Plate tectonics

From Wikipedia, the free encyclopedia

The tectonic plates of the world were mapped in the second half of the 20th century.

Global earthquake ‘epicenters/ˈepɪsentər/ (TÂM CHẤN, TÂM CỦA CƠN ĐỘNG ĐẤT), 1963–1998

Global plate tectonic movement

Plate tectonics [1] is a theory of geology. It has been developed to explain large scale motions of the Earth‘s lithosphere. This theory builds on older ideas of continental drift and seafloor spreading.[2][3]

Dissipation of heat from the mantle is the original source of energy driving plate tectonics. Exactly how this works is still a matter of debate. The driving forces of plate motion continue to be active subjects of on-going research.[4]

Earth’s crust

The outermost part of the Earth’s interior is made up of two layers. The lithosphere, above, includes the crust and the rigid uppermost part of the mantle.

Below the lithosphere is the asthenosphere. Although solid, the asthenosphere can flow like a liquid on long time scales. Large convection currents in the asthenosphere transfer heat to the surface, where plumes of less dense magma break apart the plates at the spreading centers. The deeper mantle below the asthenosphere is more rigid again. This is caused by extremely high pressure.

Thickness of plates

Ocean lithosphere varies in thickness. Because it is formed at mid-ocean ridgesand spreads outwards, it gets thicker as it moves further away from the mid-ocean ridge. Typically, the thickness varies from about 6 kilometres (3.7 mi) thick at mid-ocean ridges to greater than 100 kilometres (62 mi) at subduction zones.[4]

Continental lithosphere is typically about 200 kilometres (120 mi) thick, though this also varies considerably between basins/ˈbeɪsn/, mountain ranges, and stable cratonic interiors of continents. The two types of crust also differ in thickness, with continental crust being considerably thicker than oceanic: 35 kilometres /ˈkɪləmiːtər/ (22 mi) vs. 6 kilometres (3.7 mi).[4]

Three types of plate boundaries and a hot spot ĐIỂM NÓNG
Diagram showing a cross section though the Earth’s lithosphere (in yellow) with magma rising from the mantle (in red).
Hotspots are thought to be caused by a narrow stream of hot mantle convecting up from the Earth’s core–mantle boundary called a mantle plume.[4]

Movement of plates

The lithosphere consists of tectonic plates. There are eight major and many minor plates. The lithospheric plates ride on the asthenosphere. These plates move at one of three types of plate boundaries.[5][6][7][8][2]

  1. convergent boundaries.
  2. divergent boundaries.
  3. transform fault boundaries.

Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along plate boundaries. The lateral movement of the plates varies from:

  • 1–4 centimetres (0.39–1.57 in) per year (Mid-Atlantic Ridge). This is as fast as fingernails grow.
  • 10 centimetres (3.9 in) per year (Nazca Plate)(or Nasca /ˈnɑs kɑ, -kə/. This is as fast as hair grows.[9][10]

Consequences

Tectonic plates can create mountains, earthquakes, volcanoes, mid-oceanic ridges and oceanic trenches, depending on which way the plates are moving.

  1. together = mountains; volcanoes. The ‘Andes/ˈændiːz/ mountain range in South America and the Japanese island arc are examples. Also the Pacific Ring of Fire VÀNH ĐAI LỬA THÁI BÌNH DƯƠNG.
  2. away = earthquakes, trenches. The Mid-ocean ridges and Africa‘s Great Rift Valley are examples.
  3. side to side = earthquakes. The San Andreas Fault /’sæn æn.’dreɪ.əs ”fɔːlt/ in California is an example of a transform boundary. New Zealand is another, more complex, example.

Major plates

Depending on how they are defined, there are usually seven or eight major plates:

  • ‘African Plate /ˈæfrɪkən/
  • Antarctic Plate
  • Indo-Australian Plate, sometimes subdivided into:
    • Indian Plate
    • Australian Plate /ɔːˈstr liən/
  • Eurasian Plate. Eu.’ra.sian  /juˈreɪʒn/
  • North American Plate /əˈmerɪkən/
  • South American Plate
  • Pacific Plate /pəˈsɪfɪk/

tec•’ton•ic /tekˈtɑːnɪk/ adjective word origin mid 17th cent. (originally relating to building or construction): via late Latin from Greek tektonikos, from tektōn ‘carpenter THỢ MỘC, builder’. [only before noun] (geology) connected with the structure of the earth’s surface

ˌplate tecˈtonics noun [uncountable] (geology) the movements of the large sheets of rock (called plates) that form the earth’s surface; the scientific study of these movements

the vast span of geological time (= the whole of time since the earth began)

‘li.tho.sphere /ˈlɪθəsfɪr/ noun [singular] (geology) the layer of rock that forms the outer part of the earth

li’tho.gra.phy THẠCH QUYỂN/lɪˈθɑːɡrəfi/ noun word origin Lithographie (from litho- ‘relating to stone’ + -graphy). (also informal litho /ˈlaɪθoʊ/) [uncountable] the process of printing from a smooth surface, for example a metal plate, that has been specially prepared so that ink only sticks to the design to be printed litho•’graph•ic /ˌlɪθəˈɡræfɪk/ adjective

as·’then·o·sphere QUYỂN MỀM /æsˈθɛn əˌsfɪr/  Word Origin Greek asthen (ḗs) frail (see asthenia ) + -o- + -sphere. noun, Geology. 1. the region below the lithosphere, variously estimated as being from fifty to several hundred miles (eighty-five to several hundred kilometers) thick, in which the rock is less rigid than that above and below but rigid enough to transmit transverse seismic waves.

‘seis•mic /ˈs z mɪk/ ĐỊA CHẤN adjective word origin  from Greek seismos ‘earthquake’ (from seien ‘to shake’) + -ic.[only before noun] 1 connected with or caused by earthquakes. seismic waves SÓNG ĐỊA CHẤN. 2 having a very great effect; of very great size. a seismic shift in the political process.

‘seis•mo•graph /ˈsaɪzməɡræf/ noun MÁY GHI ĐỊA CHẤN an instrument that measures and records information about earthquakes. seis•’mol•ogy /saɪzˈmɑːlədʒi/ noun [uncountable] the scientific study of earthquakes. seis•mo•’logic•al /ˌsaɪzməˈlɑːdʒɪkl/ adjective the National Seismological Institute. seis•’molo•gist /ˌsaɪzməˈlɑːdʒɪst/ noun.

o.ce.’a.nic /ˌoʊʃiˈænɪk/ adjective  [usually before noun] (technical)connected with the ocean. word origin: from Greek ōkeanos ‘great stream encircling the earth’s disc’. “The ocean” originally referred to the whole body of water thought to encompass the earth’s single land mass.

‘Medi•ter”ra•nean /ˌmedɪtəˈreɪniən/ from Latin mediterraneus ‘inland’ (from medius ‘middle’ + terra ‘land’) + -an.

Pan’gae.a or Pan’ge.a (pronunciation: /pænˈə/[1]) TOÀN LỤC ĐỊA word origin early 20th cent.: from pan- ‘all’ + Greek gaia ‘earth’. was a ‘supercontinent that existed during the late Pa.le.o.’zo.ic /ˌpæliəˈzoʊɪk, ˌpeɪ-/and early Mesozoic eras.[2][3] It assembled from earlier continental units approximately 335 million years ago, and it began to break apart about 175 million years ago.[4] In contrast to the present Earth and its distribution of continental mass, much of Pangaea was in the southern hemisphere and surrounded by a superocean, Panthalassa. Pangaea was the most recent supercontinent to have existed and the first to be reconstructed by geologists.

Pal‧ae‧o‧’zo‧ic, Pale.o.’zo.ic /ˌpæliəˈzoʊɪk, ˌpeɪ-/ adjective: belonging or relating to the period of time in the Earth’s history, from about 570 million years ago to about 245 million years ago, when fish, insects, reptiles and some plants first started to exist → mesozoic. Origin: from palaeo/paleo- old, ancient, or prehistoric + Greek zōē life + ic

A ‘continent /ˈkɑːntɪnənt/ CHÂU LỤC=LỤC ĐỊA=ĐẠI LỤC is a large area of the land on Earth that is joined together. In general it is agreed there are seven continents: ‘Africa /ˈæfrɪkə/ CHÂU PHI, Antarctica /ænˈtɑːrktɪkə/ CHÂU NAM CỰC, Asia /ˈeɪʒə/ CHÂU Á, Europe /ˈjʊrəp/CHÂU ÂU, North America CHÂU BẮC MỸ, Austra’lasia /ˌɔːstrəˈleɪʒə/ CHÂU ÚC or O.ce.’a.ni.a/ˌoʊʃiˈɑːniə/ CHÂU ĐẠI DƯƠNG,[1] and South America  CHÂU NAM MỸ.[2][3]

Adjectives, noun person: ‘African/ˈæfrɪkən/, An.’tarc.tic/ænˈtɑːrktɪk/, ‘A.sian /ˈeɪʒn/, Euro•’pean /ˌjʊrəˈpiːən/, A’merican /əˈmerɪkən/, Aus.tra.’la.sian /ˌɔːstrəˈleɪʒə/, O.ce.’a.ni.an /ˌoʊʃiˈɑːniə/.

There are several ways of distinguishing the continents:

Models

Color-coded map showing the various continents. Similar shades exhibit areas that may be consolidated or subdivided.
Four continents[13]     Afro-Eurasia    America   Antarctica   Australia
Six continents[14]   Africa   Europe   Asia    America   Antarctica   Australia
Six continents
[15][16]
  Africa    Eurasia /jʊˈreɪʒə/   North America   South America   Antarctica   Australia
Seven continents
[16][17][18][19][20][21]
  Africa   Europe   Asia   North America   South America   Antarctica   Australia
Các kiểu phân chia

Bản dồ màu chỉ ra các châu lục. Các màu gần giống nhau thể hiện các khu vực có thể gộp lại hay phân chia ra.
7 châu lục
[1][2][3][4][5][6]
    Bắc Mỹ     Nam Mỹ     Châu Nam Cực     Châu Phi     Châu Âu     Châu Á     Châu Đại Dương
6 châu lục
[2][7][8]
    Bắc Mỹ     Nam Mỹ     Châu Nam Cực     Châu Phi        Đại lục Á Âu     Châu Úc
5 châu lục
[9][10][11]
       Châu Mỹ (không tính)     Châu Phi     Châu Âu     Châu Á     Châu Đại Dương

~~~~

Pangaea or Pangea (/pænˈə/) was a supercontinent that existed during the late Paleozoic /ˌpeɪliəˈzəʊɪk/ and early Mesozoic /ˌmezoʊˈzəʊɪk/eras. It was a very large area of land that existed as the only land on Earth about 300–225 million years ago, before it broke apart to form two large land masses, called Laurasia and Gondwanaland. These later broke apart to form the modern continents. In contrast to the present Earth and its distribution of continental mass, much of Pangaea was in the southern hemisphere and surrounded by a superocean, Panthalassa.  The name “Pangaea/Pangea” is derived from Ancient Greek pan (πᾶν, “all, entire, whole”) and Gaia(Γαῖα, “Mother Earth, land”).

Panthalassa (/’pænθəlæsə/), also known as the Pantha’lassic or Pantha’lassan Ocean, (from Greek πᾶν “all” and θάλασσα thalassa “sea”/θəˈlæs ə/),[1] was the superocean that surrounded the supercontinent Pangaea. During the PaleozoicMesozoic transition c. 250 Ma it occupied almost 70% of Earth’s surface. Its ocean-floor has completely disappeared because of the continuous subduction along the continental margins on its cir’cumference.[2] Panthalassa is also referred to as the Paleo-Pacific (“old Pacific”) or Proto-Pacific /ˈproʊtoʊ/ because the Pacific Ocean developed from its centre in the Mesozoic to the present.

Laurasia /lɔˈreɪʒə, lɔˈreɪʃə/. Word origin: Laurentian (lɔːˈrɛnʃən ) + Eurasia (jʊəˈreɪʃə , -ʒə)

Gond.’wa.na.land (ɡɒndˈwɑːnəˌlænd ) or Gondwana. Word origin: C19: from Gondwana region in central north India, where the rock series was originally found.

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