Geology of Skye with the development of an ice cap centred on the Cuillin and Red Hills. The main ice sheet that flowed westwards from the Scottish mainland was diverted around this upland area. The island is covered by large areas of glacial till, left behind when the ice melted. Geology of Skye The geology of Skye in Scotland is highly variable and the island's landscape reflects changes in the underlying nature of the rocks. A wide range of rock types are exposed on the island, sedimentary, metamorphic and igneous, ranging in age from the Archaean through to the Quaternary. The oldest rocks
Geology of Skye Part of the magma chambers for the volcanoes are exposed at the surface as major intrusions of gabbro and granite. These coarse-grained igneous rocks are relatively resistant to erosion and now form the Cuillin hills. The Black Cuillin are formed of gabbro, which erodes to form the characteristically jagged outlines, although this is in large part due to the many minor intrusions, such as dykes and cone sheets that cut the gabbro. The Red Hills are formed of granite and have a more rounded topography. All pre-Quaternary rock types on the island are affected by a major swarm of dykes,