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In this paper, we propose a multi-RREH (Remote Renewable Energy Hub) based optimization framework. This framework allows a valorization of CO 2 using carbon capture technologies. This valorization is grounded on the idea that CO 2 gathered from the atmosphere or post combustion can be combined with hydrogen to produce synthetic methane. The hydrogen is obtained from water electrolysis using renewable energy. Such renewable energy is generated in RREH, which are locations where RE is cheap and abundant (e.g., solar PV in the Sahara Desert, or wind in Greenland). We instantiate our framework on a case study focusing on Belgium and 2 RREH, and we conduct a techno-economic analysis under uncertainty. This analysis highlights, among others, the interest in capturing CO 2 via Post Combustion Carbon Capture (PCCC) rather than only through Direct Air Capture (DAC) for methane synthesis in RREH. By doing so, a notable reduction of 10% is observed in the total cost of the system under our reference scenario. In addition, we use our framework to derive a carbon price threshold above which carbon capture technologies may start playing a pivotal role in the decarbonation process of our industries. • We demonstrate PCCC technology potential for reducing RREH's CH4 production cost. • We derive a carbon price threshold for crucial industrial decarbonization. • An uncertainty analysis has been carried out on the reference scenario. [ABSTRACT FROM AUTHOR]

Abstract: Salinization caused by irrigation mismanagement is a major cause of desertification. Monitoring of land degradation caused by salinization and other processes has been subject to international scientific debates leading to the commitment by global decision-makers to address these threats collectively through the UNCCD. This paper discusses the experience of monitoring land and water degradation in the salinity-prone irrigated arid environments of the Northern Sahara in light of current international scientific developments affecting both conceptual and methodological approaches. The paper integrates a range of simple and accessible methods to achieve a multidisciplinary analysis including remote sensing, use of national research archives, interviews with decision-makers and direct surveys of cultivators. Revised assessments of the extent and ecological processes of salinization emerge from the analysis. As irrigated areas expand globally, the new conceptual and methodological techniques in dryland development science have the potential to enable scientists in affected areas to contribute to global efforts to monitor degradation effects caused by desiccation, salinity and human responses. [Copyright &y& Elsevier]

All the main Central Saharan mountainous massifs present rock art from various periods, stretching from prehistory until the recent historical era. The paintings and engravings have been documented, described, and classified into the chronological-stylistic groups. However, a special group of carvings called kettles and cupules have been given little or no attention in the rock art studies. Since these artificial formations are abundantly present in the Central Sahara their systematic study is needed. After a short presentation of the Saharan rock art groups, this paper examines kettles and cupules situated in the territory dominated by the earliest paintings called Round Heads, in the mountains of the Algerian Tassili, Algerian Tadrart and the Libyan Acacus. The results of the author's prolonged fieldwork are presented here, namely the quantity and distribution of kettles/cupules in the study area, their presumed relationship to the Round Head paintings, and their possible function. [ABSTRACT FROM AUTHOR]

Recent research has convincingly shown the advantages of combining environmental magnetism and geochemical analyses for the proxy estimation of anthropogenic pollution due to their atmospheric deposition in local environments. Few studies have also focused on anthropogenic particles deposited on snow. However, papers reporting on Sahara dust particles deposited on snow in central Europe and which involve magnetic methods are missing. To the best of our knowledge, this is the first study investigating the magnetic features of the SDE recorded in snowfall in this part of Europe (i.e. Poland). Our aim was to provide the magnetic characteristics and chemical elemental compositions of a snow horizon containing Saharan dust deposited near the Polish Jakuszyce meteorological station during a snowfall event that occurred from the 1st to the February 7, 2021. Samples of snow with and without Saharan dust were analysed with respect to iron oxide contents (magnetic susceptibility, hysteresis loop, magnetic remanence acquisition) and compared with chemical compositions. Our results revealed the presence of both ferrimagnetic magnetite and antiferromagnetic hematite in the dust-enriched horizon, and the diamagnetic behaviour of the reference layer consisting of 'pure' snow. The samples recorded the presence of geogenic elements such as Al, Fe, Mn, and Ti, anthropogenic elements such as As, Co, Cr, Cu, Ni, Pb, and Zn, and nutrients including Ca and K. The total concentrations of geogenic elements, nutrients, and anthropogenic elements in the snow samples with deposited Saharan dust were, respectively, >3700, >320, and >110 times greater than in the samples without Saharan dust. These findings may serve as reference data for a variety of environmental magnetic studies. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: We describe in this paper a traditional charcoal making technology occasionally adopted by Tuareg people in the hyper-arid central Sahara (SW Libya). This methodology (called esed) has been identified thanks to ethnobotanic and ethnographic interviews with people living in the Tadrart Acacus massif (the kel Tadrart Tuareg) and confirmed by macroscopic and micromorphological analyses of residual field evidence. Esed consisted of burning in situ trunks of dead Acacia tortilis (Forssk.) Hayne; subsequently, small portions of collapsed and still-burning wood were buried with sand in an attempt to ensure combustion under anoxic conditions. Our interviews elucidated that the esed technology is well known by people living in the region and has possibly been practiced for a long time. Surprisingly, local informants highlighted that esed was employed to made charcoal only during years marked by abrupt reduction of precipitation and consequently of natural resources. The last employment of esed dates to the dry phase of the mid-1970s, when charcoal was used as an exchangeable good. The discovery of this charcoal making technology shed new light on the capability of Tuareg to manage the few natural resources available in marginal environments and to cope with rapid climate changes. [Copyright &y& Elsevier]

Abstract: Sulfates, commonly found in evaporite deposits, were observed on Mars surface during orbital remote sensing and surface exploration. In terrestrial environments, evaporite precipitation creates excellent microniches for microbial colonization, especially in desert areas. Deposits comprised of gypsum, calcite, quartz and silicate deposits (phyllosilicates, feldspars) from Sahara Desert in southern Tunisia contain endolithic colonies just below the rock surface. Previous optical observations verified the presence of microbial communities and, as described in this paper, spectral visible analyses have led to identification of chlorophylls belonging to photosynthetic bacteria. Spectral analyses in the infrared region have clearly detected the presence of gypsum and phyllosilicates (mainly illite and/or smectite), as well as traces of calcite, but not quartz. X-ray diffraction (XRD) analysis has identified the dominant presence of gypsum as well as that of other secondary minerals such as quartz, feldspars and Mg–Al-rich phyllosilicates, such as chlorite, illite and smectite. The occurrence of a small quantity of calcite in all the samples was also highlighted by the loss of CO2 by thermal analysis (TG–DTA). A normative calculation using XRD, thermal data and X-ray fluorescence (XRF) analysis has permitted to obtain the mineralogical concentration of the minerals occurring in the samples. The combination of multiple techniques provides information about the mineralogy of rocks and hence indication of environments suitable for supporting microbial life on Mars surface. [Copyright &y& Elsevier]

Abstract: Archaeological evidence shows that populations used to transverse the Sahara Desert throughout the Holocene despite the extreme temperatures and the rough physical terrain. The current paper examines whether the desert inhibited extended gene flow among populations by means of cranial morphology as captured by geometric morphometrics. The examined populations include the Garamantes, a group centered in Southwest Libya and largely controlling trans-Saharan trade, and various Egyptian, Tunisian and Sudanese groups dating to the Middle and Late Holocene. The results showed that most inter-population comparisons were statistically significant and therefore all populations appear more or less distant to each other. The Mahalanobis biodistance measure identified four clusters. The first consists of the Garamantes alone, the second includes the populations from Kerma and Gizeh, the third includes the Badari and Naqada, while the fourth consists of the samples from Algeria, Carthago, Soleb and Alexandria. Moreover, the distance of the Garamantes to their neighbors was significantly high and the population appeared to be an outlier. This is attributed to the location of the Garamantes at the core of the desert, indicating that, despite the archaeological evidence, the Sahara Desert posed important limitations to gene flow between the Garamantes and other North African populations. [Copyright &y& Elsevier]

Abstract: The paper presents the large set of basketry and other worked fibre artefacts constituting the perishable artefacts assemblage from the Takarkori rock shelter. This site is located in southwestern Libya, central Sahara. Its well-preserved Holocene stratigraphy testifies to human occupations by foraging groups (Late Acacus culture; ca. 9000–7400 uncal years bp; ca. 8300–6100 BCE) and herders (Pastoral cultures; ca. 7400–4500 uncal years bp; ca. 6400–3000 BCE). The basketry collection includes 91 desiccated items. They have been divided into two distinct groups: basketry constructions and basketry elements (b-items: 53 fragments); ropes and other elements in the broad sense (r-items: 38 fragments). Stems were mostly used to make the b-items, while a fairly diversified set of materials was used for ropes and other elements. In a few cases, mixed animal and plant materials were also employed. SEM analyses showed some diagnostic characteristics such as epidermal stomata, phytoliths, hairs and vessels indicating monocotyledons. Many items were identified as Panicoideae, likely of the Setaria and Panicum types. Therefore, the main wild cereals collected for food and transported into the site also seem to have been the main plants used to make basketry. The only wooden item was attributed to Vitex. The majority of the basketry is made using the twined technique. Basketry remains were more common during the Late Acacus occupation of the site, possibly associated with wild cereal processing and storage, reinforcing the idea of a re-organization of food security towards a delayed use of resources. The basketry material could be interpreted as remains of large and open baskets to collect and store seeds. Decreasing availability of wild cereals, changes in resource exploitation and the nomadic mobility pattern may explain why a smaller number of basketry items was found in layers connected to the Pastoral phases of occupation. [Copyright &y& Elsevier]