Cardigan Sand & Gravel Co. was established in 1959, and has been a family run business for three generations. We pride ourselves on our innovative production methods and our wide range of tightly specified sands and aggregates, and maintain strict quality control through regular testing and checking against specifications.
Our extracted materials pass through a rigorous system of scrubbers, screens, overspill weirs, cyclones (prewash and dewatering), classifiers and an innovative new hydraulic separator. This allows us to carefully select particle size for optimum performance and also removes organic materials and mineral salts from the product.
We quarry a sand and gravel deposit that was laid down by rivers flowing off the edge of the Teifi glacier. Traces of those ancient rivers can still be seen in the bedding planes etched out by the wind on fresh sand faces. Our sands and aggregates are the result of disintegration of rock during transportation by the glacier -- unlike dredged sands, our products contain negligible amounts of shell and salt.
Research on our loose sediment deposit dates back to the first origins of ice age theory in the nineteenth century. To begin with, most authors argued for a major ice sheet that flowed southwards from North Wales into the Irish Sea, leaving terrestrial sediments behind as it receded. In the 1980s, a new theory arose that the sands and gravels bordering the Irish Sea were actually sea sediments that flowed into a depression left behind by the swiftly departing ice sheet -- departing so swiftly that the earth's surface didn't have enough time to 'bounce' back up. This theory has since been challenged in a number of sites in North Wales and northwest England.
It is now generally agreed that our interbedded sands and gravels were laid down by immense meltwater rivers flowing off a retreating glacier. Most of the gravel was derived from Ordovician mudstone, shale and sandstone, but you will also find occasional (< 1%) pebbles made of various granites, limestones, red sandstone and conglomerate. The quarry faces show excellent examples of climbing ripples, crossbedding and rafts of sand enclosed in gravel.
The most recent study of our deposit was published in 2001, by Hambrey et al. They lay out the various theories on how exactly the deposit was formed:
- That three river deltas were laid down at different times in varying water levels (Helm & Roberts, 1975).
- That an orphaned ice block melted away to leave a mountain of glacial sand and gravel (Allen, 1982).
- A compromise between the two above theories (Worsley, 1984).
- That a flat plain of glacial material was eroded away to its present form (Owen, 1997).
- That the sediments accumulated between two lobes of the receding 'Irish Sea glacier' (Hambrey et al., 2001).
The Hambrey paper notes problems with the first four theories -- chiefly that they do not explain the parallel faults found within our sand and gravel beds, and that there are no lake sediments of the same age found nearby. Hambrey et al. suggest instead that the ice of the glacier acted as a retaining wall -- sediments were laid down in bed after bed as the glacier melted and evaporated away. When the ice wall finally disappeared, the deposit collapsed, faulting in parallel with it.
Allen, JRL. 1982. Late Pleistocene (Devensian) glaciofluvial outwash at Banc-y-warren, near Cardigan (West Wales). Geological Journal 17: 31-47.
Hambrey, MJ et al. 2001. Devensian glacigenic sedimentation and landscape evolution in the Cardigan area of southwest Wales. Journal of Quaternary Science, 16: 455-482.
Helm, DG & Roberts, B. 1975. A re-interpretation of sands and gravels around Banc-y-warren, near Cardigan, West Wales. Geological Journal 10: 131-146.
Owen, G. 1997. Origin of an esker-like ridge -- erosion or channel-fill? Sedimentology of the Monington 'Esker' in southwest Wales. Quaternary Science Reviews 16: 674-684.
Worsley, P. 1984. Banc-y-Warren. In Wales: Gower, Preseli, Fforest Fawr, Bowen & Henry eds. Field Guide, Quaternary Research Association: Cambridge, pp 68-76.