ZIMSEC O Level Geography Notes: Limestone pavements
- Limestone pavements are flat areas of exposed limestone rocks.
- They are part of the dissolved bedding plate which may have been exposed because the surface soil may have been removed by glacial activity and never replaced.
- Where the pavement has joints that reach the surface, these joints may be widened by acid rain water.
- This process is called carbonation.
- The widening of the joints leaves deep incisions/gashes/fissures called grikes.
- Some grikes such as found in the Limestone regions of England can be about half a meter wide.
- Separating the grikes are flat-topped yet dissected blocks referred to as clints.
- As time passes these clints are levelled by denudation processes including the widening of the grikes until a lower bedding plane is exposed.
- This bedding plane’s joints are in turn attacked by weathering in the form of carbonation forming grikes and thus repeating the process all over again.
- Grikes can also be formed by subsurface weathering in much the same way as tors are formed.
- Acidic water may seep into the ground into joints in the underlying limestone bedding rock.
- Over time it widens these joints and when the overlying soil is washed away by erosion the clints and grikes are exposed.
A diagram showing clints and grikes.
Grikes are sometimes known as grykes.
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