Published online by Cambridge University Press: 01 May 2009
Among the many faults in the Marlborough district of the South Island of New Zealand four, the Wairau, Awatere, Clarence, and Kaikoura faults, are of the first importance as boundaries between great elongated tectonic blocks that determine the high mountain ranges of this north-eastern corner of the South Island and the basins, or valleys, that guide the principal rivers draining it (Text-fig. 1). Modification of these major landscape features by erosion has proceeded very far, continuing, apparently, for a long time after the differential earth movements that initiated them had come to an end; but quite recently there has been a general renewal of movement on the ancient lines of dislocation, in some important cases with reversal of the sense of the earlier displacement.