There is a new exposure of horizontally bedded fluvioglacial sand and gravel in Cardigan, where a hillside has been excavated out to ctreate a flat platform suitable for a new retail shopping park. One store has been built there already by Home Bargains Ltd, and a new Aldi store will soon follow on the site.
The site is north of the river, not far from Theatr Mwldan and the new NHS Integrated Care Health Centre.
Grid reference -- SN 17566 46664
The exposed face is 15- 20m high, and having been cut a few years ago it is already colonised by sand martins and is starting to degrade. But if anybody wants to take some samples for OSL dating, there are enough vertical faces left in easily accessible positions.
The OSL dates obtained by Glasser et al (2018) from Trefigin and Pantgwyn quarries, both to the south of the Teifi River, were around 26,000 yrs BP, suggesting that the ice of the Irish Sea Ice Stream was disintegrating in the lower Teifi Valley at a relatively early date -- in turn suggesting a glacial maximum around 28,000 - 27,000 yrs BP. The dates may or may not be reliable.........
Glasser, N.F. et al, Late Devensian deglaciation of south-west Wales from luminescence and cosmogenic isotope dating: LATE DEVENSIAN DEGLACIATION OF SOUTH-WEST WALESAugust 2018
Journal of Quaternary Science 33(2)
DOI: 10.1002/jqs.3061
Interesting! I must go and have a look, I've rather avoided those shops. Are we looking at fluvio-bedding planes, which might be in a large channel?
ReplyDeleteI haven't examined the gravels in detail, but this looks to me like a low-gradient outwash stream maybe feeding into a lake. There were a lot of temporary lakes sloshing about at the time in this area! It's not a deep channel situation. There appears to be more sand than gravel -- perfect for sand martins to build their nests..
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