Basic Geology Sakhiwo seLuhlobo lweBantfu

Kwakheka kwe Litje Lelikhulu

©David Fleminger
Lamatje akulesigodzi sesaSakhiwo Seluhlobo Lwebantfu atfwele kakhulu imibhedzeyematje eDolomitic, lekwakheka kulombhedze loshona kancane, emanti-lafutfumele elwandle lavala lo Basin we Witwatersrand longaba yiminyaka lemitsatfu yetigidzinetigidzi kadzeni. Ematje eDolomite akheke nge calcium carbonate (litje lelime) kanye nemoya we isotopes lefakwe/lejikwe ekhatsi kwentelwa kukala kudla. Loku kwakha indzawo ye Karstic, lekuyindlela kulokwakheka kwemihome njengemphumela lotako wekugedvuka ngasemalayinini layinkinga ngaphansi kwangetulu.
Lamatje lagegetele iSterkfontein kanye ne Krugersdorp anemalanga lahambela ku 2.6 billion ngeminyaka kantsi nalamatje lase Mphumalanga, kuya ngase Hartebeespoort anemalanga langaba ngu 2.2 billion yeminyaka. Lakhekile letako laphakamile ngakulelinye lihlangotsi kunalelinye futsi lamatje lase Nshonalanga yale Sakhiwo Seluhlobo Lwebantfu, kuya ngase Krugersdorp aphakanyiswa kucala, lokwenta kugedvuka kwemhlaba lokungetekile kanye nekwakha tintsatjana letigicikako kulelihlangotsi lwe Sakhiwo Seluhlobo Lwebantffu.

Asingenge Kulemishina Yekwakha

Uma ufuna kungena kulemishina, lefutsi ingenti, lamalayini-etintfo letafa letatfolwa kuleLicembu le Chuniespoort, aleLicembu le Malmani Lelincane, Lelicembu lelikhulu lematje eTransvaal, futsi akheka aba ngu 2.5 billion ngeminyaka yakadzeni. Lelicembu lelincane le Malmani liphindze lihlukaniseke laba macembu lasihlanu: le Oaktree, iMonte Christo, iLyttleton, iEccles kanye neKwakheka kwe Frisco. Lesigodzi siphindze sitfwele tintfo letiholako kanye ne copper, lokwagutjwa tive tandvulondvulo kanye nebahlali bakucala kulendzawo.

Kugutjwa Kanye Nekubekwa Kwetinsuku Ngemishina

©David Fleminger
Ngako, itsi iarchaeologist noma ipalaeontologist seyitfole lolokuphilako kwetintfo letafa tatfolakala tematje, bakhona kanjani kukhokha letintfo? Kahlekahle, kugubha yindlela lelula yekugamuka, kudleka-kwesikhatsi kanye nenchubeko lekabi ledzinga iminyaka yekufundzela kanye nekubeketela lokungapheli. Kuhlangahlangene kakhulu kuchaza ticeshana letimbalwa. Ngako kuhamba ngalendlela.
Kumbe lemibono lebaluleke kakhulu yekugubha yintfo letangaphambili namuva, lephindze kubitwe ngekunikwa/kunikwetwa. Kahlekahle, loku kuchaza kutsi ufuna kubhala ngendlela lejakekile ngalesigaba laph khona letintfo letafa tatfolwa: tatfolakala kuphi? Betilele kanjani? Betilele eceleni kwani? Yini lebe ingetulu kwato? Yini lebe ingephasi kwato? Lonkhe lolwati lingakunika lwati lolwengetekile kanye nemifanekiso ngaletintfo letafa letasala, indzawo yato, tintfo takhona kulendzawo ngisho ngemphilo yato lengaba yintfo lengeke seyichazeke umangabe utsetse wase ufaka kulelibhokisi.
Inkinga kungukutsi lokugubha kuyintfo lebalulekile njengentfo yekuphatamisa inchubo futsi, utsi ungasusa le breccia noma letintfo letafa tasala, ungeke ufake tibi ndzawonye futsi. Ngako, kumele ulungisele kugubha kahle bese ubhala lwati ngendlela leningi ngekushesha ngaletintfo lotitfolile ngaphambi utisuse bese utibeka endzaweni yekutigcina. Loku kufaka kutsatsa titfombe kanye nekugcina imibhalo lehlangene, lekudzingwa ngumtsetfo we Ningizimu yase Afrika. Akukameli futsi kutsi ususe tintfo letiningi kunaleto lekumele utisuse, futsi kutsatfwa ngekutsi ngemalungiselelo lamahle kugcina ngemuva ‘sehluko sebufakazi’ kwentela kutsi lolokutfoliwe ngeluphenyo kutochubeka ngalokugubha kwelikusasa.

Kwenta Emalayini Laphambanako noma Kungawenti

©David Fleminger
Emuva, ema archaeologists abevame kusebentisa indlela yemalayini laphambanako kuciniseka kukhonjiswa kwetintfo letafa tasala. Lena yindlela lapho khona ukhokha incumbi yetintsambo noma emahwayela laphambana kulendzawo kwentela kwakha emalayini latiwako etikwele, lekubitwa ngekululeka.
Ema Archaeologists abese agubha yinye intsambo kulesehluko, kutsi, emasentimitha lalikhulu leshonaphansi, sebenta ngaletintfo, khokha letintfo letafa tasala utifake tonkhe esikhwameni lesibhaliwe ngelilayini kanye nebubanti.
Lena kwabayindlela leyasetjentiswa eSterkfontein ngeliningi lekusala kwandvulo, futsi lentsambo lendzala yelihwayela solo imisiwe ngetulu kanye nalolokwagutjwa. Inkinga ngalendlela ngutotonkhe letintfo futsi tahlanganiswa ndzawonye futsi naletihamba ngakunye ngentfo yinye akukhonakali kukwetsemba.
Ngebungcondvongcondvo lobusha lobukhona etinsukwini tanyalo tema archaeologists, lendlela yemalayini ngekushesha icala kungabimcoka ngoba sekukhona lokusha lokwentiwe. Nyalo, kusebentisa indlela lephucukile yetintfo letibitwa nge Siteshi Lesiphelel (kufana nenhlangano ye theodolite ne GPS) ema archaeologists ayakhona kubhala lesikhundla lesingiso kanye nekuphakama betintfo tonkhe labatitfolako.
Loku kucedzela le 3D leliciniso lebhaliwe kuncenye ye ID yase ibekwa esikhwameni selipulasitiki ngalapho kunaletintfo letafa tase tiyatfolwaa.

Lenchubo yeku Khula

©David Fleminger
Timbili tintfo letingito tekufinyelela ekugubheni: letishona emaceleni kanye naletishona etulu naphansi. Njengemyalo lobanti wesitfupha, tintfo letitfolakala esigabeni lesifanako tentfo yinye futsi lefanako, tibe tintfo letitfolwa kulendzawo leshona etulu naphansi tikhomba umnyaka (lokuphakeme kuncane, logushonako kudzala).
Ngakoke, kukhetsa kutsi uyagubha uyisa eceleni noma uyisa phansi kushiyana ngekutsi utama kutfolani. Uma ufuna sitfombe lesibanti sesikhatsi lesitsite ngesikhatsi ugumba uyisa emaceleni; uma ufuna kuciniseka ngemlandvo wetinombolo tetintfo letentekile tendzawo, ugubha ubheke phansi. Yebo, tintfo atijubeki-kahle kantsi futsi tintfo tingaba topsy-turvy, ikakhulu emihomeni legcina kuwa kanye nekukhwesha. Ngako luhlelo lwendzawo letsite lehleliwe livame kudzingeka ngaphambi ungabanesiciniseko sebudlelwane besikhashana emkhatsini wetintfo.
Uphindze utfole timo tetinhlobo letimbili tekugubha: leto letisesihlabatsini lesiyekelako naleto letikulesicinile, tintfo tekufakelwe leti calcified kufana nemhome we breccia. Esihlabatsini lesiyekelako, lamathuluzi lamcoka kakhulu yintfo yemuntfu lowakhako kanye nemabhurashi lakhetsiwe kanye netigodzi – konkhe lokuphakeme. Lelithuluzi lekugubha lelincane lisetjentiswa kutsambisa kanye nekususa lomhlabatsi. Lokutsatsa kusetjentiswa kuveta letintfo letafa bese lelibhurashi lisetjentiswa kubhurasha lisuse lomhlabatsi lokahle.
Kwentela kukala lokukahle, wonkhe lomhlaba lokuletintfo letafa letitfolakele uvame kutsatfwa bese usakatwa etintfweni letiningi telihwayela lelikahle-letikwele kwentela kususa ngisho nematsambo lamancane kanye naletintfo letincane letafa tase tiyasala, letibese tiyahlanganiswa phindze tibekelwe luhla lwamuva kulendzawo yekusebentela ilab.

Kutsatsa

Uma usebenta nge breccia lecinile, nomakunjalo, awuvami kususa letintfo letafa kulamatje ube ukulendzawo. Esikhundleni, udzinga kujuba ukhokhe letigadla taletintfo letafa te breccia bese utitsatsa tiya elab. Kwenta loku, usebentisa kwekubhora kwesandla ekwenteni inombolo yetigodzi kulesigadla. Bese ufaka tigadla letimbili kulomgodzi bese ngesineke ushayela emkhatsini wato kwentela kuhlukanisa lamatje ngekuhloba ususe kulelibondza noma lesiyilo. Emapoyinti abese ayamakwa kulesigadla khona tintfo letihlanganako tingabonwa esigabeni lesidzala.
Utsi nase ubuyile kule lab, ungabese uyasusa kancane letintfo letifile letisuka kulamatje, kumbe ngekubhora lokukahle (njengelithuluzi lekubhala) noma ngekusebentisa ngesineke sekugeza nge esidi lelula letoncibilikisa le breccia ube ugcine letintfo letifile tiphelele/tingakagamuki. Totimbili letindlela tidzinga iminyaka yekulungiselela kanye nekubeketela lokuningi.
Ngetindlela tekufaka tinsuku kuletintfo letafa, kukhona tinhlobo letimbili tekutsintsa: tinsuku tekuhlobanisa kanye nekubangiko noma tinsuku letibekwe ngeluhlelo. Luhlobo lwekucala ngulapho utama kusebenta umangabe leyontfo iyindzala noma iyincane kunaletinye letitfolwa endzaweni yinye, futsi loku kuvame kwenteka ngekusebenta lomnyaka walomhlabatsi ngendlela letintfo letafa letatfolwa ngayo ngekuhlelisa leletinye tintfo (ikakhulu tilwane netitjalo tendzawo) letitfolwa esigabeni lesifanako kanye nekucatsanisa naletinye tindzawo. Ngaphambi kwemnyaka wa 1960, incumbi yetinsuku tentiwa ngalendlela. Tinsuku letihleliwe tiyakhatsalelwa ngekutfola leminyaka yetintfo letafa ngendlela ye ‘kutsi mingakhi iminyaka phambilini kunalena yamanje’. Loku kwenteka ngetintfo letiningi letihlangahlangene letivame kufaka kubala kutsi tingakhi tintfo temakhemikhali letitsite (kufana ne carbon) kukhona kuletintfo letifile, bese kuyameshiswa kwentela kutsi kwatiwe kanye nelinani lemnyaka lalawo makhemikhali.
Letindlela tekutfumela tingakalela ipotassium-argon (K-Ar), icarbon (kuphela umangabe letintfo tingaphansi kweminyaka letigidzi temashumi lasihlanu ngebudzala), kanye naletintfo tekutfumela letisebentako. Phindze kukhona indlela lebitwa nge Palaeo-lebambako lehlela kuma kwaletintfo ngekhatsi kwaletintfo letafa kwentela kukala kutsi tingakhi tikhatsi lemagnet yalendzawo yeMhlaba ikhweshile (intfo leyiyentako njalo ngeminyaka letinkhulungwane letimbalwa, kahlekahle), kepha nje loko kwekunaka-kuvimba kwami ngekuvisisa lokuphelele.

Translated by Phindile Malotana