Earth Science Conservation Review
| Faughan and Dungiven Basins - Overview | Londonderry |
| Site Type: | Inland exposure, Pit |
| Site Status: | TBC |
| Grid Reference: | C690095 |
| Google maps: | 54.92879,-6.92367 |
| Rocks | |
|---|---|
| Rock Age: | Quaternary |
| Rock Type: | Gravel, Sand |
| Interest | |
| Other interest: | Deglacial sediments, deltaic foresets, deltas, ice-dammed lake, proglacial lake |
Description:
The upper Roe and Faughan rivers drain the northern flanks of the Sperrin Mountains. The valleys are developed mainly in Precambrian schists flanked by Carboniferous and Permo-Triassic sediments in the east, below the basaltic escarpment. Both systems drain generally northward along entrenched valleys and are linked by a deep west to east trending structural low, the Foreglen depression.
The glaciofluvial deposits occur on at least four topographic settings:
1. Flat-topped high-level (243m O.D.) deltas are perched on north facing mountain slopes having been fed by meltwaters flowing north between cols in the Sperrin range (e.g. Murnies, Templemoyle.)
2. The main group of flat-topped deltas occurs within the valleys and along the valley sides. Generally the margins of the features have been eroded and oversteepened by glaciofluvial erosion. Present rivers are mainly misfit and occupying the former meltwater features eroded into the delta flanks. The present form and distribution of the delta fragments suggest that they once filled the valleys, but are now dissected. This situation is best seen along the middle Faughan valley around Gosheden and in the Owenrigh valley, where deltaic fragments and outwash terraces are perched on both sides of the present rivers.
3. At two sites in the upper Faughan basin, Dreen and Tamnagh, ridges form cross-valley features (moraines) associated with short halts in ice-front retreat.
4. Extensive erosion and removal of debris, post-dating delta formation, has occurred along the valley floor north and west of Dungiven and along part of the Foreglen depression. Flat spreads and terraces of resedimented material dominate the topography along the lower valley of the Owenrigh and Owenbeg Rivers.
For site specific information see the following sites:
Key Site 499 - Faughan and Dungiven Basins - The Murnies Key Site 500 - Faughan and Dungiven Basins - Derrynaflaw Key Site 501 - Faughan and Dungiven Basins - Banagher Key Site 502 - Faughan and Dungiven Basins - Templemoyle Key Site 503 - Faughan and Dungiven Basins - Tamnagh Key Site 504 - Faughan and Dungiven Basins - Cumber Key Site 505 - Faughan and Dungiven Basins - Gosheden Key Site 506 - Faughan and Dungiven Basins - Fawney Key Site 507 - Faughan and Dungiven Basins - Enagh
The glaciofluvial deposits occur on at least four topographic settings:
1. Flat-topped high-level (243m O.D.) deltas are perched on north facing mountain slopes having been fed by meltwaters flowing north between cols in the Sperrin range (e.g. Murnies, Templemoyle.)
2. The main group of flat-topped deltas occurs within the valleys and along the valley sides. Generally the margins of the features have been eroded and oversteepened by glaciofluvial erosion. Present rivers are mainly misfit and occupying the former meltwater features eroded into the delta flanks. The present form and distribution of the delta fragments suggest that they once filled the valleys, but are now dissected. This situation is best seen along the middle Faughan valley around Gosheden and in the Owenrigh valley, where deltaic fragments and outwash terraces are perched on both sides of the present rivers.
3. At two sites in the upper Faughan basin, Dreen and Tamnagh, ridges form cross-valley features (moraines) associated with short halts in ice-front retreat.
4. Extensive erosion and removal of debris, post-dating delta formation, has occurred along the valley floor north and west of Dungiven and along part of the Foreglen depression. Flat spreads and terraces of resedimented material dominate the topography along the lower valley of the Owenrigh and Owenbeg Rivers.
For site specific information see the following sites:
Key Site 499 - Faughan and Dungiven Basins - The Murnies Key Site 500 - Faughan and Dungiven Basins - Derrynaflaw Key Site 501 - Faughan and Dungiven Basins - Banagher Key Site 502 - Faughan and Dungiven Basins - Templemoyle Key Site 503 - Faughan and Dungiven Basins - Tamnagh Key Site 504 - Faughan and Dungiven Basins - Cumber Key Site 505 - Faughan and Dungiven Basins - Gosheden Key Site 506 - Faughan and Dungiven Basins - Fawney Key Site 507 - Faughan and Dungiven Basins - Enagh
| Enlander, I., Dempster, M. & Doughty, P., 2024. Faughan and Dungiven Basins - Overview, County Londonderry, site summary. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/summary.php?item=470. Accessed on 2024-12-26 |
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