Holocene neoglacial events in the Bransfield Strait (Antarctica). Palaeocenographic and paleoclimatic significance

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 sedime...

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Bibliographic Details
Published in:Scientia Marina
Main Authors: María Ángeles Bárcena, Joan Fabrés, Enrique Isla, José Abel Flores, Francisco Javier Sierro, Miquel Canals, Albert Palanques
Format: Article in Journal/Newspaper
Language:English
Published: Consejo Superior de Investigaciones Científicas 2006
Subjects:
diatoms
geochemistry
neoglacial events
palaeoceanography
palaeocliomatology
holocene
bransfield strait
antarctica
Aquaculture. Fisheries. Angling
SH1-691
Bransfield Strait
Weddell
Antarc*
Antarctica
ice core
Sea ice
Online Access:https://doi.org/10.3989/scimar.2006.70n4607
https://doaj.org/article/fc7f71361c9d4d8e9217002e1fe3326e
Description
Summary: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 Chaetoceros and opal content agree with the high productivity values previously reported for the area. The significant reduction Chaetoceros RS towards the present is interpreted as a reduction in surface productivity. Trend differences between Chaetoceros 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 CO2 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.

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