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In the Southern Maya Lowlands (SML), several scientific and technical obstacles hinder the knowledge of environmental and socio-environmental dynamics, that have occurred at the scale of the territories of the cities. This includes the research topic itself (nature-culture interface), the tropical forest (morphological studies and access to the field) and the morphological and sedimentary archives (taphonomy and discontinuity). The study of the socio-ecosystem of Naachtun (150-950 CE), a Maya city of the Classic period, is not exempt from these constraints. Recently, large-scale work in SML was conducted based on LiDAR analyses and fieldwork. They have profoundly renewed our knowledge of the complexity of landscape transformation and natural environments through the action of the ancient Maya (Canuto et al. 2018). They have provided new research perspectives which allow us to examine the following questions.How did natural resource availability (water, soil and biological resources) change in the territory of the city, with respect to climate change and social demand? How did the ancient Maya adapt their resource management strategies to these changes? How important were socio-environmental risks to the resilience and sustainability of the socio-ecosystem? In order to answer these questions, a new systemic, interdisciplinary and multiscalar research program has been implemented. It includes geoarchaeology (alluvial and agrarian), archaeogeography (LiDAR analysis, spatial analysis), palaeoecology and bioarchaeology [archaeobotany (study of phytoliths, anthrocology, pedoanthracology) zooarchaeology (vertebrate and conchyological fauna remains)], spatial archaeology (agglomeration processes, power relays), palaeodemography and geochronology (14C, OSL). Current and pre-anthropic reference frames (hydrological, pedological and ecological) have also been established.Our results reaveal the complexity of the Maya palimpsest territories produced during the ~ 1500 BCE - 1000 CE period (Preclassic and Classic periods). Hydrosedimentary flows have fluctuated in response to climate change and anthropogenic impacts, controlling the spatiotemporal dynamics of resources (water and soils). Lake levels and erosion have fluctuated according to pluricentennial-scale periods. All compartments of the hydrosystem and the sediment system were subject to transformations, to manage water and soils. A mosaic of agricultural and agroforestry strategies was developed throughout the micro-region (morphologies, practices, cropping systems, fuel economy). Intensive wetland systems and irrigated farming systems were established in poljes, sinkholes and valleys (raised fields and drained fields). In addition, in the hilly areas, agrarian systems based on terraced agriculture, rain-fed farming systems, slash-and-burn, arboriculture and horticulture systems were established. The Maya socio-ecosystem which emerged in this micro-region lasted for more than 2500 years. It experienced shits and continuities and its dynamics are framed around six main multi-secular periods. Its decline was part of the profound changes that took place in the territories of the SML cities between 750 and 1050 CE. The sustainability of this socio-ecosystem during the demographic peak of the Late and Terminal Classic (750-950 CE), before the abandonment of the epicenter of the city of Naachtun (~950 CE), is estimated and discussed in relation to the environmental carrying capacity, social demand, climate and its own resilience.

Cette étude porte sur un gisement de seize troncs subfossiles identifiés au sein d’un tronçon de la moyenne vallée du Cher (Région Centre‑Val de Loire, France) dont la géométrie et l’âge des formations sédimentaires sont par ailleurs bien connus. Ainsi, en dépit des difficultés posées par les troncs subfossiles en tant qu’objets d’étude, cet article examine les possibilités de reconstitutions des dynamiques fluviales holocènes à partir de ce gisement et interroge les événements hydrologiques dont il peut être la signature. En mettant en perspective l’âge des bois subfossiles (4 individus datés par le radiocarbone) avec celui des sédiments dans lesquels ils sont inclus (7 datations OSL et 1 datation par le radiocarbone) et en nous intéressant à l’orientation des troncs et aux contextes de sédimentation, il apparait que : (1) Les âges des 4 troncs subfossiles datés sont compris entre 8330‑8040 cal BP et 3391‑3235 cal BP, attestant des processus de remaniement et de réenfouissement partiels des macro‑débris ligneux qui composent ce gisement. Le décalage temporel, parfois de plusieurs millénaires, entre l’âge des bois subfossiles et celui des encaissants sédimentaires a permis d’identifier deux hiatus érosifs mis en relation avec le méandrage actif qui caractérise ce cours d’eau durant la seconde moitié de l’Holocène. (2) Les troncs subfossiles ont été observés au sein de deux grands paléochenaux, des bancs sableux et des anciens chenaux de taille plus modeste interprétés comme des bras de chute. Ces environnements de dépôts sont cohérents avec les observations menées sur les bois morts des cours d’eau actuels (chenaux en voie de déconnexion, bancs et îles, pieds de berge). (3) L’examen de l’orientation des troncs traduit un corpus hétérogène. Si des similitudes sont observées, en particulier au sein du banc sableux central, les deux grands paléochenaux contiennent des individus orientés différemment. Ces dispositifs sont mis en relation avec la formation d’embâcles dont il ne resterait que les bois de très grand gabarit. Les facteurs de contrôle, à l’origine de la formation de ce gisement, sont potentiellement multiples. Le retrait de berge ainsi que les paramètres hydro‑climatiques qui le favorisent, sont envisagés comme des facteurs explicatifs pertinents. Cependant, la mort physiologique des végétaux ainsi que les défrichements anthropiques (à l’échelle de la ripisylve et du bassin versant) sont également à prendre en compte. La constitution d’un référentiel régional de troncs subfossiles observés au sein des dépôts fluviatiles et datés pourrait permettre d’améliorer la connaissance de ces facteurs de contrôle. This study focuses on a deposit of sixteen subfossil tree trunks identified within a section of the middle Cher valley (Centre‑Val de Loire region, France) whose sedimentary bodies are well known and dated. Thus, despite the difficulties raised by this type of object of study, this article examines the possibilities of Holocene fluvial dynamics reconstructions based on this deposit and questions the hydrological events of which it can be the signature. By comparing the age of the subfossil wood (4 radiocarbon dated trunks) with that of the sediments in which they are included (7 OSL dates and 1 radiocarbon date) and by examining at the orientation of the trunks and the sedimentation contexts, it appears that: (1) The ages of dated subfossil tree trunks range from 8330‑8040 cal BP to 3391‑3235 cal BP, attesting to the partially reworking and reburial processes of wood debris of this deposit. The time lag, sometimes of several millennia, between the age of the subfossil woods and that of the sedimentary formations allowed the identification of two erosive hiatuses related to the active meandering processes that characterized this river during the second half of the Holocene. (2) The subfossil tree trunks were observed within two large palaeochannels, sandy banks, and smaller former channels interpreted as chute channels. These contexts of deposition are consistent with observations made of large wood debris in present‑day watercourse (disconnecting channels, banks and islands, bank bases). (3) Analysis of the orientation of the trunks reveals a heterogeneous corpus. Although similarities are observed, particularly within the central sandy bank, the two large palaeochannels contain large debris that are oriented differently. These features are related to the formation of woody debris jams, of which only the very large wood remains.The controlling factors of the formation of this deposit, are potentially multiple. Bank retreat as well as hydro‑climatic parameters that favor it, are considered as relevant explanatory factors. However, the physiological death of the tree as well as the human clearings (on the scale of the riparian zone and the catchment area) are also to be taken into account. The constitution of a regional reference system of subfossil tree trunks observed within the fluvial deposits and dated could improve the knowledge of these controlling factors.

International audience; The Naachtun archaeological project started in 2010 with the aim of understanding the sociopolitical and economic history of one of the few Maya Classic capitals located in Northern Peten. Since 2013 a paleo-environmental team carried out a program of investigation to study the landuse and the management of local resources during the last three millennium, both in the urban area of Naachtun and in the main inundated depression area (bajo), north of the city. In this presentation, using archaeological and environmental data derived from excavations contexts, combined with Lidar data obtained from a coverage of 135km² which encompasses the Naachtun hinterland area, we will draw up an overview of the agrarian practices and strategies developed since the Preclassic times until the abandonment of the core zone at the end of the Terminal Classic period (circa. 950/1000 CE). We will show in particular the diversity of the agrarian techniques used according to different geomorphological and pedagogical contexts.

International audience

International audience

International audience

International audience

Análisis ambientales del sitio arqueológico Naachtun (Petén-Norte, Guatemala), informe provisional de la fase 2017