QM19 WaitakiThe Waitaki 1:250,000 geological map covers North Otago, eastern Central Otago, and South Canterbury, in the South Island of New Zealand.Much of the map area is mountainous. The Waitaki River, which separates Otago from Canterbury, rises in glaciated catchments before flowing through a series of bedrock gorges, then widening to a broad plain. In Central Otago northeast-trending flat-topped ranges of schist are separated by intermontane basins. The so-called Otago Peneplain, a conspicuous planar to gently rolling landform, is cut into basement rocks. In North Otago, northwest-trending ranges, steep and deeply incised, lie between the subparallel Waihemo and Waitaki valleys. Rising above rolling downlands of coastal Otago are prominent volcanic hills and mesas and cuestas of limestone. Canterbury ranges trend generally north-south, and are flanked by sloping piedmont fans in the east, with till and glacial outwash further west. Offshore, a broad shelf is incised at its eastern edge by large submarine canyons feeding eastwards into the Canterbury Basin. |