FROST-PITTED FLINT: a fine example of 'pot-lid' fractures in flint
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A fine example of natural ‘frost-pitting’ in flint
The strange appearance of this stone is due to excessive changes in temperature. It is called ‘thermal fracturing’ or 'frost-pitting' and the depressions are called ‘pot-lid fractures’. Flints like this are sometimes mistaken for prehistoric stone tools but the depressions are natural.
Each depression is formed when a circular flake (the ‘pot-lid’) becomes detached due to thermal expansion. Continuous freeze-thaw action during the Ice Age meant that the surface of the flint was expanding and contracting while the centre of the stone remained at a constant temperature. The stresses built up caused cracks to form and circular flakes to ‘pop off’ from the surface.
This stone is a fine example of this phenomenon and direct evidence of the extremes of temperature during the Ice Age.
Click on a picture for a larger image.
Size: 10 x 5 x 4 centimetres
Weight: 370 grams
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