A Kopje. Image credit MediaWiki.

A Kopje. Image credit MediaWiki.

ZIMSEC O Level Geography Notes: Landforms resulting from Weathering: Kopjes

Tors/Kopjes/Castle kopjes

  • Tors/kopjes/castle kopjes are inselbergs.
  • Tors the same as kopjes even though some books make an attempt to distinguish between the two.
  • Different names are applied in different localities to what are essentially the same landforms.
  • Kopje is an Afrikaans word meaning a small and isolated hill made of granite rock piles.
  • Tor is a Scotish word meaning hill.
  • They appear appear as¬† a large, free-standing rock outcrop that rises abruptly from the surrounding smooth and gentle slopes of a rounded hill summit or ridge crest.
  • They are resistant rock features that have been made by weathering.
  • They are usually less than 5 meters in height.
  • They are a result of marginal subsurface weathering of domed landforms.
  • Granite intrusions are weathered beneath the surface due to acidic water penetrating joints in the rock.
  • When the rock is exposed the rotten parts are washed away by erosion.
  • Weathering continues in the form of both mechanical and chemical weathering.
  • Because these rocks have rectangular joints, chemical and mechanical weathering takes place in these joints.
  • The regolith (weathered/rotten parts of the rock) is stripped away by erosion to form a kopje/tor.
  • If the joints are close together the whole mass collapses and is washed away,
  • However if the joints a wider blocks of rocks fall away from the main rock creating tors/kopjes.
  • They are sometimes remnants of dwalas and bornhardts such as Dwalas/ Bornhadts and inselbergs/Monadnocks.
  • They are usually found in temperate latitudes.
  • Because of their morphology (shape) kopjes are known is some localities as castle kopjes.

Balancing rocks

  • These are a result of continued weathering on kopjes and tors.
  • If the joints in the rocks that form kopjes and tors are¬†further apart massive chunks of rock may withstand the denudation processes to remain balancing one on top of another.
  • An example are the Balancing Rocks in Epworth.
The balancing rocks in Epworth.

The balancing rocks in Epworth. Image credit travelozimbabwe.com

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