Kaapvaal Craton

izisekelo zakuqala

Kaapvaal map

Basalt of the Nondweni Greenstone Belt south of Vryheid, preserves ancient ‘pillow structures’. These are identical to the structures seen today where basalt lava erupts into the sea.

Izisekelo zeKwaZulu-Natal (KZN) ziqukethe izinhlobo ezimbili zezokumbiwa phansi, okuyi Kaapvaal Craton neNatal Metamorphic Province. Lezi zimbiwo zakha izigaxa zemihlabakazi ehlukene eseke yaba nomthelela emlandweni wezokumbiwa phansi, izigceme kanye nomnotho wale ndawo. Enyakatho nomfulakazi uThukela kulele izitini eziyizingqwengqwe ezindala kuneziningi eNingizimu neAfrica, Archaean Kaapvaal Craton (eneminyaka eyizigidi eziyizinkulungwane ezintathu ubudala). Lwakheka ngenkathi ama-granite emputsha ngamandla oqweqweni lomhlaba oluyi-basalt. Ama-basalt agcineke engamabhande ama-greenstone kanye nezingcezu kuma-granite. Ama-granite angabonakala ezigodini eziphakathi kwe-Melmoth ne-Vryheid, nasezinkwalini ezingaphakathi ne-Richards Bay. Ama-basalt angamabhande ama-greenstone aseNondweni agcine izimo ezigoqene zakuqala. Lezizimo ziyafana nezenzeka manje lapho amalava ebasalt echithekela olwandle.

Pillow Lava
Pillow Lava, White Umfolozi River
Geological cross section of KwaZulu-Natal (North-South)
Kaapvaal craton granite / Nsuze quartz sandstone unconformity, White Umfolozi River (Move your mouse here to see the boundary)
Kaapvaal granite with large (white) feldspart crystals, White Umfolozi River

Granite and Gneiss (igneous and metamorphic)

basement, mountain building

Granite

Granite is a light-coloured rock composed of the minerals quartz (generally colourless) and feldspar (which maybe pink and/or white) with some dark-coloured biotite and amphibole. The large crystals in the granite formed slowly due to the cooling deep underground. When the granite was caught up in continental collision, some of it was metamorphosed and deformed (changed by heat and pressure) into gneiss – identified by dark and light mineral banding. Once exposed by uplift and erosion, granite and gneiss typically weather to form round hills.