| Site Type: | Inland exposure | | Site Status: | TBC | | Council area: | Derry City & Strabane District Council | | Grid Reference: | C557056 | | Bing maps: | 54.89542,-7.13186 | | Google maps: | 54.89542,-7.13186 | | Rocks |
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| Rock Age: | Quaternary | | Rock Type: | Gravel, Sand | | Interest |
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| Other interest: | Glacio-fluvial sediment, deltaic foresets |
| Summary of site: |
| In an area around Cumber, south south east of Claudy, there is a flat-topped feature of around 4kmē, consisting of sands and gravels, lying in a hollow in the local bedrock. | | After a period of deposition following the initial ice retreat, ice dammed the Faughan valley creating a glacial lake with a surface 126m above modern sea level. Meltwater flowing into the lake (probably from the south) carried glacial debris, creating possibly two flat-topped deltas of cross-bedded and ripple-marked sands which were then violently scoured into channels by torrential flow and later filled with cobble and pebble gravels. This episode was followed, after the lake had drained, by a period of intense cold when the deposit froze to depth and ice wedges were able to form (six have been seen in the area). |
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