Erratic

So what do you notice in this picture?
Well yes, other than the beautiful little mischief.
A nice big lump of rock. Granite to be precise.
Perhaps not even unusual, but let me tell you the tale of this rock's long long life.
You might be reading this and not know that I live in the newest bit of National Park in the UK, the Westmorland Dales - the lovely little bit of the Yorkshire Dales National Park that belongs to Cumbria. And a part of what makes this area so special is the wonderful karst landscape or, to give it another name, the limestone pavement. A wonder of clints and grikes, creating fissures where rare wild plants still survive the onslaught of the little fluffy eco terrorists.
But back to our boulder. Our boulder made of granite. Our rough but round boulder.
She's not from here (She's a she because she's pink, she's very old so the stereotype holds true for the purposes of our tale). We know she's local because here the natural rock, just under the soil, are sheets of limestone, huge swathes in every direction. And She is, really is, a boulder. Quite possibly thrown by giants if your're out for a walk with youngsters, but for our older wiser heads she's an erratic.

And not just any erratic, she's a Shap erratic, one of the most famous, a distant cousin of the local chain that helped develop our understanding of the role the glaciers of ice ages past played in shaping our land. For erratics are travelers. Some of her famous  sisters that lie betwixt the carriageways of the M6 a few hundred metres away must weigh tonnes, she's a tiddler at two hundred weight. Erratics are rocks moved by geological processes - almost always glaciers.  Picked up from their home and carried along, they let us chart the eb and flow of millennia old ice ages, the rocks rounded as they tumble in the slowest but most powerful flows of frozen moving waters.
The pink Shap granite is especially important as it comes from such a geographically specific and small location - it occurs only in an 8km² location around Shap. So any found elsewhere has been moved. Erratics have been found as far North as Bardon Mill in Northumberland, giving strength to the hypothesis of a strong easterly flow forming the Tyne Gap. They are often found on the coastline of the East.
Locally the moors are covered with them - and they have a special place in folklore history. Large singular ones are oft called Thunderstones - believed to have been thrown by violent storms (or giants!!), and until our understanding of glaciology developed they were often cited in the 17th & 18th centuries as evidence of the great flood the bible tells of.
But the other special thing about our little erratic is her beautiful colour. Especially prized by our ancient ancestors many stone circles are made of these boulders, most religious buildings locally will display it in significant places, monuments are made from it and the houses of the rich adorned with it.
The colour is derived from the rocks composition - you'll no doubt know some rocks are formed by the vast pressures of ancient seas (limestones) or the power of volcanoes  (rhyolite) and the earths movement. Shap Pink gets its colour as it has an exceptionally high percentage of shellfish in it's composition. Formed 350million years ago during the Crustaceous period when the early Earth's oceans teemed with an explosion of arthropods, ancient ancestors of shrimps, lobsters and crabs. It was an exceptionally short period of time, so not much of this rare beautiful rock occurred. We're very lucky to have her here and to be able to see her, especially today.


Now look at the extra...