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Along active margins, the combination of predominant tectonic activity and shallow-marine mixed siliciclastic-carbonate source systems developing upon and around actively growing structures challenges traditional source-to-sink models. This study aims to investigate the implications of mixed siliciclastic-carbonate shelfal domains located in contrasting geotectonic settings (thrust forelimb and backlimb) for the development of the concomitant gravity-driven systems beyond the shelf edges. Here, we document the vertical and lateral stratigraphic variabilities of the shelf-derived turbidites and mass-transport deposits (MTDs) at outcrop-scale through the integrated interpretation of photogrammetry, field and taphonomic data from the emerged southern portion of the Hikurangi subduction margin. Results highlight the role and importance of varying structural setting of the sediment source, whereby the different morphologies of the source regions (continent-attached forelimb, continent-detached backlimb) control the development of highly varied shelf-derived gravity-driven depositional systems that interact with the structures across the same confined intra-slope basin. The deposits are tens to a few hundred of meters in thickness and have a lateral extent of several kilometers. The depositional systems are characterized by durations of 1 to 2 Ma and were primarily controlled by the geometries and tectonic motion of the underlying structures at the shelf edges. Shelf-derived mass-wasting systems occurred on both sides of the actively growing thrust structures and were sourced from both shelfal domains that were attached or detached from the continental domain. When sourced from the backlimbs however, the subsequent MTDs exhibit more complex internal architectures, ultimately recording the dynamic changes in slope gradient, and can therefore be used as proxies for unraveling the tectonic activity of an individual structure. Our study provides new insights to better predict mixed siliciclastic-carbonate depositional settings along active margins, sourced from thrust forelimb and backlimb. These results may be important for deep-marine exploration and tectonostratigraphic reconstruction of fold-and-thrust belts. International audience

The Lake Titicaca basin was one of the major centers for cultural development in the ancient world. This lacustrine environment is unique in the high, dry Andean altiplano, and its aquatic and terrestrial resources are thought to have contributed to the florescence of complex societies in this region. Nevertheless, it remains unclear to what extent local aquatic resources, particularly fish, and the introduced crop, maize, which can be grown in regions along the lakeshores, contributed to facilitating sustained food production and population growth, which underpinned increasing social political complexity starting in the Formative Period (1400 BCE to 500 CE) and culminating with the Tiwanaku state (500 to 1100 CE). Here, we present direct dietary evidence from stable isotope analysis of human skeletal remains spanning over two millennia, together with faunal and floral reference materials, to reconstruct foodways and ecological interactions in southern Lake Titicaca over time. Bulk stable isotope analysis, coupled with compound-specific amino acid stable isotope analysis, allows better discrimination between resources consumed across aquatic and terrestrial environments. Together, this evidence demonstrates that human diets predominantly relied on C(3) plants, particularly quinoa and tubers, along with terrestrial animals, notably domestic camelids. Surprisingly, fish were not a significant source of animal protein, but a slight increase in C(4) plant consumption verifies the increasing importance of maize in the Middle Horizon. These results underscore the primary role of local terrestrial food resources in securing a nutritious diet that allowed for sustained population growth, even in the face of documented climate and political change across these periods.

Several decades of field, geophysical, analogue, and numerical modeling investigations have enabled documentation of the wide range of tectonic transport processes in accretionary wedges, which constitute some of the most dynamic plate boundary environments on Earth. Active convergent margins can exhibit basal accretion (via underplating) leading to the formation of variably thick duplex structures or tectonic erosion, the latter known to lead to the consumption of the previously accreted material and eventually the forearc continental crust. We herein review natural examples of actively underplating systems (with a focus on circum-Pacific settings) as well as field examples highlighting internal wedge dynamics recorded by fossil accretionary systems. Duplex formation in deep paleo-accretionary systems is known to leave in the rock record (1) diagnostic macro- and microscopic deformation patterns as well as (2) large-scale geochronological characteristics such as the downstepping of deformation and metamorphic ages. Zircon detrital ages have also proved to be a powerful approach to deciphering tectonic transport in ancient active margins. Yet, fundamental questions remain in order to understand the interplay of forces at the origin of mass transfer and crustal recycling in deep accretionary systems. We address these questions by presenting a suite of two-dimensional thermo-mechanical experiments that enable unravelling the mass-flow pathways and the long-term distribution of stresses along and above the subduction interface as well as investigating the importance of parameters such as fluids and slab roughness. These results suggest the dynamical instability of fluid-bearing accretionary systems causes either an episodic or a periodic character of subduction erosion and accretion processes as well as their topographic expression. The instability can be partly deciphered through metamorphic and strain records, thus explaining the relative scarcity of paleo-accretionary systems worldwide despite the tremendous amounts of material buried by the subduction process over time scales of tens or hundreds of millions of years. We finally stress that the understanding of the physical processes at the origin of underplating processes as well as the forearc topographic response paves the way for refining our vision of long-term plate-interface coupling as well as the rheological behavior of the seismogenic zone in active subduction settings. Geosphere, 18 (1) ISSN:1553-040X

Des études paléoenvironnementales antérieures ont montré que des changements majeurs de la végétation et de l’environnement se sont produits en Afrique centrale à partir de l’Holocène moyen (ex. Maley & Brenac 1998). Plusieurs d’entre elles mettent en évidence une origine humaine et supposent que les grandes migrations de population, les innovations techniques (par exemple, la technologie de la fonte du fer) et/ou de nouveaux choix dans les pratiques agricoles, conduisant à la déforestation et au défrichement, sont les moteurs de ces changements. Cependant, à ce stade, l’absence de reconstitution démographique ne permet pas de soutenir pleinement ces hypothèses. Notre étude utilise une base de données archéologiques géoréférencées pour déduire la dynamique des populations et l’évolution des pratiques culturelles en Afrique centrale occidentale au cours des 5000 dernières années. Cette base de données comprend 1139 dates calibrées au 14C provenant de 425 sites – localisés dans le sud du Cameroun, au Gabon, en République du Congo, en Guinée équatoriale et dans la partie occidentale de la République démocratique du Congo –, remontant à un maximum de 5000 ans cal. BP. La modélisation des données indique une possible croissance de la population entre ~2500 et ~1500 ans cal. BP, coïncidant avec l’apparition à l’échelle régionale de techniques et de pratiques spécifiques. L’augmentation concomitante des fosses dépotoirs, des vestiges d’utilisation de palmier à huile Elaeis guineesis, l’apparition de rares restes de millet Pennisetum glaucum et la montée en puissance des vestiges de métallurgie du fer ont eu lieu pendant la seconde moitié du Néolithique, à partir d’environ 2800 ans cal. BP. Dans les régions côtières, la croissance de la population concerne le Néolithique et le début de l’âge du fer (2500-2000 ans cal. BP et 2000-1500 ans cal. BP), tandis que dans l’Hinterland cette croissance semble légèrement plus tardive (2400 et 1300 ans cal. BP). Il n’est pas possible d’identifier un phénomène commun de diffusion à partir d’un seul centre. Les innovations techniques et les nouvelles pratiques semblent plutôt s’être répandues à travers un large réseau d’interactions culturelles qui a favorisé la formation des sociétés d’Afrique centrale occidentale au cours du troisième millénaire avant notre ère. Palaeocological studies show that major vegetation and environmental changes occurred in Central Africa from the mid-Holocene (e.g. Maley & Brenac 1998). Several suggest a human origin and assume that large population migration, technical innovations (e.g. iron-smelting technology) and/or change in agricultural practice, leading to deforestation and land clearance, are the drivers of these changes. However, at this stage, the lack of demographic reconstruction does not fully support these hypotheses. Here, a georeferenced archaeological database is used to infer population dynamics and the evolution of cultural practices in Western Central Africa over the last 5000 years. This database includes 1139 14C calibrated dates from 425 sites throughout southern Cameroon, Gabon, the Republic of Congo, Equatorial Guinea and the western part of the Democratic Republic of Congo, dating back a maximum of 5000 cal. yr BP. Data modelling indicate possible population growth from 2500 to 1500 cal. yr BP, coinciding with the occurrence at a regional scale of specific techniques and practices. The concomitant increase of refuse pits, palm oil Elaeis guineesis and iron metallurgy (plus rare remains of millet Pennisetum glaucum) took place during the second half of the Neolithic, beginning around 2800 cal. yr BP. In the coastal regions, the population growth concerns the Neolithic and the Early Iron Age (2500–2000 cal. yr BP and 2000–1500 cal. yr BP), while in the Hinterland population growth seems slightly later (2400 and 1300 cal. yr BP). It is not possible to identify a common diffusion phenomenon from a single homeland. Rather, technical innovations and new practices appear to have spread through a wide network of cultural interactions, which fostered the formation of Western Central African societies during the third millennium.

Abstract Recognition of how dynamic the Antarctic ice sheets and glaciers were during the late Holocene has grown in recent years. Proxy data suggests the presence of Neoglacial advances but few moraines or glacial features from this time have been dated compared to glaciated landscapes of the Northern Hemisphere. Debate continues on whether parts of Antarctica experienced glacial advance at the same time as the “Little Ice Age” (LIA), which is well-documented in the Northern Hemisphere. We provide new evidence for late Holocene glacial fluctuations at three locations along the Antarctic Peninsula. A moraine or till sheet from a tidewater glacier cross cuts a series of dated raised beaches at Tay Head, Joinville Island along the northwestern Weddell Sea. At Spark Point, on Greenwich Island, a glacier has overrun Holocene raised beaches and a shell-bearing marine deposit is reworked into a glacial diamicton. A third site in Calmette Bay within the larger Marguerite Bay also contains a recent moraine that cuts across a series of dated raised beach ridges. The new ages constraining these glacial advances are in broad agreement with the handful of other existing ages on moraines and proxy records suggestive of cooler conditions within the Antarctic Peninsula. Combining available timing constraints into a Bayesian model yields an age of 400 to 90 cal BP (1550–1860 CE; 95%) for the LIA across the Antarctica Peninsula. Consideration of a two-phase glacial advance within our Bayesian framework does fit more of the data from across the Antarctic Peninsula and suggests advances from 575 to 330 cal BP (1375–1620 CE) and 400 to 50 cal BP (1550–1900 CE). However, more work is needed to determine if such a two-phase advance occurred. Regardless, its similar timing within the Antarctic Peninsula to that of the Northern Hemisphere supports recent assertions of a volcanic or solar forcing for the LIA. These recent readvances also provide a possible mechanism for changes in the rates of Holocene relative sea-level change recorded across the Antarctic Peninsula suggesting that the Antarctic ice sheets may have been more responsive to past climate changes than previously thought and glacial isostatic adjustment from the LIA and possibly other Holocene glacial oscillations is superimposed upon the longer relaxation from the Last Glacial Maximum.

While early maps are known from all over the world, the key questions always involve: what exactly do they show? And what spatial extent do they cover? In this context, we recently used 3D-modelling to reexamine a carved stone slab datable to the Early Bronze Age (c.2150-1600 BC) that was found at Saint-Bélec in Brittany. We show that the surface of the slab had been shaped in three dimensions to represent the relief of the surrounding landscape in which it was found, while several engraved motifs on it evoke contemporary structures known archaeologically. We argue that the Saint-Bélec slab represents an area of c.545 km 2 corresponding to the extent of a prehistoric political entity. The carving and subsequent burying of the slab can be linked to the postulated rise and fall of hierarchical societies and raises many wider questions about socioeconomic structures in temperate Europe at that time. International audience

Inflammatory bowel disease (IBD) is a set of immunological disorders which can generate chronic pain and fatigue associated with the inflammatory symptoms. The treatment of IBD remains a significant hurdle with current therapies being only partially effective or having significant side effects, suggesting that new therapies that elicit different modes of action and delivery strategies are required. TGM1 is a TGF-β mimic that was discovered from the intestinal helminth parasite Heligmosomoides polygyrus and is thought to be produced by the parasite to suppress the intestinal inflammation response to help evade host immunity, making it an ideal candidate to be developed as a novel anti-inflammatory bio-therapeutic. Here we utilized the expression system of the edible green algae Chlamydomonas reinhardtii in order to recombinantly produce active TGM1 in a form that could be ingested. C. reinhardtii robustly expressed TGM1, and the resultant recombinant protein is biologically active as measured by regulatory T cell induction. When delivered orally to mice, the algal expressed TGM1 is able to ameliorate weight loss, lymphadenopathy, and disease symptoms in a mouse model of DSS-induced colitis, demonstrating the potential of this biologic as a novel treatment of IBD. Highlights • A novel cytokine from a parasitic worm expressed in green algae induces an anti-inflammatory response when fed to mice. • Recovery from inflammatory colitis is accelerated by the algal-expressed protein. • Oral administration offers an attractive route for the novel therapy.