iVredefort Leyiyindingilizi Yetimvutfu Letincane neKutfuka kwe Metamorphics

© David Fleminger

Sisindvo Lesingetiwe Sekuhlala/Sekuchumana neNdzawo

Ngaphandle kwesikhala lesikhulu kule Vredefort Leyiyindingilizi, lesisindvo lesikhulu kakhulu lesisele ngemuva kwetinyatselo letiningi, letatsatfwa kulamatje. Letitintfo tatfolwa kuletinye tindzawo tetisindvo letiningi ngale kwemhlaba, futsi nyalo titsatfwa ngekutsi mibhaloyetikhala te sisindvo lesingetiwe sekuhala endzaweni. Kwekucala, kukhona sigogo lesicinile setintfo letaliwa/tajikiswa letawela emvuleni lenkhulu ngale kwelilayini lelisuka emkhatsini lwe makhilomitha emakhulu lamaningi. Lesisigadla semalayini netintfo letincane letindizako ticinile emkhatsini kwesigodzi sendingilizi, kuncipha ngekuphuma nawunyakata kulomkhatsi.

Kubona lokukahle lokulandzelako kwemandla entfo lenkhulu emsebentini kugucuka lokwenteka ematjeni. Ngesikhatsi ibolide ishaya, ingakhokha kushisa lokungetulu kwemadigri latinkhulungwane telishumi bese tifika kumakhulu egigapascal ngekuphushwa. Lelinani lelikhulu lwemandla kanye nekushisa kwenta lamatje lakhona kutsi ashintshe abe yintfo lensha. Lenandlela yatiwa njenge 'metamorphic letfusako'. Yinye yetintfo letatiwako tale metamorphic 'timvutfu letincane tematje'.

Timvutfu Letincane tematje

Timvutfu letincane tematje akusiko lokutfola nawuwisa le ice-cream yakho. Esikhundleni, kuyintfo letsite lesakatekako ngetulu kwematje njengoba kwetfuka kuhamba lapho. Umphumela kwakheka kwentfo lengatsi sikwele, natisuka endzaweni lejwayelekile.

Letitimvutfu tisakateka tiye etindzaweni letimbalwa nge Vredefort Leyiyindingilizi, futsi kutsiwa uma ulayine tonkhe letimvutfu kahle, ungasebenta lelilayini lebolide. Lokubuhlungu kutsi, tivakashi tesimanje ticala kuphula letimvutfu njengemhlobiso wemlandvo. Lena yindlela lekumele imiswe kantsi nekuvikela letimvutfu kutoba nguyinye indlela yekunakekela kwelicembu lelisha lebaphatsi leligadze Lendzawo lesandingilizi.

Ema Metamorphic alaMatje

Lenye intfo lemcoka yalamatje eVredefort ngulemitsambo leminyama yetintfo letivela kule granite lekhanyako. Loku kubonakala kuhhwabile ngebudze nangekucina, kepha letinye tibonakala titinkhulu ngelinani. Lena nhlobo yelitje lelimnyama lelisagilasi libitwa ngekutsi yi 'pseudotachylite' futsi yakheka ngesikhatsi lizinga leliphakeme lenta lelitje kutsi lincibilike bese kugucuka kwakheka kwechemical. Ematje lafanako atfolakala ekubhidlikeni kwematje kanye nakumalayini langakakheki kahle (lapho kushayisana emkhatsini weliplede le tectonic lenta kushisa kutsi kukhululeke). Lelitemu 'pseudo' liyangetwa nangabe kute luphawu lwentfo yekugedvuka kwematje.

Lizinga lekushisa lelihle kanye nekukhululeka kwemfutfo lokwentiwa sisindvo nako kwenta sikali lesinye lesikhulu sematje, sibitwa nge 'granophyre'. Lesisicumbi sematje lamalula lamnyama etinshwana leticocekile tasetenta intfo lenkhulu, imiciji lencama yelitje lelincibilikile, lelichubekela kumakhilomitha lamaningi. iRadiometric yetintfo tezircon kulendlela yekwakheka kwematje esisindvo yasita bafundzi bemhlaba nematje kutsi banike leVredefort lilanga lelitsite leminyaka lengu 2.023 yetigidzi tetinkhulungwane.

Tintfo-Letakhekile Letitfusako

Phakatsi kwaleletinye tintfo letimcoka tetintfo letatiwako etindzaweni tesisindvo lesiningi ngema coesite kanye ne stishovite. Lawa ngemagama lamabili lanikwe tintfo letimbili tema quartz (imineral leyatiwako ematjeni). Akheka nangabe lequartz icindzetelekile futsi ishise yaze yefika esigabeni lapho ijika tinshwana tayo tesakhiwo. Kufunwa kemamineral omabili avame kutfolwa esisindvweni semgodzi lomkhulu, kanye nasetindzaweni lapho kuhlolwa emabhomu enuclear. Litemu lekungulona lalenhlobo yekwakheka 'kwetfuka kwe quartz'.

Luphawu lekungulona lwekwetfuka kwe metamorphism alibonakali ngemehlo enyama nje. Kuphenya lokuchaphelisiwe, lapho khona ematje ajutjwe khona aphindze ahlolwa ngaphansi kwesipopolo, akhombise kwakheka ngesigaba se atomic. Loku kukhombisa njengentfo lephazamisako kumatje lamancane equartz futsi, nakakhona, ayintfo lekhombako lecinile esisindvo.

Sisindvo seDayimane

Yinye intfo letfutsako yekwakha lengakatfolwa eVredefort 'sisindvo sedayimane'. Leti tintfo letincane, letikala intfo lengangelimilimitha ngale, akheka ngesikhatsi imeteorite ishayisa litje le carbon. Lokushisa lokuphuma kulesisindvo kwenteka nale carbon kwentela kwakha tigidzi temadayimane. Lesigodzi lesikhulu sePopigal eSiberia sitfwele tigidzi temathani esisindvo semadayimane, kepha kute-namunye losebente kusetjentiswa kwawo.

Kubhicana kwetimvutfu tematje, pseudotachylite, iquartz letfukile kanye nalokunye kutfuka kwe metamorphic sekutfoliwe eVredefort kanye naletinye tigodzi letinkhulu tesisindvo. Sekawonkhe, atsatfwa njengentfo lesibonelo sesisindvo futsi asetjentiswe kutfola incumbi yetindzawo taphambilini letingatiwa lamhlabeni.

Translated by Phindile Malotana