Graded siltstones of late Precambrian age from the Garvellach islands have previously been shown to contain directions of remanence that fall into two groups interpreted as ‘primary’ (acquired during deposition) and ‘Caledonian’ (acquired during low-grade metamorphism). The magnetic anisotropy of both groups is shown to be very low so that the directions of remanence must have been unaffected by any stress fields associated with the Caledonian orogeny. The original interpretation of the shallow inclination of ‘primary’ remanence as representing low palaeolatitudes is therefore unaltered. Changes of the degree of magnetic anisotropy with temperature also confirm that the regional temperature did not exceed 400°C during the Caledonian orogeny.

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