Isikhathi se-Quaternary

Kokuthunyelwe kwangaphambilini sihlaziye ukuthi kusebenza kanjani isikhathi sokuma komhlaba futhi ibuyekeze izehlakalo ezibaluleke kakhulu ezenzeka ku- Isikhathi seMesozoic futhi ku I-Precambrian Aeon. Namuhla sibuyela ku i-Cenozoic Era lapho sizohlaziya khona ukuthi kwenzekani ku isikhathi se-Quaternary. Lesi yisikhathi sokugcina se-Cenozoic Era futhi sihlanganisa izinkathi ezimbili “zesimanjemanje”: iPleistocene neHolocene.

Ngabe uyafuna ukwazi izehlakalo ezibaluleke kakhulu ezenzeke kulesi sikhathi? Qhubeka ufunde ngoba sikutshela konke.

Ukufika kweqhwa nendoda

Ngemuva kokudlula kwezigidi zeminyaka, sisondela kulokho obekuyikho "namuhla". KuQuaternary, okuyi yaqala eminyakeni eyizigidi ezingama-2,59 edlule, yisikhathi esiphila kuso namuhla. IQuaternary ayibandakanyi iPleistocene neHolocene kuphela, kepha nokuvumelana lapho kwenziwa okutholakele mayelana nezinguquko ezenzeka emhlabeni, kungafakwa inkathi yeGelasian. Ngalesi sikhathi kube nezinguquko ezibaluleke kakhulu empilweni emhlabeni, isimo sezulu nolwandle ngenxa yeziqephu zeminyaka yeqhwa.

Izikhathi ezimbili zeQuaternary yiPleistocene neHolocene. IPleistocene yinde kakhulu futhi ihlanganisa izinguzunga zeqhwa ezingamakhulu namakhulu eminyaka. Kuyaziwa njenge Isikhathi seqhwa, umqondo ohlobene eduze ne ubucwebe. Ukuya esikhathini sakamuva kakhulu sineHolocene, ebhekwa njengengxenye yangemva kweqhwa futhi yilokho esinakho namuhla.

Lapho kukhulunywa ngePleistocene, abantu abaningi bakhuluma ngayo "Iminyaka yomuntu" selokhu uhlobo loHomo lwaqala ukuvela ngalesi sikhathi. Sekuvele lapho eHolocene, umuntu angathuthukisa impilo ehlelwe ngamaqembu ezenhlalo futhi ebizwa ngempucuko.

Izici ze-Pleistocene

Siqala ngokuchaza iQuaternary ngenkathi yayo yokuqala. Iminyaka eyizigidi ezingama-2,59 edlule inika indlela ukuqala kwePleistocene ephela eminyakeni eyi-12.000 eyedlule. Ngalesi sikhathi iqhwa lasakazeka ngesimo seqhwa kuze kube zithatha ngaphezu kwengxenye yesine yomhlaba. Iqhwa lafinyelela ezindaweni ezingakaze zifinyelelwe ngaphambili. Futhi uma sikhuluma ngeqhwa noma inkathi yeqhwa, esicabanga ngakho ukuthi umhlaba wonke umbozwe yiqhwa, kuhlanganise nolwandle. Akunjalo. Cishe u-25% wawo wonke umhlaba ombozwe yiqhwa awujwayelekile ngendlela emangalisayo.

Ngenxa yobuningi beqhwa emhlabeni, amazinga olwandle ehla aze afike kumamitha ayi-100, futhi impilo emhlabeni kwadingeka ivumelane nezimo ezintsha zemvelo noma zinyamalale. Ezindaweni lapho kwakungekho qhwa, cishe zonke izitshalo nezilwane ezivelele zazifana nenkathi edlule (Pliocene), okusiholela ekubuyekezeni ukushabalala okukhulu emlandweni.

Kwakukhona ezinkulu izinhlelo zeqhwa asatshalaliswa ezindaweni ezibanda kakhulu nezineqhwa kakhulu. Esokuqala kwakuyiqhwa eScandinavia elalinabela eningizimu nasempumalanga linqamule enyakatho yeJalimane nasentshonalanga yeRussia. Wafinyelela eziQhingini ZaseBrithani, ngakho ungase ucabange ukuthi lelo qhwa lalilikhulu kangakanani. Ngaphezu kwalokho, ungathola okwengeziwe mayelana i-polar ice cap kanye nokubaluleka kwayo esikhathini seQuaternary.

Ngakolunye uhlangothi, sithola nolunye uhlelo olukhulu lweqhwa olusendaweni yonke yeSiberia. Olunye uhlelo lweqhwa lwasakazeka ukusuka eCanada kuya e-United States futhi eziningi zalezi zinhlelo zeqhwa zaziyisisekelo kusayensi yokwakheka komhlaba I-Pleistocene. Konke lokhu kwakheka kwezinguzunga zeqhwa, emva kokuguquguquka nokwakheka kwazo, kwabangela ukwakheka kweqhwa esingakubona namuhla kuzo zonke lezi zindawo.

Ama-glaciations, izimbali nezilwane

Njengoba kungaqagelwa, izifunda ze-Arctic ne-Antarctic nazo zazimbozwe yiqhwa, njengezintaba eziningi emhlabeni wonke. Izinga leqhwa lehlele emazingeni angakaze abonwe namuhla. Njengoba ngishilo ngaphambili, zonke izenzo zezinguzunga zeqhwa nokuncibilika kwazo okulandelayo kungabonakala nanamuhla ezingxenyeni eziningi zomhlaba.

Kwakungekhona kuphela ukuthi kwakukhona i-glaciation eyodwa ngesikhathi sePleistocene, kepha kwakukhona abayisithupha. Phakathi kwazo ngakunye kwakukhona izikhathi lapho isimo sezulu sasifudumele ngandlela thile futhi neqhwa lehla futhi. Okwamanje, sithathwa njengenye yalezo zikhathi "zokuphumula" zeqhwa.

Ngokuqondene nezitshalo nezilwane okwakudingeka zijwayele izindawo eziqandiswe ngokuphelele, sithola ama-mammoth, ama-reindeer, izinyamazane ezinkulu namabhere asezintabeni. Izimila kule ndawo zakhiwe ngokuphelele ulele nolembu. Yayifana ngokuphelele ne-tundra yamanje, okuye kwaba ngesinye sezifunda ezithinteke kakhulu ukushintsha kwesimo sezulu. Ezigabeni zeqhwa, njengoba amazinga okushisa aphakeme kanye nendawo encane embozwe yiqhwa, ayekwazi ukuphila amahhashi, izinsikazi ezinamazinyo amakhulu nobhejane. Ukuze uthole ukutadisha okujulile kwezilwane zangaleso sikhathi, ngincoma ukufunda mayelana Izilwane zePleistocene nokuthi kube nomthelela kanjani ekuthuthukeni kwabantu.

Ezinye izinhlobo ezimbalwa zezilwane zizivumelanise kahle nezinguquko zezulu ukuze ziphile isikhathi eside. Sikhuluma nge-bison, i-elk, i-fox, ne-wildcat. Ezingxenyeni ezibandayo zaseNyakatho Melika, izinhlobo ezinjenge ikamela, i-yak, i-llama, i-tapir nehhashi. Ngesikhathi i-Pleistocene iphela, izinhlobo ezinkulu zezilwane ezincelisayo ezinjenge-mastodon, ingwe edume ngamazinyo ama-saber, nenyamazane enkulu kwase kuphelile ngayo yonke iplanethi.

Ukuziphendukela kwabantu kanye neHolocene

Manje sikhuluma ngokuvela komuntu lapho sinePaleolithic ePleistocene, lapho i- Homo habilis waqala ukubutha nokuzingela. Kamuva, Homo erectus ekugcineni Wenza ezinye izikhali eziyinkimbinkimbi futhi wazingela ngamaqembu. I-Homo neanderthalensis kwakuyizinhlobo eziguqulelwe emakhazeni avele eminyakeni engama-230.000 eyedlule.

Manje sichaza isikhathi sakamuva kakhulu se-Quaternary: iHolocene. Yilapho esikhona namuhla. Yaqala eminyakeni eyi-12.000 edlule futhi ukuguquka kwayo kwezinga lokushisa kwaqala isikhathi sokuncibilika emhlabeni wonke.. Lokhu kuncibilika kwabangela ukuthi izinga lolwandle likhuphuke ngamamitha angamashumi amathathu, okube yisenzakalo esithakazelisayo emlandweni we-. Kuthiwa lesi sikhathi esiphakathi kwezinhlanga ezithile singaphela enkathini entsha yeqhwa.

Kule minyaka eyi-12.000, ukuqothulwa kwezinto kuqhubekile futhi kusheshiswe kakhulu kule minyaka eyi-100 edlule ngokuba khona kwabantu nokuthuthukiswa kobuchwepheshe. Emhlabeni kube nokuqothulwa okungu-5 okukhulu. Ngalesi sizathu, ukubulawa kwabantu abaningi kangaka okubizwa ngakho namuhla kuyabizwa ukuqothulwa kwesithupha.

Impilo yokuzulazula yomuntu iphele ngokwakhiwa kwezolimo nemfuyo. Ukudoba futhi kwakuthanda kakhulu ukuthuthukiswa komuntu. Ekugcineni, iHolocene ivame ukufundwa kuze kusungulwe ukubhala, lapho lokho esikubiza ngokuthi uMlando kuqala ukufundwa.

Ngiyethemba lokhu okuthunyelwe kukwenze wazi kabanzi ngesikhathi sokugcina soMhlaba.