Lake Bourget regional erosion patterns reconstruction reveals Holocene NW European Alps soil evolution and paleohydrology
| Type | Article | ||||||||||||
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| Date | 2012-09 | ||||||||||||
| Language | English | ||||||||||||
| Author(s) | Arnaud Fabien1, Revillon Sidonie2, Debret Maxime3, 4, Revel Marie5, Chapron Emmanuel6, Jacob Jeremy6, Giguet-Covex Charline1, Poulenard Jerome1, Magny Michel7 | ||||||||||||
| Affiliation(s) | 1 : Univ Savoie, CNRS, Environm Dynam & Terr Montagne EDYTEM, F-73373 Le Bourget Du Lac, France. 2 : IFREMER, F-29280 Plouzane, France. 3 : Ecole Normale Super, Meteorol Dynam Lab, F-75231 Paris, France. 4 : Ecole Normale Super, CERES ERTI IPSL, F-75231 Paris, France. 5 : Univ Nice, CNRS, F-06000 Nice, France. 6 : Univ Orleans, CNRS, Inst Sci Terre Orleans, F-45000 Orleans, France. 7 : Univ Franche Comte, CNRS, Lab Chronoenvironm, F-25000 Besancon, France. |
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| Source | Quaternary Science Reviews (0277-3791) (Pergamon-elsevier Science Ltd), 2012-09 , Vol. 51 , P. 81-92 | ||||||||||||
| DOI | 10.1016/j.quascirev.2012.07.025 | ||||||||||||
| WOS© Times Cited | 109 | ||||||||||||
| Keyword(s) | Holocene, Alps, Erosion, Soil dynamics, Paleohydrology | ||||||||||||
| Abstract | Two well-dated ca Holocene-long sedimentary sequences from deepest parts of Lake Bourget provide new insights onto the evolution of erosion patterns at a regional scale in NW European Alps. The combination of high resolution geochemistry - XRF core scanning, calibrated by 150 punctual measurements - and isotope geochemistry (epsilon Nd) of the terrigenous fraction permitted the reconstruction not only of the intensity, but also the type (physical erosion vs. chemical weathering) and the location (Prealpine massifs vs. High Crystalline massifs) of dominant erosion processes. Those data point the persistency of weak erosion fluxes from 9600 to 5500 cal. BP due both to a dry climate and the growing sheltering effect of soils that rapidly progressed between 9600 and 8000 cal. BR Soils then reached a steady state before being destabilised around 4400 cal. BP, probably in response to human impact. The human impact then reached a sufficient intensity to change erosion patterns at a regional scale, but did not result in a significant increase of the regional terrigenous flux. The following enhancement of erosion processes occurred around 2700 cal. BP. It was first paced by changing climatic conditions, but probably reinforced by human impact during Late Iron Age - Antiquity period. Over the long-term trend, the Lake Bourget record pinpoints an evolution of paleohydrological conditions in the Alps dominated by dry conditions from 9500 to 4400 cal. BP and a subsequent drift toward wetter conditions that culminated during the so-called Little Ice Age (ca 1350-1900 AD). In such a context the current dry conditions in European Alps appear out-of-trend. At high resolution, 17 periods of enhanced hydrological activity highlight the rapid climatic changes that are typical of the Holocene. (C) 2012 Elsevier Ltd. All rights reserved. | ||||||||||||
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