Data/hora: 12/07/2025 18:42:32

Provedor de dados: 	5	
País: 	France	
Título: 	Response of Iberian Margin sediments to orbital and suborbital forcing over the past 420 ka	
Autores: 	Hodell, David; Crowhurst, Simon; Skinner, Luke; Tzedakis, Polychronis C.; Margari, Vasiliki; Channell, James E. T.; Kamenov, George; Maclachlan, Suzanne; Rothwell, Guy.	
Data: 	2013	
Ano: 	2013	
Resumo: 	Here we report 420 kyr long records of sediment geochemical and color variations from the southwestern Iberian Margin. We synchronized the Iberian Margin sediment record to Antarctic ice cores and speleothem records on millennial time scales and investigated the phase responses relative to orbital forcing of multiple proxy records available from these cores. Iberian Margin sediments contain strong precession power. Sediment "redness" (a* and 570-560 nm) and the ratio of long-chain alcohols to n-alkanes (C26OH/(C26OH+C-29)) are highly coherent and in-phase with precession. Redder layers and more oxidizing conditions (low alcohol ratio) occur near precession minima (summer insolation maxima). We suggest these proxies respond rapidly to low-latitude insolation forcing by wind-driven processes (e.g., dust transport, upwelling, precipitation). Most Iberian Margin sediment parameters lag obliquity maxima by 7-8 ka, indicating a consistent linear response to insolation forcing at obliquity frequencies driven mainly by high-latitude processes. Although the lengths of the time series are short (420 ka) for detecting 100 kyr eccentricity cycles, the phase relationships support those obtained by Shackleton [2000]. Antarctic temperature and the Iberian Margin alcohol ratios (C26OH/(C26OH+C-29)) lead eccentricity maxima by 6 kyr, with lower ratios (increased oxygenation) occurring at eccentricity maxima. CO2, CH4, and Iberian SST are nearly in phase with eccentricity, and minimum ice volume (as inferred from Pacific delta O-18(seawater)) lags eccentricity maxima by 10 kyr. The phase relationships derived in this study continue to support a potential role of the Earth's carbon cycle in contributing to the 100 kyr cycle. Citation: Hodell, D., S. Crowhurst, L. Skinner, P. C. Tzedakis, V. Margari, J. E. T. Channell, G. Kamenov, S. Maclachlan, and G. Rothwell (2013), Response of Iberian Margin sediments to orbital and suborbital forcing over the past 420 ka, Paleoceanography, 28, 185-199, doi:10.1002/palo.20017.	
Tipo: 	Text	
Idioma: 	Inglês	
Identificador: 	https://archimer.ifremer.fr/doc/00262/37304/35702.pdf

DOI:10.1002/palo.20017

https://archimer.ifremer.fr/doc/00262/37304/	
Formato: 	application/pdf	
Fonte: 	Paleoceanography (0883-8305), 2013 , Vol. 28 , N. 1 , P. 185-199	
Fonte: 	2013. American Geophysical Union. All Rights Reserved

info:eu-repo/semantics/openAccess

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