Detailed description, mapping and sampling (for sedimentology, paleontology and chronology studies) of Cenozoic bedded polymicton-type sediments within the Taylor Valley

Cenozoic bedded polymicton-type sediments within the Taylor Valley were mapped. These polymicton-type sediments are of glacial origin deposited into a body of water and therefore exhibit sorting and also contain boulders dropped from floating ice. Studies of these deposits will enable the chronology and correlation of their deposition to be extended. Silty till deposits (bedded polymictons) were examined throughout the Taylor Valley involving visually searching out and spading of all likely outcrops and detailed description and sampling when they were found. Samples were returned to New Zealand for laboratory analysis including sedimentology, paleontology and chronology. At 10 measured sections in the valley, rather similar fine sediments and inclusions, interbedded with coarse sands, pebbly sands and very coarse unsorted material are recognised below 300m elevation. These sediments are considered as having their origin within a fiord and in a similar manner to those names as basal silts in the Upper Wright Valley. A minimum age for the formation of the Taylor fiord may be determined from radiometric ages of the few tuff beds recognised and also from secondarily transported basalt scoria. A detailed study was also conducted on present day glacial drift deposition from the Taylor Glacier. Beds of till are ubiquitous throughout the Upper Taylor Valley, although exposure is poor except around the snout of the Taylor Glacier. Here meltwater streams from the Rhone and Calkin Glaciers have cut through till sequences on both sides of the valley. These till outcrops were described, sampled and measured for pebble fabrics. Correlation of till deposits throughout the upper valley was attempted, using grain size analysis, pebble orientation, mineralogy, sedimentary structures, etc. Processes of entrainment, transport and deposition of debris were analysed in an attempt to set up the Taylor Glacier as a model for glacial drift deposition. This model was extended to include proglacial, glaciofluvial, glaciolacustrine and aeolian environments by observation of recent sediment deposition in the Wright Valley and at Cape Chocolate.