Geology yale Richtersveld

Kusungula ku Hisa

©Jacques Marais

Hi hundzela emahlweni ka 100 million wa malembe, tiko ro hlawuleka ra Gondwanaland ari sungula kufambela etlhelo hika ntsongo kusuka eka ndzhawu ya southern polar naswona misava ayi funengetiwe hi ayisi yo bumbula. Milayeni leyinga siyiwa hi tiayisi leti yaha vonaka na sweswi e Grasdrift, kusuhi swinene nale ntangeni wa Richtersveld National Park, xikan’we nale Nieuwoudtville.
Hi 270 million wa malembe lawa yanga hundza, hambiswiritano, misava misava ayi sukile eka ndzhawu ya polar naswona swilo aswi sungula kuhisa. Kahle kahle, ti ayisi ati sungula kun’oka, tisiya masalela yatona lawa yanga hundzuka Dwyka group of tillites. Leswi swiendle kusungula ka Karoo Supergroup, leyi katsaka na xiphemu xikulu xa Afrika Dzonga. Masalela lawa ya hangalakile na ndzhawu ya Namaqualand, laha yanga fika yatshama ehenhla ka maribye ya Nama Group of rocks.

Ku Dzinginika ka Geology

©Shem Compion

Hi minkarhi yaliya ya masalela ya Dwyka, ndzhawu liya hinkwayo yitikume yiri ka xiyimo lexi aku ninginika eka sayense ya misava, loko ndzhawu ya Gondwanaland yisungula ku aveka kuva leswi namuntlha kunga matiko ya South America na tiko nkulu ra Afrika. Leswi swi endle leswaku kuva na ku petseka ka maribye yokarhi naku tumbuluka ka tintshava eka ndzhawu hinkwayo. Tani hixiphemu xaku humelela ka leswi, kuvile na ndzhawu yikulu leyinga vumbeka eka ndzhawu ya Karoo nale ka swiphemu swale dzongeni vuhuma dyambu bya Namaqualand. Mintlawa ya Ecca na Beaufort yivuye yi wela eka ndzhawu leyi kusuka e hansi ka Nama-Karoo biome.
Tani hi xiphemu xa maendlelo lawa, mati ya lwandle ya hungutekile kusala misava leyingale makumu ka lwandle e handle, kutani milambu yikhulukela eka tindzhawu tintshwa laha ayi khukhula misava laha ayiri ehenhla nyana. Leswi swivange leswaku, e henhla ka swin’wana, kuvumbeka Fish River Canyon (2nd hi vukulu laha misaveni, endzhaku ka Grand Canyon e North America). Hinkarhi lowu, ndzhawu ya Namaqualand hinkarhi walowo se ayi omile leswinga siya swivumbiwa swin’wana swale lwandle erivaleni kutani swifunengetiwa hi sandi.

Nhlayo ya ti Dayimani

©Nigel J Dennis

Xiphemu lexi landzelaka xa nkoka xive kona kwalomu ka 120 million wa malembe, loko ti phayiphi ta volcano tikukumukile kusuka eka Mantle kuya ehenhla ka misava. Swivumbeko leswi swa funnel swa tiphayiphi aswi khome nhlayo yokarhi ya ti dayimani, kusuka eka vuenti lebyi ringanaka kwalomu ka 250 km kusuka e hansi ka misava. Maribye lawa yankoka (ndzalama) aya phutseriwile hi maribye lawa ya fayekelaka ya vuriwaka Kimberlite. Eka malembe yotala lawa yanga landzela, tiphayiphi letinga tisa dayimani tivuye ti khukhuriwa hi milambu (ngopfu ngopfu nambu wa Orange River) kutani rifuwo leri rohatimela ri khukhuriwile kuya e lwandle ra Atlantic. Ti dayimani leti tin’wana tisale etibuweni ta nambu wa Orange naswona enon’weni wa wona, akuri na leyara yo bumbula ya maribye ya ti dayimani aya hangalakile hinkwako kuringana kwalomu ka 20 na 15 million wa malembe lawa yanga hundza.

Kwalomu ka 100 million wa malembe lawa yanga hundza, South America na Antarctica ti hambanyisiwile na misava ya Afrika xikan’we na tiko nkulu ra Afrika hiku angarhela (leri ringa tshama riva exikarhi ka tiko ra Gondwana) leri ari rhandzeriwile hi mati. Leswi swi endle leswaku swiphemu swa misava swikhomana swiendla leswi namuntlha hinge hile makumu ka lwandle laha ku hambanyisaka misava na lwandle’.

Ndzhawu ya Mati Leyikulu

Kufikela sweswi, nambu lowu awutava nambu wa Orange (kumbe !Gariep) se akuri ndzhawu ya mati swinene eka ndzhawu liya. Swisungule eti highlands ta Lesotho naswona wukhulukela evupela dyambu kukongoma e Atlantic Ocean kusuhi nalaha namuntlha hinge hile Alexander Bay. Kusuka, kwalomuya kava 65 million wa malembe lawa yanga hundza, kuve na swiphiqo swa geology leswinga endla leswaku nambu wa Orange kuva wucinca xikongomelo xa wona. Wu cince ku khulukela e dzongeni laha wunga tsutsumela etlhelo ra Koa Valley kuya fika Atlantic kusuhi na nomo wa laha namuntlha hinge i nambu wa Olifants River.
Leswi swivula leswaku mamiliyoni wa ti ton ta swiribyani leswi dayimani se aswi sungula ku khulukisiwa swikongoma e lwandle, laha aswi fambisiwa kuya e lwandle hi, mati lawa aya khulukela en’walungwini ya Benguela current. 50 million wa malembe lawa yanga hundza, hambi swiritano, xiphiqo xin’wana xale matini xi bohe leswaku nambu wa Orange wu tlhelela eka xikongomelo xa wona xosungula kuhundza hile Richtersveld kuya e Alexander Bay.
Mbuyelo wa kuya loku kale ndzhaku nale mahlweni i kuva sweswi wusuka e nwalungwini vupela dyambu bya lwandle bya Afrika Dzonga, xikan’we nale dzongeni wale Namibia, yitele hiti dayimani. Loko haha fambisa sweswo, vupela dyambu bya Afrika Dzonga byi sungule ku oma hi ka ntsongo-ntsongo eka mamiliyoni wa malembe lawa yanga landzela. Mananga ya Namib desert, lawa yanga yakhale swinene emisaveni, lawa yangava kona exikarhi ka 40 wa mamiliyoni na 25 wa mamiliyoni lawa yanga hundza.
Eku heteleleni, kwalomu ka 5 wa mamiliyoni wa malembe, Benguela current leyo titimela (leyi sungulaka e Antarctic) yisungule kutala tani hi lexi cincaka maxelo eka ndzhawu yopfumala mati. Leswi swihlangana na kucinca ka maxelo leswinga vona Namaqualand yi suka eka kuva ndzhawu leyi kumaka mpfula hi ximumu kuya eka mpfula ya xixika.

E Makumu ka Lwandle e Namaqualand

Ku ndlandlamuka ka sayense ya misava lokukulu kusungule kwalomu ka 5 wa mamiliyoni wa malembe lawa yanga hundza, loko kutlakuka Namaqualand. Leswi swiendle leswaku swivumbiwa swale lwandle leswi aswi siyiwe erivaleni swivuye swi funengetiwa hi misava. Swin’wana leswinga katsana na misava hinkarhi walowo kuve swiribyani swa nkoka swa dayimani naswona misava yoleyo hi yona leyi ceriwaka tani hi timayini namuntlha. Hi fanele ku tlhela hitekela e nhlokweni leswaku naleswinga cheriwa endzeni ka mati ya lwandle swikatsa natona ti dayimani leti naswona titekiwa hi swikepe swa tidayimani leswi tswongaka sandi naku ri yisa eka ndzhawu leyi swihlawuriwaka kona.
Xin’wana xohetelela kuxivula: maribye lawa yantshwa endzhawini yakumeka etibuweni ta nambu wa Orange River laha kunga hlengeletana leyara leyikulu ndhope yinga fumbana kona hikokwalaho ka mikhukhula. Tin’wana ta tibuwa leti tifika kwalomu ka 30m hi ku leha kutlula laha mati ya fikaka kona sweswi, leswi kombaka mikhukhula yikulu swinene e Dzongeni wa Afrika. Loko ku langutiwa vukhale bya maribye lawa, switikomba leswaku yakwalomu ka 700 wa malembe lawa yanga hundza, leswivulaka leswaku yanga humelela nakambe!

Misava yaku Hambana

Se hifika emakumu ka xiphemu xa xitori lexi, naswona mbuyelo wakona hi ndhzawu leyi hiyivonaka namuntlha: ku tshoveka, mati yotitimela ya lwandle lawa ya anameke, makumu ya lwandle lawa yangana sava lawa ya hambanyisiwaka hi moya wo hisa, wo oma kuyaeka tintshava leti hiti vonaka. Himpela leswi i nhlangano wa swotala leswihlamarisaka laha misaveni, kuhetelela ka maribye ya volcanic, igneous, sedimentary na swivumbeko swa maribye ya metamorphic. Tani hileswi Francois Odendaal na Helen Suich vanga tsala eka buku ya vona ya Richtersveld, “Kuna tindzhawu tintsongo e Afrika Dzonga laha nhlayo leyikulu ya swilo leswi fambelanaka na sayense ya misava swisungula ku vonaka, naswona i xiphemu xa maribye yohambana hambana kukatsa na kukula ka wona, leswi swiendla tindzhawu tohambana hambana ta vutshamo e Richtersveld, leswi eku heteleleni swiendlaka leswaku kuva na swimilani swohambana hambana kuya hi tinxaka letinga kona”.

Translated by Ike Ngobeni