Factors controlling the changes and spatial variability of <Emphasis Type="Italic">Junipers phoenicea</Emphasis> in Jabal Al Akhdar,Libya, using remote sensing and GIS

The Junipers phoenicea, which covers 70 % of the Jabal Al Akhdar (Green Mountain) in Cyrene on the northeast coast of Libya, has deteriorated over large scales. To deal with this problem, the images of the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and Landsat 8 Operational Land Imager (OLI) in conjunction with the Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) were used to map factors controlling the J. phoenicea mortality using a set of automated algorithms and tools. These factors include altitude, slope, aspect, curvature, drainage pattern, seawater intrusion, and land cover. As a first step, changes of J. phoenicea and land cover during the period from the year 2000 to 2015 were mapped. The results showed a sharp decline in J. phoenicea covering an area of 396 km² (22 %) of the total area. The result also showed that areas at a lower elevation with steep slope and faced to the south and southeast directions have a higher probability of J. phoenicea distribution. The spatial analysis showed a positive correlation between wetness and the intensity of J. phoenicea mortality. The results also show that altitude and slope have the most influencing power on the J. phoenicea morality. This study is of great help for decision makers and agriculture engineers and permits a better understanding of ecological and biomass changes in the Jabal Al Akhdar, Libya, over a regional scale.     

Integrated geoelectrical resistivity and hydrogeochemical methods for delineating and mapping heavy metal zone in aquifer system

A novel study on using geoelectrical resistivity, soil property, and hydrogeochemical analysis methods for delineating and mapping of heavy metal in aquifer system is presented in this paper. A total of 47 surveys of geoelectrical resistivity with Wenner configuration were conducted to determine the subsurface and the groundwater characteristics. The groundwater sample from 53 existing wells and 2 new wells has been analyzed to derive their water chemical content. The chemical analysis was done on the soil sample obtained from new two wells and from selected locations. The water and soil chemical analysis results from the new two wells were used as calibration in resistivity interpretation. The occurrence of heavy metal in aquifer system was expected to detect using the geoelectrical resistivity survey for the whole study area. The result of groundwater analysis shows that the groundwater sample contains a relatively low concentration of Fe (<?0.3 mg/L) elongating from the south up to the middle region. While in the middle and the northwestern, Fe concentration is relatively high (around 12 mg/L). Chemical analysis of soil sample shows that in the lower resistivity zone (<?18 Ωm), Al and Fe concentrations are comparatively high with an average of 68,000 and 40,000 mg/kg, respectively. Starting from the middle to the northwestern zone, the resistivity value appears to be low. It is definitely caused by higher Al and Fe concentration within the soil, and it is supported also by lower total anion content in the groundwater. While the resistivity value of more than 40 Ωm in aquifers is obtained in the zone which Fe concentration is relatively lower in the soil but not present in the groundwater. Correlation Fe concentration in the soil and Fe concentration in the groundwater sample shows the trend of positively linear; however, the Al concentration in soil has no correlation with Al content in groundwater. Finally, the probability of high heavy metal zone in the aquifer system is easily delineated by the distribution of geoelectrical resistivity presented in depth slice shapes which extend from the Boundary Range Composite Batholith in the north to the northwest.     

Hydrochemical characterization of groundwater in Balad district,Salah Al-Din Governorate,Iraq

The assessment of hydrochemical quality of groundwater is very important to explore its nature and usefulness. In this paper, groundwater quality evaluation is carried out in the Balad district, Salah Al-Din Governorate, Iraq. A total of 28 groundwater samples are collected from shallow tube wells and analyzed for various physicochemical parameters. Groundwater suitability for drinking is evaluated based on the World Health Organization (WHO) and Iraqi standards, and suitability of groundwater for irrigation is assessed based on various hydrochemical parameters. The results reveal that the dominant types of groundwater based on piper diagram are mixed CaMgCl and CaCl. Gibbs ratio indicates that the groundwater in the studied area is affected by the evaporation process. The cation-anion exchange reaction in the studied area demonstrates that 54% of the groundwater samples indicate a direct base (cation-anion) exchange reaction, while 46% of the groundwater samples indicating the chloro-alkaline disequilibrium. Furthermore, generally all of the groundwater samples are unsuitable for drinking and irrigation. Cluster analysis reveals two different groups of similarities between the groundwater samples, reflecting different pollution levels in the studied area.     

Long-term seasonal rainfall forecasting: efficiency of linear modelling technique

Using the lagged (past) climate indices, including El Nino–Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) as input parameters and long-term spring rainfall as outputs, calibration and validation of the linear multiple regression (MR) models have been performed. Since Australian rainfall varies both temporally and spatially, the analysis on the linear MR models was performed on regional scale. These models show the capability of linear MR technique for long-term predictions of Western Australian spring rainfall. The emphasis was given to assess the statistical correlations between Western Australian spring rainfall and dominating large-scale climate modes. The efficiency of linear modelling technique was evaluated to predict seasonal rainfall forecasting. At the same time, the Pearson correlation (R), mean absolute error, root-mean-square error and Willmott index agreement (d) were used to assess the capability of MR models. The models which fulfilled the limits of statistical significances were used for the prediction of future spring rainfall using independent data set. The results indicate that during calibration periods maximum achievable correlations varied from 0.47 to 0.53 for the selected stations. In regard to predict peaks and troughs of rainfall time series, it was found that correlations between predicted and actual peaks varied from 0.82 to 0.94 and between predicted and actual troughs varied from 0.53 to 0.91.     

Hydrothermal alteration and evolution of Zr-Th-U-REE mineralization in the microgranite of Wadi Ras Abda,North Eastern Desert,Egypt

Ras Abda plutonic suite, North Eastern Desert of Egypt, consists predominantly of Neoproterozoic calc-alkaline older granites. Minor exposures of pink microgranite are occurring along Wadi Ras Abda within the older granites. Previous studies on this area demonstrated that the microgranite is altered in some parts and contains anomalous concentrations of rare metal elements (Zr, Th, and U). These altered and mineralized zones are re-assessed using field observations, chemical analysis, and by the application of various transmitted light and electron microscopic techniques. The rare metals exist as mineral segregation grew freely into open cavities of the microgranite and concordant with the NNE strike-slip fault movement. The mineralized zones contain an assemblage of secondary magnetite, zircon, uranothorite, columbite-(Mn), fergusonite-(Y), and allanite-(Ce). The extreme abundance of zircon in the mineralized zone, along with other evidence, indicates a hydrothermal origin of this zircon together with associated rare metals. The geochemical investigation and mass balance calculations revealed extreme enrichment of Zr, Th, U, Y, Nb, Ta, and REE. Post-magmatic hydrothermal alterations resulted in such pronounced chemical and mineralogical heterogeneity. The hydrothermal fluids are thought to be oxidizing, alkaline and of medium temperature (>?250 °C). The average contents of the elements Zr (1606 ppm), Th (1639 ppm), U (306 ppm), Nb (955 ppm), and REE (1710 ppm) in the mineralized microgranite reach sub-economic levels and could be a potential source of these elements.     

Geology and Active Tectonics of the Lalmai Hills,Bangladesh–An Overview from Chittagong Tripura Fold Belt Perspective

The Lalmai Hills is a low amplitude anticline with significant variations in landforms, situated along the western fringe of the Chittagong-Tripura Fold Belt (CTFB) and immediate east of the Indo-Burmese deformation front. This fold belt of the Bengal Basin along with more easterly Indo-Burman Range (IBR) developed as a consequence of the oblique collision between Indian and Burmese plates. This neotectonic activity is still continuing and shaping the geomorphology of the area. This study is conducted based on the geomorphological observation of the topo maps and satellite images, and through reconnaissance field work. Stream length gradient index (SL Index) and Mountain front sinuosity (S_mf) reveals the relative status of tectonic activity. Anomalous SL index values confirm the position of the sympathetic minor faults and also relate to the local stratigraphy. A 2D structural model based on the seismic section reveals thrusts controlled wedge-shape upliftment of the central part as pop-up anticlinal structure. The western thrust is the direct result of the collision of the Indian and Burmese plates, and the eastern one is the back thrust of the western fault. Low S_mf value found in the western flank signifies recent tectonics and relatively high S_mf value in the eastern flank indicates that weathering intensity is relatively greater compared to western flank. Finally, the findings not only enhanced the understanding of geomorphic evolution and active tectonics of the Lalmai Hills area but also the overall tectonic and geomorphic evolution of the western most folded part of the CTFB.     

On the Application of the Novel Thin Spray-on Liner (TSL): A Progress Report in Mining Operations

Stability is the main problem in underground excavations that can result in rock-related accidents or closure of mines. This is often controlled by the geological condition of the rockmass and the in situ stress field where excavation is being carried out. Over the years, conventional support systems such as bolts, shotcrete and mesh have been the standard support systems used in difficult ground conditions to maintain stability of underground openings. The novel Thin Spray Liner (TSL) is a technology with an improvement in terms of support capabilities for difficult geological conditions. This technology is predicted to replace conventional support systems, as it offers a significant yielding capacity that is better than that of the traditional techniques of controlling strata. The performance of the TSL lies between that of shotcrete and wire mesh. The TSL has numerous advantages regarding rock reinforcement such as rapid curing period, fast application, high tensile strength, high adhesion properties that prevent movement of rock keyblocks, improved cycle times, reduction in material-handling compared to shotcrete, and a significant ability to penetrate joints. These advantages increase the allowance for mechanisation and improvement of safety in excavations. Despite various benefits of TSLs, there are shortcomings which make end-users to be sceptical about the technology. This study provides a detailed review of the mechanism, properties, composition and types, as well as the general and mining applications of TSLs. It also describes the challenges faced by the mining industry and other end-users in accepting the technology as a solution for stability issues in underground openings. In addition, some insightful suggestions are made as recommendations for future work on the development of suitable, effective and efficient thin surface rock support technology within limitations/constraints.