Ukuphenya kweVredefort Dome

Abacwaningi basekhaya

Emuva eNingizimu Afrika, nokho, ukuthuthuka kwenzakalo yesayensi kubonakala sengathi kwasidlula. Ngo-1916, u-S.J. Shand uqale wachaza umphumela wokuqhaqhazela-chungechunge obizwa ngokuthi 'pseudotachylite' kodwa akazange akhiphe imvelaphi yamadwala aphathelene nentaba yomlilo. Ukuphenywa kokuqala kwezemvelo zesiqongo esiyindingilizi, okwenziwe ngo-1925, kwafika esiphethweni sokuthi lesi siqongo esiyindingilizi sabangelwa ukuqhuma okukhulu kwegesi ephathelene nentaba yomlilo. Ngo-1936, abacwaningi ababili bahlongoze ukuthi umthelela wenziwe yisiqongo esiyindingilizi, kodwa lokhu kwakucatshangwa kakhulu ngabacwaningi bendawo.

Isikhubekiso kwakuyisakhiwo seDome ngokwayo. Umthelela ovela phezulu ungabangela kanjani ukuthi umhlaba uphakame? Ngokuqinisekile ukuqhuma kwangaphakathi kwakungenzeka kudale ukuphakama kunomthelela wangaphandle. Noma kunjalo, ngo-1947, umcwaningi owesayensi ephathelene ngokwakhiwa komhlaba okuthiwa u- R.A. Daily wathatha umqondo wempikiswano futhi wathi ukukhululwa kwengcindezi ngemuva kokuba nomthelela ungabangela ukuthi izingqimba zamadwala zivuselele futhi ziphakamise isiqongo esiyindingilizi. UMkhulu wesayensi ephathelene ngokwakhiwa komhlaba eNingizimu Afrika, u-Alex du Toit, wahlala engaqiniseki futhi wabika ukuthi lesi siqongo sakhiwa izinqubo ezinkulu ngaphakathi komhlaba.

Ingxabano yaqhubeka

Kwaphela iminyaka, impikiswano yaqhubeka. Umbono wamazwe omhlaba wawuvumelana nowesikolo sokushayana kwamandla.Kodwa abacwaningi baseNingizimu Afrika baqhubeka ukukhiqiza amaphepha abonisa ukuthi kwaqala ngaphakathi komhlaba.Ngama-1960, umbiko ovela ekuhlolweni kwezosayensi wase-Ottawa (Geological Survey of Ottawa) wenza umehluko phakathi kwezinhlobo ezimbili zemigodi ephezulu entabeni yomlilo: lezi eziphethe ububanzi obulinganisa amakhilomitha amaningana, okwakungenzeka ukuthi zibe nesimo sesikotela esilula, nalezi ezikhulu kunamakhilomitha amaningana, okuvamile ukuba ukuphakanyiswa okuphakathi kwamadwala amadala azungezwe ikhola yezendlalelo ezincane.

Leli phethini 'eliyinkimbinkimbi' lifanela iVredefort ngokuphelele. Noma kunjalo, ososayensi bendawo baqhubeka nokufunda kwabo, bekhuthazwa umsebenzi kachwepheshe wezokuqhuma, uWalter Bucher, owagcina ukuthi izakhiwo zesiqongo esiyindingilizi zenziwa ngenxa yokuqhuma kwegesi elishisayo elibangelwa imigqa ebuthakathaka emkhakheni woMhlaba.

Ukuguquka kwesimo

Naphezu kokubheka abacwaningi bendawo, ukuqonda kokuguquka kwesimo kwaqhubeka. Ngo-1968, ingqungquthela yamazwe ocwaningo yabanjwa, ihlanganisa ndawonye ochwepheshe bamazwe amaningi. Lokhu kwanikeza abachasisa ngokucabanga nje ukuseleleka futhi eminyakeni embalwa ezayo, kwenziwa izinyathelo ezibalulekile. Imibiko yasensimini eyemigodi ephezulu kwentaba zomlilo, imbonakaliso yamadwala aphathelene neyanga kanye nemiphumela yokuhlola eyaselebhu zaqhubeka zihambisana, futhi konke kwaqala ukuhambisa nocwaningo lokushayisana kwamandla.

Ekupheleni kweminyaka yama-1970, izakhiwo zemvelo eziyikhulu namashumi amabili zikhonjwe ezindaweni ezihlukahlukene zomhlaba kanye nokuchazwa kwamadwala anokuhambisana nemigodi ephezulu kwezintaba zomlilo. Lezi zindawo zazibizwa ngokuthi 'impactites' - igama elikhumbuza amalungu eklasi lokuvivinya umzimba, noma abantu abagcwele endaweni.

Ngama-1980, ochwepheshe abaningi bamazwe ngamazwe babeqiniseka futhi amanyuvesi angaphandle afundisa ukuthi i-Vredefort Dome yayidalwe ngumcimbi wamandla okshayana. Kodwa hhayi eNingizimu Afrika. Lapha, abantu abanenkani(beholwa usosayensi uLouis Nicolaysen) agcina ukholo lwabo ukuthi yakhiwa ngomthelela weNtabamlilo. Ekugcineni, ingqungquthela yabizwa ukuxazulula impikiswano. Wabanjelwa eParys ngo-1987 kanti ochwepheshe bezombili inhlangothi babhekana nomhlangano. Umhlangano uhlulekile ukuthola isiphetho sokugcina, noma kunjalo.Ivoti ithathwe ekupheleni komhlangano futhi iningi labahlanganyeli libonise ukusekelwa kwe-exogenic (Ukushayana kwamandla angaphandle) ekuqaleni.

Ezingeni le Athomu

Ukunciphisa indaba ende, iminyaka eyishumi ezayo yayigcwele imibiko evela kubacwaningi eNingizimu Afrika nasemhlabeni jikelele. Lesi siqongo esiyindingilizi sasike satitinywa ngososayensi bomhlaba futhi, kancane kancane, ubufakazi bubekwe. I-Coesite ne-Shishovite yatholwa, ingxenye ezincane kwamakhemikhali e-quartz atholakala futhi isimo esiqondile sengukuqosimo emadwaleni safundiswa. Ekugcineni, ngo-1997, u-Hughes Leroux wakwazi ukuhlaziya amasampula amadwala ngezinga le-athomu. Ukuthola kwakhe kwafakazela ukuthi iVredefort Dome ibhekene nesenzakalo sokushayana kwamandla esiye saqeda amatshe ezingeni eliphezulu. Ababhikishi banqotshwa ekugcineni.