Ngesikhathi Isikhathi seCenozoic Kube nezinguquko ezahlukahlukene emhlabeni ezingeni le-geology nezimbali nezilwane. Namuhla sizokhuluma ngenkathi yesithathu eyakha iCenozoic. Imayelana ne- Oligocene. I-Oligocene isabalale cishe eminyakeni eyizigidi ezingama-33.9 edlule kuya eminyakeni eyizigidi ezingama-23 edlule. Kuyo yonke le minyaka iplanethi yethu ibe nezinguquko eziphawulekayo. Lezi zinguquko yizo ezidale ukwabiwa kabusha kwezinto eziphilayo, izitshalo nezilwane. Ngaphezu kwalokho, isimo sezulu sabamba iqhaza elibalulekile ngenkathi kwenziwa izinguquko ezintweni eziphilayo ngoba kudale izimo ezithile ukuze izilwane ezithile noma izitshalo zikhule kangcono kanti ezinye zingasindi. Ngale ndlela, kwasungulwa uhlobo olusha lokukhethwa kwemvelo.
Kulesi sihloko sizokutshela konke odinga ukukwazi nge-Oligocene.
Izici eziyinhloko
I-Oligocene yisikhathi esihlale sihlaba umxhwele bonke ongoti abagxila ekutadisheni i- isikhathi sokuma komhlaba. Bonke labo asebenzise isikhathi esanele ukuthi bakwazi ukwazi izici ezifihliwe zezigaba ezahlukahlukene zomhlaba zokwakheka komhlaba bashiywe ngezinto ezithakazelisayo ezenzeka emhlabeni wethu ngesikhathi se-Oligocene.
Lesi yisikhathi esidonse isilinganiso seminyaka eyizigidi eziyi-11. Ngalesi sikhathi amazwekazi ahlelwe kabusha ngenxa yokuhamba kwamapuleti ezwekazi. Le nhlangano idale ukuthi amazwekazi abe nezikhundla ezifanayo nalezo ahlala kuzo namuhla. I-Oligocene yaziwa nangokuthi iminyaka yezilwane ezincelisayo. Futhi ukuthi yiqembu lezilwane elingathola ukwehluka okukhulu nokuhlukahluka ngalesi sikhathi. Kukulesi sikhathi seminyaka eyizigidi eziyi-11 lapho kuhlukaniswa izingxenye zezilwane ezincelisayo ezifana namagundane noma ama-canids.
Mayelana nokwakheka komhlaba kwe-Oligocene bekuyisikhathi somsebenzi omkhulu we-geological kanye ne-orogenic. Siyabona ukuthi ukwahlukaniswa kwezwekazi eliphakeme iPangea kwaqhubeka futhi izingcezu zalo eziningi zazishiya indawo yazo ukuze zithole isikhundla esifana nalesi esinazo namuhla. Izinqubo ezimbili ezinkulu ze-orogenic zenzeka ngalesi sikhathi: i-Laramide Orogeny ne-Alpine Orogeny.
I-Oligocene Geology
Sizobheka zonke izici ze-Oligocene ngamunye ngamunye. Siqala nge-geology. Ukuqhekeka kwezwekazi elikhulu elaziwa ngePangea kwaba sobala ngokwengeziwe lapho ucezu oluhambisana neNingizimu Melika luhlukaniswa. Lokhu kususwa kwezwekazi kubangele ukuhamba kancane kuya entshonalanga ukuze kuhlangatshezwane neNyakatho Melika futhi kwakheke esikwaziyo namuhla njengezwekazi laseMelika ngokuphelele.
I-Antarctica yaqhubeka nokuhlukana kwayo namanye amazwekazi futhi ikhava yeqhwa yajula njengoba yayisondela kakhulu eSouth Pole. Kunochwepheshe abaningi abaphike iziphetho ezahlukahlukene njengokuthi ngalesi sikhathi ipuleti elihambelana nezwekazi lase-Afrika lishayisane ne-Eurasia futhi bakwenza lokho ngocezu eselwazi manje njenge-India.
Ekupheleni kwe-Oligocene, bonke abantu bomhlaba base bevele besesimweni esifana ncamashi nalesi esinaso namuhla. Kungokufanayo nangolwandle. Izilwandle zahlelwa ngendlela yokuthi kube nezilwandle eziningana ezahlukanisa amazwekazi anamuhla. Phakathi kwalezi zolwandle singabala i-Pacific Ocean, i-Atlantic Ocean kanye ne-Indian.
Isimo sezulu se-Oligocene
Ngokuqondene nesimo sezulu sase-Oligocene, izimo zazimbi kakhulu. Kubonakala ikakhulukazi ngamazinga okushisa aphansi kakhulu. Phakathi naso sonke lesi sikhathi i-Antarctica neGreenland zahlala zimbozwe yiqhwa futhi zanda ngokwanda. Ngokunjalo, ngenkathi i-Antarctica ihlukaniswe ngokuphelele neNingizimu Melika, yabangela imisinga ehlukahlukene yasolwandle ukuba ijikeleze. Omunye wale misinga yolwandle yiCircumpolar Antarctica. Lo msinga wasolwandle ubhekwa njengobaluleke kakhulu, ngoba wawuphethe ukumboza lonke izwekazi lase-Antarctica ngeqhwa nokwakhiwa kwamaqhwa.
Ukwehla kwezinga lokushisa komhlaba kubangele imiphumela ekuguqulweni kwemvelo ethile. Ukuvelela kwezimila kwakungamahlathi ahlabayo futhi aqinile. Lezi zihlahla zikwazile ukusinda kulezi zindawo ezimbi kakhulu ngoba ziyakwazi ukuphila emazingeni okushisa aphansi.
Izimbali nezilwane
Yonke impilo yahluka kakhulu ezitshalweni nasezilwaneni. Ngaphandle kokuthi izimo zezulu bezingavumi ngokuphelele, izinto eziphilayo zikwazile ukuzivumelanisa nalezi zimo futhi zasinda.
Ake sixoxe ngezimbali kuqala. Izimbali ze-Oligocene zibonakaliswa iqiniso lokuthi ama-angiosperms angaqala ukusabalala ngenani elikhulu lezindawo zokuhlala. Lezi zitshalo zaze zafinyelela ekubuseni ezinakho namuhla. Ngaso sonke lesi sikhathi, ukwehla kwamahlathi ashisayo kungabonakala ngenxa yokwehla kwamazinga okushisa omhlaba. Lawa mahlathi asezindaweni ezishisayo athathelwa indawo izitshalo ezinama-herbaceous nezindawo zotshani eziguqulwe zaba yizimo zokushisa ezedlulele ngokwengeziwe. Lezi zindawo ezinotshani nezitshalo ezinamakhambi zisakazeka kuwo wonke amazwekazi.
Futhi ukuthi izitshalo ezinomuthi omkhulu waba nempumelelo enkulu yokuziphendukela kwemvelo ngenxa yokulungiswa kwezici zazo ekukhuleni. Lezi zitshalo zinezinga lokukhula eliqhubekayo elingapheli. Ngaphezu kwalokho, lezi zinhlobo zezitshalo kwakudingeka zibhekane nokwenziwa yizilwane ezahlukahlukene njengama-grazers ezazizondla. Le yindlela abangakhulisa ngayo amandla ahlukile okuguquguquka ukuze bakwazi ukusinda kulezi zindawo futhi bakhe nobudlelwano bokufanelana nezinye izilwane. Futhi izilwane eziningi zibasizile ukuthi basakaze imbewu yabo ngendle.
Ngalesi sikhathi futhi izitshalo ezinommbila ezifana nobhontshisi zakhiwa.
Ngokuqondene nezilwane, kunamaqembu amaningi ezilwane akwazile ukwehlukahluka futhi akhulisa indawo yawo yokwabiwa. Ngaphandle kwezimo zezulu ezitholakale kuzo, amaqembu amaningi ezilwane njengezinyoni, izilwane ezihuquzelayo nezilwane ezincelisayo zandisa ukusabalalisa kwazo.
Kwakukhona izinyoni nezilwane ezihuquzelayo, yize udumo olubi kakhulu lwathathwa yizilwane ezincelisayo. Kubalulekile ukuqaphela ukuthi i-Cenozoic ibhekwa njengenkathi yezilwane ezincelisayo.
Ngiyethemba ukuthi ngalolu lwazi ungafunda kabanzi nge-Oligocene.