Ukumila Komhlaba The Cradle of Humankind

Ukudaleka Kwamatye

©David Fleminger
Ubuninzi bamatye akummandla wase Cradle of Humankind aluhlobo lwe Dolomitic bedrock, neyadaleka emazantsi amanzi adikidiki olwandle olwalugqume iwhich was formed on the bed of Witwatersrand Basin malunga neminyaka ezibhiliyoni ezi 3 ezadlulayo. Amatye eDolomite enziwe nge calcium carbonate (limestone) kunye ne oxygen isotopes ezongezelweyo. Oku kwenza umhlaba okumila kwe Karstic, nowenza kubelula ukudaleka kwemiqolomba. Le miqolomba ziziphumo zokhukuliseko kumhlaba ongaphantsi.

Amatye angqonge iindawo zase Sterkfontein kunye nase Krugersdorp abalelwa kwiminyaka ezii bhiliyoni ezi 2.6 ubudala. Kwaye amatye aseMpuma, ukuya eHartebeespoort, abalelwa kwiminyaka ezii bhiliyoni ezi 2.2 ubudala. La matye ahamba aphakama, ze amatye ase Ntshona kwase Cradle of Humankind, xa usiya ngase Krugersdorp aphakama kuqala. Nto leyo yabangela ukwanda kokhukuliseko aze adala induli ezinyuka zisihla kule ngxenye ye Cradle of Humankind.

Inkcukacha Ezithe Ngqo

Ukuba ufuna ukuthetha ngenkcukacha ezithe ngqo, amatye athwele iifosili afumaneka kumatye ohlobo lwe Chuniespoort Group, nangawe Malmani Sub-group, eTransvaal Supergroup. La matye adaleka malunga neminyaka ezi bhiliyoni ezi 2.5 eyadlulayo. I Malmani subgroup nayo yohlula hluleke yazi sub-uniti eziy 5: i-Oaktree, Monte Christo, Lyttleton, Eccles kunye ne Frisco Formations. Lo mmandla ukwa qulathe nentsalela ze lead kunye ne kopolo, nezazisembiwa ziintlanga zamandulo kunye nabaphambukeli bokuqala kule ngingqi.

Ukwembiwa Kunye neeNdlela Zokubona Ubudala

©David Fleminger
Xa sele iarchaeologist okanye ipalaeontologist ifumene ilitye elithwele ifosili/okanye amathambo akudala, bawahlukanisa njani la mathambo namatye. Ukwembiwa ngumsebenzi odinga ubuchule nokwa tya ixesha elininzi. Lo ngumsebenzi onzima kwaye udinga iminyaka yoqeqesho kunye nomonde ongapheliyo. Ngumsebenzi ekunzima ukuwucacisa ngamanqakwana nje ambalwa. Kodwa masibone...

Mhlawumbi eyona nto ibalulekileyo xa kusembiwa yindawo, nekwabizwa nge provenience. Lilonke, oku kuthetha ukuba kufanele ushicilele iinkcukacha kangangoko mayelana nemmo efumaneke kuyo ifosili leyo: Ifunyenwe phi? Ibihleli njani? Ibihlel ecaleni kwantoni? Yintoni ibisentla kwayo? Yintoni ibiphantsi kwayo? Zonke ezi nkcukacha kunye nentluva mayelana nefosili, indawo ekuyo, nezinto eziyijikelezileyo nkqu nendlela yayo yokuphila kunganzima ukuzifumana ukuba usuke wayithatha wayifaka ebokisini.
Ingxaki ngokwembiwa kukuba ingumsebenzi owonakalisayo kwaye xa sele uyisusile ibreccia okanye ifosili, awunakuphinde uyingcibe kwakhona. Ngoko ke, kufanele uhlele ngendlela ukwemba kwakho kwaye ushicilele iinkcukacha kangangoko unakho mayelana ne provenience yefosili leyo ngaphambi kokuba uyisuse uyise kwigumbi lokugcinwa. Oku kuquka ukuthatha imifanekiso ugcine namanqaku asendaweni yokusebenzela, nedingwa ngu Mthetho woMzantsi Afrika. Kwaye ungaze ususe okungaphezu kokuba uyakuthatha. Kubonwa njengendlela elungileyo ukushiya ngasemva ‘isuntswana lengqina’ ukwenzela ukuba abaphandi abalandela wena babenakho ukuqhubeka nokwemba kwixa elizayo.

Ukwenza iGrid Okanye Hayi

©David Fleminger
Mandulo iiarchaeologist zazisebenzisa ubuchule be grid ukuze bafumane ubume/provenience ye fosili. Le yindlela apho uthatha imitya eliqela okanye amacingo uyiphithanise kwisiza ukuze wenze izikwere ze grid, ezibizwa nge spits.
iArchaeologist ziye zombe kwi grid nganye malunga ne 100 cm ubunzulu, bakhuphe iifosili baze bazifake zonke engxoweni ephawulwe ngobunzulu be gridi. Obu buchule babusetyenziswa kwindawo yase Sterkfontein, kwithuba eliphantse ukufikelela kwikhulu leminyaka. Kwaye lamacingo ayesetyenziswa ukwenza le grid asekhona phezu kwemingxunya eyombiwayo. Ingxaki na lendlela kukuba zonke ezi zinto zipakishene ndaweni nye, nto leyo yenza kubenzima ukufumana ubume be fosili nganye.

Ngobuchule obutsha be theknoloji ekhoyo ekwaziyo ukuncedisana nee archaelogist zalemihla, ubuchule be grid buya butshabalala. Ngoku, sele kusetyenziswa isixhobo esikwinqanaba eliphezulu elibizwa nge Total Station (sibukufana nomxhube we theodolite kunye ne GPS), iiarchaeologist ziyakwazi ukushicilela ubume ngqo kunye nobude befosili eziyifumeneyo.

Oku kunika iziphumo zemo/provenience eyi 3D neye ishicilelwe ze ifakwe kwiplastiki kunye ne fosili leyo yayo.

Indlela Yokubala Iminyaka yeFosili

©David Fleminger
Zimbini indlela zokomba: Ngobude nangokuxeswa. Ngokomthetho othe gabalala, izinto ezifunyenwe kwinqanaba elinye zezexesha elinye, logama izinto ezifunyenwe zihleli ngokwehla, zibonakalisa ubudala (ephezulu indala, ze eyona isenzulwini ibe yeyona indala. Ngoko ke, isigqibo sokuba ukhethe ukugrumba uxwese okanye wehle nomhlaba sixhomekeke ekubeni yintoni kanye le uzama ukuyifumana.
Ukuba ufuna umfanekiso othe gabalala wexesha elithile ugrumba uxwese. Ukuba ufuna ukubona imbali ngokuhambelana kwayo kweminyaka, ugrumba umngxuma owehlayo. Nangona kunjalo, izinto azihlali zicacile ngalo lonke ixesha, zisenokuba ngama jiko jiko ingakumbi kwimiqolomba ehlala idilika itshintsha tshintsha. Ngoko ke, uhlolo lwe ndlela umhlaba omile ngayo nobume bawo ludingeka ukuba lwenziwe ngaphambi kokuba ufumane ubudlelwane phakathi kwee fosili ezimbini.

Ukwafumana ndendidi ezimbini zemo yokwembiwa komhlaba: Ezo zikumhlaba othambileyo kunye nezo zikumhlaba oqinileyo, ezifana nemiqolomba. Kwimihlaba ethambileyo, ezona zixhobo zibalulekileyo zii trowel zomakhi kunye ne bhrashi ezahlukeneyo kunye nezixhobo zokukhupha amazinyo-zonke ke ezi zixhobo kufuneka zibe kubuchule obu phezulu. Itrowel isetyenziswa ukuvunguza nokususa umhlaba.
Ipiki yona isetyenziswa ukuveza ifosili ngononophelo ze yona ibhrashi isetyenziswe ukususa isanti. Njenge siqinisekiso, wonke umhlaba ojikeleze ifosili udla ngoku qokelelwa uze uhluzwe ngezihluzo eziqinisekisa ukuba kushiyeka nawona akhe amancinci amathambo kunye neentsalela, neziye zifakwe engxoweni ziphawulwe ukuze ziye kuhlolwa ethubeni elab.

Ukucaphula

Xa usebenza nge breccia eqinileyo, amathuba amaninzi awunakho ukwahlukanisa ifosili nelitye, ngethuba usekwindawo oyifumene kuyo. Ndaweni yoko, udinga ukusika eso sixwexwe se breccia sithwele ifosili uye naso kwi lab. Ukwenza oku, usebenzisa idrilll yesandla ukwenza iqela lemingxunya ejikeleze esi sixwexwe. Emva koko izixwexwana ezibini emngxunyeni uze uzame ukuqhuzula ilitye lisuke edongeni okanye phantsi. Iindawo ezibalulekileyo ziba sele ziphawulwa kwesi sixwexwe ukuzwe kwaziwe ukuba besihamba ndawoni. Kodwa ke oku kwenziwa ethubeni.

Xa sele ubuyele eLab, ungabesele usithi chu ngononophelo ususe ifosili elityeni. Usenokusebenzisa ifine drill (Efana nesixhobo sokukrola amagama). Okanye ungasebenzisa ngononophela iibhafu ze asidi ezi ethe ethe ezizakunyibilikisa ibreccia logama zishiya ifosili isaphelele. Omabini la macebo adinga iminyaka yoqeqesho kunye nomonde ongamandla. Xa kubhekiselele ekubaleni iminyaka yee fosili, zimbini iindlela ezinokusetyenziwa: relative dating kunye ne absolute okanye chronometric dating.
Le ndlela yokuqala kulapho uzama ukufumanisa ukuba ifosili leyo indala okanye incinci kunenye efunyenwe kwisiza esinye, kwaye oku kuvanyiswe ngokwenziwa ngokuzama ukwazi ubudala bomhlaba nalapho ifunyenwe khona ifosili ngokucazulula ezinye izinto ezikhoyo (ingakumbi izityalo kunye nezilwanyana) ezifumaneka kwindawo enye ze zithelekiswe nezinye zezinye iziza. Ngaphambi kweminyaka yoo 1960, kwakuqikelelwe iminyaka yee fosili ngale ndlela. iChronometric dating ijongana nokufumana ubudala be fosili ngendlela yokuba ‘mingaphi iminyaka ephambi kwalo umiyo’. Oku kwenziwa ngokusebenzisa iindlela eziliqela ezinzinyana nezivamise ukubandakanya ukubala ukuba ingakanani ikhemikhali ethile (efana ne khabon) ekhoyo kwi fosili, ze ithelekiswe neyaziwayo kunye nezinga layo lokubola.
Ezi ndlela ze radiometric zingalingana ne potassium-argon (K-Ar), khabon (kuphela, ukuba ifosili leyo ineminyaka engaphantsi kwama 50 000 ubudala), kunye nezinye iielementi ezi radioactive. Ikwakhona nenye indlela ebizwa nge Palaeo-magnetism ehlola ubume be particles eziphakathi kwi fosili ukumeta ukuba umhlaba ushukume kangaphi ( into ke ekuthiwa umhlaba iwenza rhoqo emva kwe khulu elimbalwa leminyaka), kodwa lonto inzulu kakhulu ukuba mna ndingayiqonda ngokupheleleyo.

Translated by Zizipho Silwana