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While the planet Mars is today a dry and cold wasteland dominated by aeolian processes, a large diversity of geomorphologies observed from orbit suggests that aqueous processes took place there. Most of these morphologies implies the presence of developed fluvial networks at the surface of the planet about 3.5 Ga ago. However, the precise conditions behind the formation of these valleys and the climate they evolved in are still being debated, as some of them could be linked to episodic events set in a cold climate. For more than a decade now, the rovers Curiosity and Perseverance helped to shed light on these questions thanks to a detailed in situ analysis of fluvial and lacustrine deposits.The Curiosity rover landed in August 2012 in Gale crater, and since then observed more than 500 meters of a sedimentary succession including lacustrine mudstones and fluvial sandstones and conglomerates. Locally, clay minerals have been observed to make as much as 30 % of the bulk composition, with a substantial degree of chemical alteration, highlighting the role of water in the rock formation processes. The succession, and locally alternation and interfingering of fluvial and lacustrine facies suggest rapid and marked evolutions of the depositional setting, in relation with changing environmental and climatic parameters. However, no (peri-)glacial facies has been found to date, even if glacial processes could have affected those terrains later in their history.In February 2021, the Perseverance rover landed in Jezero crater, which was chosen after the observation from orbit of both a large-scale fan-shaped edifice and the presence of clay and carbonate minerals. Remote observations of the fan and its remnants allowed to identify characteristic sigmoid structures of a deltaic architecture (bottomsets-foresets-topsets), confirming the presence of a perennial lake at the time of the deposition. Observations from both rovers illustrate that liquid water was not ephemeral at the surface of Mars. Nevertheless, the duration and extent of these processes are still yet to be exactly constrained. The detailed analysis of the delta by Perseverance and the returned samples on Earth (by a future mission early in the 2030’s) would hopefully allow to constrain these chronological questions, as well as to allow to look for potential biosignatures. International audience

The Mozambique Channel, a complex domain composed of passive margins and oceanic crust affected by younger strike-slip and volcanic activity, is still poorly studied for surface heat flow. We present 33 new marine-type heat flow estimations acquired offshore in 2014-2015 during the MOZ cruises, completed with 4 new heat flow values derived from reappraised old well sites (PAMELA project). Offshore heat flow is generally low to normal and does not display strong variations. As poor data coverage persists in large parts of the area, we performed a heat flow prediction mapping using the similarity method. Based on an extrapolation of old and new data guided by 14 geological and geophysical proxies, we obtain on a 0.1 • × 0.1 • grid a predicted heat flow and its uncertainty from the statistics of all values at global grid points with similar proxies. We succeeded to obtain good predictability on 70% of pixels and an RMS error <2.3 mW/m 2. The proxies selected for the prediction include a map of genetic domains, sediment thickness, topography and bathymetry, crustal ages, Curie point depth, Free air anomaly, distances to volcanoes, tectonic structures and continent-ocean boundaries. The new Mozambique heat flow map shows a predominantly low offshore heat flow of around 50 mW/m 2 , associated with the Jurassic and early Cretaceous age of the oceanic crust. Several heat flow anomalies standoff to this background heat flow with two main orientations: low heat flow anomalies with a N-S orientation and high anomalies with a mostly NE-SW orientation, which are linked mainly to tectonic structures. International audience

Cet article aborde la question des temporalités de l’action publique au Cap, en prenant l’exemple de la réglementation du commerce de rue depuis le début du XXème siècle. Notre principal argument réside dans une discussion sur la compréhension actuelle de la gouvernance du commerce de rue en tant que produit d’un régime néolibéral reproduisant l’ordre colonial. En utilisant la méthode généalogique de Foucault et sa conceptualisation du néolibéralisme comme une rationalité de gouvernement, nous montrons que bien que les instruments de contrôle restent les mêmes (limitation des permis, zonage spatial et identification des commerçants), leur signification politique a changé au fil du temps, reflétant le passage de la coercition et de la répression à la gouvernementalité néolibérale. Nous démontrons empiriquement comment la néo-libéralisation opère à travers une transformation de la rationalité même de ces instruments. Nous concluons en soulignant que l’utilisation de la définition de la néo-libéralisation et de la méthode de Foucault aide à construire une théorie du changement néolibéral pour les contextes postcoloniaux. This article addresses the issue of the temporalities of public action in the city of Cape Town (South Africa), using the example of the government of street trade since the early 20 th century. The main point consists in an understanding of the continuities and breaks in public action via an approach interested in the instruments of control and using the Foucauldian genealogical method. Our main argument lies in a discussion of the current understanding of the government of street trade in Cape Town as a neoliberal regime merely reproducing the colonial order and its political violence towards the traders. We show that although the instruments of control may remain the same (identification of traders, limitation of permits, and spatial zoning), their political meaning has changed throughout time, reflecting the shifting place of the informal in metropolitan economic planning. The means of governing street trade have also shifted, from mere coercion to governmentality, shedding light on how neo-liberalisation actually operates through a transformation of state practices. International audience

Large explosive volcanic eruptions from island arcs pour pyroclastic currents into marine basins, impacting ecosystems and generating tsunamis that threaten coastal communities and infrastructures. Risk assessments require robust records of such highly hazardous events, which is challenging as most of the products lie buried under the sea. Here we report the discovery by IODP Expedition 398 of a giant rhyolitic pumice deposit emplaced 520 ± 10 ky ago at water depths of 200 to 1000 m during a high-intensity, shallow submarine eruption of ancestral Santorini Volcano. Pyroclastic currents discharged into the sea transformed into turbidity currents and slurries, forming a >89 ± 8 km 3 volcaniclastic megaturbidite up to 150 m thick in the surrounding marine basins, while breaching of the sea surface by the eruption column laid down veneers of ignimbrite on three islands. The eruption is one of the largest recorded on the South Aegean Volcanic Arc, and highlights the hazards from submarine explosive eruptions. International audience co-auteur étranger

Les stratégies de subsistance des premières communautés agricoles ont été mises en évidence depuis le début du Néolithique grâce à de nombreuses études sur les résidus lipidiques des récipients en céramique menées dans diverses parties de l’Europe continentale. En revanche, très peu de données sont disponibles pour la fin du Néolithique et le début de l’âge du Bronze sur la côte atlantique, en particulier en contexte insulaire. Cet article présente les résultats de l’analyse de résidus lipidiques provenant de 129 fragments de poteries de Beg ar Loued (Molène, France), un site insulaire dont les principaux vestiges datent de l’âge du Bronze ancien (c. 2700-2600 à 1800 BCE). Dans le but de comprendre l’utilisation des récipients, les pratiques culinaires sur ce site et d’appréhender les tech-niques de finition des céramiques, des analyses de résidus visibles carbonisés, de tessons, et de surfaces/couches d’engobe ont été effectuées via des analyses chromatographiques (n = 174) et isotopiques (n = 24), après extraction des lipides par solvant (n = 174) ou méthanolyse acide (n = 31). Les résultats démontrent l’utilisation extensive de produits terrestres (carcasses de ruminants et produits laitiers), comprenant occasionnellement des produits végétaux (avec un mélange probable de différentes cires), alors que la détection des produits aquatiques est faible. Comparés aux données fauniques, ces résultats indiquent donc que les produits terrestres, tels que la viande de ruminant et les produits laitiers, sont transformés en utilisant des récipients en céramiques, tandis que les produits aquatiques semblent de préférence exploités sans avoir recours à une poterie. Ces résultats démontrent l’importance de l’analyse des résidus lipidiques pour connaître le rôle des récipients en céramique dans la production et la consommation d’aliments sur les sites de la côte atlantique. The subsistence strategies of early farming communities have been highlighted since the beginning of the Neolithic, thanks to numerous studies on lipid residues from ceramic vessels conducted in various parts of continental Europe. However, after the Early Neolithic, evidence of subsistence strategies along the northern Atlantic coast are still lacking, especially for island contexts. This paper presents the results of lipid residue analysis of 129 potsherds from Beg ar Loued (Molène, France), an island site dating primarily to the Early Bronze Age (c. 2700-2600 to 1800 BCE). Aiming to understand the use of vessels, vessel treatment and culinary practices on the settlement, analyses of visible charred residues, sherds and ceramic surfaces/coating layers were carried out using chromatographic (n = 174) and isotopic techniques (n = 24) after lipid extraction by solvent (n = 174) or acid methanolysis (n = 31). The results demonstrate the extensive use of terrestrial products (ruminant carcass and dairy) in pottery, including occasional plant products (with possible mixtures of different waxes), while the detection of aquatic products is limited. Thus, combined with evidence from faunal remains at the site, the results indicate that terrestrial resources like ruminant meat and dairy products were preferentially processed in vessels, and aquatic products mostly without the use of ceramics. These findings demonstrate the significance of lipid residue analysis for studying the role of pottery in food production and consumption at sites along the Atlantic coast. International audience

So-called ‘forgotten’ or ‘orphan’ crops are an important component of strategies aimed at preserving and promoting biodiversity. Knowledge of historical cultivation, usage, and geographic and evolutionary trajectories of plants, that is, crop history research, is important for the long-term success of such efforts. However, research biases in the crops chosen for study may present hurdles. This review attempts to systematically identify patterns in crop species representativeness within archaeology-based crop history research. A meta-analysis and synthesis of archaeo- botanical evidence (and lack thereof) is presented for 268 species known to have been cultivated for food prior to 1492 CE from the Mediterranean region to South Asia. We identified 39 genera with known crop plants in this geographical and histor- ical context that are currently absent from its archaeobotanical record, constituting ‘orphan’ crops of archaeobotany. In addition, a worldwide synthesis of crop species studied using geometric morphometric, archaeogenetic and stable isotope analyses of archaeological plant remains is presented, and biases in the species represented in these disciplines are discussed. Both disciplinary methodological biases and economic agenda-based biases affecting species representativeness in crop history research are apparent. This study also highlights the limited geographic diffusion of most crops and the potential for deeper historical perspectives on how crops become marginal- ized and ‘forgotten’. L'agrobiodiversité est un puissant levier d'action de l'agriculture durable à l'échelle mondiale. La culture, la conservation et la réintroduction de diverses espèces végétales, y compris les cultures ‘oubliées’ et ‘sous-utilisées’, contribuent à l'agrobiodiversité mondiale, aux écosystèmes vivants et à la production alimentaire durable. Ces actions bénéficient des connaissances traditionnelles et historiques des trajectoires évolutives et culturelles des plantes cultivées. Cette étude représente une première tentative de mesure systématique de la représentativité des espèces dans les études des restes archéologiques de plantes. Les résultats indiquent que, en plus des sources de biais méthodologiques spécifiques à la discipline, les biais agricoles modernes peuvent se répliquer dans la recherche sur l'histoire des cultures et influencer la compréhension des ‘cultures oubliées’. Reconnaître ces biais est un premier pas vers leur rectification et la promotion de l'agrobiodiversité dans la recherche et les applications pratiques. International audience

Abstract The development of innovative solutions for the conservation and the protection of historic aircraft is a recent and important issue raised in the cultural heritage field and represents the goal of the PROCRAFT (Protection and Conservation of Heritage Aircraft) project. Assessing and documenting the constituent materials as well as their degradation state is necessary to determine and understand factors inducing aluminium alloy corrosion, in order to develop tailored conservation treatments and identify effective protective coatings. The first step of the project was the identification of the constituent materials of aircraft wrecks. Al-Cu-Mg alloys—Duralumin and Super Duralumin, with a higher content of Mg—were the most employed alloys for structural and non-structural parts. These materials undergo a wide range of alterations, amongst which pitting, exfoliation and galvanic corrosion. In the present work, results of the characterisation of wrecks from a North American Republic P-47D Thunderbolt, crashed in Italy in 1945, are reported and compared to wrecks from a French Breguet 765 Sahara n°504 64-PH, built in 1958. The constituent alloys resulted to be similar to the modern 2024 and 2017A alloy. In order to assess the representativeness of these modern alloys in simulating the corrosion behaviour of the historic ones, exfoliation susceptibility (ASTM G34) as well as non-destructive and destructive electrochemical tests in 0.1 M NaCl were carried out on both historic and modern alloys. These results contributed to the selection of representative substrates for the development of protective coatings as well as to the expansion of the dataset on composition and microstructure of historic Al alloys for aircraft. International audience

We develop a theory of non-monetary costs incurred by CEOs when deciding about layoffs and test its predictions on French data. Our results support the idea that, being strongly embedded in their social environment, CEOs find it more difficult to fire employees closer to their own workplace. This effect is stronger whenever social interactions are less anonymous in the CEOs' local environment. It is weaker when CEOs live further away from where they work, because of limited exposure to local discontent.