Quantitative reconstruction of climatic variations during the Bronze and early Iron ages based on pollen and lake-level data in the NW Alps, France

Abstract

Vegetation and lake-level data from the archaeological site of Tresserve, on the eastern shore of Lake Le Bourget (Savoie, France), are used to provide quantitative estimates of climatic variables over the period 4000-2300 cal BP in the northern French Pre-Alps, and to examine the possible impact of climatic changes on societies of the Bronze and early Iron Ages. The results obtained indicate that phases of higher lake level at 3500-3100 and 2750-2350 cal BP coincided with major climate reversals in the North Atlantic area. In west-central Europe, they were marked by cooler and wetter conditions. These two successive events may have affected ancient agricultural communities in west-central Europe by provoking harvest failures, more particularly due to increasing precipitation during the growing season. However, archaeological data in the region of Franche-Comté (Jura Mountains, eastern France) show a general expansion of population density from the middle Bronze Age to the early Iron Age. This suggests a relative emancipation of proto-historic societies from climatic conditions, probably in relation to the spread of new modes of social and economic organisation.

Rapid climatic variability in the west Mediterranean during the last 25 000 years from high resolution pollen data

“…This method has been extensively used for the Late glacial and Holocene climate reconstructions in Europe (e.g. Cheddadi et al, 1997Cheddadi et al, , 1998Davis et al, 2003;Peyron et al, 2005;Bordon et al, 2009;Magny et al, 2009;Kotthoff et al, 2008 to compare, using a dissimilarity index, the fossil pollen assemblages with the modern pollen assemblages collected in a high-quality and taxonomically consistent modern pollen dataset, (2) and to select, for each fossil assemblage, several closest modern pollen assemblages (or best modern analogues). The selection of the best modern analogues (here 10) is based on the calculation of a chord distance measured between each fossil and modern pollen assemblage (Guiot, 1990).…”

Stratigraphic analysis of lake level fluctuations in Lake Ohrid: an integration of high resolution hydro-acoustic data and sediment cores

“…This promising location, however, has never been the subject of a quantitative study reconstructing past changes in hydrology. The detection and dating of subaquatic and subaerial terraces is a robust approach to infer past variations in the hydrological budget of an individual lake (Magny et al, 2009;Moernaut et al, 2010).…”

French Alpine Foreland Holocene Paleoseismicity Revealed by Coeval Mass Wasting Deposits in Glacial Lakes

“…This interpretation is further supported by the identification on SEM images of similar tube-like carbonate concretions both in T4 and in the littoral core (Fig. 34.3), that are typical from the edge of a littoral bench (Magny et al 2008). The siliciclastic turbidite deposited just below T4 in PAL11-6 may thus be earthquake triggered, while T4 and several MWDs may result from the following lake-level changes in AD 1870.…”