Late Quaternary climate variability in Southern Ocean Atlantic sector

Abstract

Climate variability of the late Quaternary, especially the Last Glacial (LG) to the Holocene, has become the most heated topic for the recent decades, which helps to better understand the shape of current and future climate on our planet. The millennial scale variations are mostly accepted to be modulated by the bipolar seesaw mechanism which redistributes heat between the northern and southern hemispheres through the Atlantic Meridional Overturning Circulation (AMOC). The validation of such hypothesis is hampered by the very limited high resolution records from the high latitudes Southern Ocean. This PhD project generated a series of new diatom based high resolution marine records covering wide area of the high latitudes South Atlantic, including from the Bouvet Island area and the Scotia Sea, aimed to provide new insights of the response and drive in Southern Ocean in the context of late Quaternary global climate change. A regional age model for the past 30 kyrs is established by AMS 14C dating and regional core correlation for the Southern Ocean Atlantic and western Indian sectors, and detailed climate variability has been reconstructed, mainly driven by the changes in AMOC and the status of the Western Antarctic Ice Sheet. The Scotia Stratigraphy of the past 300 kyrs has been established, the changes in stratigraphic parameters are closely related to the changes in surrounding environment; a possible correlation of the Scotia Sea ash layers and those of Antarctic ice core is established.