In this study, vesicular basalt volcanic rock was taken and its application for adsorption of chromium (VI) from aqueous solution was investigated. Different physical and chemical properties of the powdered rock was studied using Fourier transform infrared spectroscopy (FT-IR), Powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). A series of batch experiments were carried out to study the effect of various experimental parameters (pH, ionic strength and contact time) on chromium (VI) adsorption. It was found that the removal efficiency of chromium (VI) decreased with increasing pH and ionic strength. The adsorption process was optimal at pH 2. The maximum adsorption capacity was 79.20 mg kg−1 at an initial concentration of 5.0 mg L−1 and adsorbent dosage of 50 g L−1. In individual adsorption tests, Pseudo-second-order kinetic and Freundlich isotherm models could better describe chromium (VI) adsorption on the vesicular basalt. This study indicated that vesicular basalt, which is inexpensive, has the potential to remove chromium (VI) from polluted water.

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The Triassic gabbroic intrusions and associated basaltic lavas from Chukotka are mainly tholeiitic with both ocean island basalt (OIB) and island arc basalt (IAB)-type geochemical signatures. Mg-number [Mg# = 100 × Mg/(Mg + Fe 2+ )] is around 40 for OIB-type gabbros, ranges from 48 to 66 for IAB-type hornblende-rich gabbros, and 43 to 65 for IAB-type basaltic rocks (ankaramites, lamprophyres, pyroxene-phyric basalts and hornblende-phyric basaltic andesite). TiO 2 contents of the IAB-type gabbros and basaltic rocks are low (<2 wt%), but are high in OIB-type gabbros (4.3-5.3 wt%). OIB-type gabbros are typically enriched in FeO * (16-18 wt%) as compared to IAB-type gabbros (10-14 wt%) and IAB-type lavas (ankaramites,~10 wt%; lamprophyres,~14; pyroxene-phyric basalt, 11 wt% and basaltic andesite, 9-10 wt. %). In the primitive mantle normalized trace element patterns, IAB-type basalts and gabbros are characterized by depletion in HFSE (Nb, Ta, Zr and Hf ) and enrichment in LILE. OIB-type gabbros can be distinguished from the rests by the absence of HFSE depletion, with strong negative Sr anomaly. The positive Ti anomaly in the OIB-type gabbros can be attributed to high content of ilmenite in these rocks. Trace element characteristics of IAB-type gabbroic rocks and basalts are compatible with their magmas derived from subduction influenced melts, whereas OIB-type gabbros show within-plate geochemical characteristics. IAB-type gabbros and basaltic rocks display similar geochemical features to the low-Ti Nadezhdinsky suit (Noril'sk region) and Bel'kov dolerite (New Siberian Islands) of the Siberian large igneous province (LIP) in view of HFSE depletion and high H 2 O content of the magma to crystallize abundant hornblende not only in gabbros but also as phenocrysts in basalts. The Triassic gabbroic and basaltic rocks of both OIB and IAB types may as a whole represents the eastern end of the Siberian LIP.

Ever increase in population growth and drastic climatic changes augment the demand and exploration of groundwater from time to time. An integrated approach of remote sensing (RS), geographic information system (GIS) and multicriteria decision analysis (MCDA) of analytical hierarchical process (AHP) were applied to delineate groundwater potential (GWP) zones in Andasa-Tul watershed, Upper Blue Nile Basin, Ethiopia. For this purpose, nine GWP influencing thematic layers comprising lithology, lineament density, geomorphology, slope, soil, drainage density, land use/land cover, rainfall and depth to groundwater level were used. The thematic layers and classes within them were given scale values based on literature and experts' decision and calculated using Satty's AHP. The thematic layers have been integrated via their weights/rates using weighted overlay spatial function tool of ArcGIS to provide GWP map. The result shows that GWP map comprises very good (13.4%), good (7%), moderate (23.6 %), poor (35.4%) and very poor (20.5%) zones. Validation of the GWP map with existing water point yields shows 84.21 % agreement indicating good accuracy of the method. The map removal sensitivity analysis result reveals that GWP is more sensitive to lithology (mean variation index, 1.92 %) and less sensitive to geomorphology (mean variation index, 0.59 %). Similarly, from the single layer sensitivity analysis, lithology and slope are found to be more effective parameters, whereas rainfall and depth to groundwater level are less effective variables.