Changes in ecosystems, climate and societies in the Jura Mountains between 40 and 8 ka cal BP

Abstract

We present radiometric, palaeoclimatological, palaeoenvironmental and archaeological data for the period 40 000–8000 cal BP in the Jura Mountains (eastern France). These mountains culminate at ∼1700 m a.s.l. and are today characterised by a semi-continental climate. During the Last Glacial Maximum, the range supported a local ice cap. While recent data suggest a possible early ice-cap development during MIS 4, the chronology of the regional LGM and following deglaciation has still to be refined. The complete disappearance of the local ice cap at ca 17 000–16 600 cal BP marked the beginning of accumulation of sediment archives in the Jurassian lakes and mires, which favoured the reconstruction of past changes in climatic and environmental conditions, in addition to faunal remains found in caves and in archaeological sites. Three main successive stages may be distinguished regarding the history of societies. The first stage at ca 40 000–18 700 cal BP was characterized by very few archaeological sites with only discontinuous intermittent occupations, always located outside the Jura range. The second stage, around 18 700–11 700 cal BP, corresponded to an increase in the population density, as suggested by an increasing number of archaeological sites and a progressive colonisation of elevated areas of the Jura Mountains. The third stage at ca 11 700–8000 cal BP coincided with a reinforcement of settlement in the lowland areas as well as a development of long-term occupations in elevated areas. The millennial-scale GS-1 cold event had a more long-lasting and stronger impact on societies than did the 200 year-long 8.2 ka cold event.