This paper represents a synthetic overview of the main results of the CNRS Programme " Palaeoenvironments and Hominids ". This project focused on the study of interactions between human occupation and environmental modification, between 500 and 10 kyrs BP, based on multidisciplinary and diachronic studies of key sites in the Somme Basin. The main analytic results concern ESR, TL-IRSL and 14C dates, which reinforce the chrono-stratigraphical interpretation of the various Palaeolithic sites. At the same time, bioclimatic analyses of fluvial sediments (palynology, malacology, analysis of Coleoptera), combined with the measurement of δ13C variations of organic carbon, and of the low-field magnetic susceptibility in loess and fossil soils, allowed the restitution of the various Pleistocene environments, and especially of the full Interglacials, to be refined. The main conclusions of the synthesis of archaeological, chronostratigraphical and environmental data are the following. 1) The earliest human occupations in the Somme Basin are no older than 500-450 kyrs BP and are straight away represented by well evolved Acheulean industries (beginning of MIS 12, according to the data from modern excavations). 2) During the last climatic cycle, human occupation of the Somme Basin was clearly discontinuous and strongly influenced by climatic and environmental modifications: maximum during the Early-Glacial, some occupations during the Lower and Middle Maximum Glaciations, rare occurrences around 23-24 kyrs (14C), total abandonment of the area between 23 and 13 kyrs, then reoccupation with the beginning of the Lateglacial climatic improvement. 3) Although the data are less numerous, the model of the last climatic cycle seems to apply during the Middle Pleistocene for the end of the Saalian (occupation at the end of MIS 7 or at the transition MIS7/MIS6, and desertion of the area during the cold maximum of MIS 6). 4) Finally, between 500/450 and 200 kyrs human settlements mainly occurred during periods of climatic transition (Early or Lateglacial). From a general point of view, the human occupation of the Somme Basin during the Middle Pleistocene was therefore discontinuous and strongly influenced by climatic and environmental factors.

Abstract. Chinese loess sequences are interpreted as a reliable record of the past variation of the East Asian monsoon regime through the alternation of loess and paleosols units, dominated by the winter and summer monsoon, respectively. Different proxies have been used to describe this system, mostly geophysical, geochemical or sedimentological. Terrestrial mollusks are also a reliable proxy of past environmental conditions and are often preserved in large numbers in loess deposits. The analysis of the mollusk remains in the Luochuan sequence, comprising L5 loess to S0 soil, i.e. the last 500 ka, shows that for almost all identified species, the abundance is higher at the base of the interval (L5 to L4) than in the younger deposits. Using the present ecological requirements of the identified mollusk species in the Luochuan sequence allows the definition of two main mollusk groups varying during the last 500 kyr. The cold-aridiphilous individuals indicate the so-called Asian winter monsoon regime and predominantly occur during glacials, when dust is deposited. The thermal-humidiphilous mollusks are prevalent during interglacial or interstadial conditions of the Asian summer monsoon, when soil formation takes place. In the sequence, three events with exceptionally high abundance of the Asian summer monsoon indicators are recorded during the L5, L4 and L2 glacial intervals, i.e., at about 470, 360 and 170 kyr, respectively. The L5 and L4 events appear to be the strongest (high counts). Similar variations have also been identified in the Xifeng sequence, distant enough from Luochuan, but also in Lake Baikal further North, to suggest that this phenomenon is regional rather than local. The indicators of the summer monsoon within the glacial intervals imply a strengthened East-Asian monsoon interpreted as corresponding to marine isotope stages 12, 10 and 6, respectively. The L5 and L2 summer monsoons are coeval with Mediterranean sapropels S12 and S6, which characterize a strong African summer monsoon with relatively low surface water salinity in the Indian Ocean. Changes in the precipitation regime could correspond to a response to a particular astronomical configuration (low obliquity, low precession, summer solstice at perihelion) leading to an increased summer insolation gradient between the tropics and the high latitudes and resulting in enhanced atmospheric water transport from the tropics to the African and Asian continents. However, other climate drivers such as reorganization of marine and atmospheric circulations, tectonic, and the extent of the Northern Hemisphere ice sheet are also discussed.

The Harletz loess‐palaeosol sequence is located in northwestern Bulgaria and represents an important link between well‐studied loess sequences in eastern Romania and further sites to the west of the Carpathians (e.g. Serbia and Hungary). The aim of this study was to establish a chronostratigraphy of the deposits, using various methods of luminescence dating, together with basic stratigraphical field observations as well as magnetic properties. Luminescence dating was carried out using the quartz fine grain fraction and a SAR protocol, and the feldspar coarse grain fraction, applying the MET‐pIRIR protocol. Due to underestimation of the quartz fine grain fraction in the lower parts of the sequence, the resulting chronology is mainly based on the feldspar ages, which are derived from the stimulation temperature at 150 °C. A comparison with nearby sequences from Serbia, Hungary and Romania, and interpretations obtained through the stratigraphical and sedimentological signature of the sequence, supports the established chronology. Our data suggest that the prominent palaeosol (soil complex) in the upper quarter of the sequence was formed during MIS 5. It would follow that large parts of the Last Glacial loess overlying this palaeosol were probably eroded, and that the thick loess accumulation underlying this soil complex can be allocated to the penultimate glacial (MIS 6). A prominent MIS 6 tephra, which has been reported from other sequences in the area, is also present at Harletz.