More about the Programme
Future global, regional and local climatic changes will control the changes of the geo-biosphere and thus have an important influence on human societies and economies. Therefore, world-wide climate research is of vital interest for mankind in order to develop preventive measures based on climatic prediction. It is particularly important for the densely populated European continent. This Programme (ELDP), providing high resolution paleoclimate data to facilitate our understanding of the controlling processes and feedback mechanisms for a predictive model, is of prime importance.
Understanding these processes is of particular value given the background of ongoing discussions about possible climatic consequences of the anthropogenically-induced increase of CO2 in the atmosphere (the ‘greenhouse effect’) and other recent atmospheric observations like the ozone hole. These problems can only be addressed reliably if we are able to differentiate between anthropogenic and natural causes of climatic system change. It is of great importance to record climatic variations not only over long geological periods, but also over times and periods that can be comprehended by humans.
For this reason ELDP focuses on the investigation of high resolution sedimentary successions, which enables the sedimentary sequence to be divided into annual or even seasonal increments by means of varve chronology as basic time control. Time series analyses give evidence for the existence of short and intermediate cycles under such conditions. The coincidence of these cycles with solar cycles indicates a strong solar forcing of climate.
Long-term climatic variations are clearly dependent on changes in orbital parameters of the Earth, while short- and medium-term cycles have not been explained satisfactorily. However, periodicities between 5,5 and about 1,000 years are fundamental in terms of terrestrial climate control and thus are one of the main focal points of the planned investigations.
Climatic variations lead to changes in the environment and these changes are recorded and stored in a variety of geological and biological systems. Analysis of such "archives" is at present the only way to obtain basic climatic information from prehistoric times.
Extrapolation of results from oceanic to continental conditions is still problematic. A similar problem is related to ice core investigations, which originate from the extreme climatic regions in Greenland and the Antarctic. Tree ring studies are convenient, but are limited to the Holocene and the Late Glacial. Therefore, ELDP stresses the use of lacustrine (lake) sediments which are particularly suitable archives for the type of data we require: firstly, these consequences are located within the continents and give information about paleoclimatic conditions in areas which are presently densely populated, and, secondly, lakes often contain annually laminated sediments (varves). This latter feature is a basic requirement to enable an exact and absolute time control for these sediments to be determined by varve chronology.
Two types of lakes can be distinguished in terms of their recording of environmental changes. Small lakes with hydrologically closed basins (e.g. maar lakes) are little influenced by processes in the catchment area and thus reflect even minor climatic variations. Large lakes with large catchment areas provide more processes in the catchment area and district climate response.
As our climate is characterised by strong regional dynamics, it is important to achieve a high regional resolution of paleoclimate archives, particularly when looking at the strong regional differences of climate in the past. Both a north-south and an east-west profile across Europe are needed to obtain a general continent-wide view of climate and to record regional variations.
But European climate cannot be explained without knowledge of the influence of tropical and subtropical Africa. ELDP therefore even is a first step towards accessing paleorecords for an analysis of the dynamics of past interhemispheric teleconnections: Pole-Equator-Pole, Europe-Africa, PEP III. The PEP III PAGES (PAst Global ChangES) Project serves as the interhemispheric link for ELDP and concentrates on global key questions.
Although ELDP emphasises the observation of solar activities (a very specific topic in climate research, as developed by PEP III) it is clear that solid interactions of the widespread inter- and multidisciplinary research fields must be developed, especially in drilling activities and for exploitation of sediment cores.
To reconcile PEP III and ELDP goals as far as possible, we have decided to focus in the first step on crater lakes along a north-south transect. Selection of particular lake types will further the possibilities of comparing and correlating the different records. Furthermore, the quality of cores from such lakes allows high resolution reconstruction, as deep crater lake sediments commonly show annual laminations.
Main scientific requirements for ELDP are:
- Lacustrine sediments with high resolution time control (organic, clastic, evoporitic varves);
- Precision coring and subsampling;
- Interdisciplinary cooperation;
- Permanent exchange of results and methods between scientists to develop concise multi-proxy studies.
The project concentrates at first on the European continent not only because of its high population density with a vital interest in climate change prediction and sufficient background knowledge about suitable drill sites together with a large amount of recent and historical meteorological data. Additionally, the Alps represent a unique continental divide resulting in separated "climatic regimes" where climatic changes show significantly different effects on the environment.
The aim of ELDP is coring of lacustrine sediment profiles along a traverse through Europe, north and south of the Alps based on known drill sites. ELDP as a PEP III activity is the first step in the study of the whole transsect, Europe-Africa.
Since the basic requirement for the project is precise time control the project outline focuses particularly on varve chronology and the calibration of dating methods. Moreover, the study of possible solar periodicities as reflected in varved sediments is emphasised. Time series analyses, for example, of varve thickness variations are strongly related to, and based on, the construction of varve chronologies. However, in summary it should be emphasised that the main goals of these studies are multi proxy-parameter studies with an annual or seasonal resolution.
The crucial research fields in this Programme include:
Varve Chronology – an imperative method of continuous absolute dating providing year-by-year resolution of palaeoclimate dating.
Solar Periodicities – the key to understanding basic solar forcing of the earth’s climate and an urgent requirement for long-term climate dynamics.
Tephrochronology – volcanic eruptions and their tephra as important time makers for both age control and correlation of continental and marine sequences.
Organic Petrology – organic production recorded annually in lake sediments as an environmental response to climate change.
Quantitative Calibrations – enable pollen and macrofossil remains to provide estimates of three critical aspects of past climate.
Ostracod Valve Geochemistry – a new and essential tool to accurately quantify paleotemperature.
Magnetostratigraphy
Secular variation records can be used as dating and correlation tools whereas rock magnetic parameters (e.g. magnetic susceptibility) are useful as proxy data for climate change in terms of "environmental magnetism". Paleointensity studies can give information concerning the influence of the geomagnetic field strength on the production of 14C.
Physical Properties
Basic sedimentological parameters (bulk density, water content, carbonate content, p-wave velocity, grain size distribution) reflect the variable environmental input of detrial and biogenic origin throughout time and therefore are also useful as proxy data for climate change.
AMS14C-dating
Absolute age determination for the age range up to 40-50 ka.
Palynology and Plant Macrofossil Analysis
Plant micro- and macrofossils provide the only direct evidence of paleovegetation. Quantitative rule-based models are able to accurately reconstruct the paleobio-production.
Stable Isotopes
The stable isotope composition of lacustrine sediments provides unique information on environmental conditions at the time of deposition and therefore can be used as a direct paleolimnological and paleoclimatological indicator.
Diatom Analysis
Diatoms can give pertinent information on a large number of climate-related variables like ionic composition, alkalinity, temperature and trophic state of a lake.
Geochemistry
Geochemical analyses yield basic information about the syn- and post- depositional processes within the interstitial processes within the interstitial pore water and the solid sediment constituents. Such information is of basic importance in order to verify the results of other stratigraphic methods.
SELECTION OF DRILL SITES
European traverses of lake sediment sequences are planned in order to provide a continental overview of climate dynamics in Europe. It is especially important to obtain and correlate climate records from both north and south of the Alps since they form the main climatic divide.
Proposed drill sites are shown on the map (on page x). The selection of sites are being assessed for their reliability and importance for the evaluation of the project goals during the first scientific meeting of the participating labs.
The organisational and logistic aspects of the drilling programmes are being coordinated by GeoForschungsZentrum Potsdam (GFZ). This institute will also organise the storing of sediment core material, and arrange subsampling sessions. The results of the Programme will be published in the form of reports, articles in academic journals and other publications.
Activities
Publications
In October 2000 the proceedings of the 3rd workshop in Ptolemais (Greece) were published as a special thematic issue of Quaternary International entitled "Mediterranean lacustrine records". This volume includes ten contributions of circum-Mediterranean lake records as archives of climatic and human history.
For 2001 a special issue of Quaternary International is scheduled as proceedings of the 4th ELDP workshop in Lund (Sweden). This will be entitled "Correlations of late Weichselian and Holocene palaeoenvironment proxy data" and presently 9 papers are listed for this volume.
A proceedings volume from the ALDP/ELDP joint meeting in Kyoto is in preparation as a special issue of Quaternary International entitled "Environmental Change in Eurasia". The extended abstract volume for the 5th ELDP workshop in Pallanza has been published as Terra Nostra – Schriften der Alfred-Wegener-Stiftung 2000/07 (157 pages).
An outcome of the Central Europe working group is a publication on the correlation and synchronization of Central European lake records along a West – East transect which is in press for Quaternary Science Reviews: Litt, T., Brauer, A., Goslar, T., Merkt, J., Balaga, K., Müller, H., Ralska-Jasiewiczowa, M., Stebich, M., and Negendank, J. F. W. (in press). Correlation and synchronisation of Lateglacial continental sequences in northern central Europe based on annually-laminated lacustrine sediments. Quaternary Science Reviews.
Publications arising from the final ELDP workshop are:
(1) Extended abstracts volume (Terra Nostra, Vol. 2001/3) including 45 contributions and an excursion guide to the Pommeranian terminal moraines.
(2) Proceedings volume entitled “High-resolution lake sediment records in climate and environment variability studies”. Scheduled for publication in Quaternary International (Pergamon Press) early 2003 with eleven scientific manuscripts announced.
(3) Workshop report in the PAGES Newsletter, Vol. 9/2.
