Located in the North-West Highlands UNESCO Global Geopark, Scourie is known worldwide for its exceptional exposures of ancient metamorphic rock – the Lewisian gneiss – and as the home of the Scourie dykes, which are massive vertical black magmatic intrusions.

The area around Scourie on the northwest coast of the Highlands has become a classic site for the study of the geological history of Scotland’s Precambrian basement rocks.

Summary These are the type localities of the Scourie dyke suite; they have historical significance as the dykes were first studied by Teall in the 19th century. The dyke to the north of the bay is an iron-rich quartz dolerite with clinopyroxene, autometamorphic garnet, …

The Lewisian complex or Lewisian gneiss is a suite of Precambrian metamorphic rocks that outcrop in the northwestern part of Scotland, forming part of the Hebridean terrane and the North Atlantic Craton. These rocks are of Archaean and Paleoproterozoic age, ranging from 3.0–1.7 billion years (Ga).

This GCR site comprises two localities on the north and south sides of Scourie Bay that include the type locality for the mafic and ultramafic Scourie Dyke Suite, which Peach et al. (1907) first recognized as crucial in interpreting the history of the Lewisian Gneiss Complex.

Rocks like these probably make up much of the lower continental crust of the Earth. The original igneous rocks were produced by melting in the Earth's mantle. The melts rose as magmas and crystallized at shallower levels, building up the crust.

This GCR site comprises two localities on the north and south sides of Scourie Bay that include the type locality for the mafic and ultramafic Scourie Dyke Suite, which Peach et al. (1907) first recognized as crucial in interpreting the history of the Lewisian Gneiss Complex.

Classic outcrops of the assemblages of gneisses and igneous rocks that constitute the oldest part of the continental crust of this part of Europe. Used to train generations of geologists in unravelling the metamorphic structural and igneous processes that create continental crust.

The type locality for the mafic and ultramafic Scourie Dyke Suite occurs on the north side of Scourie Bay, where a thick quartz dolerite intrusion (the “Geologist’s Dyke”) is exposed on the beach at Poll Eorna and in the crags of Creag a Mhail.

All the geology considered so far is very old, associated with and following directly on from the igneous formation of the crust. This geology is cross-cut by dark, vertical igneous intrusions, the so-called Scourie dykes.