The age of the first manifestations of Art in South Africa, as well as the chronology of the Middle Stone Age (MSA) lithic industries to which they are associated, are hotly debated. This is due to a lack of consensus about the available dating results obtained these last years by the application of the luminescence dating techniques. We propose in this ANR project to develop a new chronology of the MSA based on the direct dating of bio-minerals (ostrich eggshells –OES, snails and other carbonated and phosphated materials –teeth) using the U-series dating method (U/Th). But, conversely to the usual way of application of this method, our first objective is to map in our samples the distributions of uranium (238U-234U) and thorium (230Th-232Th) on large areas (typically, a few square millimetres) in order to identify zones not affected by post-depositional processes. Getting such spatial distributions has recently become possible thanks to the development of a high performance, unique in the world, high repetition rate UV femtosecond laser-ablation system allowing to achieve a resolution of typically 6 µm. Mapping the distributions of uranium and thorium would allow, theoretically, to compute ages but, because of the extremely low 230Th signal intensity, we will use the same laser-ablation system to sample the unaltered parts of these materials and get enough material for precise measurements. The second objective will then concern the analysis of these micro-samples (ranging from the sub mg to 100 mg): we will develop novel approaches in order to address the analytical challenge consisting in determining low uranium and thorium contents (2-500 ppb) and low abundant 234U and 230Th in these microsamples. Preliminary tests performed recently on OES by the partners of this consortium showed these new approaches could be successful: if it is confirmed, this would open new horizons for establishing a detailed chronology of numerous MSA sites, fuel the debate on the emergence of modern behaviors during the MSA period and perhaps, allow in the future the direct dating of engraved OES whose age could be as old as 80,000 years, what has never been done before. Beyond South African MSA, numerous studies could also be undertaken for archaeological sites spread all over the world with the ambitiousness to revisit the chronology of the Prehistory (<500 ka) on all continents. Moreover, these analytical developments could likely be transposed as well in other scientific domains, such as environmental sciences, nuclear safety or upstream petroleum industry where technical improvements usually open new perspectives. Keywords : High repetition rate UV femtosecond Laser-Ablation (fsLA-), Inductively Coupled Plasma Mass Spectrometry (ICPMS), U-series Dating method (U-Th); Geochronology; Ostrich EggShells (OES); Teeth; Art; Prehistory; Middle Stone Age (MSA); Early Modern Humans; Early Modern behavior; South-Africa. PARTNERS-list: Partner 1 = IRAMAT-CRP2A: UMR 5060 CNRS-Université Bordeaux Montaigne (France) + Prehistorians from South-Africa, Germany, France; Partner 2 = IPREM-LCABIE : UMR 5254 CNRS-Université de Pau et des Pays de l’Adour (France) ; Partner 3 = LSCE/IPSL : UMR 8212 CEA-CNRS-Université Versailles Saint-Quentin (France). Requested funding to the ANR = 126.9 k€. Project duration = 24 months, starting in January 2017 and finishing in December 2018.

The ENBRUNI project is in line with the current challenges of French and European research by being at the interface of several fields structuring the action plan of the APP ANR 2023. The team is composed of three UMRs and one UAR in the humanities and materials sciences, and is associated with professionals in the field of conservation-restoration of built heritage, whose complementary skills are in line with the interdisciplinarity of the project. It also relies on the metal working group (GT Metal) of the CNRS/Ministry of Culture scientific project created after the fire at Notre-Dame Cathedral in Paris. The impact of climate change on heritage buildings is at the heart of the concern of heritage conservation actors. Lead metal, which covers or adorns many buildings, has taken on a dark-red staining colour in recent decades that differs significantly from its usual grey appearance. The formation of plattnerite, a lead dioxide, is responsible for this, without modifying the corrosion resistance properties of this metal. However, it remains poorly understood. The problematic of the ENBRUNI project is therefore built from a concrete field observation. This research aims to contribute to the understanding of the appearance of the phenomenon of the dark-red staining on lead used in historical monuments. It is articulated in three axes. The first axis is devoted to the establishment of a thorough report on the emergence of this phenomenon: from the collection of archival data (photographs and climatic data), the aims is to compare the evolution of the dark-red staining on the national buildings, according to the uses of lead (rooftop, sculpture, geographical orientation), with the environmental changes (evolution of pollutants such as ozone, the dioxide of sulphur, the dioxide of nitrogen, the pluviometry, the temperature...) during the last thirty years. The second axis aims at characterizing the mechanisms of dark-red staining formation by the implementation of ageing in climatic chambers (sulphur dioxide, nitrogen dioxide, ozone) and multi-scale studies of real samples taken from a selection of buildings under restoration works (Saint-Pierre de Beauvais cathedral, Notre-Dame de l'Assomption cathedral of Clermont-Ferrand, the Sainte-Chapelle, Notre-Dame de Paris cathedral...). Finally, the third axis will be dedicated to the communication of the conclusions of this research. Indeed, in a context where the lead issue is essentially based on public health injunctions, the results obtained will contribute to an update of the knowledge acquired so far on the ageing of this material used for the roofing and the decorations of prestigious buildings of our heritage.

An LED-pumped luminescent concentrator (LC) is a parallelepiped-shaped luminescent material with LEDs on its large sides. After absorbing light from the LEDs, the material re-emits light into the LC which is guided to its edges. Concentration is achieved through total internal reflections. This leads to a luminance 10 to 20 times higher than that of the LEDs. This is an emerging field of research with a very high disruptive potential. The aim of the NewLight project is to develop concentrators over a large part of the optical spectrum (visible SWIR-short-wavelength infrared- and MWIR-medium-wavelength infrared) with a systematic, multidisciplinary approach, combining materials and systems. Inspired by solar concentrators, we will explore the concept of a "cascade concentrator": a first LED-pumped concentrator, called "primary", is used to pump a second concentrator, called "secondary". The materials are chosen so that the absorption and emission bands are matched, creating a cascade of wavelengths from the pumping LEDs to the emission of the secondary concentrator. Cascaded concentrators have the potential to emit an order of magnitude more light than current concentrators. The strategy of the NewLight project is to use well-known materials for the primary concentrators and to explore new materials for the secondary concentrators. New crystals will be developed for the visible and SWIR bands. New glasses will be developed for the SWIR and MWIR bands. In parallel, the NewLight project faces technological challenges related to the applications: concentrator efficiency, cooling and coupling to an output optical fibre. By using the symmetries of the concentrator structure and the recycling of light in the material, the NewLight project has the keys to solve these problems. The NewLight project is very ambitious, starting with new materials and ending with concentrator devices that are as close as possible to applications. This ambition is compatible with the duration of the project (48 months) thanks to the unique properties of LED-pumped concentrators: very low cost thanks to commercial LEDs and rapid development possible thanks to the simplicity of the architectures. The project is organised in 4 tasks coordinated by a "management" task, in a spirit of strong iteration. Two "materials" tasks and two "systems" tasks are combined, with a multidisciplinary approach. The proposed structures should allow to break luminance and power records for incoherent broad spectrum sources, setting up LCs as new reference sources. The NewLight project will open up new fields of application, with simple, reliable and robust solutions with a high potential impact on the photonics industry. Potential applications include: metrology, micro-spectroscopy, active SWIR imaging, red-green-blue projection, inspection and control of objects on production lines or light treatments in dermatology. Our strategy to maximize the impact of the NewLight project is built on the large experience of the consortium in the dissemination of scientific culture and in research valorization. The strategy includes patenting, scientific communication in large international conferences, publications in specialized and general open-access journals, and wide range dissemination to the general public. The goal is to raise the awareness of a large scientific community to the exceptional opportunities offered by luminescent concentrators, that the NewLight projet will contribute to reveal.

The aim of this project is to better understand the last stage of the production chain of a metal, lead, which was omnipresent in the Roman period, from the end of the Republic and under the Empire, that is, its marketing, its organisation, its logistics and its constraints, and the management of the resource. We propose here to work on one of the manufactured products that required large quantities of metal, the fistulae aquariae, or lead pipes that formed the water conveyance networks that Roman cities were equipped with. The latter provide information, both epigraphic (names of the craftsmen and/or clients) and geochemical (elemental and isotopic composition of the metal, which is that of the original ore), which, if duly analysed and cross-referenced, could provide information on the techniques used to manufacture the pipes, the origin of the metal used on them and, consequently, the sources of supply for the market, the evolution of the latter over time and the commercial strategies put in place. Epigraphy will allow us to better understand, thanks to the systematic inventory and the study of the names found on the pipes, the organisation of the lead market from the point of view of its actors, both private and public (emperors, cities), and the relationships they maintained between them. The project is therefore fundamentally interdisciplinary: it brings together researchers in history, archaeology and archaeometry around common problems. It will focus on several distinct geographical sectors, Rome and Ostia, Campania, Aquileia and Veneto, the middle Rhone valley and the cities of Mediterranean Gaul, which functioned as independent markets, but which should be compared in order to draw general conclusions about the global trade in Roman lead.

The “Neolithic way of life" developed in the Caucasus ca. 6200 BCE, which is fairly late when compared with the astonishing steps taken by Near-Eastern cultures in the neighbouring Fertile Crescent as early as the 9th mill. BC. The existence of organic links between the Neolithisation process of the Near-East and that of the Caucasus is still a matter of debate, but the Caucasus no doubt appears as a marginal, backward area in the overall dynamics that shaped part of South-western Asia in the early Holocene. During the following period, i.e. the Chalcolithic, these dynamics seemingly changed completely and South-Western Asia underwent a progressive shift in its centre of gravity: some time ca. the 5th-4th mill. BC, a change in circulation flows appeared in the obsidian procurement strategies of Iranian and north Mesopotamian communities, which started to exploit Caucasian obsidian beds as well, instead of focusing on East Anatolian deposits. This shift in obsidian sourcing networks is coeval with the development of major technical innovations such as extractive copper metallurgy and the production of wool fabrics, which led to the systematic exploitation of a new range of raw materials (salt and metal ores) and probably entailed the appropriation of new territories - the Highlands. At any rate, it appears that Transcaucasia became a major source of attraction for human groups living in Iran, North Mesopotamia and beyond from the Late Chalcolithic onwards (ca. 4500 BCE), as shown by the number of Chalcolithic and Early Bronze Age sites found in the Araxes and Urmiah basins. How should these profound, structural, changes be interpreted? The explanation that leaps to mind is of course that major changes in economic flows were prompted by technical innovations. We need to test this hypothesis by breaking down the intricate relationships between the development of these innovations, the quest for raw materials, and the rise of other practices, such as vertical pastoralism or long-distance nomadism. Indeed, innovations, which may be technological or zootechnological, may have involved the migrations and/or increasing mobility of human groups living in the Near and Middle East, as claimed by several studies. But the processes underlying the changes in economic flows are still poorly understood, while the reality of human migrations from the Near-East towards the Caucasus during the 4th mill. BC has been actively challenged. Altogether, it is the agency of Late Prehistoric Caucasian communities that is being debated, between a centre-vs-periphery perspective that considers the Highlands as a mere source of raw materials, exploited by the proto-urban communities of the lowlands, and an analytical stance that places the evolution of the Caucasus within the complexity of Eurasian dynamics in Late Prehistory, which integrates not only the Near and Middle East but also the Pontic universe and the northern steppes. Thus, this project lies at the core of on-going international research on: a) the neolithisation processes of the Caucasus, b) the interactions between the Caucasus and the Near and Middle-East from the Neolithic to the Bronze Age. Considering the state of the art, we have three goals in mind: i) the study of the Caucasian Neolithic, as seen from the Araxes basin, with a special emphasis on its possible connections with the Neolithic communities of the Fertile Crescent; ii) the study of interregional economic networks between the Neolithic and the Bronze Age, in relationship with the emergence of new economic hubs; iii) the study of the human mosaic developing in the Highlands during the 4th mill., with a view to identifying the various cultural groups involved in what appears as a "copper rush".