Phakathi kwazo zonke izigidi zeminyaka ezidlulile selokhu kwakhiwa uMhlaba, kube nezikhathi zeqhwa. Babizwa ngokuthi i-ice Age. Lezi yizikhathi zesikhathi lapho kwenzeka khona izinguquko zezulu ezehlisa izinga lokushisa emhlabeni jikelele. Benza ngendlela yokuthi indawo enkulu yomhlaba iqhwalele ngaphezulu. Kubalulekile ukwazi ukuthi uma ukhuluma ngokushintsha kwesimo sezulu kufanele ube nesethenjwa sokuzibeka endaweni yeplanethi yethu.
Ngabe ufuna ukwazi izinqubo ze-glaciation ne-ice age kwiplanethi yethu? Lapha siveza konke.
Izici zobudala beqhwa
Isikhathi seqhwa sichazwa njengesikhathi sesikhathi esibonakala ngokuba khona okungapheli kwesembozo seqhwa esikhulu. Leli qhwa lidlulela okungenani kwesinye sezingongolo. Umhlaba waziwa ngokudlula Isikhathi sakho esingu-90% phakathi neminyaka eyizigidi ezedlule ku-1% wamazinga okushisa abanda kakhulu. La mazinga okushisa aphansi kakhulu kusukela eminyakeni eyizigidi ezingama-500 edlule. Ngamanye amagama, uMhlaba ubhajwe esimweni esibandayo kakhulu. Lesi sikhathi saziwa njengeQuaternary Ice Age.
Iminyaka emine yokugcina yeqhwa yenzeke nayo Izikhawu zeminyaka eyizigidi eziyi-150. Ngakho-ke, ososayensi bacabanga ukuthi kungenxa yezinguquko ekuzungezeni komhlaba noma izinguquko ekusebenzeni kwelanga. Abanye ososayensi bakhetha incazelo yasemhlabeni. Isibonelo, ukuvela kwenkathi yeqhwa kukhomba ekusatshalalisweni kwamazwekazi noma ukugcwala kwamagesi abamba ukushisa.
Ngokwencazelo ye-glaciation, kuyisikhathi esibonakala ngokuba khona kwamaqhwa ezigxotsheni. Ngaleso simiso sesithupha, njengamanje sesicwiliswe esikhathini seqhwa, ngoba amakepisi asezindaweni ezibandayo ahlala cishe ku-10% womhlaba wonke.
I-Glaciation iqondakala njengenkathi yeminyaka yeqhwa lapho izinga lokushisa liphansi kakhulu emhlabeni jikelele. Amaqhwa eqhwa, ngenxa yalokho, adlulela ngasezindaweni eziphansi futhi abusa amazwekazi. Kutholakale izingqimba zeqhwa ebangeni le-equator. Isikhathi sokugcina seqhwa senzeka cishe eminyakeni eyizinkulungwane eziyi-11 eyedlule.
Izikhathi zeqhwa ezaziwayo
Kukhona igatsha lesayensi elibhekele ukutadisha izinguzunga zeqhwa. Imayelana ne-glaciology. Nguye ophethe ukutadisha konke ukubonakaliswa kwemvelo kwesimo esiqinile. Ngamanzi asesimweni esiqinile abhekisa kumaqhwa eqhwa, iqhwa, isichotho, i-sleet, iqhwa nokunye ukwakheka.
Isikhathi ngasinye se-glaciation sehlukaniswe izikhathi ezimbili: glacial futhi interglacial. Esokuqala yileso lapho izimo zemvelo zimbi kakhulu futhi isithwathwa senzeka cishe yonke indawo emhlabeni. Ngakolunye uhlangothi, abahlanganisi baphakathi nendawo njengoba kunjalo nanamuhla.
Kuze kube manje, izikhathi ezinhlanu zobudala beqhwa ziyaziwa futhi seziqinisekisiwe: I-Quaternary, iKaroo, i-Andean-Saharan, iCryogenic neHuronia. Zonke lezi zinto zenzekile kusukela ngesikhathi sokubunjwa komhlaba.
Izikhathi zeqhwa azibonakali nje ngokuwa okungazelelwe kokushisa, kodwa futhi nangokunyuka okusheshayo.
Isikhathi se-Quaternary saqala eminyakeni eyizigidi ezingama-2,58 edlule futhi siqhubeka kuze kube namuhla. IKaroo, eyaziwa nangokuthi iPermo-Carboniferous period, yayingenye yezinde kunazo zonke, ehlala cishe eminyakeni eyizigidi eziyi-100, phakathi kweminyaka engama-360 nengama-260 million edlule.
Ngakolunye uhlangothi, isikhathi seqhwa lase-Andesan-Sahara sesigcine iminyaka eyizigidi ezingama-30 kuphela futhi senzeka phakathi kweminyaka engama-450 nengama-430 edlule. Isikhathi esibi kakhulu esike senzeka emhlabeni wethu ngokungangabazeki yisikhathi se-cryogenic. Yisikhathi seqhwa esinzima kunazo zonke emlandweni wokwakheka komhlaba weplanethi. Kulesi sigaba kulinganiselwa ukuthi i-ice sheet ebimboze amazwekazi ifinyelele enkabazwe yezwe.
I-Huraciation glaciation yaqala eminyakeni eyizigidi eziyizinkulungwane ezingama-2400 edlule futhi yaphela cishe eminyakeni engama-2100 eyedlule.
Isikhathi sokugcina seqhwa
Njengamanje sisesikhathini esihlangene phakathi kwe-Quaternary glaciation. Indawo lapho kuhlala khona amakepisi asezindaweni ezibandayo ifinyelela ku-10% womhlaba wonke. Ubufakazi busitshela ukuthi phakathi nalesi sikhathi sekota, kube nezikhathi eziningi zeqhwa.
Lapho inani labantu libhekise ku- "The Ice Age" kushiwo inkathi yokugcina yeqhwa yalesi sikhathi se-quaternary. Kwaqala u-quaternary Iminyaka engama-21000 edlule futhi yaphela cishe eminyakeni eyi-11500 XNUMX edlule. Kwenzeka ngasikhathi sinye kuwo womabili ama-hemispheres. Izandiso ezinkulu zeqhwa zafinyelelwa enyakatho yezwe. EYurophu, iqhwa laqhubekela phambili, lamboza lonke iGreat Britain, iGerman nePoland. Yonke iNyakatho Melika yangcwatshwa ngaphansi kweqhwa.
Ngemuva kweqhwa, ulwandle lwehla ngamamitha ayi-120. Izikhala ezinkulu zolwandle namuhla zazisemhlabeni ngaleyo nkathi. Le datha ibaluleke kakhulu lapho kufundwa ukuvela kwezakhi zofuzo kubantu abaningi bezilwane nezitshalo. Ngesikhathi behamba bengena ezindaweni zomhlaba ngenkathi yeqhwa, bakwazile ukushintshanisa izakhi zofuzo bathuthela kwamanye amazwekazi.
Ngenxa yolwandle oluphansi, ngakwazi ukuhamba ngezinyawo ukusuka eSiberia kuya e-Alaska. Uquqaba olukhulu lweqhwa bafinyelele ebubanzini bamamitha ayi-3.500 4.000 kuya ku-XNUMX ehlanganisa ingxenye yesithathu yamazwe avelile.
Njengamanje, kubaliwe ukuthi uma izinguzunga zeqhwa ezisele zingancibilika, ulwandle belungakhuphuka phakathi kwamamitha angama-60 kuya kwangama-70.
Izimbangela ze-glaciation
Ukuthuthuka nokubuyela emuva kweqhwa kuhlobene nokupholisa komhlaba. Lokhu kungenxa yezinguquko kufayela le- ukwakheka komkhathi kanye nezinguquko emjikelezweni woMhlaba ozungeze iLanga. Kungenzeka futhi ukuthi kube ngenxa yezinguquko ekuzungezeni kweLanga ngaphakathi komthala wethu, iMilky Way.
Labo abacabanga ukuthi ukuqhwaqhakala kubangelwa izimbangela zangaphakathi zoMhlaba bakholelwa ukuthi kungenxa yokuguquguquka kwamacwecwe ama-tectonic nomphumela wawo esimweni esihambisanayo nenani lolwandle nolwandle emhlabeni. Abanye bakholelwa ukuthi kungenxa yezinguquko zomsebenzi welanga noma amandla we-Earth-Moon orbit.
Ekugcineni, kunemibono exhumanisa umthelela wama-meteorites noma ukuqhuma okukhulu kwe-volcanic ne-glaciation.
Izimbangela zihlale zidala impikiswano futhi ososayensi bathi sesiseduze nokuphela kwalesi sikhathi sezinhlanga. Ngabe ucabanga ukuthi kuzoba nenkathi entsha yeqhwa kungekudala?
Mtro othandekayo.
Ngikuhalalisela ngemizamo yakho nangezinhloso zakho zolwazi. NginguDkt kwi-Administration Sciences futhi nginemodeli yokubikezela yokukala ukusimama ezinqubweni zezolimo. Nginentshisekelo olwazini lwakho ngodaba lweqhwa. Ngikushiyela imininingwane yami ngenjabulo. Ngiyabonga.