Little Scar is a limestone outcrop, though more specifically it is a limestone pavement. As the name suggests, it is not as big as other nearby limestone pavements at Middle Scar or Runscar. It is however a gem of a place, with good views down Upper Ribblesdale to Penyghent and across to Ingleborough.
Now Ribblehead is known for the viaduct on the Settle to Carlisle railway line, but go back in time, a long way back in time, and the area formed a significant area geologically.
The Dales, were shaped by glaciation during the ice ages, if it wasn't for ice and snow, then Upper Ribblesdale, Crummackdale, Twistleton and Kingsdale would look very different. There have been more than one ice age, though during the last one, a vast amount of ice and snow collected around the Garsdale, Baugh Fell and Howgills. Glaciers, which are a slowly moving body of ice (imagine a frozen river still moving), moved southwards. The geological giants of Craven, the Three Peaks existed even then, and the ice flow was slowed by the Ingleborough massif. If you look towards Ingleborough, the flat topped mountain, you will see the Ingleborough massif. It is made up of various felltops, and from here we can see Park Fell at the end, Souther Scales Fell in the middle, then the mighty Ingleborough.
The ice flow was slowed here, and the flow diverted in different directions, one down Upper Ribblesdale, and the other towards Ingleton. The very steep side of the Ingleborough massif is due to glacial action, scouring away the hillside.
The ice age eventually ended, and the glaciers retreated and then dissapeared. What they left in their wake, was a barren landscape, with mounds and lines of rocks, and also bare limestone pavements. The limestone had basically been scrapped clean, so what was left was an expanse of bare limestone.
The effects of the ice age are still apparent in Craven, due to areas of bare limestone pavements.
Limestone pavement, Crummackdale.
The glaciers picked up rocks from further afield as they progressed and scoured the land beneath them, and when the ice sheet retreated and melted, it left these rocks behind, which are called erratics. Basically, an erratic is a rock which has been left, and is not native to the original location.
Glacial erratics on a granite pavement, in the Galloway Hills.
The story, however does not end then. You, will very quickly notice the limestone outcrop does not appear like a flattened barren pavement. It has over time been eroded away, by the action of rain, and ice. Water, with carbon dioxide in it, fell as rain with a weak acid in it, known as carbonic acid. This over time slowly dissolved areas of limestone, exploiting weaknesses and fissures in the limestone pavement. Then when it snowed, and winter came, ice formed in the cracks and fissures. Since ice expands , it further weakened and expanded cracks and fissures. As a result we now have a pavement which is covered in a multitude of lines going across and through the limestone.
These features on the limestone pavement can be described geologically.
The blocks or individual bodies of limestone are known as clints, which the lines or rather fissures are known as gryykes. Some grykes can be very deep. As grykes widen and deepen due to erosion, clints eventually became smaller or more isolated from the rest of the limestone pavement.
So, we are here to look at examine a glacial erratic and its relation to the limestone pavement. The coordinates should take you to a glacial erratic. In order to undertake the EarthCache, you need to be stood from where the below picture is taken.
This being an EarthCache, in order to log it, I ask that you complete the above tasks. Please send the answers to me, and do not include them in your log. You can send them to me by using the message facility or email, both of which can be found by looking at my profile.
1. Please describe the position of the erratic in relation to the features of the limestone pavement.
2. Having read the above information, please explain to me, why the erratic is in its current position.
3. Please describe the glacial erratic in terms of colour, and feel.
4. Please have your photograph taken, or that of your device positioned next to a gryke, but not near the EarthCache.