Early Metamorphic Complex of the Lewisian north-east of Gairloch, Ross-shire, Scotland

Abstract

THE Lewisian of the Gairloch area has been recently divided¹ into an older Ialltaig and a younger Gairloch complex, the former tentatively equated with the Scourian² of the Assynt-Scourie region and the latter with the post-Scourian sequence (the ‘Laxfordian’ of Sutton and Watson²) of the Laxford area. More recently, the post-Scourian sequence of the Assynt-Scourie region has been shown to include two separate metamorphic episodes, at 2200 m.y. (Inverian) and 1600–1500 m.y. (Laxfordian sensu stricto)³. Preliminary dating of rocks from Gairloch⁴ indicates that recrystallization of the early lalltaig complex occurred in the period 1600–1500 m.y. and that this is probably the age of the main phase of metamorphism and deformation of the later Gairloch complex—that is, equivalent to the Laxfordian, sensu stricto, of the north.