Rhinns complex

It has also been recognised in three other inliers extending to the southwest as far as Inishtrahull, off the north coast of County Donegal.

The Rhinns complex has been recognised in a series of four outcrops that form inliers within younger cover sequences of the Dalradian Supergroup and the Colonsay Group.

The most easterly of these exposures is on the islands of Colonsay, where the complex consists of strongly retrogressed orthogneisses,[1] although the correlation of this outcrop with the Rhinns complex has been questioned on the basis of new radiometric dating and Hf isotope analyses.

Between Islay and Inishtrahull, a third submarine outcrop has been recognised from dredged seabed samples and geophysical data.

[1] The Rhinns complex consists of a set of Palaeoproterozoic igneous rocks that were intruded about 1.78 Ga (billions of years ago).