Dynamique holocène de la végétation et occupation des Pyrénées andorranes depuis le Néolithique ancien, d'après l'analyse pollinique de la tourbière de Bosc dels Estanyons (2180 m, Vall del Madriu, Andorre)

This paper presents an innovative multisensor, multitemporal machine-learning approach using remote sensing big data for the detection of archaeological mounds in Cholistan (Pakistan). The Cholistan Desert presents one of the largest concentrations of Indus Civilization sites (from ca. 3300 to 1500 BC). Cholistan has figured prominently in theories about changes in water availability, the rise and decline of the Indus Civilization, and the transformation of fertile monsoonal alluvial plains into an extremely arid margin. This paper implements a multisensor, multitemporal machine-learning approach for the remote detection of archaeological mounds. A classifier algorithm that employs a large-scale collection of synthetic-aperture radar and multispectral images has been implemented in Google Earth Engine, resulting in an accurate probability map for mound-like signatures across an area that covers ca. 36,000 km2. The results show that the area presents many more archaeological mounds than previously recorded, extending south and east into the desert, which has major implications for understanding the archaeological significance of the region. The detection of small (<5 ha) to large mounds (>30 ha) suggests that there were continuous shifts in settlement location. These shifts are likely to reflect responses to a dynamic and changing hydrological network and the influence of the progressive northward advance of the desert in a long-term process that culminated in the abandonment of much of the settled area during the Late Harappan period.

a b s t r a c tPrevious research acknowledges the ancient and complex land-use history of European mountainous areas, which are characterised by a remarkable regional variability in terms of human practices and patterns of occupation during the Holocene. However, the combined palaeoenvironmental and archaeological study of highland human management at a micro-regional scale remains a largely unexplored research field, especially in the Pyrenees. A combined pollen, stomata, non-pollen palynomorphs (NPPs) and macrocharcoal study was carried out at three nearby alpine and subalpine peat basins from a relatively small territory (ca.1700 ha) at the Madriu valley (Andorra, eastern Pyrenees), following a fine spatialresolution strategy. The purpose was to test the suitability of high altitudinal palaeoecological sequences when reconstructing past small-scale land-use variability. The palaeoecological results of those peat records are compared and further integrated with archaeological local data, and together underline the marked complexity of high mountain land-use system over the Holocene period. Main phases of microregional land-use and landscape variability can be distinguished from the middle Neolithic to the early Bronze Age and from the Roman Period to the Modern Era. Conversely, several phases of homogeneous landscape management are distinguishable during the early Neolithic, and from the late Bronze to the late Iron Age. Results drawn from this study show that landscape variability is not necessarily connected to topographic or climatic parameters, and underline the role of social, economical and cultural parameters in the land-use organisation and the landscape shaping of high mountain spaces since Prehistory.

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Although high mountain areas have traditionally been viewed as predominantly grazing areas, with low population and a high degree of land-use stasis, recent research suggest that land-use complexity and change over time has been underestimated. This interdisciplinary palaeoenvironmental analysis has been carried out on the Pradell calcareous fen, located in the eastern Pre-Pyrenees (Spain) at 1975 m a.s.l., and it comprises different environmental indicators: pollen, stomata, non-pollen palynomorphs, macrocharcoal particles, lithostratigraphy, sedimentology and geochemistry. The results of this high temporal resolution study are integrated with archaeological data, and together provide strong evidence for the complexity of the high-mountain land-use system over the last 1500 years. Archaeological fieldwork has shown the rise of highland mining activities during the Roman period. Later, frequent fires resulted from the farming and settlement that followed the Christian conquest. Geochemical analysis of sediment cores records late-Mediaeval metal production, while the expansion of feudal cropping and the advent of several Mediaeval crises are clearly recorded in both the pollen and the historical data. Finally, the rise of a mixed economy system based on transhumance, farming, metallurgy and woodland exploitation was established during Modern and Contemporary times. The high correlation between the palaeoenvironmental, archaeological and historical data at the Pradell fen stresses the value of calcareous fens for palaeoenvironmental reconstructions of historical landscapes. Results obtained also depict high mountain landscapes as the result of the long-term interaction of many human practices, including mining and smelting, grazing, cropping and tree exploitation for the production of wood, charcoal and resin.