83 Were Abrupt Climate Changes at the Last Glacial Termination Globally Synchronous?

Wednesday, 30 July 2003
8:00 AM - 12:00 PM

ASYNCHRONOUS CLIMATE CHANGES BETWEEN THE SOUTH PACIFIC AND THE NORTH ATLANTIC DURING THE LAST GLACIAL-INTERGLACIAL TRANSITION (LGIT; 14-9 KA 14C BP)?

Paper number: 83-6
Program: SYMPOSIA
Time: 9:30 AM – 9:50 AM

Authors

Abstract

The LGIT was characterized by a series of abrupt climatic changes, with broadly similar trends identified in palaeoclimate records obtained from many sites throughout the North Atlantic region. The extent to which the North Atlantic sequence of climatic changes is reflected in palaeoclimatic records from the Southern Hemisphere is, however, far from clear. Conflicting evidence has been reported from various parts of South America and New Zealand, seemingly supporting both hypotheses that events in the Southern Hemipshere were synchronous with, or markedly asynchronous with, those of the North Atlantic. There is also some evidence that suggests that climate changes in the Southern Hemisphere were more gradual (‘progressive’) during the LGIT than is inferred for the northern hemisphere. Little in the way of detailed LGIT reconstructions have been reported from Australasia and Southeast Asia. Few studies from these regions have been undertaken with sufficient temporal resolution required to establish high-resolution correlations with other regions of the world. Here we present the results of multi-proxy investigations of several terrestrial sites which form a transect from Indonesia, through Australia and New Zealand, and terminating at Campbell Island (52degS). Comprehensive series of radiocarbon dates are available for each sequence. The collective data provide a robust chronology for estimating fluctuations in atmospheric radiocarbon content, and the reconstruction of palaeoclimatic events on a calendar timescale. The results underpin a new palaeoclimate scheme for the LGIT for the low- and mid-latitudes of the Southern Hemisphere and will be compared with global terrestrial, marine and ice core palaeoclimatic records.