Ubudlelwano Phakathi Kwezintaba-mlilo Nezinhlayiya Ze-Plate
Izintaba-mlilo zingenye yezinto zemvelo ezihlaba umxhwele kakhulu eMhlabeni. Ukuqhuma kwazo kungadala izindawo ezintsha zomhlaba, kufake umanyolo enhlabathini, futhi kubangele nezinhlekelele ezinkulu. Kodwa izintaba-mlilo aziveli ngokungahleliwe. Uma simaka izindawo zezintaba-mlilo ezisebenzayo emhlabeni, kuvela iphethini ecacile: eziningi zazo zilele emingceleni yepuleti le-tectonic . Lobu budlelwano abuyona ingozi, kodwa umphumela oqondile wendlela uMhlaba okhipha ngayo ukushisa kwawo kwangaphakathi ngokuhamba kwepuleti kanye nokwakheka kwe-magma.
Ukuqonda amapuleti e-tectonic kanye nesakhiwo soMhlaba
Umhlaba wakhiwe ngezingqimba eziningana. Okungaphandle ungqimba oluncane kakhulu, ngaphansi kwalo kukhona i-mantle, bese kuba yi-core yangaphandle kanye ne-inner core. Ungqimba kanye nengxenye ephezulu ye-mantle kwakha i-lithosphere eqinile. Le-lithosphere ayiqinile, kodwa ihlukaniswe yaba "amapulangwe" amakhulu abizwa ngokuthi ama-tectonic plates. Lawa ma-plate ahamba kancane phezu kwengqimba yepulasitiki (i-asthenosphere) ngesivinini samasentimitha amaningana ngonyaka.
Ukunyakaza kwamapuleti kwenzeka ngoba ukushisa okuvela ngaphakathi eMhlabeni kubangela imisinga ye-convection ku-mantle. Izinto ezishisayo ziyaphakama, zipholile phezulu, bese zibuyela phansi. Le misinga "iyacindezela" futhi "idonse" amapuleti, okubangela ukusebenzisana emingceleni yamapuleti: ayahlukana (ayahlukana), asondela (ayahlangana), noma ashelele komunye nomunye (ayashintsha). Lokhu kuxhumana kuchaza ukuthi kungani ukuzamazama komhlaba okuningi kanye nezintaba-mlilo kugxile ezindaweni ezithile.
Izintaba-mlilo zakhiwa kanjani?
Izintaba-mlilo zakheka lapho i-magma—idwala elishisayo elincibilikisiwe elivela ngaphansi komhlaba—iphakama futhi iphume ngemifantu eqoqweni. I-Magma ingakheka ngezindlela ezintathu eziyinhloko:
1. Ukuncibilika ngenxa yokuncipha kwengcindezi (ukuncibilika kwe-decompression): kwenzeka lapho izinto zokwakha ziphakama eduze kobuso ukuze ingcindezi yehle futhi enye yayo incibilike.
2. Ukuncibilika ngenxa yokwengezwa kwamanzi/ama-volatiles (ukuncibilika kwe-flux): kwenzeka lapho amanzi nezinye izinto eziguquguqukayo zingena endaweni ende, zehlisa iphuzu lokuncibilika kwamatshe ukuze ancibilike kalula.
3. Ukuncibilika ngenxa yokushisa okuphezulu (ukudluliselwa kokushisa): kwenzeka lapho i-magma eshisayo ishisa amatshe azungezile kuze kube yilapho amanye awo encibilika.
Lezi zindlela ezintathu zihlobene eduze nohlobo lomngcele wepuleti le-tectonic owenzekayo.
Izintaba-mlilo emingceleni ehlukene: lapho amapuleti ehlukana
Umngcele ohlukanisiwe yisifunda lapho amapuleti amabili ehlukana khona. Isibonelo esidumile kakhulu unqenqema oluphakathi nolwandle, njenge-Mid-Atlantic Ridge. Lapho amapuleti ehlukana, i-mantle iyaphakama ukuze igcwalise isikhala. Njengoba ikhuphuka, ingcindezi iyancipha, okuholela ekuncibilikeni okungaphelele (ukuncibilika kwe-decompression). I-magma ephumelayo ivame ukuba yi-basaltic, i-fluid, futhi yakha uqweqwe olusha lolwandle.
Ukuqhuma emingceleni ehlukene ngokuvamile akuqhumi kakhulu kunasezindaweni ezingaphansi komhlaba. I-lava evulekile ye-basaltic igeleza kalula futhi ayiqhumi kakhulu, yize ihlala iyingozi, ikakhulukazi uma itholakala eduze kwezindawo zokuhlala (isibonelo, e-Iceland, ephezu kogu lolwandle futhi iyindawo eshisayo).
Ngaphandle kwezilwandle, imingcele ehlukene ingenzeka nasemhlabeni ngesimo semifantu, isibonelo, i-East African Rift System. Uma umfantu uqhubeka nokukhula, umhlaba ungahlukana phakathi, wakhe ulwandle olusha phezu kwezikhathi ze-geologic.
Izintaba-mlilo emingceleni ehlanganayo: ukwenziwa kabusha njengefektri ye-magma
Umngcele ohlanganayo yindawo lapho amapuleti amabili ehambela khona. Uma ipuleti elilodwa liminyene futhi lipholile, livame ukuncibilika ngaphansi kwelinye. Lezi zindawo zokuncibilika yilapho kutholakala khona izintaba-mlilo ezisebenza kakhulu neziyingozi emhlabeni.
Njengoba amapuleti olwandle ewela e-mantle, athwala amaminerali aqukethe amanzi kanye ne-sediment. Ekujuleni okuthile, amanzi kanye ne-volatiles kukhishwa e-mantle engaphezulu. Ukuba khona kwamanzi kunciphisa iphuzu lokuncibilika kwamatshe e-mantle, okuholela ekuncibilikeni kwe-flux. I-magma ephumelayo ivame ukuba nkulu (i-andesitic kuya ku-rhyolitic) futhi icebile ngegesi, okuholela ekuqhumeni okukhulu okuqhumayo. Lokhu kuchaza ukuthi kungani izintaba-mlilo eziningi eziseduze ne-Pacific Ring of Fire zivame ukuqhuma ngamandla.
I-Indonesia iyisibonelo esiyinhloko sesifunda esakhiwe yile nqubo. I-Indo-Australian Plate engaphansi kwe-Eurasian Plate yakha umugqa wentaba-mlilo weSumatra, iJava, iBali, neNusa Tenggara. Ngasempumalanga, ukusebenzisana kwamapuleti kuba nzima kakhulu, okubandakanya i-Pacific Plate kanye namapuleti amancane ahlukahlukene, okuholela ekusebenzeni okukhulu kokuzamazama komhlaba kanye nentaba-mlilo.
Ngaphezu kokuhlanganiswa kwezwekazi nolwandle, kukhona futhi ukuhlanganiswa kwezwekazi nolwandle okwakha imigqa yeziqhingi efana naleyo eJapane nasePhilippines. Okwamanje, ukushayisana kwezwekazi nezwekazi (isibonelo, iNdiya ne-Eurasia okwakha iHimalaya) kubangela kakhulu izintaba nokuzamazama komhlaba, kodwa kunezintaba-mlilo ezimbalwa, ngoba azikho izingqimba zolwandle ezithwala amanzi ukuze zincibilike kalula.
Umngcele wokuguqula: ukuzamazama komhlaba okuningi, izintaba-mlilo ezimbalwa
Imingcele yokuguqula yizindawo lapho amapuleti amabili eshelela khona. Isibonelo esivame ukuxoxwa ngaso yi-San Andreas Fault eCalifornia. Kule mingcele, ukungqubuzana kanye nokulungisa amaphutha kudala ukuzamazama komhlaba, kodwa ngokuvamile akudali izimo ezifanele zokwakheka kwe-magma, ngakho-ke izintaba-mlilo azivamile. Kodwa-ke, kwezinye izindawo, amaphutha okuguqula amaphutha angahlotshaniswa nomsebenzi wezintaba-mlilo uma eseduze neminye imingcele yamapuleti noma edala imifantu eyenza kube lula ukukhuphuka kwe-magma.
Indawo Eshisayo: intaba-mlilo engalandeli njalo umngcele wepuleti
Nakuba izintaba-mlilo eziningi zitholakala emingceleni yamapuleti, kunezimo ezibalulekile ezihlukile: izindawo ezishisayo. Izindawo ezishisayo yizindawo lapho izinto ezishisayo ezivela ku-mantle ziphakama khona njenge-plume futhi zincibilikise i-lithosphere ephezu kwayo. Njengoba amapuleti ehamba phezu kwezindawo ezishisayo eziqinile, kwakheka uchungechunge olude, olufana "nomzila" lwezintaba-mlilo.
Isibonelo esivamile yiziQhingi zaseHawaii. Izintaba-mlilo ezisebenzayo ziphezu kwezindawo ezishisayo, kanti iziqhingi ezindala zikude kakhulu ngenxa yokukhukhuleka eduze kwePacific Plate. Izindawo ezishisayo zingavela ngaphansi kwamapuleti ezwekazi, njengeYellowstone (e-United States), enekhono lokukhiqiza ukuqhuma okukhulu yize ingekho emngceleni wepuleti.
Izindawo ezishisayo zisiza ososayensi ukuqonda isiqondiso kanye nesivinini sokuhamba kwamapuleti. Izimpawu zeminyaka zezintaba-mlilo ochungechungeni lwezindawo ezishisayo zingasetshenziswa "njengomlando" wokuhamba kwamapuleti eminyakeni eyizigidi.
Kungani ukuqonda lokhu kuxhumana kubalulekile?
Ubudlelwano phakathi kwezintaba-mlilo kanye ne-plate tectonics akuyona nje indaba yezemfundo, kodwa bunemiphumela eqondile yokuphepha kanye nokuhlela kwesifunda . Ngokuqonda izinhlobo zemingcele ye-plate, ochwepheshe bangabikezela:
– Uhlobo lokuqhuma okungase kwenzeke (okuvelayo noma okuqhumayo),
– Izingozi ezinkulu (ukugeleza kodaka, amafu ashisayo, ama-lahar, imvula yomlotha),
– Amaphethini okusabalala kwezintaba-mlilo kanye namathuba okuvela kwezikhungo ezintsha zokuqhuma kwezintaba-mlilo,
– Ubudlelwano nokuzamazama komhlaba okubangelwa ukunyakaza kwamapuleti.
Ezifundeni ezifana ne-Indonesia, lolu lwazi lubalulekile ekunciphiseni izinhlekelele . Ukudweba imephu yezindawo ezingaphansi komhlaba, ukuqapha umsebenzi wokuzamazama komhlaba, ukuguquka komhlaba, kanye namagesi ezintaba-mlilo konke kuyingxenye yesimiso sokuxwayisa kusenesikhathi. Imiphakathi nayo iyazuza emfundweni yezinhlekelele ukuze ikwazi ukusabela ngendlela efanele emsebenzini owandisiwe wezintaba-mlilo.
Isiphetho
Izintaba-mlilo kanye ne-plate tectonics kuhlobene kakhulu ngoba ukunyakaza kwe-plate kudala izimo ezikhuthaza ukwakheka kwe-magma. Emingceleni ehlukene, i-magma yakheka ngenxa yokucindezela okuncishisiwe njengoba i-mantle ikhuphuka. Emingceleni ehlangene, ikakhulukazi ezindaweni ezingaphansi, i-magma yakheka ngoba amanzi kanye ne-volatiles kwehlisa iphuzu lokuncibilika kwamadwala, okuholela ezintabeni eziqhumayo ezivame ukwakha ama-arcs ezintaba-mlilo. Imingcele eguqukayo, ngakolunye uhlangothi, ibangela ukuzamazama komhlaba okuningi kunezintaba-mlilo. Ngaphezu kwalokho, izindawo ezishisayo zibonisa ukuthi imisebenzi yezintaba-mlilo ingenzeka futhi kude nemingcele ye-plate.
Ukuqonda lobu budlelwano kusisiza ukuthi sichaze "imephu yezingozi" yoMhlaba, kuchaza ukuthi kungani izindawo ezithile zinezintaba-mlilo eziningi kangaka, futhi kuqinisa imizamo yokunciphisa izinhlekelele. Ngakho-ke, isayensi ye-plate tectonics ayichazi nje kuphela ukuguquguquka kwamaplanethi kodwa futhi inikeza isisekelo esibalulekile sokuvikela impilo yabantu ezindaweni ezithambekele ekuqhumeni kwezintaba-mlilo.
