Norber boulders
The Norber erratic boulders are a number of glacial erratic boulders in a scree field on the southern slopes of Ingleborough, near the village of Austwick in Craven in the Yorkshire Dales in England .
The Norber boulders are geomorphological consequences of the Ice Age in the north of England. The blocks were deposited by the glaciers at the end of the Würm glacial period more than 12,000 years ago. A surface exposure dating published in 2013 showed that the surface of the blocks was exposed to cosmic rays for 17,900 ± 1000 years.
Many of the rocks from Silurian greywacke of the Austwick Formation stand on limestone bases up to 30 cm high . The bases were created because the boulders protected the limestone subsoil from being dissolved by precipitation. Since the boulders were deposited on their bases, an average of 330 mm of the limestone base has dissolved, which corresponds to an annual layer breakdown of 20 µm, a geologically very fast breakdown process.
literature
- Andrew Goudie, Rita Gardner: Discovering Landscape in England & Wales. Chapman and Hall, London 1992, ISBN 0-412-47850-1 , p. 177 ff.
Web links
Individual evidence
- ^ A b P. Wilson et al .: Dating in the Craven Dales. In: Geology Today , Volume 29, Issue 1, January / February 2013, pp. 16–22, doi : 10.1111 / j.1365-2451.2013.00859.x
Coordinates: 54 ° 7 '24.2 " N , 2 ° 21' 36.4" W.