Marie Emilie Forget

Magali Rossi
email: magali.rossi@univ-smb.fr

Yann Gunzburger

Kristina Maud Bergeron

Agnès Samper

Estelle Camizuli

Trajectories of mining territories: An integrated and interdisciplinary concept to achieve sustainability

Keywords: Mining territories, territorial trajectories, interdisciplinary approach, social geology

à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction: Mines and societies

The extraction of mineral resources has contributed to the development of human societies since prehistoric times. Hematite was extracted and transformed for parietal art during the late Palaeolithic. Native metals, especially copper, gold and silver were first mined out for tool carving and jewellery during the Neolithic. The use of metals spread out as metallurgical processes (smelting) developed during the Late Neolithic and antiquity. Apart from jewellery and tool carving, gold and silver have been used for trade and money since antiquity, thus initiating development of monetarized societies. The ancient civilizations that controlled silver mines, such as the Athenians and subsequently, the Spartans, grew wealthy and expanded their territories by producing military equipment and financing armies for war [START_REF] Flament | Une économie monétarisée : Athènes à l'époque classique (440-338) : Contribution à l'étude du phénomène monétaire en Grèce ancienne[END_REF]. From antiquity to the industrial era, metals have been intensively mined out for manufacturing tools and other necessary goods, and for funding local and national economies. The extraction of mineral resources significantly increased during the 18 th and 19 th century, with the development of industries and infrastructures (railways, transportation, manufacturing, etc.) and personal consumption (clothing, building, furniture, etc.). The technical skills developed in mining territories together with the development of infrastructures for ore transportation and trading, contributed to developing new industries in these territories. Mining, therefore, frequently appears to be one of the first steps of territorial development and of other industrial or economic development [START_REF] Barbier | Scarcity, Frontiers and Development[END_REF]. Today, due to the development of high-tech industries and to the transition to low-carbon energies, metal needs have evolved and a wider variety of minerals are used and mined, such as base metals, trace and rare earth elements (nickel, molybdenum, cobalt, lithium, graphite, etc.).

Mining, as an activity with the potential to cause serious environmental impacts (some irreversible) but which is important economically, raises concerns in communities and sometimes accentuates or provokes tensions. Various types of conflicts are likely to arise during mine construction and operation, and often even after mine closure, as local people may struggle with environmental impacts for decades in case of ineffective remediation or its absence [START_REF] Merino Acuña | The politics of extractive governance: Indigenous peoples and socio-environmental conflicts[END_REF][START_REF] Arsel | The extractive imperative and the boom in environmental conflicts at the end of the progressive cycle in Latin America[END_REF][START_REF] Vargas | Social mobilisation in Colombia's extractive industries, 2000-2015[END_REF][START_REF] Smart | The political economy of Latin American conflicts over mining extractivism[END_REF]. Conflicts are likely to be related to the struggle for transversal resources (like water and energy) between mining companies and local communities [START_REF] Forget | Territorial Trajectories within a New Centre for the Globalised Mining Industry: the Andes of Northern Argentina[END_REF][START_REF] Bos | L'eau : ressource naturelle, ressource politique ? Reconstruction de la ressource hydrique en contexte d'opposition au secteur minier dans le nord du Pérou[END_REF], or to contrasting visions about territorial development. The role of governance, and the way it intertwines with local, national, and global politics, is also a key issue [START_REF] Liping | Global mining governance evaluation methods[END_REF][START_REF] Coumans | Minding the "governance gaps": Re-thinking conceptualizations of host state "weak governance" and re-focussing on home state governance to prevent and remedy harm by multinational mining companies and their subsidiaries[END_REF][START_REF] Haikola | Evolutionary governance in mining: Boom and bust in peripheral communities in Sweden[END_REF]. Social sciences widely documented the notion of the "social license to operate" [START_REF] Moffat | The paths to social licence to operate: An integrative model explaining community acceptance of mining[END_REF][START_REF] Zhang | Understanding the social licence to operate of mining at the national scale: a comparative study of Australia, China and Chile[END_REF][START_REF] Vanclay | Conceptualizing Company Response to Community Protest: Principles to Achieve a Social License to Operate[END_REF], the changes affecting territorial identity or the construction process of a mining identity [START_REF] Harner | Place Identity and Copper Mining in Sonora, Mexico[END_REF]Ballesteros and Ramirez, 2007;[START_REF] Parmenter | Aboriginal cultural awareness training for mine employees: Good intentions, complicated outcomes[END_REF], as well as uneven distribution of mining benefits, environmental injustices and unequal power relations [START_REF] Bridge | Contested Terrain: Mining and the Environment[END_REF][START_REF] Bebbington | Governing Extractive Industries[END_REF][START_REF] Rodríguez-Labajos | Environmental justice through the lens of mining conflicts[END_REF]. The social aspects of mining are thus key to understanding how this activity distinguishes itself as a human endeavour.

In this paper, we call for analysis of the complex interactions between mining and societies using the lens of "mining territories" and their "trajectories". As evidenced from the contributions in this special section, an integrative and interdisciplinary approach is the most adapted to characterize and understand in new ways mining territories. We believe that by broadening perspectives through these concepts, more paths towards sustainable solutions in mining will appear.

Mines and territories

Mining territories

A territory can be defined as a geographical entity with a variable extent, which has environmental, cultural, economic, administrative, and social specificities that differentiates it from others. The term "mining territory" hereafter refers to an arrangement of material and symbolic mining resources capable of structuring the practical conditions of the existence of a social collective and of informing this collective in return about its own identity (Debarbieux, 2003). It belongs to the large category of ''place'' used in geography, history and sociology [START_REF] Massey | A Global Sense of Place[END_REF][START_REF] Casey | The Fate of Place: A philosophical History[END_REF]. Historical roots and identity create specificities and constitute a resource for local development. Mining territories are therefore identified as portions of space, that are the object of intentions, and that are organised for and by mining activities. They are of various sizes but mostly fall within the sub-national scale, the local scale being generally referred to when addressing these territories. Their specificities are determined by the shape and type of the ore deposit, the techniques used for extraction (open-pit, underground) and mineral processing, the initial configuration of the territory (topography, climate, land use, etc.), the integration of mining activities in the life of the territory (e.g. labour force employed, specific service structures that can serve the population and economic spin-offs).

A mine --and its associated services --strongly impacts the site as well as the ecosystem and the neighbouring communities (Forget and Rossi; Scammacca et al., this issue). Mining strongly structures territorial organization through its infrastructures, investments in the territory and local communities, economic aspects, and contributions to the political life and identity of the territory. This territorial structure is configured by negotiations between local landowners (sometimes Indigenous communities) and mining companies [START_REF] O'faircheallaigh | Negotiations in the Indigenous World[END_REF], and through interactions with governmental entities. Specific territorial systems can be defined with a much larger meaning than their impact on landscape in mining enclosures. As mining tends to become the main economic activity of the local territory, it has a significant impact on the social and cultural local structures [START_REF] Admiraal | Maximizing the impact of mining investment in water infrastructure for local communities[END_REF]. It increases economic endowment and inequalities [START_REF] Mcdonell | The co-constitution of neoliberalism, extractive industries, and indigeneity: Anti-mining protests in Puno, Peru[END_REF], can trigger land-use and resources conflicts, and alters community identity [START_REF] Werner | Assessing impacts of mining: Recent contributions from GIS and remote sensing[END_REF][START_REF] Horowitz | Indigenous peoples' relationships to large-scale mining in post/colonial contexts: Toward multidisciplinary comparative perspectives[END_REF][START_REF] Smart | The political economy of Latin American conflicts over mining extractivism[END_REF].

Different territorial configurations may appear as a result of mining activity, from mining enclaves [START_REF] Le Meur | La politique du nickel en Nouvelle-Calédonie : entre gouvernance locale et gouvernance d'entreprise[END_REF][START_REF] Sidaway | Enclave space: a new metageography of development?[END_REF][START_REF] Magrin | Voyage en Afrique rentière. Une lecture géographique des trajectoires du développement[END_REF] to the (ideal but infrequent) coconstruction of mining territories. Beyond a local territory, a national political economy intercedes structurally in the functioning of the mining sector, both for material reasonsdeposits are often located in remote areas, far from existing infrastructures and networksand strategic reasons linked to regulatory frameworks, to social movements, etc. The logic of mining enclaves exists when local employment is disproportionate to the import of labour power by a "fly in-fly out" system [START_REF] Saxinger | Mobile Workers Guide -Fly-in/Fly-out and Rotational Shift Work in Mining[END_REF]. In contrast, a co-constructed mining territory may appear when the exploitation of the ore deposit cannot be physically separated from the other functions of the territory. Artisanal and small-scale mining generate other types of territories, much more complex than in the case of industrial mining [START_REF] Kemp | Characterising the interface between large and small-scale mining[END_REF].

Over the past 20 years, many studies have highlighted the close relationships and interdependence of nature and societies, which should be considered as integrated socioecological systems [START_REF] Berkes | Linking Social and Ecological Systems[END_REF][START_REF] Collins | An integrated conceptual framework for long-term social-ecological research[END_REF], considering: (i) that nature provides ecosystem services to societies (for the definition of ecosystem services, see [START_REF] De Groot | Environmental functions as a unifying concept for ecology and economics[END_REF][START_REF] Costanza | The value of the world's ecosystem services and natural capital[END_REF], (ii) that nature is impacted by human activities, and (iii) that both natural and social systems respond to endogenous and exogenous drivers (natural and/or anthropogenic), displaying resilience and complex reciprocal feedbacks (Liu et al., 2007). Mining territories can thus be considered as socio-ecological sub-systems, for which the natural and social systems are strongly driven and affected by mining activity, with complex feedback loops (Forget and Rossi; Scammacca et al., this issue).

For the purpose of this paper, four broad types of mining territories will be distinguished based on a temporal approach and on the notion of trajectory (see the y-axis on Figure 1). They are as follows:

• Former mining territories that used to host mining activities in the past, but that no longer have active mines (e.g., many regions in European countries). In these territories, the mining identity has often been lost or relegated to heritage [START_REF] Hendrychová | An analysis of 200-year-long changes in a landscape affected by large-scale surface coal mining: History, present and future[END_REF][START_REF] Oakley | After mining: Contrived dereliction, dualistic time and the moment of rupture in the presentation of mining heritage[END_REF]. Most raw materials are imported and the social acceptability of new potential mining projects is low (Beauloye et al., this issue).

• Territories with a long mining history and a strong mining identity nowadays, where mining has been taking place for more than a century (e.g., within Ireland, Scandinavia, the USA, Canada, Australia and Chile). There, mining remains one of the main economic activities and social acceptance is rather high [START_REF] Devenin | Characterizing a mining space: Analysis from case studies in Chile and Australia[END_REF]. • Territories without any former mining activity, but affected by a relatively recent (over the last decades) and rapid mining boom (e.g., within Latin America and Africa) that frequently generates socio-environmental conflicts [START_REF] Haslam | The determinants of social conflict in the Latin American mining sector: new evidence with quantitative data[END_REF][START_REF] Walter | Community mining consultations in Latin America (2002-2012): The contested emergence of a hybrid institution for participation[END_REF]). • Potential mining territories are territories with no former mining activities, but where mining projects are being developed or where advanced exploration is taking place. They may have been inaccessible regions, or areas with minerals in low concentration, or where the mineral resource is currently being re-evaluated (e.g., [START_REF] Mason | Charting the territory: Exploring stakeholder reactions to the prospect of seafloor exploration and mining in Australia[END_REF].

As indicated in Figure 1, the study of the abovementioned mining territories is only relevant at specific time-scales. Indeed, former mining activity may have occurred and structured the territory for tens to thousands of years, so that investigations at a short time-span (less than 10 years) are not relevant. On the opposite, investigation on emergent mining activity and possible future mining activity can only be realized with a short to medium-term perspective (up to ten years). The upper and lower grey triangles in Figure 1 represent areas in which the socio-environmental trajectories are thus either hard to predict or hard to study (e.g. short-term consequences of mining that happened a long time ago).

The contributions gathered in this special section cover the whole range of mining territories and time-scales, thus providing a rather good overview of these territories. The contributions of Balan, Beauloye et al., Jébrak et al., and Méndez even cover different types of mining territories (droplet symbols).

Trajectories of mining territories

Each mining territory can be defined by its specific socio-environmental trajectory. In physics, a trajectory describes the path of a moving mass in space and time. This dynamic concept has been recently applied to environmental sciences and humanities to describe the "pathways of changes" of socio-ecological systems facing climate change and natural phenomena, to discuss the drivers of these changes [START_REF] Fazey | Maladaptive trajectories of change in Makira, Solomon Islands[END_REF][START_REF] Wise | Reconceptualising adaptation to climate change as part of pathways of change and response[END_REF], as well as their response and their vulnerability (e.g., [START_REF] Wise | Reconceptualising adaptation to climate change as part of pathways of change and response[END_REF][START_REF] Murphy | Theorizing climate change, (im)mobility and socio-ecological systems resilience in low-elevation coastal zones[END_REF][START_REF] Li | Understanding socio-ecologicalvulnerability to climatic change through a trajectories of change approach: a case study from an indigenous community in Panama[END_REF]. It has also been used to describe changes in ecosystem services (e.g., [START_REF] Smiraglia | Linking trajectories of land change, land degradation processes and ecosystem services[END_REF][START_REF] Locatelli | Characteristic trajectories of ecosystem services in mountains[END_REF] and overall territorial changes (e.g., [START_REF] Rana | Explaining long-term outcome trajectories in social-ecological systems[END_REF] from the perspective of sustainable development.

Studies investigating the changes induced by mining activities at the territorial scale are mostly discipline-oriented (e.g., [START_REF] Forget | Territorial Trajectories within a New Centre for the Globalised Mining Industry: the Andes of Northern Argentina[END_REF][START_REF] Carrizo | Implantaciones mineras y trayectorias territoriales. El noroeste argentino, un nuevo centro extractivo[END_REF]. Interdisciplinarity is more widely used in economics, development studies, rural studies, geography, regional planning, and political sciences [START_REF] Watts | Resource curse? Governmentality, oil and power in the Niger Delta, Nigeria[END_REF][START_REF] Bainton | Stepping Stones Across the Lihir Islands: Developing Cultural Heritage Management in the Context of a Gold-Mining Operation[END_REF][START_REF] Kowasch | Le de ́veloppement de l'industrie du nickel et la transformation de la valeur environnementale en Nouvelle-Cale ́donie[END_REF][START_REF] Imbun | Maintaining land use agreements in Papua New Guinea Mining: 'Business as usual[END_REF], but generally, no attention is given to the ore deposit properties nor to the environment. In the approach we are proposing, considering a mining territory as a socio-geo-ecological system, a territorial trajectory must integrate the interactions between mining-related human activities, societies/communities, and the physical environment, as well as their evolution in space and time. In that perspective, the development of an integrated and multi-disciplinary approach is required, in order to (i) describe the social, economic, cultural, identity, geological, and environmental components of the system, (ii) describe and analyse their response to anthropogenic and natural drivers, (iii) characterize the feedback loops among the system components, and (iv) analyse the role of local policy and governance (Forget and Rossi, this issue).

Investigating territorial trajectories offers a better understanding of present-day territorial structuration and of past changes and their inheritance. Understanding how events that took place in the past currently impact socio-ecological systems is relevant to anticipate future alterations and to develop appropriate adaptation strategies (e.g., Liu et al., 2007;[START_REF] Fazey | Maladaptive trajectories of change in Makira, Solomon Islands[END_REF][START_REF] Fazey | Past and future adaptation pathways[END_REF]. Learning from the past to prepare for the future is a key to building sustainable territories.

3. Towards an interdisciplinary approach of mining territories

Mining territories at the crossroads of disciplines

Mining territories are, by their nature, at the crossroads of various scientific disciplines (Erb et al., this issue). To get a full understanding of their evolution and dynamics, one may use different lenses associated with:

• Geosciences: detailed geological investigations at the regional and local scales are involved during exploration; a good knowledge of the ore deposit geometry and distribution, local geology, and ore mineralogy is required for exploration, operation, and ore processing. • Engineering: mining productivity has been greatly enhanced in the last 50 years due to technological development in ore processing and exploitation techniques; • Environmental sciences: mining activity (metal extraction and ore processing) strongly impacts the environment through landscape modifications, removal of topsoils (for open-pit mining), dust emission, increased noise, habitat degradation, induced hydrological changes, air, water and soil contamination due to pollution or trace metal dispersion, etc. (e.g., [START_REF] Ripley | Environmental Effects of Mining[END_REF][START_REF] Dudka | Environmental impacts of metal ore mining and processing: a review[END_REF][START_REF] Younger | Mine water: hydrology, pollution, remediation, Environmental pollution[END_REF]. • Economics: mining activity, especially the exploration and exploitation phases, is driven by economic interests and profitability. Secondary economic activities, including services to the mine and services related to the growth of human settlements, also develop in a close dependence with mining activity (e.g. [START_REF] Xing | The effect of local supply chain on regional economic impacts of mining[END_REF]. Even though mining is important in structuring the territory, it may override other economic activities and finally lead to weakened economic development outcomes (see Dutch disease and resource curse theories; e.g., [START_REF] Watts | Resource curse? Governmentality, oil and power in the Niger Delta, Nigeria[END_REF]; van der Ploeg, 2010; Thistle 2016)

• Social and Human sciences: mining shapes and transforms social and cultural structures and human relationships; it may also increase economic endowment and inequalities, result in land-use and resources conflicts, and reshape community identity (e.g., Batterbury et al., 2018;[START_REF] Horowitz | Indigenous peoples' relationships to large-scale mining in post/colonial contexts: Toward multidisciplinary comparative perspectives[END_REF][START_REF] Werner | Assessing impacts of mining: Recent contributions from GIS and remote sensing[END_REF][START_REF] Smart | The political economy of Latin American conflicts over mining extractivism[END_REF]. • Political science and law: mining activities are framed by various laws, regulations, and public policies that oversee environmental protection, labour rights, economic orientations, or land planning, among other issues. The wider geopolitical context also influences corporate and public decision-making, as well as the relative attractivity of a given mining territory (e.g. [START_REF] Gale | Lies and misdemeanours: Nauru, phosphate and global geopolitics[END_REF]. Power relationships can be particularly salient in such contexts (e.g. [START_REF] Kirsch | Mining capitalism: the relationship between corporations and their critics[END_REF].

These fields of knowledge belong to three main groups of disciplines, each a replication of the three components of the mainstream definition of sustainable development (Figure 2):

-economics for all aspects related to economy and wealth; -social and political sciences for issues connected to power, governance, the social license to operate, social disparities, identity and heritage; and -natural sciences for assessing ore formation, environmental impacts, risks and vulnerability.

The exploitation of mineral resources is one of the most disturbing forms of anthropogenic activities considering both the social and cultural changes it provokes and its long-term environmental impacts and landscape modifications. Therefore, it essentially follows an unsustainable pathway (e.g., [START_REF] Kowasch | Nickel mining in northern New Caledonia -a path to sustainable development[END_REF]. To achieve a more sustainable development of mining territories, a deeper understanding of the complex relationships between all these aspects is required, which can only be obtained by crossing disciplinary perspectives. For example, the study of ore mineralogy, ore grade, rock and mineral textures, and deposit geometry determine the exploitation mode and ore-processing techniques that will be used in the mill; the type of exploitation and initial transformation circumscribe the local and national economic benefits and environmental impacts. In turn, local and national governance as well as the local and national political contexts directly influence the social impacts of mining. Apart from the researchers' point of view, there are other mechanisms at stake within the industry and society at large in demand for action against climate change and for better sustainability, that contribute to the push for interdisciplinary approaches.

Economic geology (Figure 2) is the part of geosciences focusing on earth materials that can be used for economic and/or industrial purposes. It aims at providing knowledge on the ore genesis, the ore mineralogy and geochemistry, the ore content and distribution of ore deposits, etc., that is relevant for the industry in order to plan more efficient exploration, and to develop more efficient ore processing techniques. However, as proposed by Stuart and Gill (2017), the links with social sciences are key to harness the contributions geosciences can make to sustainability thinking, a stance the editors of this special section are sharing.

Social geology could be defined as the study of the interactions between the geological environment and the social sphere. It represents a third applied geoscience, alongside economic geology and environmental geology. According to social geology, an ore deposit is both a geological and a social object, thus sharing the idea that it is a socio-geo-ecosystem. The characteristics of an ore deposit (its size, its accessibility, its toxicity, its usefulness or its value, for example) influence the way a community (or even a society) will relate to it, in a physical sense (how it will be used) as much as in a psychological sense (how it will be part of its identity). Social geology helps us consider how geology impacts human beings, and how human communities connect with their geological environment. In some cases, human activities can also impact geology --as we are seeing with the omnipresence of plastics and the use of "Anthropocene" to describe the current geological era --but this may be better captured by the idea of anthropogeology [START_REF] Häusler | Did anthropogeology anticipate the idea of the Anthropocene?[END_REF].

If economic geology was born around 1910 [START_REF] Jébrak | Geology of Mineral Resources[END_REF][START_REF] Arndt | Classification, Distribution and Uses of Ores and Ore Deposits[END_REF], social geology is a much more recent expression to describe this focus on the nexus between the two spheres. [START_REF] Jébrak | Social geology applied to mineral deposits[END_REF] has traced a few articles using the concept, going back no further than 2012 [START_REF] Mata-Perello | Social geology: a new perspective on geology[END_REF], although much more work can be classified as part of this new discipline since social scientists and economists have been considering social dynamics around mining and other earth-related phenomena (like earthquakes) for many decades. The booming literature on the social license to operate can certainly be associated with social geology in many instances.

The contributions of this special issue to interdisciplinary research on mining territories

Conducting new, interdisciplinary research thus appears to be key in understanding the growth and evolution of mining territories (Forget and Rossi, this issue). Most of the literature on mining and its related territorial developments is currently essentially segmented by disciplines, whereas interdisciplinary studies are essentially restricted within a disciplinary field (either geosciences, or environmental sciences or social sciences). Encouraging interdisciplinary studies across disciplinary fields is not an easy task. Apart from institutional obstacles, scientists interested in pushing for interdisciplinary works must face cognitive obstacles, including methodological and conceptual barriers [START_REF] Szostak | The state of the field: Interdisciplinary research[END_REF]MacLoad, 2018). Indeed, in order to understand each other, scientists from various disciplinary fields must share the same language and be ready to open-up to new concepts, methods and ways of thinking. At the same time, few scientific journals interested in mineral resources and extractives industries are open to welcoming papers tackling these topics from the point of view of different scientific disciplines. The Extractive Industries and Society is one of very few.

A first step in breaking down barriers among scientific communities and to get to know each other is organising interdisciplinary meetings and meeting sessions. The TRAMIN conference ("Socio-environmental Trajectories of Mining Territories") was co-organized in Chambéry (France) in October 2018 by Marie Forget (human geography), Magali Rossi (geosciences), Estelle Camizuli (environmental sciences), Kristina Maud Bergeron (political science), Yann Gunzburger (mining engineering), and Agnès Samper (geosciences) for this purpose. It gathered more than 80 scientists from all over the world, in the fields of archaeology, history, human geography, anthropology, political science, economics, environmental sciences and geosciences, in order to discuss the social and environmental impacts of mining on communities' development, and the transformation and conversion of both former and current mining territories. The same year, a session dedicated to Social Geology was set up by Michel Jébrak and Yann Gunzburger (geosciences) during the international RFG conference ("Resources for Future Generations") held in Vancouver (Canada).

This special issue of The Extractive Industries and Society is gathering papers from people who attended these two conferences. These papers have in common not to focus on isolated mining projects, but to discuss the relationships between mining and its human and physical environment at the scale of a territory. Indeed, the territorial scale is the most adapted to cross disciplines regarding mining activities, enabling apprehension of the various facets of mining.

The papers gathered hereafter have been plotted on Figure 1 and Figure 2. Charting all the above-mentioned contributions on Figure 2 highlights their interdisciplinarity. The papers with the most multidisciplinary approach are located in the center; they investigate the sustainability of socio-environmental trajectories of mining territories. Most of the papers fall into the social geology field. As mentioned above, the contributions of this special section cover a wide range of territories and time spans (y-axis and x-axis respectively on Figure 1). Mining territories have been studied over a time scale of a couple years up to several centuries. It illustrates the fact that the consequences of mining are long-lasting and may even be perceptible a long time after mining ended (e.g., Zheng et al. and Camizuli et al. who respectively investigated the environmental impacts during mining and hundreds of years after mine closure). The temporal approach allows an analysis of the past through research on very old mines that have left their mark on the landscape and on today's societies. Mines that are currently mined will themselves leave traces in the very long term. The notion of mining heritage is multiple and contains environmental, social, industrial, and patrimonial aspects (Balan; Bozzuto and Geroldi; Camizuli et al., Heer et al.; Marot and Harfst). Whole territories are structured by places of production and places of use of the resources, and their development generally goes beyond the mining site alone. Mining projects have to be seen as development projects of the territories, in particular for network development (transportation, energy and communications). Nonetheless, only a few papers examine the case of territories that may face new mining activities in the future (Balan; Beauloye et al.), which demonstrates how difficult it is to anticipate the trajectories of areas that will be concerned by mining for the first time.

Perspectives for future research on mining territories

Mining-led development and its effects are the result of complex interactions, at different scales (local, regional, national, international), between private and public actors, between local communities, private companies, and public and political institutions. Taking better account of the spatial and temporal dimensions of mining activities is key to sustainably manage the positive and negative impacts of mining. A broader lens takes into account how stakeholders interplay, how political economy influences decision-making, how conflicts and negotiations sometimes interfere with technical aspects, how public policies and state building guide entrepreneurial endeavours, or how environmental impacts are perceived by communities. It shows why it is important to consider the persistent impacts of mining, for the environment, the economy, and society, in the design and implementation of new projects.

An interdisciplinary dialogue ultimately makes it possible to re-historicize and re-spatialize the issues related to the deployment of mining activities. It allows the highlighting of territorial specificities over a long time span, and underlines the numerous spatial scales related to the study of mining territories. Interdisciplinarity also helps in analysing the footprints on the territory, and the inheritance and management of transverse services (water and energy in the first instance) as a complex system.

In order to face the challenge of developing sustainable mining, geologists must be trained not only in the knowledge of geological objects and processes, but in the relationships between geological objects and processes and the other components of socio-geoecosystems [START_REF] Katz | The need for socially responsible university educated professionals in the extractive industries[END_REF]. By changing our perspective in this way, we could redefine the notions of economic, environmental and social geology as interdisciplinary fields bringing respectively together geologists and economists, geologists and environmental scientists, and geologists and social and human scientists, in regards to the socio-geo-ecosystems characteristics and to local governance.

The analysis of the integration of mineral deposits and mines into their territories and the study of their trajectories makes it possible to define sustainable development strategies, taking into account the past, the present, and the future, and the characteristics and uniqueness of a given area.

Figure 1 .

 1 Figure 1. Overview of the time spans (x-axis) and types of territories (y-axis) covered by the papers gathered in this special section. Papers gathered in this issue: 1: Balan: 2: Beauloye et al., 3: Bergeron; 4: Bozzuto & Geroldi; 5: Camizuli et al.; 6: Erb et al.; 7: Forget & Rossi; 8: Heer et al.; 9: Jébrak et al.; 10: Le Meur et al.; 11: Marot & Harfst; 12: Méndez; 13: Rey et al.; 14: Rey-Coquais; 15: Richard et al.; 16: Scammacca et al.; 17: Zheng et al.

Figure 2 .

 2 Figure 2. Overview of the papers gathered in this special section, in terms of the scientific disciplines they rely on. Papers gathered in this issue are listed in the caption of Figure 1.

  Jébrak et al. show how mineral resources benefits are kept out of reach of the territory's community within territories such as French Guiana. Future mining development must therefore integrate the territorial economy benefits, together with impact and risk assessment (Rey et al.; Scammacca et al.), and negotiations with local stakeholders and civil society for decision-making (Le Meur et al.; Rey-Coquais; Richard et al.; Scammacca et al., Beauloyeet al.). Social geology appears to be a good approach in order to evaluate and enhance social acceptability and to develop more sustainable mining (Bergeron; Erb et al.), and to avoid social and land-use conflicts (Balan; Méndez).

	Zheng et al. investigate the effects of mining on the environment and human health,
	providing guidelines to live close to an active mine, whereas Camizuli et al. investigate the
	long-term environmental impacts of mining over centuries. Mining heritage is being
	discussed considering mine closure, rehabilitation of mining sites and post-mining activities
	(Bozzuto and Geroldi; Heer et al.; Marot and Harfst), and in the perspective of mine
	reopening in former mining territories (Balan). Forget and Rossi present a new framework
	for assessing territorial changes (considering the geological, environmental, economic,
	social and cultural aspects) during the life cycle of a mining project, from exploration to post-
	mining activities and rehabilitation.

Acknowledgements

The authors are very grateful to Michel Jébrak, Maribeth Erb, Matthias Kowasch and Dominique Gasquet for their support and constructive comments in the organisation of the

Acknowledgements

The authors are very grateful to Michel Jébrak, Maribeth Erb, Matthias Kowasch and Dominique Gasquet for their support and constructive comments in the organisation of the TRAMIN meeting and for reviewing several contributions of this special section. We would also like to thank all the reviewers for their time and the quality of their feedback, and all the conferences' participants for the exciting discussions. This work was supported by the University Savoie Mont-Blanc and the French National Research Agency through the national program "Investissements d'avenir" with the reference ANR-10-LABX-21 -RESSOURCES21. It was also sponsored by the Mine & Society network of excellence.

TRAMIN meeting and for reviewing several contributions of this special section. We would also like to thank all the reviewers for their time and the quality of their feedback, and all the conferences' participants for the exciting discussions. This work was supported by the University Savoie Mont-Blanc and the French National Research Agency through the national program "Investissements d'avenir" with the reference ANR-10-LABX-21 -RESSOURCES21. It was also sponsored by the Mine & Society network of excellence.


Sébastien Villotte
email: sebastien.villotte@cnrs.fr

Frédéric Santos

Umr7206

The effect of age on entheseal changes: a study of modifications at appendicular attachment sites in a large sample of identified human skeletons Authors

Keywords: fibrous enthesis, fibrocartilaginous enthesis, musculoskeletal stress markers, regression model, log-linear model, adjusted standardized residual, generalized odds ratio

Entheseal changes (EC) are frequent in older individuals, and age-at-death is the main variable explaining the distribution of EC stages in adult skeletal samples. While this is already well known, the underlying process has not been studied in biological anthropology to date. The aim of the article is to describe the relationship between age and stages of EC in detail for 30 appendicular entheses in a large sample of adult skeletons (N=721) with known age-at-death and sex, using several statistical tools (such as Spearman's rank correlation coefficients, logistic regression models, adjusted standardized residuals, and generalized odds ratios). The analyses indicate a moderate to strong relationship between age-at-death and EC for all the appendicular attachment sites, but also striking differences between fibrous and fibrocartilaginous entheseal attachment sites. These differences are discussed in light of the available biomedical data.

Introduction

The study of skeletal changes at entheses (i.e., tendon and ligament attachment sites) has a long history. Early on, these changes were directly linked to muscular recruitment, often in a rather simplistic cause and effect relationship (see [START_REF] Jurmain | Bioarchaeology's Holy Grail: The Reconstruction of Activity[END_REF]. Since then, many scholars have expressed concerns about the validity of this approach, highlighting several factors that influence the appearance of such changes, the main one being age [START_REF] Dutour | Activités physiques et squelette humain : le difficile passage de l'actuel au fossile[END_REF][START_REF] Jurmain | Bioarchaeology's Holy Grail: The Reconstruction of Activity[END_REF][START_REF] Villotte | Understanding Entheseal Changes: Definition and Life Course Changes[END_REF]. In identified skeletal collections, it has been shown repeatedly that age-at-death is the main variable explaining the distribution of entheseal changes (EC) in adults [START_REF] Cardoso | Enthesopathy formation in the humerus: Data from known age-atdeath and known occupation skeletal collections[END_REF][START_REF] Cunha | What can bones tell about labour and occupation: the analysis of skeletal markers of occupational stress in the Identified Skeletal Collection of the Anthropological Museum of the University of Coimbra (preliminary results)[END_REF][START_REF] Henderson | The new Coimbra method for recording entheseal changes and the effect of age-at-deathLa nouvelle méthode Coimbra: changement au niveau des enthèses et influence de l'âge au décès[END_REF][START_REF] Listi | The Use of Entheseal Changes in the Femur and Os Coxa for Age Assessment[END_REF][START_REF] Mariotti | Enthesopathies -Proposal of a Standardized Scoring Method and Applications[END_REF][START_REF] Mariotti | The Study of Entheses: Proposal of a Standardised Scoring Method for Twenty-Three Entheses of the Postcranial Skeleton[END_REF][START_REF] Milella | The effect of age, sex, and physical activity on entheseal morphology in a contemporary Italian skeletal collection[END_REF][START_REF] Niinimäki | What do muscle marker ruggedness scores actually tell us?[END_REF][START_REF] Shaibani | The significance of enthesopathy as a skeletal phenomenon[END_REF][START_REF] Takigawa | Age changes of musculoskeletal stress markers and their inter-period comparisons[END_REF]Villotte et al., 2010a). When Pearson correlation coefficients are provided, a substantial part of variation (ca. 20%, but up to 48%) is explained by age alone (Table 1). While the influence of age is now integrated in most studies of EC in bioarchaeology, the underlying process is not well understood and, at present, does not appear to have been properly studied in biological anthropology.

<INSERT TABLE 1 HERE>

For some bioarchaeologists, skeletal changes gradually appear throughout the life course and become more and more extreme due to the accumulation of stress produced by physical activity (e.g., [START_REF] Alioto | A New Division of Labor? Understanding Structural Violence Through Occupational Stress: An Examination of Entheseal Patterns and Osteoarthritis in the Hamann-Todd Collection[END_REF][START_REF] Robb | The interpretation of skeletal muscle sites: a statistical approach[END_REF]. Alioto (2020, p. 184) considers, for instance, that "older individuals will have built up stronger attachment sites over time than younger individuals." It seems that for these scholars, most EC are "physiological", and the mechanism behind the appearance of entheseal changes can be ascribed to "muscle use". According to other scholars who consider skeletal changes at entheses as pathological (and call them enthesopathies), at least two phases can be identified during adulthood: an early phase where overuse can induce microtrauma, and a second phase in adulthood, starting during the 6 th decade of life, marked by a generalized degeneration of the soft and hard tissues (e.g., [START_REF] Dutour | Enthesopathies (lesions of muscular insertions) as indicators of the activities of Neolithic Saharan populations[END_REF]Villotte et al., 2010b). This apparent discrepancy is, in our opinion, likely related to the nature of the entheses analyzed in these studies: both fibrocartilaginous and fibrous entheses in the first case and only fibrocartilaginous attachment sites in the second.

The relevance of the distinction of fibrous and fibrocartilaginous entheses in biological anthropology has been previously discussed in detail (e.g., [START_REF] Jurmain | Bioarchaeology's Holy Grail: The Reconstruction of Activity[END_REF][START_REF] Villotte | Understanding Entheseal Changes: Definition and Life Course Changes[END_REF]. Briefly, in fibrous muscular attachment sites, which occur typically on the diaphysis of long bones, collagen fibers from tendons or ligaments attach to bone directly or via a mediating layer of periosteum [START_REF] Benjamin | The skeletal attachment of tendons -tendon "entheses[END_REF]. The surface of such entheses is usually irregular and poorly delimited on adult skeletal remains. Lesions at fibrous attachment sites are rarely mentioned in the medical literature (for a review, see [START_REF] Henderson | Do diseases cause entheseal changes at fibrous entheses?[END_REF][START_REF] Villotte | Enthésopathies et activités des hommes préhistoriques Recherche méthodologique et application aux fossiles européens du Paléolithique supérieur et du Mésolithique[END_REF], justifying avoidance of the term "enthesopathy" for the EC frequently seen at these sites. Fibrocartilaginous entheses are mostly found at long bone extremities and are characterized by two mediating layers, uncalcified and calcified fibrocartilage, between tendon/ligament fibers and bone. These two fibrocartilaginous layers are avascular and separated from each other by a regular calcification front, which represents the surface observed on dry bones [START_REF] Benjamin | The skeletal attachment of tendons -tendon "entheses[END_REF]. The role of age, mechanical stresses, and systemic conditions (such as spondyloarthropathies) in the occurrence of enthesopathies at fibrocartilaginous sites is relatively well documented in the biomedical literature (for a review, see [START_REF] Jurmain | Bioarchaeology's Holy Grail: The Reconstruction of Activity[END_REF][START_REF] Villotte | Enthésopathies et activités des hommes préhistoriques Recherche méthodologique et application aux fossiles européens du Paléolithique supérieur et du Mésolithique[END_REF][START_REF] Villotte | Understanding Entheseal Changes: Definition and Life Course Changes[END_REF].

At first glance, the relationship between age and EC does not appear to dramatically differ between fibrous and fibrocartilaginous entheses in identified skeletal collections [START_REF] Listi | The Use of Entheseal Changes in the Femur and Os Coxa for Age Assessment[END_REF][START_REF] Milella | Estimation of adult age-at-death from entheseal robusticity: A test using an identified Italian skeletal collection[END_REF][START_REF] Takigawa | Age changes of musculoskeletal stress markers and their inter-period comparisons[END_REF][START_REF] Villotte | Enthésopathies et activités des hommes préhistoriques Recherche méthodologique et application aux fossiles européens du Paléolithique supérieur et du Mésolithique[END_REF]. However, it seems that this subject has only been studied superficially to date. The aim of this study is thus to describe in detail the relationship between age-at-death and changes at fibrocartilaginous and fibrous entheseal attachment sites in a large sample of skeletons of known age-at-death and sex. Previous analyses [START_REF] Villotte | Enthésopathies et activités des hommes préhistoriques Recherche méthodologique et application aux fossiles européens du Paléolithique supérieur et du Mésolithique[END_REF]Villotte et al. 2010a) have shown that a strong and significant positive correlation exists between age-at-death and EC stages in this skeletal sample. In order to better understand the underlying processes governing the appearance of such changes, the hypotheses we aim to test here are the following: 1) Considering the anatomical differences between fibrous and fibrocartilaginous entheses, the relationship between age-at-death and EC stages should not be identical in the two groups;

2) In our sample, the distribution of EC at fibrocartilaginous attachment sites should be in accordance with medical data (e.g. [START_REF] Bakirci | Entheseal Changes in Response to Age, Body Mass Index, and Physical Activity: An Ultrasound Study in Healthy People[END_REF][START_REF] Bard | Physiopathologie, réparation, classification des tendinopathies mécaniques[END_REF][START_REF] Durigon | Enthèse au cours de la vie[END_REF][START_REF] Rodineau | Pathogénie des enthésopathies du membre supérieur[END_REF], with major skeletal changes mainly seen in individuals who died after the 5 th decade of life;

3) In our sample, the distribution of EC at fibrous attachment sites may reflect a more gradual increase in skeletal changes throughout the life-course.

Material and methods

Identified skeletal collections

The sample includes skeletons of Europeans who died between the 18th and 20th centuries, from four collections: the Christ Church Spitalfields Collection at the British Museum of Natural History, London (UK) [START_REF] Molleson | The Spitalfields project[END_REF]; the identified skeletal collection of the Anthropological Museum of the University of Coimbra, Portugal (Rocha, 1995;[START_REF] Santos | A skeletal picture of tuberculosis. Macroscopic, radiological, biomolecular, and historical evidence from the Coimbra Identified Skeletal Collection[END_REF]; and the Sassari and Bologna collections of the Museum of Anthropology, University of Bologna, Italy [START_REF] Facchini | Les collections ostéologiques et ostéoarchéologiques du musée d'Anthropologie de l'université de Bologne (Italie)[END_REF]. Personal information (age-at-death, sex, cause-of-death, occupation…) is available for most of these individuals, but only the age-at-death and sex were considered in the analyses of the present study. Only skeletally mature individuals (arbitrarily fixed at an age-at-death of 20 years or over) were included in this study.

Poorly preserved skeletons, as well as pathological specimens, especially cases of diffuse idiopathic skeletal hyperostosis and seronegative spondyloarthropathy (for a detailed presentation of the criteria used, see [START_REF] Villotte | Enthésopathies et activités des hommes préhistoriques Recherche méthodologique et application aux fossiles européens du Paléolithique supérieur et du Mésolithique[END_REF]Villotte et al., 2010a), were excluded. Fractured limb bones were not scored.

Ultimately, 721 subjects were selected for this study (Table 2). The data set is available at https://zenodo.org/record/6805623.

<INSERT TABLE 2 HERE>

Recording method

Thirty (12 fibrous and 18 fibrocartilaginous) appendicular entheses were studied using an ordinal scale with three scoring stages [START_REF] Villotte | Connaissances médicales actuelles, cotation des enthésopathies : nouvelle méthode[END_REF]. Here, we briefly present these stages for both groups of entheses (for definitions and illustrations of the terms used, see [START_REF] Villotte | Connaissances médicales actuelles, cotation des enthésopathies : nouvelle méthode[END_REF][START_REF] Villotte | In search of consensus: Terminology for entheseal changes (EC)[END_REF].

The 12 fibrous entheses are presented in the Table 3 Stage A: the site of attachment is smooth, well circumscribed and devoid of vascular foramina; Stage B: Slight modifications affecting the margin (irregularities or enthesophyte(s)), and/or the inner part (irregularities, foramina, cystic changes, calcified deposits, bony production, or osseous defects) of the enthesis;

Stage C: Major modifications affecting both the margin and the inner part of the enthesis.

Statistical analyses

In previous studies [START_REF] Villotte | Enthésopathies et activités des hommes préhistoriques Recherche méthodologique et application aux fossiles européens du Paléolithique supérieur et du Mésolithique[END_REF]Villotte et al., 2010a), this data set was (completely or partially) analyzed using generalized estimating equations. While such an approach seems appropriate in order to describe the overall effect of contributing factors, such as age-at-death and occupation, at the individual level, we preferred a different approach in this study. Using several statistical methods, we analyzed the relationship between stages in EC and age-at-death for each of the 30 entheses, but illustrated in detail only the results for one fibrous (the left deltoid tuberosity) and one fibrocartilaginous (the left lateral epicondyle of the humerus) attachment sites. These entheses were chosen as they are: 1) frequently studied in bioarchaeology, and 2) "typical" of each type of attachment site.

In this study focusing on the effect of age on entheseal modification, we used the information about age-at-death as both a continuous and a categorical (age groups) variable, depending on the analysis employed. Five age groups (Table 2) were arbitrarily defined in order to obtain similar numbers of individuals in each group. The mode and relative stage frequency were used to describe the distribution of the EC data for each enthesis, and its relationship with age-at-death was assessed using Spearman's rank correlation coefficients and Fisher exact tests. Distributions of changes according to age groups were illustrated using stacked bar plots, and mosaic plots [START_REF] Friendly | Mosaic Displays for Multi-Way Contingency Tables[END_REF] were created to visualize the effect of sex on these distributions.

For each attachment site, an ordinal logistic regression model (Agresti, 2002) was defined, with the trichotomic entheseal stage as the ordered response variable, and age group, sex and their interaction as explanatory variables. For each ordinal logistic regression model, the main effects of age and sex, along with the effect of their interaction terms, were tested in an analysis of deviance table using type II tests. Alternatively, log-linear models (Christensen, 1997) were built to assess the significance of the interaction between sex, age group and entheseal changes for each locus; theoretical details and results are provided in Supporting Information A, section 4.4.2.

We also used several approaches described in [START_REF] Sharpe | Chi-Square Test is Statistically Significant: Now What? Practical Assessment[END_REF] in order to determine the source of statistically significant differences between age groups. Specifically, we computed "adjusted standardized residuals", as defined in [START_REF] Sharpe | Chi-Square Test is Statistically Significant: Now What? Practical Assessment[END_REF], in order to identify specific cells making the greatest contribution to chi-square test results. When there are many cells (as in our analyses), an absolute value for an "adjusted standardized residual" exceeding about 3 is a good indicator of lack of fit of H0 for that specific cell. We thus used that value as a guide to which cells were of interest.

In order to compare the distributions of entheseal changes (considered as ordinal variables) across two given age groups, Fisher exact tests were performed and generalized odds ratios [START_REF] Agresti | Generalized Odds Ratios for Ordinal Data[END_REF] were computed. A generalized odds ratio expresses the probability that entheseal changes are stochastically greater in one given age group; i.e., it is equal to the ratio P(X > Y) / P(Y > X), where X is the random variable for entheseal changes in the first group and Y the random variable for entheseal changes in the second group.

All statistical analyses were performed using R 4.2.1 (R Core Team, 2022). For all tests, the significance threshold was set to α = 0.05. A PDF export of a notebook created with Org mode 9.5.5 [START_REF] Schulte | A Multi-Language Computing Environment for Literate Programming and Reproducible Research[END_REF]) contains all corresponding R codes, and can be found online as Supporting Information A.

<INSERT TABLES 3 AND 4 HERE>

Results

3.1. Frequencies, and their relationship with age-at-death in the entire sample For all fibrocartilaginous sites, changes are relatively rare in the whole sample: the mode corresponds to stage A. In comparison, changes at fibrous entheses appear far more common, with stage B as the mode for all fibrous sites, except for the tibial origin of the M. soleus (Table 3).

Figure 1 presents the bar plots for the left lateral epicondyle and the left deltoid tuberosity of the humerus as examples of trends seen for fibrocartilaginous and fibrous entheses, respectively (bar plots for the other entheses are available in the online as Supporting Information B). For both types of entheses, changes tend to be more common in older age groups (Fig. 1). This is illustrated by a positive, significant, and moderately strong correlation between age (as a continuous variable) and ordinal stages, which is seen for all (fibrous and fibrocartilaginous) entheses under study (Tables 3 and4).

<INSERT FIG 1 HERE>

While the correlation coefficients between age-at-death and stages of entheseal changes are similar for fibrocartilaginous and fibrous sites, the distribution of entheseal changes in age groups differ completely, as observed graphically between the two groups of entheses (Fig. 1

Ordinal logistic regressions for each enthesis

Results of models testing the main effects of the two covariates (age and sex), along with their interaction terms, for each enthesis, are summarized in Table 5. At a significance level of 0.05, the effect of age-at-death (as a continuous variable) is highly significant in all models, the effect of sex is significant for 10 (out of 12) fibrous entheses, and 13 (out of 18) fibrocartilaginous attachment sites.

The effect of the interaction of these two covariates is significant in relatively few (4 out of 30) models.

Similar results were obtained when age groups (as a categorical variable) were used instead of age classes as the response variable, although a few models associated with the entheses with the highest proportions of missing values did not converge correctly in this case (results not shown). Overall, changes are more frequent in older individuals for all entheses and tend to be more frequent in males than in females for most of them, regardless of the nature of the enthesis (Table 5).

<INSERT TABLE 5 HERE> 3.3. Models and post-hoc analyses for the left deltoid tuberosity of the humerus Figure 2 presents a mosaic plot describing the distribution of stages by age groups and sex for the left deltoid tuberosity of the humerus.

Main effects of sex

In an ordinal logistic regression predicting entheseal changes for the left deltoid tuberosity, the main effects of age group and sex are found to be significant (P < 0.001 in both cases), whereas the interaction was not (P = 0.852). These results are identical to those obtained when raw age (in years) is used instead of age groups (full results are given in Supporting Information A, Section 4.4.1).

When adjusted for age, males tend to display more changes than females: for each age group, changes are more frequent in males (Figure 2). Moreover, major changes (stage C) seem to appear earlier in life in the male sample than in the female sample (Figure 3).

<INSERT FIGURES 2 AND 3 HERE>

Main effects of age

Table 6 presents the results of Fisher exact tests and generalized odds ratios for each comparison of paired age groups for the male sample. The highest odds ratio is seen for the comparison between the [20-29] and [30][31][32][33][34][35][36][37][38][39] age groups (Gen OR = 2.23; 95% CI = [1.62, 3.05]), and then the values decrease regularly down to ca. 1 in subsequent pairwise comparisons of consecutive age groups. These results can be interpreted as a very rapid increase in frequencies of changes (most at stage B) during early adulthood (i.e., before 40 years old) followed by a plateau (Figure 2). As for males, the main differences in pairs of consecutive age-groups are seen in early adulthood in the female sample, although the increase in entheseal change scores appear more regular (Figure 2), with no significant differences between [30-39] and [40][41][42][43][44][45][46][47][48][49], [40-49] and [50-59], and [49-59] and [60-99] age groups (Table 7).

<INSERT TABLES 6 AND 7 HERE> 3.4. Models and post-hoc analyses for the left lateral epicondyle of the humerus Figure 4 is a mosaic plot describing the distribution of EC stages by age and sex for the left lateral epicondyle.

Main effects of sex

In an ordinal logistic regression model predicting entheseal changes for the left lateral epicondyle, the main effects and age group and sex are significant (P < 0.001), whereas the interaction is not (P = 0.748). Once again, the overall conclusions remain unchanged when using raw age (in years) instead of age groups. When adjusted for age, females tend to display greater changes than males. This is especially clear after 40 years of age (Figure 4). However, major changes (stage C) seem to appear slightly earlier in life for males than for females (Figure 3).

<INSERT FIGURE 4 HERE>

Main effects of age

Table 8 presents the results of Fisher exact tests and generalized odds ratios for each comparison of paired age groups for the male sample. These results indicate very similar (and relatively low, see Figure 4) frequencies of EC in age groups before 50 years of age, and a significant, dramatic and regular increase of changes after that age. Very similar results were obtained for the female sample (Table 9), although the increase in changes with age appears more regular than for males, both graphically and based on the values of generalized odd ratios. In both sexes, major changes appear after 50 years of age (Figures 3 and4).

<INSERT TABLES 8 AND 9 HERE>

Discussion and conclusions

Several variables have been identified as possibly or probably influential factors that affect the frequencies of EC in archaeological samples, including physical activities, mobility patterns and body mass (e.g. [START_REF] Carballo-Pérez | Quotidian lives on isolated bodies: Entheseal changes and cross-sectional geometry among the aboriginal population of La Gomera (ca. 200-1500 AD, Canary Islands)[END_REF][START_REF] Godde | Entheseal changes and demographic/health indicators in the upper extremity of modern Americans: Associations with age and physical activity[END_REF][START_REF] Laffranchi | Gendered division of labor in a Celtic community? A comparison of sex differences in entheseal changes and long bone shape and robusticity in the PRE-ROMAN population of Verona (Italy, third-first century BC)[END_REF][START_REF] Refai | Entheseal changes in ancient Egyptians from the pyramid builders of Giza-Old Kingdom[END_REF]Sparacello et al., 2020), but age-at-death remains the main factor explaining EC distribution in human skeletal samples. In our study, stages clearly correlate with age for both fibrocartilaginous and fibrous entheses. This result is in agreement with previous analyses of EC in identified collections (Table 1). As noted previously by many other scholars [START_REF] Cardoso | Enthesopathy formation in the humerus: Data from known age-atdeath and known occupation skeletal collections[END_REF][START_REF] Cunha | What can bones tell about labour and occupation: the analysis of skeletal markers of occupational stress in the Identified Skeletal Collection of the Anthropological Museum of the University of Coimbra (preliminary results)[END_REF][START_REF] Henderson | The new Coimbra method for recording entheseal changes and the effect of age-at-deathLa nouvelle méthode Coimbra: changement au niveau des enthèses et influence de l'âge au décès[END_REF][START_REF] Listi | The Use of Entheseal Changes in the Femur and Os Coxa for Age Assessment[END_REF][START_REF] Mariotti | Enthesopathies -Proposal of a Standardized Scoring Method and Applications[END_REF][START_REF] Mariotti | The Study of Entheses: Proposal of a Standardised Scoring Method for Twenty-Three Entheses of the Postcranial Skeleton[END_REF][START_REF] Milella | The effect of age, sex, and physical activity on entheseal morphology in a contemporary Italian skeletal collection[END_REF][START_REF] Niinimäki | What do muscle marker ruggedness scores actually tell us?[END_REF][START_REF] Shaibani | The significance of enthesopathy as a skeletal phenomenon[END_REF][START_REF] Takigawa | Age changes of musculoskeletal stress markers and their inter-period comparisons[END_REF]Villotte et al., 2010a), age appears to be an important (if not the most important) factor influencing the appearance of changes at entheses. Fibrous and fibrocartilaginous attachment sites clearly differ in our analyses in terms of frequencies of EC (much more frequent for fibrous entheses), but also in terms of the relation between EC and ageat-death. Based on the data presented in Tables 2 and3, and Supporting Information B, it appears that fibrous and fibrocartilaginous entheses form two very distinct groups. Before discussing the patterns of aging identified for these two groups of entheses in detail, some limitations of our study should be highlighted.

In this study, we applied a specific scoring system to each group of entheses (see [START_REF] Villotte | Connaissances médicales actuelles, cotation des enthésopathies : nouvelle méthode[END_REF]. It is thus possible that a portion of the differences seen between fibrous and fibrocartilaginous entheses in our analyses are the consequence of methodological choices. Nevertheless, it seems also likely, taking into account the large number of anatomical and pathological differences between fibrous and fibrocartilaginous attachment sites, that these results are, in some measure, also linked to their very different natures, and thus reflect real biological processes. As a consequence, considering that similar entheseal change "scores" for several attachment sites as indicative of a group of muscles working together (e.g. [START_REF] Alioto | A New Division of Labor? Understanding Structural Violence Through Occupational Stress: An Examination of Entheseal Patterns and Osteoarthritis in the Hamann-Todd Collection[END_REF][START_REF] Hawkey | Activity-induced musculoskeletal stress markers (MSM) and subsistence strategy changes among ancient Hudson Bay Eskimos[END_REF] appears problematical when both types of entheses are studied together: fibrous entheses will group together and tend to display higher ranks than fibrocartilaginous ones (see also [START_REF] Villotte | Enthésopathies et activités des hommes préhistoriques Recherche méthodologique et application aux fossiles européens du Paléolithique supérieur et du Mésolithique[END_REF] for other issues regarding the effect of this approach). Considering the obvious differences illustrated here, inferences based on direct comparisons of stages between fibrous and fibrocartilaginous entheses should be avoided in our opinion.

Another limit of our study on the effect of age on EC distribution is the lack of control for factors other than sex. This choice permitted us to carry out many different analyses and to present our results in detail, but also limits the scope of the study. As skeletal age changes are not uniform across populations (e.g. [START_REF] Katz | Race differences in pubic symphyseal aging patterns in the male[END_REF][START_REF] Schmitt | Variability of the Pattern of Aging on the Human Skeleton: Evidence from Bone Indicators and Implications on Age at Death Estimation[END_REF], pooling four collections of different origins and with different demographic profiles may have had an impact on our results. However, previous studies of this sample have shown that the "collection" factor has few effects on the distribution of EC [START_REF] Villotte | Enthésopathies et activités des hommes préhistoriques Recherche méthodologique et application aux fossiles européens du Paléolithique supérieur et du Mésolithique[END_REF], Villotte et al. 2010a), likely due to the fact that European groups seems to be rather homogenous with regard to skeletal changes associated with aging [START_REF] Schmitt | Variability of the Pattern of Aging on the Human Skeleton: Evidence from Bone Indicators and Implications on Age at Death Estimation[END_REF]. It thus appears relevant to consider an expanded sample including extra-European collections on the effect of age on EC in subsequent studies. Body mass has been identified as a possible factor influencing frequency distributions of EC (mostly for fibrous entheses, see for instance [START_REF] Godde | Entheseal changes and demographic/health indicators in the upper extremity of modern Americans: Associations with age and physical activity[END_REF]. Body mass is not known for the individuals studied here and the reliability of current methods to estimate body mass from the skeleton remains poor [START_REF] Lacoste Jeanson | Body mass estimation from the skeleton: An evaluation of 11 methods[END_REF], preventing the analysis of this factor in these collections. Identified skeletal collections with known individual body masses should be taken into account in further studies in order to look for a possible interaction between age and body mass. Finally, we did not attempt to include occupations, which are known for most of the males studied here (see [START_REF] Villotte | Enthésopathies et activités des hommes préhistoriques Recherche méthodologique et application aux fossiles européens du Paléolithique supérieur et du Mésolithique[END_REF], Villotte et al. 2010a), for three reasons. First, whereas the variable "occupation" does explain a part of the distribution of EC in identified samples (e.g. Villotte et al. 2010a;[START_REF] Milella | The effect of age, sex, and physical activity on entheseal morphology in a contemporary Italian skeletal collection[END_REF]Alves Cardoso & Henderson, 2013;[START_REF] Milella | Exploring the relationship between entheseal changes and physical activity: A multivariate study: A Multivariate Study of Entheseal Robusticity[END_REF], its effect is clearly smaller than is that for age. Second, it has been shown that the way occupations are categorized may affect the results (Alves [START_REF] Cardoso | The Categorisation of Occupation in Identified Skeletal Collections: A Source of Bias?: Categorisation of Occupation in Identified Skeletal Collections[END_REF], creating potential biases. Finally, in the collections studied here, descriptions of female occupations are scarce and hard to interpret with regard to physical activities [START_REF] Molleson | The Spitalfields project[END_REF][START_REF] Cunha | What can bones tell about labour and occupation: the analysis of skeletal markers of occupational stress in the Identified Skeletal Collection of the Anthropological Museum of the University of Coimbra (preliminary results)[END_REF]Villotte et al., 2010a), preventing analyses on the complete dataset. It would certainly be beneficial to include all these foctors (and likely others) in further analyses, but the aim of this paper was to clarify first and foremost the relationship between EC and age-at-death, a relationship which has never been studied in detail previously.

For fibrous entheses, the frequency of entheseal changes (stages B and C) increased rapidly during the third and fourth decades of life and then stabilized (around ca. 70% for the attachment of M. deltoideus) in later age groups. Most of the changes before 40 years old correspond to stage B (i.e., diffuse cortical irregularity). Sometimes called "robusticity", diffuse cortical irregularity at fibrous entheses has long been considered the product of bone remodeling stimulated by repeated -normal or strenuous-muscle contractions during adulthood. Even if this hypothetical relationship seems reasonable, it is based on almost no medical or experimental data (see [START_REF] Villotte | Understanding Entheseal Changes: Definition and Life Course Changes[END_REF]. In immature animals, tendons and ligaments attach to the diaphysis via the periosteum, and the periosteal layer may or may not disappear (depending on the species and the enthesis) when growth stops (e.g. [START_REF] Gao | An immunohistochemical study of enthesis development in the medial collateral ligament of the rat knee joint[END_REF][START_REF] Hurov | Soft-tissue bone interface: How do attachments of muscles, tendons, and ligaments change during growth? A light microscopic study[END_REF][START_REF] Matyas | The development morphology of a "periosteal" ligament insertion: Growth and maturation of the tibial insertion of the rabbit medial collateral ligament[END_REF]. In mature humans, the mediating layer of periosteum is absent in most appendicular fibrous entheses and the soft tissue attaches directly to bone [START_REF] Benjamin | The skeletal attachment of tendons -tendon "entheses[END_REF], except where muscles attach to a large area by short fibrous tissues [START_REF] Kenesi | Anatomie et biomécanique des enthèses[END_REF]. At what point during life the transition from a periosteal to a bony attachment occurs has not been documented in humans. Based on the fact that adolescent skeletons exhibit specific features at fibrous entheses that are not observed in adults, it has been hypothesized that this physiological transition also occurs when growth stops in humans [START_REF] Villotte | Understanding Entheseal Changes: Definition and Life Course Changes[END_REF]. This may explain (combined or not with the potential effect of muscular contractions) the increasing frequency of skeletal changes (i.e., "diffuse cortical irregularity") seen in young/middle-aged adults.

The frequency of stage C for fibrous entheses increases regularly during adulthood. As the frequency of entheseal changes, stages B and C, reach a plateau after the fifth or sixth decade, it seems that major changes, as represented by stage C, progressively replace more minor ones (stage B) in older individuals. Stage C, as represented by crests or other bony protrusions at fibrous entheses, appear to be in direct and progressive continuity with diffuse cortical irregularity, and thus the "muscle use" hypothesis may be valid for these attachment sites. In view of the paucity of histological and biomedical data for these sites, this interpretation does not imply a direct cause and effect relationship between physical activity and EC at fibrous entheses. The "muscle use" hypothesis may be useful as a theoretical framework for these changes, but more histological and experimental analyses are required before considering EC at fibrous entheses as reliable activity-related skeletal changes.

For fibrocartilaginous sites, the percentage of individuals exhibiting entheseal changes grows exponentially across age classes, with most changes appearing in the older age classes. The turning point seems to occur in the 5 th or 6 th decade of life, when significant differences appear in comparison with those of previous age groups. Major changes as represented by stage C also appear around this period of life, and become frequent (i.e., more than would be expected by chance) after 60 years of age. This result is in agreement with biomedical data available for appendicular fibrocartilaginous entheses. In young/mature healthy adults, lesions at the enthesis are uncommon and often mechanically induced when they do occur [START_REF] Bard | Physiopathologie, réparation, classification des tendinopathies mécaniques[END_REF][START_REF] Rodineau | Pathogénie des enthésopathies du membre supérieur[END_REF], see Villotte & Knüsel, 2013 for a review). These enthesopathies are generally associated with minor skeletal changes. From the sixth decade onwards, a generalized disruption of the soft and hard tissues and the appearance of major skeletal changes is observed and, during this second phase, mechanical factors play only (if any) a secondary role in the appearance of lesions [START_REF] Bakirci | Entheseal Changes in Response to Age, Body Mass Index, and Physical Activity: An Ultrasound Study in Healthy People[END_REF][START_REF] Bard | Physiopathologie, réparation, classification des tendinopathies mécaniques[END_REF][START_REF] Durigon | Enthèse au cours de la vie[END_REF][START_REF] Rodineau | Pathogénie des enthésopathies du membre supérieur[END_REF]. It has been hypothesized that this rapid appearance of major skeletal changes may be exacerbated in women [START_REF] Villotte | Enthésopathies et activités des hommes préhistoriques Recherche méthodologique et application aux fossiles européens du Paléolithique supérieur et du Mésolithique[END_REF][START_REF] Villotte | Understanding Entheseal Changes: Definition and Life Course Changes[END_REF]) by a drop in circulating estrogen at the menopause and the related changes in the composition of collagen connective tissues (e.g. [START_REF] Falconer | Changes in paraurethral connective tissue at menopause are counteracted by estrogen[END_REF]. However, the effect of the interaction of age and sex was significant for only one fibrocartilaginous attachment site (out of 18) in our analyses (table 5). Further studies seem necessary in order to better understand the effect of the interaction between hormones and age in the appearance of skeletal EC.

It should be noted that, contrary to the situation in fibrous entheses, the increase in frequency of stage C with age is not achieved to the detriment of the frequencies of stage B (for which the frequency also increases in older age groups) in our study. Based on the empirical data presented here and the medical data available, it seems possible that stage C appeared, for the most part, relatively quickly from a previously healthy (i.e. unmodified) enthesis (i.e., stage A) in individuals over 50 years of age. Then, it appears that the "muscle use" hypothesis should be rejected in the case of fibrocartilaginous entheses.

As noted previously [START_REF] Villotte | Understanding Entheseal Changes: Definition and Life Course Changes[END_REF], EC seen in older individuals are probably not directly related to physical activity, and certainly not only to micro-trauma at the enthesis. On the contrary, minor changes at fibrocartilaginous entheses in early/middle adult skeletons may be good indicators of microtrauma during life.

To sum up, detailed statistical analyses permitted us to illustrate two different patterns of relationships between EC and age according to the nature of the attachment site. The patterns seem to be related to physiological and pathological processes that should be taken into account when studying EC in archaeological human skeletal samples. Moreover, the two groups of entheses appear very homogeneous with regard to the effect of age on the appearance of EC. Further analyses of each type of enthesis are required in order to identify what other factors interact with age in order to explain the distribution of EC in skeletal samples.

Acknowledgements

S.V. thanks Sarah Schrader and Jared Carballo Pérez for inviting him to the "Adaptive Tools for Resilient Bones" conference. The authors thank the three reviewers for their useful comments and Christopher Knüsel for his editorial assistance with the English expression of this contribution. For proofreading the article. S.V. is grateful to the curators and staff of the Natural History Museum in London, the Department of Anthropology of the University of Coimbra, and the Department of Anthropology of the University of Bologna for providing access to the material and for their helpful comments on the collections. Study of the skeletal collections were partly funded by the European Union (Synthesys, grant number GB-TAF-636), and the French Ministry of Higher Education, Research and Innovation ("Aires Culturelles"). The research was carried out during a project funded by the CNRS (International Emerging Actions, grant number IEA00540). Both authors declare that they have no conflicts of interest.

  and Supporting Information B). For each fibrocartilaginous site, the percentage of individuals exhibiting entheseal changes grows roughly exponentially across age classes (most of the changes appearing in the oldest age classes); whereas this percentage grows roughly logarithmically across age classes for fibrous entheses, reaching a plateau after a substantial increase when compared with the youngest age classes.Chi-square tests for each enthesis indicate that stages and age groups are related (P < 0.001, results not shown). For the deltoid tuberosity, when the distribution of stages A, B and C by age group is examined in detail, and based on the analysis of the adjusted standardized residuals, there are more entheses scored as stage A in the age group[20][21][22][23][24][25][26][27][28][29] and fewer entheses scored as stage A in the age groups after 40 years than would be expected by chance (see Section 5.1 in Supporting Information A). Regarding stages B and C, they are more frequent than expected in the [60-99] age group and less frequent than expected in the [20-29] age group. For the left lateral epicondyle, there are more stage A scores in the age group[20][21][22][23][24][25][26][27][28][29] and fewer entheses scored as stage A in the age groups after 50 years than would be expected by chance (see Section 5.1 in Supporting Information A). There are fewer entheses scored as stage B before 50 years than expected, and more entheses scored as stages B and C than would be expected by chance in the age group.