The glacial sequences in the Rangitata and Ashburton valleys, South Island, New Zealand
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
Extensive areas of glacial, fluvioglacial and associated landforms and deposits are preserved in the Rangitata and Ashburton Valleys. Geomorphologic and lithostratigraphic maps of this area are presented. Three main glacial sequences are identified: those formed by the main lobe and distributary lobe of the Rangitata glacier, and that associated with the combined Rakaia distributary lobe and Cameron glaciers. The smaller Ashburton glacial sequence is also mapped. A sequence of five Late Pleistocene glacial advances representing at least three glaciations can be recognised as follows (from youngest to oldest): Spider Lakes/Lake Heron Advances minor interstadial Hakatere/Emily Advances major interstadial Trinity Advance interglacial Dogs Hill Advance interglacial Pyramid Advance Analysis of a large area of deglacial landforms, formed during the retreat of the distributary lobe of the Rangitata glacier after the Spider Lakes Advance, allows a detailed pattern of deglaciation to be determined. The fan surfaces of the southern part of the Canterbury Plains have also been studied to determine the relationship between them and the inland glacial sequences. Good correlations can be proposed between these glacial sequences and others in the Canterbury region.