Isikhathi se-Ordovician

Esinye sezikhathi zenkathi yePaleozoic esasibonakala ikakhulu ngokukhuphuka kwamazinga olwandle nokwanda kwempilo ezindaweni zasolwandle yisona Isikhathi se-Ordovician. Kuyisikhathi esitholakala ngokushesha ngemuva kwe- Isikhathi seCambrian nangaphambi kwalokho I-Silurian. Ngalesi sikhathi kube nokuncipha okukhulu kwezinhlobonhlobo zezinto eziphilayo ekugcineni okwaveza umcimbi wokuqothulwa kwabantu abaningi.

Kulesi sihloko sizokutshela zonke izici, i-geology, isimo sezulu, izimbali nezilwane zesikhathi se-Ordovician.

Izici eziyinhloko

Lesi sikhathi sithathe cishe iminyaka eyizigidi ezingama-21. Kwaqala cishe eminyakeni eyizigidi ezingama-485 edlule futhi kwaqhubeka kwaze kwaba cishe eminyakeni eyizigidi ezingama-433 edlule. Bekunokwehluka okukhulu kwesimo sezulu kwazise kube nomehluko omkhulu phakathi kokuqala kowamanqamu. Ekuqaleni kwenkathi, amazinga okushisa ayephezulu impela, kepha kwakwenzeka uguquko oluningi kwezemvelo olwaholela esikhathini seqhwa.

Njengoba sishilo ekuqaleni kwendatshana, kube nokuqothulwa okukhulu ekupheleni kwesikhathi esiphele ngaso cishe ama-85% azo zonke izinhlobo zezinto eziphilayo ezazikhona ngaleso sikhathi, ikakhulukazi imvelo yasolwandle.

Lesi sikhathi sihlukaniswe izinkathi ezintathu: Lower, Middle and Upper Ordovician.

I-Ordovician Geology

Esinye sezici ezibalulekile maqondana nokwakheka komhlaba kwalesi sikhathi ukuthi amazinga olwandle ayephakeme kunawo wonke ake aba khona. Sonke lesi sikhathi kwakukhona ama-supercontinents amane: IGondwana, iSiberia, iLaurentia neBaltica. Njengasenkathini edlule, iNyakatho nenkabazwe yeplanethi cishe yayigcwele i-Panthalassa Ocean. Kule nkabazwe kwakukhona kuphela iSiberia eyi-supercontinent nengxenye encane yeLaurentia.

Izwe eliseningizimu, sinezwekazi laseGondwana elalihlala cishe sonke isikhala. Kwakukhona nengxenye yeBaltica neLaurentia. Izilwandle ezazikhona ngalesi sikhathi zazi: UPaleo Tetis, uPanthalasa, uLapetus noRheico. Kuningi okwaziwayo mayelana ne-geology ye-Ordovician ngenxa yezinsalela zamatshe ezitholiwe. Iningi lalezi zinsalela zitholakala emadwaleni e-sedimentary.

Esinye sezimo zokwakheka komhlaba ezaziwa kakhulu kulesi sikhathi yi-orogeny yeTaconic.. Le orogeny yakhiqizwa ukungqubuzana kwama-supercontinents amabili. Lokhu kuxhumana kudonse iminyaka eyizigidi eziyi-10. Njengomphumela wale nqubo yokwakheka komhlaba, i Izintaba ze-Appalachian lokho kungabonwa namuhla.

Isimo sezulu sesikhathi se-Ordovician

Njengoba sishilo ngaphambili, isimo sezulu senkathi ye-Ordovician sasifudumele futhi sishisa. Ikakhulukazi ekuqaleni kwalesi sikhathi, amazinga okushisa ayephakeme, amanye abonisa nokuthi ezinye izindawo zaziqopha amazinga okushisa angama-60 degrees. Nokho, ngasekupheleni kwenkathi, amazinga okushisa aqala ukwehla kangangokuthi kwaba neziqhwa eziphawulekayo. Le qhwa yahlasela kakhulu i-supercontinent Gondwana. Ngalesi sikhathi i-supercontinent yayisengxenyeni eseningizimu yeplanethi. Iqhwa lathatha cishe iminyaka eyizigidi ezingu-1.5.. Ngenxa yale nqubo yokwehla kwamazinga okushisa, inani elikhulu lezinhlobo zezilwane ebelingakwazi ukuzivumelanisa nezimo ezintsha zemvelo lanyamalala.

Kukhona ezinye izifundo ezithi iqhwa laze lafinyelela eNhlonhlweni yase-Iberia. Lokhu kuyayiphikisa inkolelo yokuthi iqhwa ladlulela eSouth Pole kuphela. Izimbangela zalokhu kuqhwa kweqhwa azikaziwa.. Kukhona ukukhuluma ngokuncipha kokugxila kwe-carbon dioxide njengesizathu esingaba khona.

ukuphila

Ngesikhathi se-Ordovician, kwavela inani elikhulu lezizukulwane ezazala izinhlobo ezintsha. Ukuphila olwandle kwathuthukiswa ngokukhethekile. Ake sihlaziye izitshalo nezilwane ngokwehlukana.

Flora

Uma kucatshangelwa ukuthi izinto eziningi eziphilayo zakhula endaweni yasolwandle, kunengqondo ukucabanga ukuthi izitshalo zaba nentuthuko engcono. Ulwelwe oluhlaza lwanda olwandle. Izinhlobo ezithile zesikhunta nazo zazikhona ezagcwalisa umsebenzi wokubola nokuhlakazeka kwezinto eziphilayo ezifile. Le yindlela ulwandle olwalungalawula ngayo.

Umlando wokuthola izinhlelo zasemhlabeni bewuhlukile kulowo wasolwandle. Futhi ukuthi izimbali bezicishe zingabikho. Kwakunezitshalo ezimbalwa kuphela ezincane ezaqala ukoloni nezwekazi. Lezi zitshalo bezingezakudala futhi ziyisisekelo. Njengoba bekulindelekile, kwakungezona izitshalo ezinemithambo yegazi, okungukuthi, ayengenayo i-xylem noma i-phloem. Ngenxa yokuthi kwakungezona izitshalo ezinemithambo yegazi, kwakudingeka zihlale ziseduze nemisele yamanzi ukuze zikwazi ukuthola ukutholakala kwamanzi okuhle. Lezi zinhlobo zezitshalo zifana nama-liverwort esiwaziyo namuhla.

Fauna

Phakathi nenkathi ye-Ordovician, izilwane zazichichima ngempela olwandle. Kwakukhona izinhlobonhlobo zezinto eziphilayo ezinkulu kusukela kwencane kunazo zonke nezindala kakhulu kuye kwezinye izilwane ezivele zavela futhi eziyinkimbinkimbi.

Saqala ukwenza ama-arthropods. Ingenye ye-phyla eningi kakhulu kulesi sikhathi. Ngaphakathi kwama-arthropods sithola ama-trilobite, ama-sea scorpions nama-brachiopods, phakathi kwabanye. Ama-molluscs nawo athola ukwanda okukhulu kokuziphendukela kwemvelo. Ama-Cephalopod, ama-bivalves nama-gastropods agcwele olwandle. Laba bamuva babedinga ukuya ngasogwini lolwandle, kodwa njengoba babengenakho ukuphefumula kwamaphaphu, babengakwazi ukuhlala endaweni yabo esemhlabeni.

Ngokuqondene namakhorali, aqala ukuhlangana ndawonye ukuze akheke amakhorali okuqala ezakhiwe ngezibonelo ezihlukahlukene. Futhi babenezinhlobo eziningana zezipontshi ezazivele zihlukahluka ngesikhathi seCambrian.

Ukuqothulwa kwesisindo se-Ordovician

Lokhu kucishwa kwesisindo kwenzeka cishe eminyakeni eyizigidi ezingama-444 edlule futhi kuthinta ukuphela kwesikhathi se-Ordovician nokuqala kwesikhathi seSilurian. Izimbangela ezenza ososayensi babheje yilezi ezilandelayo:

• Nciphisa i-carbon dioxide esemkhathini. Lokhu kudale ukuqabuleka komhlaba okunciphise inani lezilwane nezitshalo.
• Ukwehla kolwandle.
• I-glaciation uqobo.
• Ukuqhuma kwe-supernova. Le mbono yathuthukiswa eminyakeni eyishumi yokuqala yekhulu lama-XNUMX. Uthi kube nokuqhuma esikhaleni okuvela enkathini enkulu edale umhlaba okhukhuliswe yimisebe ye-gamma. Le misebe ye-gamma ibangele ukuba buthaka kongqimba lwe-ozone nokulahleka ezinhlotsheni zokuphila zasogwini lapho kunokujula okuncane.

Ngiyethemba ukuthi ngalolu lwazi ungafunda kabanzi mayelana nesikhathi se-Ordovician.