Ijiyoloji yeRichtersveld

Sekuthoma Ukutjhisa

©Jacques Marais

Seqela eminyakeni eyi-100 million eyadlulako, iGondwanaland gade sele ifudukela kabuthaka esifundeni esisepumalanga begodu indawo leyo gade ivalwe lirhwaba. Ukungwareka okwenziwa yirhwabalazelo kusabonakala e-Grasdrift, eduze kweRichtersveld National Park, kanye ne-Niewoudtville.

Eminyakeni eyi-270 eyadlulako, nanyana kunjalo inarha gade sele ifudukele esifundeni esimakhaza begodu izinto gade sele zithoma ukutjhisa. Irhwaba lathoma ukuncibilika, litjhiya ngemva iinsalela ezatjhuguluka zaba yi- Dwyka group. Lokhu kwaba kuthoma kwe-Karoo Supergroup, efika phakathi eSewula Africa kwanjesi. Iinsalelezi zasabalaliswa ngokulingana esifundeni seNamaqualand, begodu zilele phezu kwamatje we-Nama Group.

Ukusuka Komoya Obukhali Wejiyoloji

©Shem Compion

Ukusuka ngesikhatheso angena ngaso, isifunda soke Saba nokusuka komoya obukhali wejiyoloji, lokha Gondwanaland ithoma ukuhlukana phakathi iya ngilokhu esele kubizwa kwanje bona yiSewula America kanye ne-Africa. Lokhu kwabanga kobana kugoqeke amatje kanye nemakhiwo yentaba esifundenesi, kwenzeka nesikotlelo esikhulu esifundeni seKharu kanye nepumalanga ye-Namaqualand. Iinqhema ze-Ecca kanye nezeBeufort zangena esikotlelenesi zenza inbhayomi ye-Nama-Karoo.

Nangaphandle kwesigesi, ileveli yelwandle yaveza iintaba zetlhagu kanye nemilambo egijima etlhagwini etja yaragela phambili yarhurhula iindundumezo. Lokhu kwabanga ,hlangana kwezinye izinto, ukwakheka kwe-Fish River Canyon (yesibili ngobukhulu ephasini, ngemva kwe-Gand Canyon ye-North America) Ngeskhathesi, isifunda seNamaqualand gade sele somile begodu inarha espara etja egade sele ivelile yavalwa yisanda.

Inani lamaDayimani

©Nigel J Dennis

Esinye isigaba esiqakathekileko senzeka ngeminyaka yabo 120 million eyadlulako, lokha amaphayiphi we-volcano asunduzelwa kude ne-mantle. Amaphayiphi abumbeke njenge-funnel la gade anedayimani enengi ngaphakathi, eyeneke emgodini otjhingela nge-250 km ngaphasi kwehllabathi. Idayimani le ngade ivaleleke elitjeni elikhethekileko elibizwa bona yi-Kimberlite. Ngemva kwe-millenium eyalandela lapho, amaphayiphi wedayimani la arhurhulwa milambo (i-Orange River) ayokungena e-Antlantic. Amadayimani angena emlonyeni we-Orange River, ilitje elikhulu elihlangene nedayimani langena lapho eminyekeni eyi-20 kanye neyi-15 million eyadlulako.

Eminyakeni eyi-100 million eyadlulako, iSewula America kanye ne-Antartica sele zihlukene nenarha ye-Africa (ekhe yaba sesenta yeGondwana) egade izonjwe mamanzi. Lokhu kwabanga bona kube ne-rimu elasuka ku-escarpment ephezulu.

Unobangela Wamanzi Omkhulu Wesifundesi

©Roger DelaHarpe

Kwanjesi, umlambo osele uzokuba yi-Orange (nanyana i-Gariep) besele umthombo wamanzi omkhulu esifundenesi. Uvela eLesotho Highland ugelezele epumalanga uyokungena e-Antlatic Ocean eduze kwendawo ebizwa bona yi-Alexander Bay kwanjesi. Eminyakeni eyi-65 million eyadlulako, kwenzeka irarano elincani lejiyoloji elabanga bona umlambo i-Orange ube khona. Ngemva kwalokho wafudukela etjonalanga wagijimela e-Koa Valley wayokufika e-Antlatic eduze kwemlonyeni womlambo obizwa bona yi-Olifants River kwanjesi. Lokhu kwatlhadlula bona kwaba namatje amathani amakhulukhulu wehlabathi emumethe amadayimani agelezela elwandle, ayokuthuthelwa etlhagwini, athuthwa mimoya ebizwa bona yi-Benguela current. Eminyakeni eyi-50 million yangemva kwalokho, elinye irarano le-subterranean labanga kobana umlambo i-Orange ubuyele lapha ekhabe ukhona ngendlela ye-Richtersveld uya e-Alexander Bay. Umphumela wakho koke lokho kwaba yitlhagu leSewula Africa kanye neleNamibia elinamadayimani.

Itlhagu leSewula Africa lathoma loma eminyakeni emakhulukhulu eyalandela lapho. Irhalawumba le Namibia, elingamanye amadala khulu, lathoma ngeminyaka eyi-40 million kanye neyi-25 million eyadlulako. Kokugcina eminyakeni eyi-5 million eyadlulako, imimoya emakhaza ye-Bengula (evela e-Antarctic) sele ilethe bujamo bezulu obukhamba phambili

Isifundeni esomileko lesi. Lokhu kukhambela nobujamo bezulu obutjhugulukako obenza bona iNamaqualand ifuduke ingasaba nezulu lehlobo ibe nelebusika.

Indunduma Zetlhagu ye-Namaqualand

Ukutlameka okukhulu kwejioloji kwathoma eminyakeni eyi-5 million eyadlulako, lokha itlhagu leNamaqualand naliphakanyiswako. Lokhu kwaveza iindawo ezisipara ezimbalwa emanzini egade avalwe kancanikancani mihlobohlobo yehlabathi. Nasele ihlangene nehlabathi, nanyana gade kukhulunywe ngamakhulukhulu wamadayimani wekhwalithi ngaphezulu, imibhede yehlabathi le sele imayiniwa kwanjesi. Kufanele sitjheje bona iinsalela zelwandle ezihlezi ngaphasi kwamanzi zimumethe amadayimani, begodu zithathwa zinkepe zamadayimani ezimunya ihlabathi eligugu le ziyithuthele lapha ziyihlenga khona.

Into yokugcina ekufanele ngiyitjho: Amatje atholwe mhlapha esifundenesi eduze komlambo i-Orange River gade kuyi-silt edege esale ngonobangela wenkhukhula. Nezinye iindundumezi ziphezulu ukudlula amanzi, okukhombisa iinkhukhula ezikulu ukuzidlula zoke eSewula Africa. Amalanga atlolwe ematjeni la akhombisa bona ezinye iinkhukhulezi zenzeka eminyakeni eyi-700 eyadlulako, okukhombisa bona zingenzeka godu.

Indawo Enemihlobohlobo

Njeke sifike emaphethelweni wencenye yendaba le, begodu umphumela wokugcina wendawo esele siyibona namhlanje: nekuyindawo ehlukaniswe phakathi zintaba ezimbalwa. Ngembala kuyarara bona yindawo engakajwayeleki emhlobohlobo, ehlezi ematjeni enziwe yi-volcano. Njengombana uFrancois Odendaal kanye noHelen Suich batlolile encwadini yabo ngeRichtersveld. Kunendawo ezimbalwa eSewula Africa lapha kunenani eliphezulu lamatje wejeyoloji abonakalako, begodu mihlobohlobo yamatje edala imihlobohlobo yendawo eRichtersveld, okwenza bona kurhonakale kobana kube nemihlobohlobo yentjalo endaweni leyo.

Translated by Busisiwe Skhosana