UNR - From The Viewing Platform EarthCache
UNR - From The Viewing Platform
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This Earthcache is situated in the Umtamvuna Nature Reserve overlooking the Umtamvuna River Gorge near Port Edward on the lower KwaZulu Natal South Coast.
The Nature Reserve from the viewing platform features some impressive scenery; high sandstone cliffs contrast with deep gorges floored with hard crystalline rocks and rolling grasslands. To understand how how this scenery reached its present form we must follow two billion years of the earth's history. During that time, oceans formed and disappeared, continents collided, volcanoes erupted and ice-sheets crawled all over the landscape. Where reedbuck now roam sharks once swam, and dinosaurs wallowed in the pools of a long vanished river. Sadly, the ancient creatureshave left no traces within the nature reserve, but we know that they were once there because not far away, at Mzamba, fossils still remain in the Cretaceous sandstones.
The coordinates will take you to a magnificent viewpoint of the Umtamvuna River Gorge. The Umtamvuna River has cut this dramatic Gorge into the rock plateau. It is one of the most spectacular gorges in Southern Africa. The Umtamvuna Nature Reserve (UNR) has preserved its wild nature through many vicissitudes aided by the inaccessibility of the terrain. Precipitous gorges, cut deeply into the Msikaba Formation Sandstone, wind and twist there way to the sea. The UNR for its size, contains more rare trees than anywhere else in southern Africa and a figure of at least 1 350 indigenous flowering plants together with a figure of at least 100 species of mosses, and lichens. The UNR covers about 3 257ha and lies along 25km of the Mtamvuna River. The river runs from north to south within the reserve and rises on Ngele Mountain at Weza, draining a catchment of 1 600 square kilometers, along its 160km length. Since 1971 the UNR has flourished under the care of Ezemvelo KZN Wildlife, and only now is its rich and fascination biodiversity becoming known.
Geology: In the Umtamvuna Nature Reserve you can see the altered gneisses, intrusive charnockite-granite and the much younger sandstones formed in the pre-Gondwana ocean. The high cliffs of the gorge are formed from Msikaba Formation Sandstones, whose coarse beds lie almost horizontally. From a distance the blocky appearance is striking and this reflects the well-spaced joints and fractures that developed as erosion de-stressed this relatively resistant rock. The sandstones are termed quartz-arenites, because they consist mainly of silica sand bound together with silicecous cement. As this sand weathers it forms the mineral poor “sour” soils which host the unique flora of the Pondoland Center of Endemism. Below the sandstones, in the floor of the gorge, three types of rocks occur. Where exposed these have been worn smooth by the river, but in much of the gorge they are hidden under a mass of sandstone boulders and cobbles, with occasional pieces of tillite, dolerite or gneiss.
To log this earthcache: Answer the following questions and email them to me. Any logs not accompanied by an email will be deleted.
1) Standing at the listed coordinates, and looking across describe the gorge in terms of layers, colours and rock formation.
2) Estimate the depth of the gorge.
3) What classification of rocks forms the cliffs of the gorge?
4) What erosion processes do you think formed this gorge?
5) What does the attachment on the pole read as you enter the platform?
Please do NOT detail your answers in your Found log. Email answers directly to me via the GC.com website. You may submit your Found log without waiting for confirmation. if there is a problem with your answer(s) I will get back to you.
Additional Hints
(Decrypt)
Ubcr lbh rawbl guvf pnpur.
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