A younger ``earliest human migration'' to Southeast Asia

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Soil archives: where soilscape history meets present-day ecosystems

International audienceThe interpretation of soil archives, although complex, is nevertheless essential for understanding the impact of soils on present-day environments and deciphering the environmental history of a site. Soil archives are local, although within a continuous soilscape, they allow the study of spatial structures. This chapter presents some key elements for understanding the archiving process through to the reconstruction of a fragment of paleoenvironmental history. It describes the biological, physical and anthropological archiving elements of pedological processes. Geomorphological processes also affect the soilscape and can produce excellent soil and sediment archives or destroy them. The combined study of the different soil archives (plant remains, soil organic matter, chemical parameters, macro- and micromorphological features, microtopography, archaeology) allows an increasingly less lacunary picture to emerge of the environmental history and its legacies in the soil; an environmental story whose heritage, while fading, still structures today's terrestrial ecosystem

Les séquences tourbeuses des fonds de vallées du bassin de la Somme (France): Historique des recherches, diversité des concepts et perspectives

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Pedo-sedimentary dynamics of the Grenzbank zone in the Sangiran dome (Java central, Indonesia): the witness of a complex transitional period in the hominid bearing series

International audienceThe thick sedimentary series of the Sangiran dome are known to reflect the geological evolution of Central Java since the beginning of the Quaternary until the Lower to Middle Pleistocene boundary. The site is furthermore famous for numerous discoveries of Homo erectus, the oldest ones dated at c. 1.5 M.a.An orogenic phase took place during the late Lower Pleistocene, resulting into the shaping of hill ranges in the Northern and Southern borders of the Solo basin, from which emerge the Sangiran boutonnière. It resulted into synorogenic deposits which abruptly interrupt the clayey sedimentation in the depression. These often conglomeratic deposits are cemented by a calcareous matrix (either contemporaneous of the sedimentation or post-depositional in a phreatic context). They are likely to have formed during a quite long time, but have often been used to mark a stratigraphic boundary (Grenzbank in German).This study combines field survey and micromorphological approach in order to precise the pedo-sedimentary dynamics of the Grenzbank unit. In a palaeogeographical perspective, we sample 25 sections, which yielded 95 micromorphological samples.We define three lithostratigraphic microfacies with various geographical distributions. Facies 1 constitutes an independent unit present in the NW part of the dome. Important quantities of mud aggregates and carbonate rhizolithes are also described. It reflects the development of alluvial fans coming from the north during a tectonic episode, associated with strong erosion of pedological covers. Two other facies are defined as the basal part of the overlying Kabuh volcano-alluvial series, and reflect complex changes of river pathways over Central Java. They are more developed in the southern part, and indicate the transport of both siliceous raw material (quartzite, gneiss, chalcedony, jasper, silicified limestone) and small sized artifacts (whose type matches the so called ‘Sangiran flakes’) that are the oldest discovered in Sangiran

Pedo-sedimentary dynamics of the Grenzbank zone in the Sangiran dome (Java central, Indonesia): the witness of a complex transitional period in the hominid bearing series

International audienceThe thick sedimentary series of the Sangiran dome are known to reflect the geological evolution of Central Java since the beginning of the Quaternary until the Lower to Middle Pleistocene boundary. The site is furthermore famous for numerous discoveries of Homo erectus, the oldest ones dated at c. 1.5 M.a.An orogenic phase took place during the late Lower Pleistocene, resulting into the shaping of hill ranges in the Northern and Southern borders of the Solo basin, from which emerge the Sangiran boutonnière. It resulted into synorogenic deposits which abruptly interrupt the clayey sedimentation in the depression. These often conglomeratic deposits are cemented by a calcareous matrix (either contemporaneous of the sedimentation or post-depositional in a phreatic context). They are likely to have formed during a quite long time, but have often been used to mark a stratigraphic boundary (Grenzbank in German).This study combines field survey and micromorphological approach in order to precise the pedo-sedimentary dynamics of the Grenzbank unit. In a palaeogeographical perspective, we sample 25 sections, which yielded 95 micromorphological samples.We define three lithostratigraphic microfacies with various geographical distributions. Facies 1 constitutes an independent unit present in the NW part of the dome. Important quantities of mud aggregates and carbonate rhizolithes are also described. It reflects the development of alluvial fans coming from the north during a tectonic episode, associated with strong erosion of pedological covers. Two other facies are defined as the basal part of the overlying Kabuh volcano-alluvial series, and reflect complex changes of river pathways over Central Java. They are more developed in the southern part, and indicate the transport of both siliceous raw material (quartzite, gneiss, chalcedony, jasper, silicified limestone) and small sized artifacts (whose type matches the so called ‘Sangiran flakes’) that are the oldest discovered in Sangiran

Approche paléopédologique de l’environnement des hominidés fossiles du dôme de Sangiran (Java central, Indonésie)

International audienceThe thick volcano-sedimentary series in the area of the Sangiran dome (Kalibeng, Pucangan, Grenzbank, Kabuh and Notopuro) formed during the whole Quaternary period and represent successively coastal marine then continental terrestrial environments. The palaeosoils in between these series are good indicators of past landscapes which witnessed early humans spreading through Southeast Asia during the Lower and early Middle Pleistocene.This paleopedological study deals with on seven localities distributed over the ca. 50 sq.km. area. It allows characterizing six palaeosoil orders (histosol, gleysol, vertisol, argillisol, protosol, oxisol) in which 18 pedotypes were distinguished. We investigated the south-east and north-west fossiliferous regions which delivered very different sedimentary sequences. The characterization of successive pedoclimatic contexts and the study of toposequences help to reconstruct the local palaeogeography and are informative about the climates under which the paleosoils developed (dominated by the influence of the southeast asian monsoon cycles).The first fully terrestrial levels were identified at the base of the upper Pucangan unit, corresponding to the development of an open landscape succeeding to wide coastal swamps. Above are recorded environments depicting a constrasted seasonal climate with a long dry season, alternating with periods of more humid palustrine conditions. Recurrent aridity proxies are then found in the overlying Grenzbank and Kabuh series (those which yielded the most numerous hominid fossils), where the soils reflect a long dry season and an open vegetation landscape, in accordance with stratigraphical and palynological observationsLes épaisses séries volcano-sédimentaires fossilifères à Java central (Indonésie) dans la région du dôme de Sangiran (unités de Kalibeng, Pucangan, Grenzbank, Kabuh et Notopuro) se sont mises en place durant tout le Quaternaire et représentent une succession d’environnements marins, côtiers puis terrestres. Les paléosols inclus dans ces séries permettent de décrire différentes facettes des paysages anciens qui se sont succédés lors des périodes de colonisation par les hominidés au Pléistocène inférieur et moyen ancien.Notre étude paléopédologique porte sur 7 localités réparties sur les 50 km² du dôme. Elle a permis de caractériser six ordres de paléosols (histosol, gleysol, vertisol, argillisol, protosol, oxisol), parmi lesquels 18 pédotypes ont été distingués. Nous nous sommes notamment intéressés à la comparaison entre les régions fossilifères du sud-est et du nord-ouest du dôme, aux séquences de faciès très différentes. La caractérisation des ambiances pédoclimatiques successives et l’étude des toposéquences contribuent à restituer l’histoire paléogéographique locale et fournissent des données sur le climat régnant lors de la formation des sols (dominé par l’influence des cycles de la mousson sud-est asiatique). A la base des séries de Pucangan supérieur ont été localisés les premiers niveaux terrestres francs, lors de la mise en place d’un paysage ouvert succédant à de vastes marécages côtiers. Plusieurs environnements à saisonnalité contrastée, pouvant être interprétés comme semi-arides, sont ensuite enregistrés dans ces séries, alternant avec des environnements humides palustres. Les indices d’aridité sont ensuite récurrents dans les couches fluviatiles du Grenzbank et de Kabuh, qui ont livré le plus grand nombre de restes d’hominidés. Les sols révèlent une saison sèche de longue durée et un paysage de plaine alluviale à végétation ouverte, concordant avec les observations stratigraphiques et palynologiques antérieures

Inferring changes in agricultural soil amendments, from the late Bronze Age until Late Antiquity, in northern France, by investigating the weed flora composition

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Pedo-sedimentary dynamics of Sangiran dome hominid bearing layers (L/M Pleistocene, Java central, Indonesia): a palaeopedological approach of 'Pithecanthropus' (Javanese Homo erectus) environments

International audienceFossil soils and pedosediments displayed in Quaternary fossil‐bearing series are an important proxy to describe the evolution of climates and environments. We studied those paleosols in the Sangiran dome, a rich hominid‐bearing site of central Java (Indonesia), in order to characterize the environments and landscapes colonized by hominids.The thick sedimentary series of the Sangiran dome are known to reflect the geological evolution of Central Java since the beginning of the Quaternary until the Middle Pleistocene. Homo erectus fossils are found in the c. 1.5 M.a. Pucangan series up to the c.0.8 M.y. Kabuh layers.This study combines field survey, micromorphological approach and use of palynological data. The characterisation of successive pedoclimatic contexts and toposequences help to reconstruct the local palaeogeography and inform about climates (mainly influenced by south‐eastern Asia monsoon cycles) that predominated during periods of palaeosoil development.The basis of Upper Pucangan series displays the earliest fully continental deposits, corresponding to the development of an open landscape that succeeds to wide coastal swamps and rain forest. Upper in the stratigraphy, environments depicting a contrasted seasonal climate with a long dry season alternate with periods of more humid palustrine conditions.A further tectonic uplift of the hill ranges bordering the Solo depression (in which is located the Sangiran dome) resulted into severe erosion of the regional soil cover. Transported by ephemeral streams, series of pedorelics and pedological concretions accumulated in the topographic depressions.Recurrent aridity proxies occur in the studied paleosoils found in the overlying Kabuh series (which yield the most numerous hominid fossils), reflecting a long dry season and an open vegetation landscape

Pedo-sedimentary dynamics of the Grenzbank zone in the Sangiran dome (Java central, Indonesia): the witness of a complex transitional period in the hominid bearing series

International audienceThe thick sedimentary series of the Sangiran dome are known to reflect the geological evolution of Central Java since the beginning of the Quaternary until the Lower to Middle Pleistocene boundary. The site is furthermore famous for numerous discoveries of Homo erectus, the oldest ones dated at c. 1.5 M.a.An orogenic phase took place during the late Lower Pleistocene, resulting into the shaping of hill ranges in the Northern and Southern borders of the Solo basin, from which emerge the Sangiran boutonnière. It resulted into synorogenic deposits which abruptly interrupt the clayey sedimentation in the depression. These often conglomeratic deposits are cemented by a calcareous matrix (either contemporaneous of the sedimentation or post-depositional in a phreatic context). They are likely to have formed during a quite long time, but have often been used to mark a stratigraphic boundary (Grenzbank in German).This study combines field survey and micromorphological approach in order to precise the pedo-sedimentary dynamics of the Grenzbank unit. In a palaeogeographical perspective, we sample 25 sections, which yielded 95 micromorphological samples.We define three lithostratigraphic microfacies with various geographical distributions. Facies 1 constitutes an independent unit present in the NW part of the dome. Important quantities of mud aggregates and carbonate rhizolithes are also described. It reflects the development of alluvial fans coming from the north during a tectonic episode, associated with strong erosion of pedological covers. Two other facies are defined as the basal part of the overlying Kabuh volcano-alluvial series, and reflect complex changes of river pathways over Central Java. They are more developed in the southern part, and indicate the transport of both siliceous raw material (quartzite, gneiss, chalcedony, jasper, silicified limestone) and small sized artifacts (whose type matches the so called ‘Sangiran flakes’) that are the oldest discovered in Sangiran