Abstract

J. R. Andrews, A. J. Barker, T. J. Chapman, C. F. Pamplin & R. Seago write: in our discussion of the structural evolution of central South-West England (Andrews et al. 1988; Seago & Chapman 1988) we emphasize the consistency of structural facing of first phase structures over a wide area of outcrop and the abrupt change in facing across the Polzeath confrontation and its eastwards extension. The geometry of the south-facing structures in this eastern area (Seago & Chapman 1988), and their common occurrence over large areas, suggests that the phase of southward deformation was indeed significant and of considerable importance. We agree with Selwood & Thomas that major thrusts exert considerable control over the stratigraphic successions but deduce that there are also major recumbent folds present. Selwood and Thomas's arguments for an essential continuum of northwards transport are based upon the recognition of northwards directed thrusting north of the Polzeath facing confrontation. Their acknowledgment that the nappes ‘bear records of opposed facing’ is inconsistent with the concept of a northward continuum though they claim this can be caused by a variety of explanations. Whilst this is true, it is clear that two of the most obvious causes, pre-cleavage folding and non-axial planar cleavage are not responsible for the wide zone of southwards facing D1 structures which can be followed from Wanson Mouth to Polzeath.

Selwood & Thomas choose to highlight the interpretation of outcrops at one locality, Gravel Caverns where interference of two sets of folds and cleavages is

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