Search Results (56)

Zoharite (IMA 2017-049), (Ba,K)₆ (Fe,Cu,Ni)₂₅S₂₇, and gmalimite (IMA 2019-007), ideally K₆□Fe²⁺₂₄S₂₇, are two new sulfides of the djerfisherite group. They were discovered in an unusual gehlenite–wollastonite paralava with pyrrhotite nodules located in the Hatrurim pyrometamorphic complex, Negev Desert, Israel. Zoharite and gmalimite build grained aggregates confined to the peripheric parts of pyrrhotite nodules, where they associate with pentlandite, chalcopyrite, chalcocite, digenite, covellite, millerite, heazlewoodite, pyrite and rudashevskyite. The occurrence and associated minerals indicate that zoharite and gmalimite were formed at temperatures below 800 °C, when sulfides formed on external zones of the nodules have been reacting with residual silicate melt (paralava) locally enriched in Ba and K. Macroscopically, both minerals are bronze in color and have a dark-gray streak and metallic luster. They are brittle and have a conchoidal fracture. In reflected light, both minerals are optically isotropic and exhibit gray color with an olive tinge. The reflectance values for zoharite and gmalimite, respectively, at the standard COM wavelengths are: 22.2% and 21.5% at 470 nm, 25.1% and 24.6% at 546 nm, 26.3% and 25.9% at 589 nm, as well as 27.7% and 26.3% at 650 nm. The average hardness for zoharite and for gmalimite is approximately 3.5 of the Mohs hardness. Both minerals are isostructural with owensite, (Ba,Pb)₆(Cu,Fe,Ni)₂₅S₂₇. They crystallize in cubic space group Pm$\overline{3}$m with the unit-cell parameters a = 10.3137(1) Å for zoharite and a = 10.3486(1) Å for gmalimite. The calculated densities are 4.49 g·cm⁻³ for the zoharite and 3.79 g·cm⁻³ for the gmalimite. The primary structural units of these minerals are M₈S₁₄ clusters, composed of MS₄ tetrahedra surrounding a central MS₆ octahedron. The M site is occupied by transition metals such as Fe, Cu, and Ni. These clusters are further connected via the edges of the MS₄ tetrahedra, forming a close-packed cubic framework. The channels within this framework are filled by anion-centered polyhedra: SBa₉ in zoharite and SK₉ in gmalimite, respectively. In the M₈S₁₄ clusters, the M atoms are positioned so closely that their d orbitals can overlap, allowing the formation of metal–metal bonds. As a result, the transition metals in these clusters often adopt electron configurations that reflect additional electron density from their local bonding environment, similar to what is observed in pentlandite. Due to the presence of shared electrons in these metal–metal bonds, assigning fixed oxidation states—such as Fe²⁺/Fe³⁺ or Cu⁺/Cu²⁺—becomes challenging. Moreover, modeling the distribution of mixed-valence cations (Fe²⁺/³⁺, Cu⁺/²⁺, and Ni²⁺) across the two distinct M sites—one located in the MS₆ octahedron and the other in the MS₄ tetrahedra—often results in ambiguous outcomes. Consequently, it is difficult to define an idealized end-member formula for these minerals. Full article

This study reconstructs the agricultural landscape of the southern coastal plain of late Ottoman and British Mandatory Palestine (today southwestern Israel) utilizing late 19th and early 20th century cartographic materials and aerial photographs. Immense human effort and ingenuity were required to maintain sustainable agricultural on the fringes of the desert. Given today’s increasingly severe climate crisis, the lessons drawn from these historical agricultural practices have particular resonance. The agricultural land use described in this work extended into the coastal dunes of the region where the shallow water table was exploited to create complex agricultural systems that enabled the growth of citrus trees, grapes, and other crops for export and trade. Aerial photos and maps reveal the critical aspects of this region’s neglected agricultural history. The stability and resilience of these systems, some of which are still in existence 76 years or more after they were abandoned, as seen in the survey conducted for this study, point to the importance of understanding and preserving this chapter of the region’s agricultural heritage. The unique varieties of fruit trees adapted to the local climate of the western Negev still have significant economic value and are threatened with extinction from rapid urban encroachment. The remnants of this tradition serve as historical testimony of a bygone agricultural era which was replaced by mechanized monoculture. The discussion centers on the ways n which the study of heritage agriculture in rapidly changing areas can contribute to the broader field of historical geography by reconstructing landscapes that preserve the knowledge and societal patterns of behavior of past communities for future generations. Full article

Background: The wine industry in arid area serves as a crucial livelihood source at the frontiers of anti-desertification and anti-poverty. By making use of a carbon footprint (CF) management system, formerly untapped climate values can be explored, embedded, and cherished to connect rural communities with the global goals of sustainable development. However, the current standards of CF management mainly represent the traditional wine grape growing areas of Europe, Oceania, and North America. Limited study of the arid areas in lower-income regions exists, which offers a kind of potential development knowledge regarding creating climate-related livelihoods. Methods: This paper attempts to construct a cradle-to-gate CF Life Cycle Assessment (LCA) framework based on the prominent emission factors in three GHG emission phases (raw material input, planting management, and transportation) of a wine grape variety, Cabernet Sauvignon (chi xia zhu), planted at the Eastern Foothills of the Helan Mountains in the Ningxia Hui Autonomous Region of China. Results: It is found that viticulture processes (instead of wine-making, bottling, or distribution) account for a larger proportion of GHG emissions in Ningxia. Due to the large amount of irrigation electricity usage, the less precipitation wine producers have, the larger CF they produce. By using organic fertilizer, the CF of Ningxia Cabernet Sauvignon, being 0.3403 kgCO₂e/kg, is not only lower than that of the drier areas in Gansu Province (1.59–5.7 kgCO₂e/kg) of Western China, but it is even lower than that of the Israel Negev Region (0.342 kgCO₂e/kg) that experiences more rainfall. Conclusions: The measurement of CF also plays a role in understanding low-carbon experience sharing. As the largest wine grape production area in China, CF analysis of the Ningxia region and its commercial value realization might practically fill in the knowledge gap for desert areas in developing countries. It is inspiring to know that by applying green agricultural technologies, the viticulture CF can be effectively reduced. For the potential exchanges in global carbon markets or trading regulations under the Carbon Border Adjustment Mechanism (CBAM), positive variations in CF and soil organic carbon (SOC) storage volume need to be considered within financial institutional design to lead to more participation toward SDGs. Full article

Silicocarnotite, Ca₅[(PO₄)(SiO₄)](PO₄), was first described from slag over 140 years ago. In 2013, it was officially recognised as a mineral after being discovered in the larnite–gehlenite hornfels of the pyrometamorphic Hatrurim Complex. This paper describes the composition and structure of V-bearing silicocarnotite, crystals of which were found in a thin paralava vein cutting through the gehlenite hornfels. A network of thin paralava veins a few centimetres thick is widespread in the gehlenite hornfels of the Hatrurim Basin, Negev Desert, Israel. These veins, typically coarse crystalline rock and traditionally referred to as paralava, have a symmetrical structure and do not contain glass. Silicocarnotite in the paralava, whose primary rock-forming minerals are gehlenite, flamite, Ti-bearing andradite, rankinite and pseudowollastonite, was a relatively late-stage high-temperature mineral, crystallising at temperatures above 1100 °C. It formed from the reaction of a Si-rich residual melt with pre-existing fluorapatite. A single-crystal structural study of silicocarnotite (Pnma, a = 6.72970(12) Å, b = 15.5109(3) Å, c = 10.1147(2) Å) suggests that the phenomenon of Ca1 position splitting observed in this mineral is most likely related to the partial ordering of Si and P in the T2O₄ tetrahedrons. Raman studies of silicocarnotite with varying vanadium content have shown that phases with V₂O₅ content of 3–5 wt.% exhibit additional bands at approximately 864 cm⁻¹, corresponding to vibrations of ν₁(VO₄)³⁻. Full article

Two zoogenic deposits from the central part of the Negev Desert (Israel) were investigated by stable isotopes (carbon ¹³C/¹²C and nitrogen ¹⁵N/¹⁴N) and pollen analyses. The merger of these data and results of radiocarbon dating of Atzmaut and Ramon I deposits enabled us to reconstruct climate and vegetation changes in the Negev Desert over the past 8500 years. Decrease of the δ¹³C value in plant remains is a sensitive indicator of paleoclimatic conditions in the region. The decline of the δ¹³C value over the past 8500 years almost fully coincides with an increase of the total pollen concentration, the proportion of Poaceae pollen in the profile of zoogenic deposits and wetter periods. Thus, four humid periods are identified, from the middle of the 4th millennium to the end of 3rd millennium BC, the 1st half of the 2nd millennium BC, from the 2nd half of the 1st millennium BC to the 1st half of the 1st millennium AD and the middle of the 2nd millennium AD. The δ¹⁵N value of plant remains is a less sensitive indicator of climate dynamics and represents the most significant change of precipitation in the region by the end of the 3rd millennium BC. Full article

Based on an examination of the outlooks and practices held by past and present Negev desert viticulturists vis-à-vis their environs, the article offers insights into how the wine sector can bolster its response to current climate adversity. The discussion fuses bio-archaeological research on the evolution of ancient grape cultivars (Vitis vinifera) in the Negev with an extensive ethnographic inquiry into the ongoing wine revival in arid southern Israel. Ancient DNA analysis of relic grape material led to the identification of an historical Negev viticulture lineage. The findings provide a temporal framework for contextualizing tphe interrelated anthropological data obtained on contemporary dryland viticulturalists and wine makers in Israel. Since the climate in the Negev has remained relatively stable over the last several millennia, it makes for an apt point of comparison via which to gauge the outlooks held by both historical and modern viticulturalists towards the local landscape. We suggest enacting two evidence-based adjustments to counter ecological instabilities: the holistic revival and applied renewal of historical cultivars, and the attendant agronomic routines that sustained their growth in the past. A more nuanced understanding of the unique terroir arid viticulturalists are operating in, together with the learned incorporation of the hardy genetic traits of age-old cultivars, will benefit wine growers to attune their responses to the array of challenges wrought by climate change on the wine industry. It is therefore our hope that the research methodologies and heritage-oriented horticultural perspectives we present in this paper will prove beneficial to broader wine growing regions (pax-Mediterranean and beyond) who are fortunate to likewise possess their own rich viticultural histories and lineages. Full article

The Negev desert, the southern half of Israel, is an arid-to-hyper-arid region. Despite that, some 13,000 ancient sites have been recorded here to date, and many were excavated. One characteristic of the Negev (as well as of other deserts) is the abundance of prehistoric and early historic cult sites, dated ca. 8000–2000 BCE. Another is the many ancient roads. The roads, the main types of cult sites and the connection between them are described and discussed in the following sections. Full article

On 15 September 2015, a convective storm yielded heavy rainfalls that caused the strongest flash flood in the last 50 years in the South Negev Desert (Israel). None of the operational forecast models predicted the event, and thus, no warning was provided. We analyzed this event using satellite, radar, and numerical weather prediction model data. We generated cloud-free climatological values on a pixel basis using Temporal Fourier Analysis on a time series of MSG geostationary satellite data. The discrepancy between the measured and climatological values was used to detect “cloud-contaminated” pixels. This simple, robust, fast, and accurate method is valuable for the early detection of convection. The first clouds were detected 30 min before they were detected by the official MSG cloud mask, 4.5 h before the radar, and 10 h before the flood reached the main road. We used the “severe storms” RGB composite and the satellite-retrieved vertical profiles of cloud top temperature–particle’s effective radius relations as indicators for the development of a severe convective storm. We also reran the model with different convective schemes, with much-improved results. Both the satellite and model-based analysis provided early warning for a very high probability of flooding a few hours before the actual flooding occurred. Full article

We report ground-based measurements of the atmospheric electric field (Ez = −potential gradient (PG)) and current density (Jz) that were conducted at two locations in Israel. One is at the Emilio Segre cosmic ray station located on Mt. Hermon (34.45° N, 2020 m AMSL) in northern Israel near the Syrian-Lebanon border, and the other is at the Wise astronomical observatory in the Negev desert highland plateau of southern Israel (31.18° N, 870 m AMSL). We searched for possible effects of strong, short-term solar events on the potential gradient and the vertical current density, as disruptions to the global electric circuit are often observed following strong solar events. The first case study (St. Patrick’s Day, 17 March 2015) was classified as the strongest event of 2015. The second case study (8 September 2017) was categorized as the strongest event of 2017 and one of the twenty strongest events on record to date. The results show that the electrical parameters measured at ground level at both stations were not affected during the two massive proton events and the ensuing geomagnetic storms. The magnetospheric shielding in lower latitudes is strong enough to shield against the flux of energetic particles from solar events, obscuring any impact that may be noticeable above the local daily variations induced by local meteorological conditions (aerosol concentrations, clouds, high humidity, and wind speed), which were investigated as well. Full article

We examined fungal communities in soil profiles of 0–10 cm depth along the altitudinal gradient of 250–530–990 m.a.s.l. at the Central Negev Desert, Israel, which benefit from similar annual precipitation (95 mm). In the soil samples collected in the summer of 2020, a mycobiota accounting for 169 species was revealed by both culture-dependent and culture-independent (DNA-based) methodologies. The impact of soil depth on the variations in fungal communities was stronger than the impact of altitude. Both methodologies displayed a similar tendency in the composition of fungal communities: the prevalence of melanin-containing species with many-celled large spores (mainly Alternaria spp.) in the uppermost layers and the depth-wise increase in the proportion of light-colored species producing a high amount of small one-celled spores. The culturable and the DNA-based fungal communities had only 13 species in common. The differences were attributed to the pros and cons of each method. Nevertheless, despite the drawbacks, the employment of both methodologies has an advantage in providing a more comprehensive picture of fungal diversity in soils. Full article

A scientific collaboration between the U.S. and Israel is underway to assess the suitability of a potential site for subsurface radioactive waste disposal in the Negev Desert, Israel. The Negev Desert has several favorable attributes for geologic disposal, including an arid climate, a deep vadose zone, interlayered low-permeability lithologies, and carbonate rocks with high uranium-sorption potential. These features may provide a robust natural barrier to radionuclide migration. Geologic and laboratory characterization data from the Negev Desert are incorporated into multiphase flow and transport models, solved using PFLOTRAN, to aid in site characterization and risk analysis that will support decision-making for waste disposal in an intermediate-depth borehole design. The lithology with the greatest uranium sorption potential at the site is phosphorite. We use modeling to evaluate the ability of this layer to impact uranium transport around a proposed disposal borehole. The current objective of the simulations is focused on characterizing hypothetical leakage from waste canisters and subsequent uranium migration under three infiltration scenarios. Here, we describe a hydrogeologic model based on data from a local exploratory borehole and present results for uranium flow and transport simulations under varying infiltration scenarios. We find that under the current climate conditions, it is likely that uranium will remain in the near-field of the borehole for thousands of years. However, under a hypothesized extreme climate scenario representing an increase in infiltration by a factor of 300x above present-day values, uranium may break through the phosphorite layer and exit the base of the model domain (~200 m above the water table) within 1000 years. Simulation results have direct implications for the planning of nuclear waste disposal in the Negev Desert, and specifically in intermediate-depth boreholes. Full article

Ground-based measurements of the atmospheric electric field have been recorded continuously since 2013 at the Wise Observatory, located in the Negev Desert Highland in southern Israel. The data have been used for defining the characteristics of fair weather and to identify the signatures of dust storms, lightning activity, and clouds. We report here on new results from observations of the variability of the electric field (transformed into the potential gradient, PG) during several foggy days, along with meteorological data on wind speed and relative humidity. The results show a substantial increase in the electric field (up to 400–650 V m⁻¹) compared with the mean fair weather values observed at the site (180–190 V m⁻¹). This increase is especially clear during times of high relative humidity values (95%+) and low wind speed (<3 m s⁻¹). This increase is likely a consequence of the reduction in the atmospheric conductivity at low levels, due to the attachment of charge carriers to fog droplets. Based on this discovery, it is suggested that continuously monitoring the electric field may offer an additional operational tool to alert for the onset and termination of fog at specific locations, such as airports and harbors, where this nowcasting capability is required. Full article

For the first time, chromium disulphides, known from meteorites, such as caswellsilverite, NaCrS₂; grokhovskyite, CuCrS₂; and a potentially new mineral, AgCrS₂, as well as the products of their alteration, such as schöllhornite, Na_0.3CrS₂∙H₂O, and a potentially new mineral with the formula {Fe_0.3(Ba,Ca)_0.2} CrS₂·0.5H₂O, have been found in terrestrial rock. Layered chromium disulphides were found in unusual phosphide-bearing breccia of the pyrometamorphic Hatrurim Complex in the Negev Desert, Israel. The chromium disulphides belong to the central fragment of porous gehlenite paralava cementing altered host rock clasts. The empirical formula of caswellsilverite is (Na_0.77Sr_0.03Ca_0.01)_Σ0.81(Cr³⁺_0.79Cr⁴⁺_0.18V³⁺_0.01 Fe³⁺_0.01)_Σ0.99S₂·0.1H₂O, and the end-member content of NaCrS₂ is 76%. It forms single crystals in altered pyrrhotite aggregates. Grokhovskyite has the empirical formula {Cu⁺_0.84Fe³⁺_0.10Ca_0.06 Na_0.01 Sr_0.01Ba_0.01}_Σ1.03(Cr³⁺_0.94 Fe³⁺_0.05 V³⁺_0.05)_Σ1.00S₂·0.35H₂O, and the CuCrS₂ end-member content is 75–80%. A potentially new Ag-bearing chromium disulphide is characterised by the composition (Ag_0.89Cu_0.07)_Σ0.96(Cr_0.98 Fe_0.03V_0.01Ni_0.01)_Σ1.04S₂. Caswellsilverite, grokhovskyite and AgCrS₂ form in gehlenite paralava at high temperatures (near 1000 °C) and low pressure under reducing conditions. The structure of the layered chromium disulphides, MCrS₂, is characterised by the presence of hexagonal octahedral layers (CrS₂)¹⁻, between which M-sites of the monovalent cations Ag, Cu and Na set. A low-temperature alteration of the layered chromium disulphides, when schöllhornite and {Fe_0.3(Ba,Ca)_0.2}CrS₂·0.5H₂O form, is reflected in the composition and structural modification of the layer with monovalent cations, whereas the octahedral layer (CrS₂)¹⁻ remains unchanged. Full article

Ecological restoration has recognized explicitly the recovery of ecosystem functions. The emphasis on ecosystem functions in restoration efforts can be defined as functional restoration. Functional restoration, i.e., rehabilitation of ecosystem functions, is particularly applicable to highly degraded landscapes such as desertified areas, where restoration to the original state is impossible. This review paper produced a general conceptual model of the fundamental processes that regulate ecosystem functions in water-limited ecosystems. The Israeli Negev Desert was used as a case study to test the model results in the field. We developed general guiding principles for functional restoration of degraded landscapes that integrate functional restoration methods and include four successive steps: (1) identifying the fundamental processes that regulate ecosystem functions in alternative states; (2) detecting drivers leading to degraded states; (3) functional restoration: changing the state of the degraded landscape; and (4) monitoring the impact of the restoration effort and assessing its success in terms of ecosystem services. Our case study, the Negev, provided us with insights on how to reverse desertification in water-limited systems by restoring source–sink networks as a subset of functional restoration. The four suggested steps of functional restoration are essential for ecosystem recovery in the Anthropocene. Full article

Lipids and their oxidation products were quantified in loess samples from the Negev Desert (Israel), well known to be a source of desert dusts in the eastern Mediterranean Basin. The results obtained showed the presence of higher plant material (angiosperms and gymnosperms), but also bacteria and fungi. Although a strong autoxidation of lipids could be demonstrated, the resulting oxidation products appeared to be weakly accumulated, likely due to the high temperatures and solar irradiance observed in the Negev Desert. Incubation of this dust analogue in fresh water (to mimic their behavior in rainwater) resulted in the release of metal ions (mainly iron), but also a fast heterolytic degradation of their weak content of hydroperoxides. Induction of autoxidation processes in dry and wet atmospheric dusts arising from the Negev Desert in seawater (needing simultaneous presence of metal ions and hydroperoxides) seems thus very unlikely due to the relatively high pH of seawater hindering metal dissolution and the degradation of hydroperoxides in rainwater. Full article