RT Journal Article
T1 Respuesta del registro sedimentario a la ciclicidad solar en el estrecho de Gerlache (península Antártica)
T1 Sedimentary response to Solar Cyclicity in the Gerlache Strait (Antartic Peninsula)
A1 Bárcena, María Ángeles
A1 Sesma, J.
A1 Isla, E.
A1 Palanques, Albert
AB The Gerlache Strait (Antarctic Peninsula) is a semi-enclosed basin that acts as a giant sedimentary trap collectinglarge amounts of material. Previous biogenic and glacial deposits are the main suppliers of sediments. Thebasin is also an area of high sea-surface productivity, mostly restricted to the summer months of Decemberand January. In this study we present micropaleontological and geochemical data obtained from a set of foursediment cores obtained by the Spanish research vessel Hespérides during the Fruela-96 expedition. Thecores were collected using a multiple corer allowing recovery of up to eight replicates, with core lengthsranging between 32 and 34 cm. The stratigraphic framework of the cores, based in 210Pb activity, shows thatthere has been a continuous sedimentation in the sites during the last 220 years BP.The diatom assemblage varies between absolute values of 0.9 to 240 x 108 valves/g of dry sediment.Chaetoceros RS are the main contributor showing values from 66 to 90 %. The Thalassiosira antarctica/scotia group and Sea-ice taxa, mainly Fragilariopsis curta, are secondary contributors.The total abundance of diatoms and the content of biogenic silica are interpreted as paleoproductivityproxies. In this sense, a progressive reduction in paleoproductivity is observed towards the core top, witha sharp minimum around 100 yr B.P. Moreover an increase of Sea-ice Taxa is observed for the last 100 yr.These changes could be related to the onset of a neoglacial event during this period.In order to evaluate the cyclicity record, Spectral analyses (Multi-Tapered Method) were performed ondifferent parameters (TOC, Opal, total diatom abundance, Sea-ice Taxa and T. antarctica). The time seriesstudy shows two main types of cyclicities, 80-90 and 20-30 years in two cores, G4 and G5, both recoveredfrom central Gerlache Strait. This cyclicity seems to be in agreement with the Hale (22 years) and theGleissberg (83 years) Solar Cycles. Both cycles are related to strong solar eruptive activity, which modulatethe amplitude of the 11-year sunspot cycle (Schawe Cycle); this cycle was also recognised in our record
PB Sociedad Geológica de España
YR 2005
FD 2005
LK http://hdl.handle.net/10272/8756
UL http://hdl.handle.net/10272/8756
LA spa
DS Repositorio Institucional de la Universidad de Huelva
RD 31 may 2026