The intrusion and deformation of Tertiary minor sheet intrusions, west Suardal, Isle of Skye, Scotland

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Abstract
The arcuate Broadford anticline of south‐central Skye folds a sequence of strata ranging in age from late Precambrian to Jurassic. The Ordovician carbonate rocks of the core of the anticline are strongly extended parallel to bedding and deformation at some localities reaches up into unconformable Mesozoic strata. Three classes of Tertiary minor intrusion are recognized in the deformed sediments. The younger two are post‐kinematic. The effect of deformation on discordant sheets of the oldest class is obvious, as they are folded. It now seems, however, that the boudins previously reported (Nicholson 1970; Longman and Coward 1979) are sections through finger‐like igneous bodies (Farmin 1941; Pollard et al. 1975). Stiff in relation to the carbonate country rock, the latter retained igneous textures and chilled margins when deformed. Deformation probably took place as the main period of plateau‐lava eruption ended and the succeeding phase of shield volcanoes and major intrusive centres began. As deformation is restricted to the core of an arcuate fold forming part of a volcanic complex, it may speculatively be suggested that the deformed rocks lie above an arcuate diapir, formed in an acid magma body subjected to volcanic load.