Typologie d'actualités : Publications

Source : https://doi.org/10.1016/j.quascirev.2026.109882

RESUME: In south-eastern Arabia, climatic reconstitutions mainly derive from the study of speleothems, dune sands, lacustrine deposits, and alluvial sediments. In the Hajar Mountain range, which covers a major part of SE Arabia, the Late Quaternary is relatively poorly documented, notably due to the lack of preserved archives. We explore the potential of oasis soil sequences as archives of past landscapes and climate in the Emirate of Ras al-Khaimah, in the piedmont oases of Dhayah, Sir, and Jiri. Geomorphological surveys, mapping and geoarchaeological investigations combined with luminescence and radiocarbon dating were conducted in these oases. We propose a detailed typology of the deposits and provide a first interpretation of their origin and depositional modes (alluvial, aeolian, anthropogenic). Our results show that Holocene agricultural activity has preserved natural archives from deflation and alluvial erosion. This allows us to identify phases of aeolian reactivation during Marine Isotope Stage (MIS) 4 (∼65 ka) and MIS 2 (∼21 ka), whereas alluvial sedimentation occurred in early MIS 3 (∼54 ka), the Late Glacial (∼15 ka) and the early Holocene (∼8-6.5 ka). Two important shifts of active lobe and distal incisions were identified in the Sir plain between 9-8 ka and 6-3.5 ka and potentially linked with base level evolution and/or climatic changes. Oases development is recorded during the second half of the Holocene. Despite a voluntary control of water supply, we identified phases of alluvial reactivation between ∼3.5 and 3 ka and ∼1.3 and 1 ka, and intense fluvial detritus dated to ∼2.7-2.4 ka. This study demonstrates that oasis pedo-sedimentary sequences in arid environments are valuable archives for the reconstruction of climatic conditions and landscapes evolution.

Source : https://doi.org/10.1146/annurev-earth-032524-013254

This review examines the societal ramifications of large volcanic eruptions—not the proximal impacts of lava, ash, pumice, and gaseous emissions but rather the consequences of the climate forcing triggered by dispersal of volcanic sulfate aerosol in the stratosphere. Using ice core records of volcanism and tree-ring data of summer temperature anomalies, we analyze 38 preindustrial eruptions that injected an estimated 6 Tg or more of sulfur into the stratosphere. We then explore more than 100 works that consider the volcanism-climate-society nexus, teasing out the key elements of their arguments for or against the role of volcanically forced climate change in far-field societal impacts. As well as summarizing and interrogating the history of ideas and state of the art on this topic, we hope to stimulate further holistic, interdisciplinary approaches to assess the broader implications of volcanic eruptions, particularly for global food security—both in the past and in the future.

Source : https://doi.org/10.1007/s10816-025-09757-x

Several syn and post-depositional processes are responsible for different degrees of site and assemblage formation and disturbance. Understanding the processes that lead to archaeological site formation is essential for interpreting past human activities, settlement patterns, and occupation dynamics. Among these processes, water flow is commonly recognized as a major factor influencing site and assemblage formation and integrity. Lithic taphonomy can add valuable information to the understanding of these natural processes. To better evaluate how different flint types react to both mechanical and chemical stresses, we carried out controlled and sequential experiments on knapped flint artifact replicas. These were realized on two different flint varieties, recognized in the archaeological assemblage of a Middle Stone Age open-air site located at Wadi Lazalim (Southern Tunisia). Our methodological framework is based on a sequential tumbling experiment that simulates the remobilization of artifacts by water. The resulting post-depositional surface modifications (PDSM) were observed and recorded. In addition, a sample of flint replicas underwent chemical alteration in a controlled environment, allowing us to document and measure both patina formation and changes in surface roughness. These experimental results were then compared with a sample of archaeological materials, providing the basis for a preliminary and exploratory hypothesis concerning the taphonomic processes at the site. Here, we observed that most of the alterations appear to be linked to patina formation, whose variable degree and kind are more strongly correlated with differences in raw material texture rather than to the co-occurrence of artefacts from different chronological spans.