Essays /

Not By Not Essay

Essay preview

The mechanically rigid outer layer of the Earth, the lithosphere, is broken into pieces called tectonic plates. These plates are rigid segments that move in relation to one another at one of three types of plate boundaries: Convergent boundaries, at which two plates come together, Divergent boundaries, at which two plates are pulled apart, and Transform boundaries, in which two plates slide past one another laterally. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation can occur along these plate boundaries.[60] The tectonic plates ride on top of the asthenosphere, the solid but less-viscous part of the upper mantle that can flow and move along with the plates,[61] and their motion is strongly coupled with convection patterns inside the Earth's mantle. As the tectonic plates migrate across the planet, the ocean floor is subducted under the leading edges of the plates at convergent boundaries. At the same time, the upwelling of mantle material at divergent boundaries creates mid-ocean ridges. The combination of these processes continually recycles the oceanic crust back into the mantle. Due to this recycling, most of the ocean floor is less than 100 myr old in age. The oldest oceanic crust is located in the Western Pacific, and has an estimated age of about 200 myr.[62][63] By comparison, the oldest dated continental crust is 4030 myr.[64] The seven major plates are the Pacific, North American, Eurasian, African, Antarctic, Indo-Australian, and South American. Other notable plates include the Arabian Plate, the Caribbean Plate, the Nazca Plate off the west coast of South America and the Scotia Plate in the southern Atlantic Ocean. The Australian Plate fused with the Indian Plate between 50 and 55 mya. The fastest-moving plates are the oceanic plates, with the Cocos Plate advancing at a rate of 75 mm/year[65] and the Pacific Plate moving 52–69 mm/year. At the other extreme, the slowest-moving plate is the Eurasian Plate, progressing at a typical rate of about 21 mm/year.[66] Surface

Main articles: Landform and Extreme points of Earth

Circle frame.svg
Features of Earth's solid surface shown as percentages of the planet's total surface area Oceanic ridges (22.1%)
Ocean basin floors (29.8%)
Continental mountains (10.3%)
Continental lowlands (18.9%)
Continental shelves and slopes (11.4%)
Continental rise (3.8%)
Volcanic island arcs, trenches, submarine volcanoes, and hills (3.7%) The Earth's terrain varies greatly from place to place. About 70.8%[13] of the surface is covered by water, with much of the continental shelf below sea level. This equates to 361.132 million km2 (139.43 million sq mi).[67] The submerged surface has mountainous features, including a globe-spanning mid-ocean ridge system, as well as undersea volcanoes,[36] oceanic trenches, submarine canyons, oceanic plateaus and abyssal plains. The remaining 29.2% (148.94 million km2, or 57.51 million sq mi) not covered by water consists of mountains, d...

Read more

Keywords

+15 0.4 000 1.3 1.332 1.35 1/4400 10 10.3 100 101 101.325 1015 1018 102 103 107 108 109 11 11.4 13 13.31 139.43 14 148.94 17 18 18.9 196 2 2.5 2.7 200 2005 2013 21 22.1 29.2 29.8 3 3.05 3.4 3.5 3.618 3.7 3.8 30 35 36 361.132 3682 4.71 40 4030 418 5 50 52 55 57.51 60 61 62 63 64 65 66 67 68 68.7 69 7.91 70 70.8 700 71 72 73 74 75 76 77 78 79 8 8.5 80 81 82 83 84 840 848 85 86 87 88 89 90 91 911.4 92 93 94 95 96 97 97.5 98 99 abil abund abyss accord accumul achiev across act activ advanc aerob africa african age agent ago air align allen along also alter although altimetri altitud america american amount amphibol andesit angl annual anoth antarct antarctica anti anti-solar apart approxim aquat arabian arabl arbitrarili arc area arid articl asia asthenospher atlant atmospher aurora australia australian averag away back band basalt base basin bathymetri becom believ belt besid beyond biospher block blue boundari bow broad broken build build-up built burn bya c calcit call canyon captur carbon caribbean caus center challeng chang chaotic character charg chemic chiefli circl circul circulatori classif classifi climat close cloud coast coastal coco cold collis column combin come common compact comparison compon compos concentr condens condit conduct consist constitu contain contin continent continu contrast contribut convect converg convert cool cooler coral core coupl cover creat crop cropland crust current cycl data date day dead decreas deep deepest defin definit deflect deform degre denser densiti deposit depth desert destruct determin develop diagram differ digit dioxid dipol direct dissolv distinguish distribut diverg divid dolomit drift drive due dynamo earth earthquak eastern edg effect el electr elev emit enabl energet energi enter equat equatori eros escap essenti estim eurasian europ evapor even everest everi evolv exampl exist exospher expans extract extrem factor fade fair fall fastest fastest-mov featur feldspar field first five floor flow form format found frame.svg free fresh full function fuse gase gaseous gass geiger generat geograph geolog geomorpholog geophys glaciat global globe globe-span gram granit graviti great greater greenhous ground group heat heat-retent height hemispher henc high higher higher-dens hill histogram homogen humid hydrogen hydrospher ice igneous imag impact import includ increas indian indo indo-australian influenc initi inland insid instead interact interfac interv irregular island kilogram km km2 km3 known kpa kármán köppen lake land landform landscap laps larg last later latitud latitudin layer lead leak leakag left less less-visc level life light like limeston line lithospher locat logic loss low lower lower-dens lowest lowland m m3 magnet magnetospher main major mani mantl mariana mass materi maximum may mean mechan mesospher metamorph meteor meteorit meter methan metric mi mica mid mid-latitud mid-ocean middl migrat millimet million miner mm/year model moder moderate-resolut modifi molecul molecular molten moment moon motion mount mountain mountain-build move movement much must mya myr nasa nation natur nazca near necessari nitrogen niño niño-southern north northern notabl note obscur occur ocean old oldest olivin one opportun orbit organ oscil other outer outermost oxid oxygen oxygen-rich ozon pacif pair part partial particl particular pass past pastur pastureland pattern pedospher peopl per percentag period perman permit phenomenon photosynthesi piec place plain planet planetari plasma plate plateaus point polar pole pre pre-exist precipit precondit present present-day pressur primari primarili process produc progress prolifer provid proxim pull push pyroxen quarter quartz radiat radius rais rang rate reach readili recent recogn recycl redistribut reduc reef region relat releas remain replac reservoir reshap resolut result retent return revers rich ride ridg right rigid rise river rock rough rudolph salin salt satellit scale schemat scotia sea season sediment sedimentari see segment serv settl seven sever shape shelf shelv shield shift shock show shown signific silic slide slope slow slowest slowest-mov slowli small soil solar solid sourc south southern space span specif spectroradiomet spread sq state steadi stratospher strength strike strong student subdivid subduct subject submarin submerg subtrop subtyp sun sunlight sunward support surfac surviv swept system technic tecton temper temperatur terrain terrainbas theori therebi thermal thermohalin thermospher thicker thin thinner third three three-quart thus time today togeth ton top topolog torus torus-shap total trace trade tradit transform transport trench tropic tropospher turn two type typic ultraviolet undergo underground undersea underwat unfix uniform uniqu uplift upper upwel use usual van vapor vari variat various veloc view viscous vital volcan volcano volum warm water weather weight well west wester western wide widespread wind within without wladimir work world would year