limestone and glaciers
There was a very interesting programme on over the weekend about limestone deposits in the uk. There are great ‘beds’ of limestone that were originally (in the ice age) underneath the glaciers that were over the most of the uk (not that it was the ‘uk’ then!) These vast beds of stone were rubbed completely smooth by the gradual sliding, abrasive action of the ice flows.
Once the ice receded after the ice age, then the limestone was exposed to the elements. The rain, some of it acid rain, then gradually eroded the limestone with the help of wind and frost. And what we have left now is fields of what look like stone paving blocks.
None of this is used for stuff like stone fireplaces or stone staircases though. In fact these areas are geologically very important, and are thus protected. Though the presenter on the programme, says they still get a few slabs ‘going missing’ from time to time…. in the backs of peoples’ cars!
On the programme there were also shown, great walls and gorges of beautiful limestone. Virtually natural ’stone stairs’ in a sense. (needless to say, there weren’t any natural stone fireplaces!)