Response of Iberian Margin sediments to orbital and suborbital
[1] 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 orbit...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.652.6613 2023-05-15T14:02:50+02:00 Response of Iberian Margin sediments to orbital and suborbital The Pennsylvania State University CiteSeerX Archives application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.652.6613 http://eprints.soton.ac.uk/353618/1/palo20017_Hodell.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.652.6613 http://eprints.soton.ac.uk/353618/1/palo20017_Hodell.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://eprints.soton.ac.uk/353618/1/palo20017_Hodell.pdf text ftciteseerx 2016-01-08T16:28:04Z [1] 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+C29)) 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+C29)) 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 d18Oseawater) 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. Text Antarc* Antarctic Unknown Antarctic Pacific Shackleton |
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English |
description |
[1] 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+C29)) 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+C29)) 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 d18Oseawater) 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. |
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The Pennsylvania State University CiteSeerX Archives |
format |
Text |
title |
Response of Iberian Margin sediments to orbital and suborbital |
spellingShingle |
Response of Iberian Margin sediments to orbital and suborbital |
title_short |
Response of Iberian Margin sediments to orbital and suborbital |
title_full |
Response of Iberian Margin sediments to orbital and suborbital |
title_fullStr |
Response of Iberian Margin sediments to orbital and suborbital |
title_full_unstemmed |
Response of Iberian Margin sediments to orbital and suborbital |
title_sort |
response of iberian margin sediments to orbital and suborbital |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.652.6613 http://eprints.soton.ac.uk/353618/1/palo20017_Hodell.pdf |
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Antarctic Pacific Shackleton |
geographic_facet |
Antarctic Pacific Shackleton |
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Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
http://eprints.soton.ac.uk/353618/1/palo20017_Hodell.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.652.6613 http://eprints.soton.ac.uk/353618/1/palo20017_Hodell.pdf |
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1766273249975468032 |