The deflation of the upland limestone landscape by slow solution weathering is demonstrated at Norber in the Yorkshire Dales. Limestone is dissolved very slowly over a period of time. Erratics at Norber are boulders of gritstone standing on a plinth of limestone. The boulders protect the limestone from chemical weathering. The depth of the limestone indicates how long the weathering has taken. Thanks to Ordnance Survey.

First broadcast:
17 February 2001

Use as a stimulus for fieldwork on the rate of limestone erosion. Consider the factors that can affect erosion rate, including human factors such as acid rain. The contrast between erratic and limestone beneath can act as a very stark example of different rates of erosion for different rock types. This could be related to any landscape.