The structural development of the Lewisian rocks on the north shore of Loch Torridon, Ross-shire.

D. Cresswell
Scottish Journal of Geology, 8, 293-308, 1 January 1973, https://doi.org/10.1144/sjg08040293

Synopsis

Nine phases of deformation, D1–D9, are recognised in the Lewisian complex of Torridon. D1–D5 pre-date the Scourie dykes and are thus of Scourian age, whilst D6–D9 post-date the dykes and belong to the Laxfordian.

The N.-S. to NE.-SW. S3 foliation which is dominant in the north of the area has been affected by NW.-SE. large-scale (F3A) and subsequent small-scale (F4) folds and related axial-planar foliation (S4). S4 was originally regarded as Laxfordian by Sutton (in Sutton and Watson 1951), but has been assigned here to the late Scourian or Inverian. In D5 both large and small scale F5 folds were produced with SE.-plunging axes, affecting sub-horizontal belts of S4. L5 is co-axial with L4.

The earliest Laxfordian structure S6 is usually parallel or sub-parallel to dyke margins. In D7 were formed F7 folds, S7 axial-planar foliation and L7 lineation which increase in intensity towards the south. S7 is co-planar with S4 and S6, and L7 is co-axial with L4. The D8 structures are restricted to narrow NW.-SE. belts in which F8 small-scale folds and L8 lineations were formed. The last penetrative structure is the S9 mylonite banding affecting certain NW.-SE. belts and is co-planar with S4 and S7.

Correlations are made with other areas in the southern Laxfordian belt.

References

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