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| Jaouadi, Sahbi; Lebreton, Vincent; Bout-roumazeilles, Viviane; Siani, Giuseppe; Lakhdar, Rached; Boussoffara, Ridha; Dezileau, Laurent; Kallel, Nejib; Mannai-tayech, Beya; Combourieu-nebout, Nathalie. |
| Pollen and clay mineralogical analyses of a Holocene sequence from Sebkha Boujmel (southern Tunisia) trace the climatic and environmental dynamics in the lower arid bioclimatic zone over the last 8000 years. During the mid- to late Holocene transition, between ca. 8 and 3aEuro-kaaEuro-BP, a succession of five wet-dry oscillations is recorded. An intense arid event occurs between ca. 5.7 and 4.6aEuro-kaaEuro-BP. This episode marks the onset of a long-term aridification trend with a progressive retreat of Mediterranean woody xerophytic vegetation and of grass steppes. It ends with the establishment of pre-desert ecosystems around 3aEuro-kaaEuro-BP. The millennial-scale climate change recorded in the data from Sebkha Boujmel is consistent with records from... |
| Tipo: Text |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53281/54321.pdf |
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| Peyron, Odile; Combourieu-nebout, Nathalie; Brayshaw, David; Goring, Simon; Andrieu-ponel, Valerie; Desprat, Stephanie; Fletcher, Will; Gambin, Belinda; Ioakim, Chryssanthi; Joannin, Sebastien; Kotthoff, Ulrich; Kouli, Katerina; Montade, Vincent; Pross, Jörg; Sadori, Laura; Magny, Michel. |
| Climate evolution of the Mediterranean region during the Holocene exhibits strong spatial and temporal variability, which is notoriously difficult for models to reproduce. We propose here a new proxy-based climate synthesis synthesis and its comparison -at a regional (similar to 100 km) level - with a regional climate model to examine (i) opposing northern and southern precipitation regimes and (ii) an east-to-west precipitation dipole during the Holocene across the Mediterranean basin. Using precipitation estimates in-ferred from marine and terrestrial pollen archives, we focus on the early to mid-Holocene (8000 to 6000 cal yr BP) and the late Holocene (4000 to 2000 cal yr BP), to test these hypotheses on a Mediterranean-wide scale. Special attention was... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00420/53173/55186.pdf |
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| Lambert, Clement; Vidal, Muriel; Penaud, Aurelie; Combourieu-nebout, Nathalie; Lebreton, Vincent; Ragueneau, Olivier; Gregoire, Gwendoline. |
| Modern palynological investigations (pollen and non-pollen palynomorphs) have been carried out for the first time in the entire Bay of Brest (BB; NW France), a semi-enclosed oceanic basin flooded during the Holocene that today is exposed to both marine (North Atlantic surface waters) and fluvial (Aulne and Elorn rivers) influences. Palynological analyses were conducted on 41 surface sediments collected in several mudded bays where low-energy conditions prevail, allowing for fine particle decantation, and also on 12 moss samples considered to be pollen rain collectors taken on the periphery of the BB. Furthermore, the BB allows a direct comparison between landscapes and fossilized pollen assemblages in sediments thanks to relatively small watersheds and... |
| Tipo: Text |
Palavras-chave: Pollen; Dinocyst; Surface sediment; Estuarine dynamics; Vegetation cover. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00382/49371/49784.pdf |
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| Jalali, Bassem; Sicre, Marie-alexandrine; Azuara, Julien; Pellichero, Violaine; Combourieu-nebout, Nathalie. |
| The 4.2 ka BP event, spanning from ca 4200 to 3900 cal BP, has been documented in numerous archaeological data and continental archives across the Northern Hemisphere as an abrupt shift to dry and cold climate. However, data on synchronous ocean circulation changes are notably lacking, thus preventing us from getting a full insight into the physical mechanisms responsible for this climate deterioration. Here, we present two high-resolution (5–20 years) sea surface temperature (SST) records from the subpolar gyre and off north Iceland in the vicinity of the polar front obtained from alkenone paleo-thermometry and compare them with proxy data from the western Mediterranean Sea to gain information on regional temperature and precipitation patterns. Our... |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00488/60005/63242.pdf |
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