Umswakama wamanzi, i-carbon dioxide kanye nomoya oxutshwe nobuthi obuvela emalahleni aqhamuka emhlabathini futhi zaqala ukwakha umoya.Imvula yaqala ukuwa futhi izilwandle zaqala ukwanda phezu kweqweqwe lwamadwala. Amanzi ebusweni bomhlaba ayekhona okungenani eminyakeni eyizigidigi ezingu-3.9 ezedlule.
Isikhathi Lapho Kungekho khona Ukuphila Emhlabeni
Lokhu kungukuqala kwesikhathi se-Archaean (okusho ukuthi 'sasendulo') futhi saqhubeka kuze kube izigidigidi ezingu-2.5 eminyakeni edlule.Phakathi nalesi sikhathi, kwakhiwa amabhande amadwala aluhlaza, okwakhiwa isesekelo esingaphansi kwayo yonke imisebenzi elandelayo yokusebenza kwemvelo.Isibonelo esilondolozwe kakhulu sesikhathi lapho kungekho khona ukuphila emhlabeni esbonakalayo eMhlabeni manje singatholakala eMpumalanga, esiseduze nedolobha laseBarberton, lapho amadwala aluhlaza endulo aguqulwe khona futhi abonakala ebusweni bomhlaba.Lamadwala ezintabamlilo, abizwa ngokuthi ama-komatiities, akhiwe ngasolwandle lwasendulo oluphakathi kweminyaka eyi-3.6 kuya ku-3.2 izigidigidi ubudala. Ukubunjwa kwawo kubonisa ukuthi kwakhiwa ngesikhathi lapho amazinga okushisa ephezulu ephakeme kakhulu kunamanje, okubonisa ukuthi uMhlaba uye waqhubeka upholile.
Njengoba lesi sikhukhula saqhubeka siqinisa, izinto ezicebile ze-silika (okwakucinene ngaphansi kwezinto ezincibilikisiwe ngezansi) zazivame ukuphakama bese ziqoqa phezulu kwesembeso.Njengoba 'kwakululaza' kunesembeso kanye nolwandle olwandle, lezi zindonga ezicebile zasilika azizange zithathwe futhi zihlale zihamba phansi, ekugcineni zikwazi ukuphakama ngokwanele ukuba ziphakame ngaphezu kwamanzi njengeziqhingi.
Ama-Cratons
Ngokuhamba kwesikhathi, iziqhingi ezanda kusungulwa zaqhubeka zihamba phezu kweziqweqwe zomhlaba(tectonic plates), ziqhubisana futhi zahlanganiswa, kwaze kwaba yilapho kutholakala iziqu zomhlaba ezindaweni eziningi eMhlabeni. Lezi zimboni zibizwa ngokuthi 'micro-continent' okusho ukuthi izwekazi elincane ngesingisi.Ngesikhathi esifanayo, amatshe adalulwe ngaphezu kwamanzi aqhutshwa umoya namanzi, futhi izingcezu zedwala ezidlulile zafakwa eceleni kwendawo phakathi kolwandle nolwandle njengenhlanganiso yamatshe ahlukene kanye namadwala.Izwekazi lokuqala lalisungulwa.
Ukunciphisa indaba ende, lezi zinekazikazi zakuqala zaqhubeka zikhula futhi, njengoba zincane kakhulu kunezilwandle, zaba nzima kakhulu ukwehlisa. Ngakho ezinye izingxenye zoqwaqwa lezwekazi zahlala zingaphezu kweminyaka eyizinkulungwane ezintathu ezizayo. Kungenzeka ukuthi bahlukanisile futhi bavuselela izikhathi eziningana, kodwa azizange zishabalale noma ukubuyiselwe kabusha. Namuhla, sibiza lezi zicucu ezinqanyuliwe zesikhumba esidala, 'ama-cratons'.
I-Kaapvaal Craton
Enye ye-craton yokuqala kunazo zonke emhlabeni yi-Kaapvaal Craton engase Ningizimu ye Africa. Ubukhulu bokuqala be-craton abaziwa, kodwa ukuhlaziywa kubonise ukuthi ingxenye engasempumalanga yeNingizimu Afrika, ingxenye engasentshonalanga ye-Australia, iNdiya neMadagascar bonke babehlanganisiwe ndawonye kuleli zwekazi lasendulo. Phakathi neminyaka, izingqimba ezintsha zamatshe zafakwa ngaphansi kwe-craton samadwala aluhlaza, kanye nenani elimangalisayo lamaminerali ayigugu. I-Kaapvaal Craton nayo izoba yinto evelele emthonjeni weVredefort.Isendlalelo sokuqala samadwala amasha okwakhiwa kwi-craton kaKaapvaal ibizwa ngokuthi iqembu lokubusa. Iqukethe ungqimba oluncane lwamadwala olwenziwe ingqimba elincane lamadwala angenalutho. Amadwala angaphansi adalwe lapho izingxenyana zamadwala adiliziwe zifakwa endaweni entsha futhi kancane kancane ziphenduka zibe amatshe, ngenqubo ebizwa ngokuthi i-lithification. Ngakolunye uhlangothi, ama-igneous, adalwa ngokusebenza kwamatshe entabamlilo engxenyeni engenhla kanye neziqwaqwa, lapho amanzi omlilo ashisayo avela emkhawulweni womhlaba afakwe khona ngokuchotshozwa emgqeni kuze kube yilapho ijiya. Ukugeleza komlilo osamanzi okuvela emkhathini womhlaba nakho kungakha amatshe angenalutho.
Translated by Nsika Khoza