested in Carey's expansion theory , the idea suggests that the newly formed surface of the earth in the form of oceanic crust must disappear again elsewhere. The fact that today's oceans (apart from special tectonic positions such as in the Mediterranean Sea) do not contain any lithosphere that is older than 200 million years ( Mesozoic ) supports this idea. Half of the seabeds of all oceans are not even older than 65 million years ( Cenozoic ). This refuted the original idea that the oceans were ancient depressions that had already formed together with the continents when the first solid crust was formed around the glowing liquid primordial earth . Instead, the ocean floors consist of geologically extraordinarily young rocks compared to the continents. Taking into account the continuous formation of the ocean floor at the mid-ocean ridges, the conclusion is drawn that there must have been large areas of ocean floors that formed before the Mesozoic, but that they have disappeared from the surface of the earth.

In the 1970s, the deep-sea inlets, which mainly surround the Pacific Ocean, were recognized as the site of the disappearance of the oceanic lithosphere . Because of the strong seismic and volcanic activity associated with it, this zone is also known as the Pacific Ring of Fire .

  • Geophysical measurements revealed diagonally inclined seismic reflection surfaces ( Benioff zone ), where oceanic crust is pushed under continental (or other oceanic) crust and sinks. Typical of these zones are the deep earthquakes , the hypocenters of which can lie at depths of 320 to 720 km. This finding is explained by the phase changes of the minerals in the subducted plate.
  • The approximately 100 km thick asthenosphere is considered to be the base on which the lithosphere can drift sideways . It is also known as the “Low-Velocity Zone” because the seismic P- and S-waves only move slowly through it. The low wave speeds can be explained by the generally lower strength of the asthenosphere compared to the lithosphere and the deeper mantle of the earth . The top layer of the asthenosphere seems to be particularly weak mechanically and to form a kind of film on which the lithosphere can slide.

The new satellite geodesy and VLBI methods , which approached centimeter accuracy in the 1990s, provide direct evidence of continental drift . The speed of the ocean floor spreading is a few centimeters per year, but varies between the individual oceans. The geodetically determined drift rates between the large plates are between 2 and 20 cm per year and largely agree with the geophysical NUVEL models.

In addition to Wegener's theory of continental drift, plate tectonics also contains elements of Otto Ampferer's undercurrent theory (see also history of geology , permanence theory ).

Mountain formation and volcanism in the light of plate tectonics

Schematic representation of the processes along the plate boundaries and essential associated geological phenomena

In contrast to the classic geosynclinal theory, it is now assumed that most mountain-forming and volcanic processes are tied to the plate edges or plate boundaries . Natural phenomena that are significant for humans, such as volcanic eruptions, earthquakes and tsunamis, arise here as side effects of the moving plates .

There are "simple" plate boundaries where two tectonic plates meet and triple points where three tectonic plates meet. Hotspots caused by thermal anomalies in the lower mantle are not bound to plate boundaries .

Constructive (diverging) plate boundaries

This bridge in Iceland spans a fracture zone in the area where the North American and Eurasian plates move apart.

The drifting apart of two plates is called divergence . New lithosphere is being created here.

Mid-ocean ridges

The mid-ocean ridges (MOR) are regarded (as so-called ridges and thresholds ) with a total length of around 70,000 km as the largest connected mountain systems on planet earth.

The flanks of the MOR rise relatively gently. The ridge region often shows depressions over long stretches - the central ditch . The actual formation of the earth's crust or lithosphere takes place on the longitudinal axis of the MOR, where large amounts of mostly basaltic magma melt, rise and crystallize. Only a small fraction reaches the sea floor as lava . The young lithosphere with the freshly crystallized crustal rocks has a lower density compared to the older lithosphere. This is one reason that the MOR rise several thousand meters above the neighboring ocean floor. As the age of the lithosphere increases, its density increases, which is why the ocean floor lies deeper with increasing distance from the longitudinal axis of the MOR. Fracture zones run across the central ditch (see conservative plate boundaries ), where the individual sections of the MOR are offset from one another. Therefore the MOR do not have a continuous ridge line.

A peculiar volcanic phenomenon tied to the mid-ocean ridges are black and white smokers - hydrothermal vents from which superheated, mineral-saturated water escapes. In the process, ores are deposited on black smokers, which then form so-called sedimentary-exhalative deposits .

Intracontinental rifts (rift zones)

Rift zones such as the East African Rift , which can be seen as the first phase of ocean formation, are also associated with volcanic activity. However, these are not actually constructive plate boundaries. The plate divergence is largely compensated for by the sinking and tilting of continental blocks of crust. Characteristic is the bulging of the surrounding continental crust, which results from the heating and the associated decrease in density of the thinned lithosphere and manifests itself in the form of raised basement massifs , which form the rift flank mountains (rift shoulders) of the rift system.

Rift systems such as the East African Rift are created through the activity of so-called mantle diapirs . These heat the lithosphere, thin it out and bulge it up like a dome . The resulting tensions ultimately lead to the crust yielding and triple-beam trench systems, starting from the dome-like bulges, spreading out radially, whereby rift rays directed towards one another grow together and form an elongated trench system. The remaining branches of the rift system wither. Magma rises at the deep fractures in the crust that arise during these processes, which is responsible for the typical alkaline volcanism of continental rift zones.

With increasing expansion of the fracture zones, narrow, elongated sea ​​basins are formed which, like the Red Sea , are already underlaid with oceanic crust and can expand into extensive ocean basins over time.

Destructive (converging) plate boundaries

The opposing movement of two plates is called convergence. Either the denser of the two plates dips into the deeper mantle of the earth ( subduction ), or a collision occurs in which one or both plates are severely deformed and thickened in the edge areas.

Cordilleras or Andes type

Subduction of denser oceanic crust under a block of continental crust

The classic cordillera type of the chain mountains can be found above those subduction zones in which oceanic lithosphere is subducted directly under continental lithosphere, such as on the west coast of South America.

As the oceanic plate descends below the continental block, a deep sea channel is located directly on the subduction front . On the continent, the horizontal pressure exerted by the subducted plate creates a mountain range of folds, but without extensive overthrusts . The increased pressures and temperatures of the mountain formation can lead to regional metamorphoses and melting ( anatexis ) in the affected continental crustal areas.

A volcanic arch forms within the folds. This is due to the fact that the subducted plate transports fluids bound in the rock - especially water - into the depths. Under the prevailing pressure and temperature conditions there, phase transformations occur in the rock, with water being released from the submerged plate into the mantle above. As a result, the melting temperature of the mantle rock is reduced and partial melting occurs . The initially basaltic melt rises through the overlying lithosphere and differentiates itself partly gravitationally or mixes with crust material. The resulting viscous andesitic to rhyolite magmas can reach the surface and sometimes cause highly explosive volcanic eruptions. The Andes as a type region of the Andean-type subduction are accordingly also exemplary for the associated volcanism, which is caused by numerous active volcanoes, such as B. the Cerro Hudson or the Corcovado , but also represented by widespread fossil lava rocks and ignimbrite .

When the oceanic and continental crusts collide, the ocean floor is not always completely subducted. Small remnants of seabed sediments and basaltic material ( ophiolites ) are sometimes “scraped off” (sheared off) from their base during subduction and do not sink into the upper mantle. Instead, they are pushed onto the continental margin in a wedge shape ( autopsied ) and integrated into the chain of mountains and thus the continental crust. Since they are closest to the subduction front, they experience the highest pressure and, together with the rest of the rocks on the continental margin, are folded and subjected to a high pressure-low-temperature metamorphosis.

Volcanic island arches (Mariana type)

On the western edge of the Pacific as well as in the Caribbean , oceanic crust is subducted under other oceanic crust. Deep-sea channels and volcanic arches also form there. The latter are called island arches because only the highest parts of the volcanic arches are above sea level. The arch shape is due to the geometric behavior of a spherical surface, such as the earth's crust, when a plate part is bent and submerged. The convex side of the arch always points in the direction of the subducted plate. Examples are the Marianas , the Alëuts , the Kuriles or the Japanese islands as well as the Lesser and Greater Antilles .

Typical of subduction zones of the Mariana type are so-called backarc basins (from back for 'behind' and arc for 'arch'). The name indicates that these expansion zones are located in the crust behind the arch of the island (as seen from the subducted plate).

Collision type

The drift of the Indian land mass to the north

When the oceanic crust has been completely subducted between two continental blocks , the Andean-type convergence changes to the collision-type convergence. In such a collision, the continental lithosphere is enormously thickened by the formation of extensive tectonic nappes ( mountain formation through continental collision ). A well-known example of this is the Himalaya , which was formed when the Indian subcontinent collided with the Eurasian plate .

After a multi-phase mountain formation (orogenesis), i. H. Temporally staggered collisions of several small continents or volcanic island arcs (so-called terrane ) with a larger continental block and interim subduction phases, ophiolite zones can indicate the boundary between the individual small continental blocks (see also Geosutur ). On both the west and east coasts of North America there are indications that the North American continent has accumulated more and more crust in the course of its geological history as a result of such multiphase orogenesis .

The picture can become even more complicated if the blocks meet at an angle, as in the case of the Apennine peninsula in the Mediterranean . There is evidence that the oceanic Mediterranean crust was temporarily subducted under both the African and the Eurasian plate, while the Iberian Peninsula , the Sardo Corsican Block and the Apennine Peninsula rotated counterclockwise between the large continental blocks.

Conservative plate boundaries (transform perturbations)

San Andreas Fault

At conservative plate boundaries or transform faults , the lithosphere is neither newly formed nor subducted, because the lithospheric plates “slide” past each other here. At and near the earth's surface, where the rocks are brittle, such a plate boundary is designed as a leaf displacement . As the depth increases, the rock is not brittle, but rather highly viscous , due to the high temperatures . that is, it behaves like an extremely tough mass. Therefore, at greater depths, the blade displacement turns into a so-called ductile shear zone .

Transform faults in continental crust can reach a considerable length and, like all plate boundaries, belong to the earthquake centers of gravity. Well-known examples are the San Andreas Fault in California or the North Anatolian Fault in Turkey.

At the mid-ocean ridges (MOR) there are not only volcanically active longitudinal trenches, but also transverse faults, which are also leaf displacements or shear zones. These cut the flanks of the MOR at irregular intervals and divide the back into individual, mutually offset sections. However, only the areas of the faults that run between the central trenches of two neighboring MOR sections are actually conservative plate boundaries and thus transform faults in the true sense. The transform faults of the MOR are also seismically active.

Hot spots

Mauna Loa eruption in Hawaii, 1984

Hotspot volcanism is not directly related to plate tectonics and is not tied to plate boundaries. Instead, hot material in the form of so-called mantle diapirs or plumes is pumped into the upper mantle from sources in the deeper mantle , where basaltic magmas with a characteristic chemical composition melt out of this material, known as Ocean Island Basalts (OIBs, " Ocean Island Basalts ") or reach the surface of the earth. The island of Hawaii , located in the middle of the Pacific plate, is considered a prime example of hotspot volcanism . The Hawaiian island chain ( up to and including Midway and Kure ) and its submarine continuation, the Emperor Ridge , were created when the oceanic lithosphere continuously slid over a hotspot, the magmas of which penetrated the ocean floor at regular intervals. Since hotspots are traditionally considered to be stationary, the direction and speed of lithospheric plates were reconstructed from the course of such volcanic chains and the age of the lava rock of their volcanoes.

At least for the Hawaii-Emperor ridge, new findings suggest that it is not a stationary but a moving hotspot. Scientists examined paleomagnetic data in basalts of several submarine mountains (English: sea ​​mounts ), i. H. former volcanic islands, the Hawaii-Emperor Ridge, which provide indications of the geographical latitude in which the lava solidified at the time ("paleobreite"). The results of the analysis showed that as the age of the rock, the paleobin also increased, suggesting that the hotspot was not stationary, but rather moved southward over the past 80 million years, at an average speed of 4 cm per year. Since these speeds are in the same order of magnitude as the plate speeds (Pacific plate currently approx. 10 cm per year), possible intrinsic movements of hotspots must be taken into account when calculating the direction of movement and the speed of lithospheric plates on the basis of age data from hotspot volcano chains.

There is also a hotspot under Iceland . There, however, there is the special case that hotspot volcanism coincides with the volcanism of a mid-ocean ridge.

Causes of plate tectonics and unsolved problems

Even if the reality of continental drift is hardly doubted by geoscientists , there is still almost as much uncertainty about the forces in the earth's interior that trigger and drive the movements of the plates as in Wegener's time (see also mantle convection ). The two theories cited here have long been considered to be contradicting and incompatible. From today's perspective, they are increasingly viewed as complementary to one another.

Convection currents

The principle of plate tectonics (not to scale)

The most common opinion today is based on slow convection currents that result from the heat transfer between the hot core of the earth and the earth's mantle. The earth's mantle is heated from below. According to a model, the energy for heating up the jacket material could still come from the accretion energy that was released when the earth was formed. In some cases, radioactive decay processes also contribute to the heating. The frictional energy of the tidal action of the moon on the earth's body can probably be neglected. However, under laboratory conditions , for example in heated viscous liquids, convection currents form very highly structured and symmetrical shapes. B. have a honeycomb structure . This can hardly be reconciled with the actually observed shape of the geotectonic plates and their movements.

Another theory is based on only two opposite convection centers. A dominant cell today would be under Africa, which would explain the prevalence of elongation fractures there and the lack of a subduction zone at the edge of the African plate. The other convection cell would be on the opposite side of the globe - under the Pacific plate, which is constantly losing size. The Pacific, which interestingly does not contain any continental crust, would thus be the remnants of a primeval superocean Panthalassa , which once enclosed Pangea . Only when all the continents had reunited to form a new supercontinent in the area of ​​today's Pacific would the movement reverse ( Wilson cycle ). The new Pangea would break apart again to close the new superocean, which would have formed from the Atlantic, Indian and Arctic Oceans, one more time.

Active lithospheric plates

Other authors see the plates not just passively on the coat. The thickness and density of an oceanic lithospheric plate increase steadily as it moves away from the mid-ocean ridge and cools down, which means that it sinks a little into the mantle and can therefore be pushed over by the upper plate more easily. After descending below the top plate, the subducted rock is finally transformed into rock of higher density under the pressure and temperature conditions with increasing depth . So the basalt of the oceanic crust eventually becomes eclogite , whereby the density of the subducted plate exceeds the density of the surrounding mantle. For this reason, the plate that sinks into the mantle during subduction is pulled deeper by its own weight, and in extreme cases, plate material can sink to close to the lower edge of the earth's mantle . The force exerted on the lithospheric plate is called slab pull , from pull ' to pull'; slab 'plate'. A force that is about a factor of 10 smaller also arises on the side of a lithospheric plate facing the mid-ocean ridge, since the crust there experiences a downhill force , the back pressure ( ridge push , from ridge 'back' and push 'push'). A force, a tensile stress, also acts on the opposite plate, which does not sink into the mantle, in a subduction zone. The speed at which an oceanic lithospheric plate actually moves, however, also depends on the size of the opposing forces.

Plate tectonics on other celestial bodies

According to the current state of research, the plate tectonics mechanism seems to be effective only on earth. This is still plausible for the small planet Mercury and for the large moons of the gas planets and the earth's moon. The lithosphere of these celestial bodies, which are much smaller than the earth, is too powerful in relation to being able to be mobile in the form of plates. However, the crust of Jupiter's moon Ganymede shows signs of plate tectonics that has come to a standstill. With Venus , which is almost the size of the Earth , it is difficult to understand why plate tectonics should not have started despite strong volcanism. Free water , which only occurs on earth, could play a significant role in this . Obviously it serves as a friction-reducing " lubricant " in the subduction zones of the earth down to the crystal lattice level . Liquid water and consequently oceans are no longer present on Venus, at least today.

The Mars contrast, seems to possess an intermediate position. Water or ice is present and it is believed that the beginnings of plate tectonics can be recognized. The gigantic shield volcanoes and rift systems that span half the planet are in a certain way reminiscent of rifting on earth. Against this is the lack of clear swallowing zones. The internal heat development and the resulting convection on this relatively small planet were probably not quite sufficient to really set the mechanism in motion, or the process came to a standstill again in the early history of the planet.

It is not known whether a kind of plate tectonics takes place on celestial bodies with a different structure, but it is conceivable. The moons Europa and Enceladus can be considered candidates for convection-driven large-scale horizontal crustal shifts . Europe, the size of the Earth's moon, has an ice sheet about 100 km thick over a rocky lunar body, which could have partially or completely melted in the lower areas, so that the ice sheet may float like pack ice on an ocean. The only 500 km small Enceladus is likely to be heated up by tidal forces. Liquid water or ice that is ductile due to high pressure could rise in deep faults in both celestial bodies and push the brittle ice of the crust to the side, which in turn would mean that crust elsewhere would have to be swallowed. In any case, the surface of these moons has been geologically active, or at least active, and shows evidence that crust renewal has taken place there. The volcanism on Io, on the other hand, seems to be so strong that stable crustal areas like the plates have not even formed.

See also

literature

  • Wolfgang Frisch, Martin Meschede: Plate tectonics. 2nd Edition. Primus-Verlag, Darmstadt 2007, ISBN 3-89678-525-7
  • Oceans and continents, their origins, their history and structure. Spectrum-der-Wissenschaft-Verlagsgesellschaft, Heidelberg 1985, ISBN 3-922508-24-3
  • Hans Pichler: volcanism. Force of nature, climatic factor and cosmic form power. Spectrum-der-Wissenschaft-Verlagsgesellschaft, Heidelberg 1985, ISBN 3-922508-32-4
  • Hubert Miller: Outline of the plate tectonics. Enke, Stuttgart 1992, ISBN 3-432-99731-0
  • Rainer Kind, Xiaohui Yuan: Colliding Continents. In: Physics in Our Time. 34, No. 5, 2003, ISSN  0031-9252 , pp. 213-217, doi: 10.1002 / piuz.200301021
  • Dennis McCarthy: Geophysical explanation for the disparity in spreading rates between the Northern and Southern hemispheres. In: Journal of Geophysical Research. Vol. 112, 2007, p. B03410, doi: 10.1029 / 2006JB004535
  • Christiane Martin, Manfred Eiblmaier (Ed.): Lexicon of Geosciences: in six volumes, Heidelberg [u. a.]: Spektrum, Akademischer Verlag, 2000–2002
  • Wolfgang Jacoby: Plate tectonics on the edges of the American continents. In: The Geosciences. 10, No. 12, 1992, pp. 353-359; doi: 10.2312 / geosciences.1992.10.353
  • Alfred Wegener: The Formation of the Continents and Oceans. 4th edition (= Die Wissenschaft, Volume 66). Friedrich Vieweg & Sohn, Braunschweig 1929 ( HTML version in Wikisource )

Web links

Commons : Plate Tectonics  - collection of images, videos and audio files
Wiktionary: plate tectonics  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ↑ a b Hitoshi Kawakatsu, Prakash Kumar, Yasuko Takei, Masanao Shinohara, Toshihiko Kanazawa, Eiichiro Araki, Kiyoshi Suyehiro: Seismic Evidence for Sharp Lithosphere-Asthenosphere Boundaries of Oceanic Plates. In: Science. 324, No. 5926, 2009, pp. 499–502, doi: 10.1126 / science.1169499 (alternative full-text access: Washington University in St. Louis ).
  2. ↑ a b T. A. Stern, SA Henrys, D. Okaya, JN Louie, MK Savage, S. Lamb, H. Sato, R. Sutherland, T. Iwasaki: A seismic reflection image for the base of a tectonic plate. In: Nature. 518, 2015, pp. 85-88, doi: 10.1038 / nature14146 .
  3. ^ Kurt Stüwe: Geodynamics of the Lithosphere: An Introduction. 2nd edition. Springer, Berlin · Heidelberg 2007, ISBN 978-3-540-71236-7 , p. 253 ff.
  4. ↑ J. Heirtzler, X. Le Pichon, J. Baron: Magnetic anomalies over the Reykjanes Ridge. In: Deep Sea Research. 13, No. 3, 1966, pp. 427-432, doi: 10.1016 / 0011-7471 (66) 91078-3 .
  5. ↑ John A. Tarduno, Robert A. Duncan, David W. Scholl, Rory D. Cottrell, Bernhard Steinberger, Thorvaldur Thordarson, Bryan C. Kerr, Clive R. Neal, Fred A. Frey, Masayuki Torii, Claire Carvallo: The Emperor Seamounts: Southward Motion of the Hawaiian Hotspot Plume in Earth's Mantle. In: Science. 301, No. 5636, 2003, pp. 1064-1069, doi: 10.1126 / science.1086442 (alternative full-text access: Woods Hole Oceanographic Institution ).
  6. ↑ on average 0.952 degrees per million years, see Table 3 in Charles DeMets, Richard G. Gordon, Donald F. Argus: Geologically current plate motions. In: Geophysical Journal International. 181, No. 1, 2010, pp. 1–80, doi: 10.1111 / j.1365-246X.2009.04491.x (alternative full text access: California Institute of Technology )
  7. ↑ Alexander R. Hutko, Thorne Lay, Edward J. Garnero, Justin Revenaugh: Seismic detection of folded, subducted lithosphere at the core-mantle boundary . In: Nature. 441, 2006, pp. 333-336, doi: 10.1038 / nature04757 .
  8. ↑ Harro Schmeling: Plate tectonics: drive mechanisms and forces. In: Geodynamics I and II (lecture notes, WS 2004/2005, Goethe University Frankfurt am Main, PDF ( memento of November 8, 2011 in the Internet Archive )).
This article was added to the list of excellent articles on June 17, 2006 in this version .