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| Xu, Jian; Kuhnt, Wolfgang; Holbourn, Ann; Regenberg, Marcus; Andersen, Nils. |
| We measured oxygen isotopes and Mg/Ca ratios in the surface-dwelling planktonic foraminifer Globigerinoides ruber (white s.s.) and the thermocline dweller Pulleniatina obliquiloculata to investigate upper ocean spatial variability in the Indo-Pacific Warm Pool (IPWP). We focused on three critical time intervals: the Last Glacial Maximum (LGM; 18-21.5 ka), the early Holocene (8-9 ka), and the late Holocene (0-2 ka). Our records from 24 stations in the South China Sea, Timor Sea, Indonesian seas, and western Pacific indicate overall dry and cool conditions in the IPWP during the LGM with a low thermal gradient between surface and thermocline waters. During the early Holocene, sea surface temperatures increased by similar to 3 degrees C over the entire... |
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| Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00230/34131/33063.pdf |
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| Fraser, Nicholas; Kuhnt, Wolfgang; Holbourn, Ann; Bolliet, Timothe; Andersen, Nils; Blanz, Thomas; Beaufort, Luc. |
| Proxy records of hydrologic variability in the West Pacific Warm Pool (WPWP) have revealed wide-scale changes in past convective activity in response to orbital and suborbital climate forcings. However, attributing proxy responses to regional changes in WPWP hydrology versus local variations in precipitation requires independent records linking the terrestrial and marine realms. We present high-resolution stable isotope, U-37(K) sea surface temperature, X-ray fluorescence (XRF) core scanning, and coccolithophore-derived paleoproductivity records covering the past 120ka from International Marine Global Change (IMAGES) Program Core MD06-3075 (6 degrees 29N, 125 degrees 50E, water depth 1878m), situated in the Davao Gulf on the southern side of Mindanao.... |
| Tipo: Text |
Palavras-chave: Intertropical Convergence Zone; West Pacific Warm Pool; Walker circulation; Seawater 18O; X-ray fluorescence. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00289/40057/39357.pdf |
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| Andersen, Nils; Lauterbach, Stefan; Erlenkeuser, Helmut; Danielopol, Dan L.; Namiotko, Tadeusz; Huels, Matthias; Belmecheri, Soumaya; Dulski, Peter; Nantke, Carla; Meyer, Hanno; Chapligin, Bernhard; Von Grafenstein, Ulrich; Brauer, Achim. |
| The so-called 8.2 ka event represents one of the most prominent cold climate anomalies during the Holocene warm period. Accordingly, several studies have addressed its trigger mechanisms, absolute dating and regional characteristics so far. However, knowledge about subsequent climate recovery is still limited although this might be essential for the understanding of rapid climatic changes. Here we present a new sub-decadally resolved and precisely dated oxygen isotope (5180) record for the interval between 7.7 and 8.7 ka BP 10(3) calendar years before AD 1950), derived from the calcareous valves of benthic ostracods preserved in the varved lake sediments of pre-Alpine Mondsee (Austria). Besides a clear reflection of the 8.2 ka event, showing a good... |
| Tipo: Text |
Palavras-chave: Holocene; Palaeoclimatology; Europe; Stable isotopes; 8.2 ka event; Lake sediments. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00504/61597/65876.pdf |
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| Wang, Yiming V.; Leduc, Guillaume; Regenberg, Marcus; Andersen, Nils; Larsen, Thomas; Blanz, Thomas; Schneider, Ralph R.. |
| Different proxies for sea surface temperature (SST) often exhibit divergent trends for deglacial warming in tropical regions, hampering our understanding of the phase relationship between tropical SSTs and continental ice volume at glacial terminations. To reconcile divergent SST trends, we report reconstructions of two commonly used paleothermometers (the foraminifera G. ruber Mg/Ca and the alkenone unsaturation index) from a marine sediment core collected in the southwestern tropical Indian Ocean encompassing the last 37,000 years. Our results show that SSTs derived from the alkenone unsaturation index (U-37(K)) are consistently warmer than those derived from Mg/Ca by similar to 2-3 degrees C except for the Heinrich Event 1. In addition, the initial... |
| Tipo: Text |
Palavras-chave: Sea surface temperature; Tropical Indian Ocean; Last Deglacial. |
| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00291/40174/39037.pdf |
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| Xu, Jian; Kuhnt, Wolfgang; Holbourn, Ann; Andersen, Nils; Bartoli, Gretta. |
| We use a multiproxy approach to monitor changes in the vertical profile of the Indonesian Throughflow as well as monsoonal wind and precipitation patterns in the Timor Sea on glacial-interglacial, precessional, and suborbital timescales. We focus on an interval of extreme climate change and sea level variation: marine isotope (MIS) 6 to MIS 5e. Paleoproductivity fluctuations in the Timor Sea follow a precessional beat related to the intensity of the Australian (NW) monsoon. Paired Mg/Ca and delta(18)O measurements of surface- and thermocline-dwelling planktonic foraminifers ( G. ruber and P. obliquiloculata) indicate an increase of > 4 degrees C in both surface and thermocline water temperatures during Termination II. Tropical sea surface temperature... |
| Tipo: Text |
Palavras-chave: Vertical profile; Indonesian Throughflow (ITF); Termination II. |
| Ano: 2006 |
URL: https://archimer.ifremer.fr/doc/00234/34512/33420.pdf |
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| Sierro, Francisco J.; Andersen, Nils; Bassetti, Maria-angela; Berne, Serge; Canals, Miquel; Curtis, Jason H.; Dennielou, Bernard; Abel Flores, Jose; Frigola, Jaime; Gonzalez-mora, Beatriz; Grimalt, Joan O.; Hodell, David A.; Jouet, Gwenael; Perez-folgado, Marta; Schneider, Ralph. |
| Direct traces of past sea levels are based on the elevation of old coral reefs at times of sea level high-stands. However, these measurements are discontinuous and cannot be easily correlated with climate records from ice cores. In this study we show a new approach to recognizing the imprint of sea level changes in continuous sediment records taken from the continental slope at locations that were continuously submerged, even during periods of sea level lowstand. By using a sediment core precisely synchronized with Greenland ice cores, we were able to recognize major floods of the Mediterranean continental shelf over the past 270 kyr. During the last glacial period five flooding events were observed at the onset of the warmest Greenland interstadials.... |
| Tipo: Text |
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| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/2009/publication-6969.pdf |
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| Bolliet, Timothe; Holbourn, Ann; Kuhnt, Wolfgang; Laj, Carlo; Kissel, Catherine; Beaufort, Luc; Kienast, Markus; Andersen, Nils; Garbe-schoenberg, Dieter. |
| We present sea surface, upper thermocline, and benthic delta O-18 data, as well as temperature and paleoproductivity proxy data, from the International Marine Global Change Study Program (IMAGES) Core MD06-3067 (6 degrees 31' N, 126 degrees 30' E, 1575 m water depth), located in the western equatorial Pacific Ocean within the flow path of the Mindanao Current. Our records reveal considerable glacial-interglacial and suborbital variability in the Mindanao Dome upwelling over the last 160 kyr. Dome activity generally intensified during glacial intervals resulting in cooler thermocline waters, whereas it substantially declined during interglacials, in particular in the early Holocene and early marine oxygen isotope stage (MIS) 5e, when upwelling waters did... |
| Tipo: Text |
Palavras-chave: Mindanao Dome; East Asian monsoon; Oceanic circulation. |
| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00213/32472/30924.pdf |
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