ZIMSEC O Level Geography Notes: Landforms resulting from weathering: Dwala
- Known as ruware in Shona, dwala in Ndebele (Nguni languages) and whaleback in English.
- An example is Domboshava where several such landforms can be found.
- It is a hill or rock which is dome shaped and rises several metres from the ground.
- It is a near level rock outcrop, that develops where the basal surface is undulating.
- Dwalas are gently sloping,low lying and rounded or elongated hills.
- They are about 2-5m in height.
- They have a gentle, convex summit that is usually smooth but can have sheet joints as a result of pressure release and regolith that is onion-peel shaped as a result of exfoliation.
- Its slopes are convex/rectilinear and gentle.
- Might also have vertical joints which begin as fractures as a result of pressure release but are further widened weathering processes.
- They are surrounded by deeply weathered regolith
- They are usually bare of vegetation but can be lightly populated by shrubs and bushes.
The formation of dwalas
The diagrams below detail the possible formation of a dwala.
The overburden is removed by denudation processes resulting in pressure release and the formation of a dwala/ruware.
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