TY - JOUR AU - Bárcena, María Ángeles AU - Fabrés, Joan AU - Isla, Enrique AU - Flores, José Abel AU - Sierro, Francisco Javier AU - Canals, Miquel AU - Palanques, Albert PY - 2006/12/30 Y2 - 2024/03/29 TI - Holocene neoglacial events in the Bransfield Strait (Antarctica). Palaeocenographic and paleoclimatic significance JF - Scientia Marina JA - Sci. mar. VL - 70 IS - 4 SE - Articles DO - 10.3989/scimar.2006.70n4607 UR - https://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/view/67 SP - 607-619 AB - <p align=justify>Geochemical analysis, micropalaeontological analysis and radiometric dating techniques were performed on four gravity cores, G-1, G-2, A-3 and A-6, recovered during the BIO Hesperides expeditions GEBRA-93 and FRUELA-96 from the Bransfield Strait (Antarctica). Moreover, in order to improve the sedimentation rate control we tentatively relate abundance variations in the sea-ice taxa group (SITG) to air temperature estimations based on Deuterium contents in Vostok ice-core. The results of diatom analyses were related to the sequence of neoglacial events that have occurred over the last three millennia. For these periods, a restricted communication between the Weddell, Bransfield and Bellingshausen seas has been proposed. The abundance patterns of diatom valves, resting spores (RS) of the diatom <em>Chaetoceros</em> and opal content agree with the high productivity values previously reported for the area. The significant reduction <em>Chaetoceros</em> RS towards the present is interpreted as a reduction in surface productivity. Trend differences between <em>Chaetoceros</em> RS and TOC contents are explained in terms of organic matter preservation. Diatom communities from the Bransfield Strait did not play an important role in the global CO<sub>2</sub> cycle during cold periods. Bio- and geochemical changes have overprinted high frequency cyclicity at about 200-300 yr, which might be related to the 200-yr solar cycle. </p> ER -