Reflectance spectroscopy and remote sensing data for finding sulfide-bearing alteration zones and mapping geology in Gilgit-Baltistan,Pakistan

Gilgit-Baltistan region is covering the northern most part of Pakistan where the rocks of the Kohistan-Ladakh island arc and Karakoram plate are exposed. The area has greater potential for precious and base metals deposits which are needed to be explored through spectroscopy and remote sensing techniques. Minerals and rocks can nowadays be identified through the measurement of their absorption and reflectance features by spectroscopic analysis. Spectral reflectance analysis is also very important in selecting the appropriate spectral bands for remote-sensing data analysis of unknown or inaccessible areas. In this study, reflectance spectra in the spectral range of 0.35–2.5 μm of different types of unaltered and altered rocks found in the Machulu and Astor areas of northern Pakistan were obtained using an ASD spectroradiometer. The fresh rock samples showed low spectral reflectance as compared to the altered rock samples. The minerals jarosite, goethite, and hematite showed depth of absorption minima in the range of 0.4–1.15 μm due to the presence of iron (Fe), while jarosite and limonite showed absorption depth at 2.2 μm due to the presence of hydroxyl ions (OH^¯). The clay minerals montmorillonite and illite showed absorption depth at 1.93 and 2.1 μm, respectively. Muscovite showed depth of absorption minima at 1.4 and 1.9 μm in some samples. Calcite showed deep absorption minima at 2.32 μm, while anorthite showed absorption features at 1.4, 1.9, 2.24, and 2.33 μm. Olivine showed a slight depressed absorption feature at 1.07 μm. The copper-bearing phases malachite, chrysocolla, and azurite showed, respectively, a broad absorption feature in the range of 0.6–0.9 μm, a small absorption at 1.4 μm, and a deep absorption at 1.93 μm. The unmineralized samples exhibited high reflectance in the wavelength ranges of 0.6–0.8, 1.6–1.9, 2.0–2.3, 2.1–2.25, and 2.4–2.5 μm, respectively, while the mineralized samples showed reflectance bands in the wavelength ranges of 0.4–0.6, 1.3–1.8, and 2.1–2.2 μm. On this basis, the band ratio combinations 7/5–4/3–6/3 and 7/5–6/3–4/3 of Landsat 8 and 4/7–4/3–2/1 for ASTER data were found to be very effective in the lithological differentiation of major rock units.     

A spatio-temporal three-dimensional conceptualization and simulation of Dera Ismail Khan alluvial aquifer in visual MODFLOW: a case study from Pakistan

Dera Ismail Khan (DIK) is situated in the Lower Indus Basin of Pakistan. The land use has been changed in the canal command area due to irrigation activities near the Indus River. To check the current status and predict the groundwater levels in the area, the unconfined aquifer has been simulated in Visual MODFLOW for a period of 35 years, i.e., from 1985 to 2020. The 2900-km² area has been modeled with a grid of 500 by 500 m and the depth set to 100 m. The aquifer in the study area has been divided vertically and laterally into three and ten zones, respectively, for the characterization. Water wells and streams were used as the sinks and hydrologic boundaries, respectively. The model was successfully calibrated in steady and the non-steady state. The simulation revealed that the whole simulation can be divided into two phases, i.e., before and after the construction of the Chashma Right Bank Canal (CRBC), whereas the results were summarized in the form of water table depth maps and groundwater budget calculations. To determine the groundwater sustainability, a conjunctive use scenario has been employed to simulate the aquifer dynamics till 2020. The simulation revealed incremental drawdowns till the end.     

Seismic stratigraphy of the Mianwali and Bannu depressions,north-western Indus foreland basin

International Journal of Earth Sciences - Regional seismic reflection profiles, deep exploratory wells, and outcrop data have been used to study the structure and stratigraphic architecture of the...     

Health risk of heavy metals from vegetables irrigated with sewage water in peri-urban of Dera Ismail Khan,Pakistan

Health risks of heavy metals in vegetables irrigated with sewage water were investigated in the present study. The findings indicated a massive accumulation of heavy metals in soil and vegetables collected from Dera Ismail khan, Pakistan. The concentration levels of heavy metal in vegetables grown on soil irrigated with untreated sewage water were significantly higher at (P ≤ 0.001) than in vegetables grown on fresh-water-irrigated soil and proceeded the recommended limits of World health organization. Moreover, the findings also indicated that the adults and children consuming such vegetables ingested a large proportion of the selected toxic metals. Health risk index was greater than one for Pb and Cd in all the selected vegetables and was greater than one for Ni in three vegetables like Spinacia oleracea, Benincasa fistulosa and Lactuca sativa. Health risk assessment would be a useful tool for information regarding any threats of heavy metals contamination in vegetables.     

High-performing antifouling bacterial consortium for submerged membrane bioreactor treating synthetic wastewater

Biofouling, associated with membranes, is considered as a major operational challenge in membrane bioreactor (MBR) technology. Interrupting the process for the formation of biofilm by the action of interspecies quorum quenching (QQ) has received a significant attention since recent years. An antifouling bacterial consortium was identified to improve biofouling inhibition performance during MBR operation. For this purpose, various QQ bacteria were isolated from laboratory-scale MBR using enrichment culture method and identified via 16S rRNA. Potential quenching strains including Enterobacter cloaca, Delftia sp., and Pseudomonas sp. were utilized to control biofouling in the MBR operated in the continuous mode for 38 days. Three laboratory-scale MBRs, including two MBRs with different anti fouling consortium and a control, were operated in parallel under similar operating conditions. Biofouling control by QQ bacteria was compared based on the membrane permeability and EPS secretion from biofilm on the membrane. Both MBRs with antifouling consortium (AC-MBRs) experienced around three times less biofouling as compared to conventional MBR leading to significant decrease in acyl homoserine lactones (AHLs) concentration in the biocake. More than 90, 45, and 49% of COD, NH₄–N, and PO₄ ^3?–P removal efficiencies elucidate that QQ bacterial consortium could effectively reduce membrane biofouling without compromising the MBR efficiency. Comparatively lower concentration of bound EPS in AC-MBRs restricted the bacterial adhesion to membrane resulting in enhanced membrane permeability depicting that a broader range of signal molecules could be hydrolyzed using antifouling consortium than single or no QQ strain in the submerged MBR.     

Diagenetic evolution vis-a-vis reservoir characteristics of Dhosa sandstones,Ler dome,Kachchh, western India

The detrital mineralogy as well as diagenetic characters of the Dhosa Sandstone Member of Chari Formation exposed at the Lerdome, south of Bhuj was studied. In order to assess the potential of the Dhosa Sandstone as a reservoir, it is substantial to understand the diagenetic processes that are controlled largely by post-depositional cementation and compaction in addition to framework composition and original depositional textures. The petrologic analysis of 33 thin sections was carried out to discern primary composition and diagenetic features including primary and secondary porosity patterns. Monocrystalline quartz dominates the detrital mineralogy followed by polycrystalline quartz. Among the polycrystalline variety recrystallized metamorphic quartz surpasses stretched metamorphic quartz in terms of abundance. Feldspars comprise microcline and plagioclase where the former is dominant over the latter. Orthoclase too comprises a very small percentage. Mica, chert, rock fragments, and heavies form the remaining detrital constituent in descending order of their constituent percentage. The diagenetic precipitates are mainly carbonate (8.30%) and iron (7.80%) followed by clay (0.66%) and silica (0.88%) that are minor constituent of the total cementing material. The main paragenetic events identified are early cementation, mechanical compaction, late cementation, dissolution, and authigenesis of clays. The overall reservoir quality seems to be controlled by compaction and authigenic carbonate cementation. The minus cement porosity average 29.4%. The porosity loss due to compaction is 21.92% and by cementation is 29.71%. The loss of original porosity was due to early cementation followed by moderate mechanical compaction during shallow burial. Preservation of available miniscule primary porosity was ascribed to dissolution of carbonates and quartz overgrowth which resisted chemical compaction during deep burial. The studied sandstones may have low reservoir quality owing to existing porosity of less than 9%. More carbonate dissolution and its transformation in dolomite in sub-surface condition and macro-fracture porosity may result in enhanced secondary porosity and good diagenetic traps.     

Synthesis of biochar from sugarcane filter-cake and its impacts on physiological performance of lettuce (<Emphasis Type="Italic">Lettuce sativa</Emphasis>) grown on cadmium contaminated soil

Soil contamination with cadmium has become major concern all over the world because of its adverse impacts on ecosystem health and agricultural land. Soil amendment with biochar may have varied effects on physical and chemical properties of soil. The objective of the study was to explore the impact of sugarcane filter-cake biochar on physiological performance and growth of lettuce in an aged soil. Four different doses (0, 1.5%, 3%, and 5%) of biochar were used in the soil and conditioned for 1 month. After this, lettuce seedlings were grown in the soil. The results showed that the biochar treatment improved the fresh and dry biomass of leaves and roots as well as plant height while diminished the bioavailability of cadmium from the soil. As compared to control, biochar significantly enhanced the chlorophyll content in lettuce leaves. Due to the biochar amendment, the oxidative stress decreased in lettuce shoots over the control. As compared to control, concentration of cadmium in lettuce significantly decreased after the application of biochar. It was concluded that biochar could mitigate the toxicity of cadmium in lettuce by altering the biochemical and physiological processes in cadmium contaminated soil.     

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.