Title: Late pleistocene glaciations of the Waimakariri Valley, Canterbury, New Zealand
Abstract:Summary Five distinct periods of major ice advance recorded in the Waimakariri Valley by a variety of glacial and glacifluvial deposits are distinguished by differences of elevation, surface gradients...Summary Five distinct periods of major ice advance recorded in the Waimakariri Valley by a variety of glacial and glacifluvial deposits are distinguished by differences of elevation, surface gradients, distribution, weathering, and extent of defacement of original surface detail. Glaciations are grouped and named as follows: Avoca Glaciation (probably multiple, but not subdivided) ; Waimakariri Glaciation (comprising in chronological order Woodstock, Otarama, Blackwater, and Poulter 2.dvances, of which at least the last two were multiple). Interglacial deposits are rare. The Waimakariri glacier system was. a complex pattern of ice streams, including large tributaries mainly from the north-west and distributaries between which transfluence occurred through numerous saddles. The ice in the middle reaches of the main valley was about 4,000 ft thick during the Avoca Glaciation, and perhaps from 500 ft to 1,000 ft thick at the height of later advances. Glacial geomorphic features are essentially the work of the later advances. The Avoca Glaciation, which was the most extensive, corresponds with the Waimaungan Glacial Stage and dates from early in the second half of the Pleistocene. An interglacial stage separates it from the last four advances, which together represent locally the Otiran Glacial Stage. The Otarama advance was the last occasion when ice reached as far as the eastern margin of the mountains, and outwash gravels from this advance built most of the Waimakariri segment of the Canterbury Plain. Several lakes existed temporarily during recessive phases, the largest lake having been at least 10 miles long in the main valley upstream from Poulter River.Read More