Squaring the circle. Social and environmental implications of pre-pottery neolithic building technology at Tell Qarassa (South Syria)

We present the results of the microstratigraphic, phytolith and wood charcoal study of the remains of a 10.5 ka roof. The roof is part of a building excavated at Tell Qarassa (South Syria), assigned to the Pre-Pottery Neolithic B period (PPNB). The Pre-Pottery Neolithic (PPN) period in the Levant coincides with the emergence of farming. This fundamental change in subsistence strategy implied the shift from mobile to settled aggregated life, and from tents and huts to hard buildings. As settled life spread across the Levant, a generalised transition from round to square buildings occurred, that is a trademark of the PPNB period. The study of these buildings is fundamental for the understanding of the ever-stronger reciprocal socio-ecological relationship humans developed with the local environment since the introduction of sedentism and domestication. Descriptions of buildings in PPN archaeological contexts are usually restricted to the macroscopic observation of wooden elements (posts and beams) and mineral components (daub, plaster and stone elements). Reconstructions of microscopic and organic components are frequently based on ethnographic analogy. The direct study of macroscopic and microscopic, organic and mineral, building components performed at Tell Qarassa provides new insights on building conception, maintenance, use and destruction. These elements reflect new emerging paradigms in the relationship between Neolithic societies and the environment. A square building was possibly covered here with a radial roof, providing a glance into a topologic shift in the conception and understanding of volumes, from round-based to square-based geometries. Macroscopic and microscopic roof components indicate buildings were conceived for year-round residence rather than seasonal mobility. This implied performing maintenance and restoration of partially damaged buildings, as well as their adaptation to seasonal variability

Dendrorremediación: El uso de Betula alba para monitorizar y reducir el contenido de metales en suelos mineros.

[EN] The intense industrial activity that took place over the past century resulted in large contaminated áreas. This is an important risk to human health and environmental safety. Recent biotechnological techniques for bioremediation include phytoremediation, which uses plants to remove or stabilize contaminants in soils. In our study we choose birch (Betula alba) as the preferred species to remedy mining soils, due to it produces a large biomass and can accumulate high levels of toxic elements in its tissues. The aim of this study was (i) to determine the possibility of using this species in reforestation and/or remediation of mining soils (ii) to elucidate the potential of tocopherol levels as indicators of heavy metal pollution. Trees growing in mining soils with high concentrations of Zn, Cd and Pb were sampled and the metal content in various organs and in tree rings was analyzed. α-tocoferol levels were also analyzed as an indicator of stress. The results showed a different distribution of metals in plant tissues. Zn and Cd had a higher accumulation in leaves, whereas Pb was stored in the timber. In addition, the metal content in tree rings was higher in older rings, leading to a conclusion that older tissues present a detoxification strategy. Furthermore, we saw how the presence of α- tocoferol on branches can be an indicator of metal stress in plants and it can be also used as a monitoring factor.