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| Deplazes, Gaudenz; Lueckge, Andreas; Peterson, Larry C.; Timmermann, Axel; Hamann, Yvonne; Hughen, Konrad A.; Roehl, Ursula; Laj, Carlo; Cane, Mark A.; Sigman, Daniel M.; Haug, Gerald H.. |
| During the last glacial period, the North Atlantic region experienced pronounced, millennial-scale alternations between cold, stadial conditions and milder interstadial conditions-commonly referred to as Dansgaard-Oeschger oscillations-as well as periods of massive iceberg discharge known as Heinrich events(1). Changes in Northern Hemisphere temperature, as recorded in Greenland(2-4), are thought to have affected the location of the Atlantic intertropical convergence zone(5,6) and the strength of the Indian summer monsoon(7,8). Here we use high-resolution records of sediment colour-a measure of terrigenous versus biogenic content-from the Cariaco Basin off the coast of Venezuela and the Arabian Sea to assess teleconnections with the North Atlantic climate... |
| Tipo: Text |
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| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00264/37556/35774.pdf |
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| Meckler, A. Nele; Haug, Gerald H.; Sigman, Daniel M.; Plessen, Birgit; Peterson, Larry C.; Thierstein, Hans R.. |
| For the last deglaciation and Termination V ( the initiation of MIS 11 at around 430 ka) we report high-resolution sedimentary nitrogen isotope (delta(15)N)records from Cariaco Basin in the Caribbean Sea. During both terminations the previously reported interglacial decrease in delta(15)N clearly lags local changes such as water column anoxia as well as global increases in denitrification by several thousand years. On top of the glacial-interglacial change, several delta(15)N peaks were observed during the last deglaciation. The deglacial signal in Cariaco Basin can be best explained as a combination of (1) local variations in suboxia and water column denitrification as the reason for the millennial-scale peaks, (2) a deglacial maximum in mean ocean... |
| Tipo: Text |
Palavras-chave: Cariaco Basin; N fixation; Deglaciation. |
| Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00233/34457/32869.pdf |
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| Serno, Sascha; Winckler, Gisela; Anderson, Robert F.; Hayes, Christopher T.; Mcgee, David; Machalett, Bjoern; Ren, Haojia; Straub, Susanne M.; Gersonde, Rainer; Haug, Gerald H.. |
| Eolian dust is a significant source of iron and other nutrients that are essential for the health of marine ecosystems and potentially a controlling factor of the high nutrient-low chlorophyll status of the Subarctic North Pacific. We map the spatial distribution of dust input using three different geochemical tracers of eolian dust, He-4, Th-232 and rare earth elements, in combination with grain size distribution data, from a set of core-top sediments covering the entire Subarctic North Pacific. Using the suite of geochemical proxies to fingerprint different lithogenic components, we deconvolve eolian dust input from other lithogenic inputs such as volcanic ash, ice-rafted debris, riverine and hemipelagic input. While the open ocean sites far away from... |
| Tipo: Text |
Palavras-chave: Eolian dust; Subarctic North Pacific; INOPEX; Helium-4; Th-232; REE. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00291/40196/38719.pdf |
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| Deplazes, Gaudenz; Meckler, A Nele; Peterson, Larry C.; Hamann, Yvonne; Aeschlimann, Beat; Günther, Detlef; Martínez‐garcía, Alfredo; Haug, Gerald H.. |
| High‐resolution palaeorecords of climate are critical to improving current understanding of climate variability, its sensitivity and impact on the environment in the past and in the future. Sediments from the Cariaco Basin off the coast of Venezuela have proven to be sensitive recorders of tropical palaeoclimate variability down to an annual scale. However, the fingerprint of climate and sea level in the sediments of the last glacial period is still not completely understood. In this study, lamination analysis of sediments from the Cariaco Basin is extended to the last glacial period. Detailed sedimentological and geochemical analysis (laser ablation–inductively coupled plasma–mass spectrometry) reveals couplets of light‐coloured, terrigenous‐rich and... |
| Tipo: Text |
Palavras-chave: Cariaco Basin; Caribbean Sea; Flooding events; Glacial; Interglacial climate; Sea-level oscillations; Varved marine sediments. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00471/58302/60827.pdf |
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| Stockhecke, Mona; Timmermann, Axel; Kipfer, Rolf; Haug, Gerald H.; Kwiecien, Ola; Friedrich, Tobias; Menviel, Laurie; Litt, Thomas; Pickarski, Nadine; Anselmetti, Flavio S.. |
| Millennial to orbital-scale rainfall changes in the Mediterranean region and corresponding variations in vegetation patterns were the result of large-scale atmospheric reorganizations. In spite of recent efforts to reconstruct this variability using a range of proxy archives, the underlying physical mechanisms have remained elusive. Through the analysis of a new high-resolution sedimentary section from Lake Van (Turkey) along with climate modeling experiments, we identify massive droughts in the Eastern Mediterranean for the past four glacial cycles, which have a pervasive link with known intervals of enhanced North Atlantic glacial iceberg calving, weaker Atlantic Meridional Overturning Circulation and Dansgaard-Oeschger cold conditions. On orbital... |
| Tipo: Text |
Palavras-chave: Dansgaard-Oeschger variability; Mediterranean droughts; Milankovitch cycles; Lake Van; ICDP PALEOVAN. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53271/54623.pdf |
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| Meckler, A. Nele; Ren, Haojia; Sigman, Daniel M.; Gruber, Nicolas; Plessen, Birgit; Schubert, Carsten J.; Haug, Gerald H.. |
| Constraining variations in marine N(2)-fixation over glacial-interglacial timescales is crucial for determining the role of the marine nitrogen cycle in modifying ocean productivity and climate, yet paleo-records from N2-fixation regions are sparse. Here we present new nitrogen isotope (delta(15)N) records of bulk sediment and foraminifera test-bound (FB) nitrogen extending back to the last ice age from the oligotrophic Gulf of Mexico (GOM). Previous studies indicate a substantial terrestrial input during the last ice age and early deglacial, for which we attempt to correct the bulk sediment delta(15)N using its observed relationship with the C/N ratio. Both corrected bulk and FB-delta(15)N reveal a substantial glacial-to-Holocene decrease of delta(15)N... |
| Tipo: Text |
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| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00227/33786/32567.pdf |
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