Diatom Succession Representing the Paleoclimatic Change from Laminated Sediments around Antarctica

Abstract

This study investigated the paleoclimatic change using diatoms that were extracted from the high-resolution laminated layers of diatom ooze sediment cores GC08-EB01 in the eastern basin of the Bransfield Strait, Antarctica. The range of diatom valves per gram of dry sediment was from 0.4 to 4.2×10⁸ g-^-1 in quantitative diatom assemblage analysis. Laminations are classified using visually dominant diatom species and terrigenous content. Biogenic diatom ooze laminae characterised by bloom of <em>Corethron crilophilum, Eucampia antarctica, Fragilariopsis curta, F. kerguelensis</em>, <em>Odontella weissflogii, Proboscia inermis, R. styliformis, Thalassiosira antarctica,</em> and <em>Chaetoceros resting spores.</em> Terrigenous laminae characterised by mixed diatom assemblage. The ratio of (<em>Fragilariopsis curta</em>+<em>F</em>. <em>cylindrus</em>)/<em>Thalassiosira antarctica</em> increase in horizons, suggesting increased sea-ice cover in the study area during the late Holocene (cold events). As a result, five cold events are identified on the basis of frequency of the critical taxa throughout the section.