Geology In common with the rest of the Western Isles, North Uist is formed from the oldest rocks in Britain, the Lewisian gneiss which dates from the Archaean eon. A zone running west from Lochmaddy to Baleshare has abundant metasediments and metavolcanics. The direction of inclination of layered textures or foliation in this metamorphic rock is typically to the north but varies widely across the island. Pockets of metabasic rocks equivalent to the Scourie dyke suite are developed in certain areas, particularly in the north. Banded metabasic rocks and Archaean granites are found in the northwest around Loch Phaibeil. A band of pseudotachylyte curves north the northwest through the centre of the island. The island is traversed by numerous normal faults many of which run broadly NW-SE though ranging from E-W to NNW-SSE. Loch Eport is developed along one such fault. The Outer Hebrides Thrust Zone runs along the eastern coast of the island and brings distinctive gneisses which form the rough hilly terrain along that coast. More recent geological deposits include blown sand along the northern and western coasts and peat inland.
geology in common with the rest of the western isles north uist is formed from the oldest rocks in britain the lewisian gneiss which dates from the archaean eon a zone running west from lochmaddy to baleshare has abundant metasediments and metavolcanics the direction of inclination of layered textures or foliation in this metamorphic rock is typically to the north but varies widely across the island pockets of metabasic rocks equivalent to the scourie dyke suite are developed in certain areas particularly in the north banded metabasic rocks and archaean granites are found in the northwest around loch phaibeil a band of pseudotachylyte curves north the northwest through the centre of the island the island is traversed by numerous normal faults many of which run broadly nw-se though ranging from e-w to nnw-sse loch eport is developed along one such fault the outer hebrides thrust zone runs along the eastern coast of the island and brings distinctive gneisses which form the rough hilly terrain along that coast more recent geological deposits include blown sand along the northern and western coasts and peat inland