Research project EV/10 (Research action EV)
A better understanding of past climate changes and interhemispheric teleconnections between climate processes requires continuous records of climate proxies from key areas of our planet. The aim of this project is to provide a new record from paleoprecipitation in the Chilean Lake District (SW South America) during the last 12000 years, in order to define the regional impact of "El Niño Southern Oscillation" (ENSO) and to evaluate possible teleconnections with the northern hemisphere, especially the North Atlantic area. Precipitation in the Lake District (39°- 41°S), is essentially controlled by westerlies, advecting humid polar air from the Pacific, and by the Andean topography. ENSO-events in the area are inducing positive precipitation anomalies, and should be recorded within the lakes as changes in terrigenous sedimentation, under the form of e.g. flood deposits. Special attention will be paid to millennium-timescale abrupt climate changes (like the "Little Ice Age") during the Holocene and on how they affect the ENSO-system, but also to pluri-decadal cyclicity (i.e. 50-60 yrs) overprints on ENSO-intensities, as recent studies highlight their possible global impact through thermo-haline circulation anomalies.
This proposal is based on a multidisciplinary analysis of four long sediment cores from two selected lakes in the Lake District. A first reconnaissance of the lacustrine infills will be done by high-resolution reflection seismic profiling in the 17 lakes. The two most interesting lakes will subsequently be mapped in detail, which will help to select two coring sites in each lake, one in a proximal and one in a distal depositionnal setting. Field work around these lakes will allow to define the sediment source characteristics and mineralogies, the present-day vegetation and the geomorphology of the drainage basins. Surface sediment sampling in the lakes will give an insight in the spatial variability in present-day terrigeneous sediment supply and dispersion. Multi-disciplinary analysis of the cores will include: physical properties, sedimentary structures, mineralogy, age dating, tephrochronology and pollen studies. The chronology will be established by 210Pb, 137Cs and 14C dating, as well as by correlation of sedimentary events with historical records since 1575 AD (human impacts, floods, fires, earthquakes, volcanic eruptions), and similar pre-historical events. The most appropriate sedimentary proxy for precipitation (clay minerals, grain size, lamination, magnetic susceptibility,...) will be carefully selected after a first analysis of the core. The final result will thus be a well-dated, high-resolution, multi-proxy record of Holocene variations in terrigeneous sediment supply. This record will be integrated with a pollen record of the vegetation changes, the tephrostratigraphy and the regional seismic-stratigraphy, in order to reconstruct the paleoenvironmental changes that affected the lakes and their drainage basins, in terms of precipitation and temperature variations.
Robust linear and evolutive spectral analysis techniques, as well as recent statistical tools, will be used to analyse the multi-proxy record variability, and to highlight the ENSO-cyclicities and the occurrence of decadal to millennium-scale climate variations. The results of the spectral analysis and the paleoenvironmental recontructions will be compared and confronted with various 2-D and 3-D climate models, in order to recognise possible interhemispheric teleconnections, as well as the evolution of climate response to natural and/or antropogenic perturbations.
Methodology
The project is based on a multidisciplinary analysis of long sediment cores from two selected lakes in the Lake District. A detailed reconnaissance will allow to select the most suitable lakes and to locate in these lakes the most appropriate sites for coring. Fieldwork around the lakes will allow defining the sediment source characteristics, the present-day vegetation and the geomorphology of the drainage basins. Multi-disciplinary analysis of the cores will include physical properties, sedimentary structures, mineralogy, age dating, tephrochronology and pollen studies. The final result will be a well-dated, high-resolution, multi-proxy record of paleo-environmental and/or paleoclimate changes that affected the lakes and their drainage basins, and this in terms of precipitation and temperature variations. Special analysis techniques will be applied to analyse the variability of this multi-proxy record, and to highlight the ENSO-cyclicities and the occurrence of decadal to millennium-scale climate variations. The results will be confronted with existing climate models, in order to recognise possible long-distance interactions, as well as the evolution of climate responses to natural and/or anthropogenic perturbations.
Interaction between the different partners
The project tasks will be executed jointly by the three project partners, in close concert with the main sub-contractors and the Chilean collaborators.
Expected results
The expected outcome of the project will be a well-dated, high-resolution, multi-proxy record of variations in precipitation and temperature in southern Chile during the last 10000 years,and of the effects and evolution of the ENSO-system during this time period. Such a record will be instrumental in improving our knowledge of the natural cyclicities of a number of basic components of the World climate system and on how and how fast specific climate changes may have a global impact. As such, the project may produce results that are useful for outlining the climatic boundary conditions to be taken into account by future policies on sustainable development.
Link with international programmes
- The project fits the objectives of Focus 1 ("Global Paleoclimate and Environmental Variability") of IGBP's Core Project PAGES. It aims to study the past climate variability (Timestream 1: Holocene with special emphasis on the last 2000 yr.) in a site along the PEP-1 (Pole-Equator-Pole) transect of the Americas.
- The project also corresponds to the themes defined in Key Action 2 "Global change, climate and biodiversity" of the "Energy, Environment & Sustainable Development" Programme of EC DG-XII.
- To a certain extent, the project will also answer to some of the objectives of WCRP's CLIVAR-DecCen Component Program aimed at "...describing and understanding the patterns of global decadal-to-centennial climate variability in the instrumental, paleo-climatic, and model records...".
Partners
Activities
Universiteit Gent, Renard Centre of Marine Geology (RUG)
RUG will be involved with the reconnaissance of the study area, with the regional study of the different lakes, with the actual sediment coring (subcontract to Université de Savoie) and with the development of an age model for the different cores.
Université de Liège, Département de Géologie (ULg)
Three laboratories of ULg will closely collaborate in the multidisciplinary analysis of the sediment cores (sedimentary structures, mineralogy, dating, tephrochronology and pollen-analysis) and of the characteristics of the drainage basin.
Université de Louvain la Neuve, Institut d'Astronomie et de Géophysique Georges Lemaître (UCL)
UCL will focus on the mathematical analysis of the sedimentary signal and on the climate modelling.
Coordinates/Details
Project co-ordinator
Marc De Batist
Universiteit Gent (RUG)
Renard Centre of Marine Geology
Krijgslaan 281, s-8
B-9000 Gent
Tel: +32 (0)9 264 45 87; Fax: +32 (0)9 264 49 67
marc.debatist@rug.ac.be
http://allserv.rug.ac.be/~jphenrie/
Partners:
Nathalie Fagel
Université de Liège (ULg)
Département de Géologie - Laboratory of General Geology, - Siliciclastic Sedimentology and Clay Crystalogenesis
Sart-Tilman B18
B-4000 Liège
Tel: +32 (0)4 366 22 09; Fax: +32 (0)4 366 22 02
nathalie.fagel@ulg.ac.be
Andre Berger
Université Catholique de Louvain (UCL)
Institut d'Astronomie et de Géophysique Georges Lemaître
2, Chemin du Cyclotron
B-1348 Louvain-la-Neuve
Tel: +32 (0)10 47 33 03; Fax: +32 (0)10 47 47 22
berger@astr.ucl.ac.be
http://www.astr.ucl.ac.be/
Users Committee
An external Users Committee has been established, composed of scientists involved in related research projects, or involved in national or international scientific or policy-supporting programmes:
- Jean-Claude Thouret - Université Blaise Pascal - Laboratoire "Magmas et Volcans" - Clermont-Ferrand, France
- Florence Sylvestre - Université d'Angers - Laboratoire de Bio-Géologie - Angers, France
- Flavio Anselmetti - ETH - Limnogeology Laboratory - Zürich, Switzerland
- Françoise Gasse - PAGES - Leader of PEP III project
- Luc Hens - Federal Council for Sustainable Development - Brussels, Belgium
A continuous holocene record of ENSO variability in southern Chile (ENSO-CHILE) : final report
De Batist, M. - Fagel, N. - Loutre, M.F. ... et al Brussels : Belgian Science Policy, 2007 (SP1854)
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