Modelling sea-level observations to investigate the source and magnitude of major meltwater pulses during termination 1

Abstract

The research presented in this thesis utilises available near and far-field sea- level records to provide constraints on the major rapid sea-level rise events that occurred during the most recent period of deglaciation (Termination 1).The far-field modelling results show that previous, large discrepancies between predictions and observations of sea-level at Barbados, Huon, Tahiti and Sunda Shelf can be resolved by utilising a model of glacial isostatic adjustment characterised by a high viscosity lower mantle (4 X lO22 Pa s) and a major Antarctic contribution (-15 m) to meltwater pulse lA (-14.5-13.5 cal. kyr BP). The latter constraint is contrary to previous suggestions that this event was sourced from northern hemisphere ice sheets, and adds further to the hypothesis that an Antarctic source for mwp-IA is a possible mechanism to explain the progression of millennial scale climatic events that occurred during Termination 1. Furthermore, the far-field sea-level records preclude the existence of the smaller meltwater pulse IB event (-11 cal. kyr BP) and can not conclusively rule out a meltwater pulse event at 19 cal. kyr BP. Modelling of all available near-field sea-level data from the coast of Antarctica supports the far-field results in that the data do not preclude a dominant Antarctic source to mwp-IA and indicate that this event may have been caused by rapid melting of the Weddell and Ross Sea regions.