Hydrochemical characteristics of groundwater in the plains of Phalgu River in Gaya, Bihar, India

Assessment of groundwater quality is essential to ensure sustainable use of it for drinking, agricultural, and industrial purposes. The chemical quality of groundwater of Gaya region has been studied in detail in this work to delineate the potable groundwater zones. A total of 30 groundwater samples and 2 surface water samples were collected in and around Gaya district of Bihar. The major cations follow the trend: Ca²⁺?>?Mg²⁺?>?Na⁺?>?K⁺. The domination of calcium ions in the groundwater is due to weathering of rocks. The K⁺ ranged between 0.2 and 47.95 ppm, suggesting its abundance the below desired limit; but some samples were found to be above permissible limit. K⁺ weathering of potash silicate and the use of potash fertilizer could be the source. The major anions abundance followed the order HCO ₃ ^? ?>?Cl^??>?SO ₄ ^2? ?>?NO ₃ ^? ?>?PO ₄ ^3? . Dissolution of carbonates and reaction of silicates with carbonic acid accounts for the addition of HCO ₃ ^? to the groundwater and oxidation of sulphite may be the source of SO ₄ ^2? . Principal component analysis was utilized to reflect those chemical data with the greatest correlation and seven major principal components (PCs) representing >80 % of cumulative variance were able to interpret the most information contained in the data. PC1, PC2 and PC3 reflect the hydrogeochemical processes like mineral dissolution, weathering and anthropogenic sources. PC4, PC5, PC6 and PC7 show monotonic, random and independent relationships.     

Petrographic and geochemical characterization of coal from Talcher coalfield,Mahanadi Basin,India

In the present study an attempt has been made to characterize the coals of Talcher coalfield employing petrographic and geochemical techniques on a large number of coal samples. Pillar coal samples were collected from all the six workable coal seams, which occur in the Karharbari (Seam-I) and the Barakar (Seams II, III, IV, V and IX) formations.     

Spatial variability of fluorine in agricultural soils around Sidhi District,Central India

The systematic and comprehensive geochemical analysis of fluoride (F) in twenty agricultural soil samples was carried out to understand spatial variability, mechanism of retention and release, and the areas of potential risk due to high concentrations of F in soil around Sidhi District, Central India. The spatial variations in physico-chemical parameters revealed significant difference in the methods of cultivation due to geomorphological constraints, availability of surface water and ground water etc., in the study area. The north and small pocket in central Sidhi were rich in fertile soils due to availability of surface and ground water. The southern and eastern Sidhi were rainfed areas, hence, the monocropping system by traditional methods showed less impact on the soil physico-chemical parameters. The soil F varied from 366.94 to 1178 mg/kg and 2-4 times greater than the background soil value (320 mg/kg) of the world. The pollution indexes were > 1 indicating prevalence of elevated soil fluorine.     

Observed and simulated water and energy budget components at SCAN sites in the lower Mississippi Basin

Land surface models are typically constrained by one or a few observed variables, while assuming that the internal water and energy partitioning is sensitive to those observed variables and realistic enough to simulate unobserved variables. To verify these assumptions, in situ soil climate analysis network (SCAN) observations in the Lower Mississippi Basin (2002–2008) are analysed to quantify water and energy budget components and they are compared to Community Land Model (CLM3·5) simulations. The local soil texture is identified as a major indicator for water storage characteristics and the Normalized Difference Vegetation Index shows potential as a drought indicator in summer months. Both observations and simulations indicate a regime where, except in some summer months, evapotranspiration controls soil moisture. CLM simulations with different soil texture assignments show discharge sensitivity to soil moisture, but almost no impact on evapotranspiration and other energy balance components. The observed and simulated water budgets show a similar partitioning. However, the SCAN observed water balance does not close because of precipitation measurement errors, unobserved irrigation, lack of specific storage change measurements and errors in the computed actual evapotranspiration. The simulated heat flux partitioning differs from that ‘observed’, with a larger (resp. smaller) fraction of net radiation being used by latent (resp. sensible) heat flux, and unobserved freeze and thaw events. The comparison between observations and model simulations suggests that a consistent observation collection for multiple variables would be needed to constrain and improve the full set of land surface variable estimates. Copyright © 2010 John Wiley & Sons, Ltd.     

Intra-day variability of three Seyfert galaxies measured with XMM-Newton

We present and analyze the variability of three Seyfert galaxies on intra-day timescales. We have analyzed in a uniform manner the 38 longest( 30 ks) observations made for NGC 4051, MCG-06–30–15 and NGC 4151 by XMM-Newton between 2000 and 2015. The nuclei were quite active during essentially all of these observations and the overall X-ray fluxes(0.3–10 keV) varied by an order of magnitude. Most of the observations do appear to show characteristic timescales, estimated through their auto-correlation functions, ranging between ~2.9 ks and ~45.3 ks. The hard(2–10 keV) and soft(0.3–2.0 keV) bands are very well correlated but consideration of their hardness ratios shows that the sources typically soften during flares. We also provide new estimates of the central black hole masses for these three AGNs that support the hypothesis that Narrow Line Seyfert 1 galaxies have relatively small central black holes.     

Spatial Modeling for Base-Metal Mineral Exploration Through Integration of Geological Data Sets

This study involves the integration of information interpreted from data sets such as LandsatTM, Airborne magnetic, geochemical, geological, and ground-based data of Rajpura—Dariba,Rajasthan, India through GIS with the help of (1) Bayesian statistics based on the weights ofevidence method and (2) a fuzzy logic algorithm to derive spatial models to target potentialbase-metal mineralized areas for future exploration. Of the 24 layers considered, five layers(graphite mica schist (GMS), calc-silicate marble (CALC), NE-SW lineament 0–2000 mcorridor (L4-NESW), Cu 200–250 ppm, and Pb 200–250 ppm) have been identified from theBayesian approach on the basis of contrast. Thus, unique conditions were formed based onthe presence and absence of these five map patterns, which are converted to estimate posteriorprobabilities. The final map, based on the same data used to determine the relationships, showsfour classes of potential zones of sulfide mineralization on the basis of posterior probability.In the fuzzy set approach, membership functions of the layers such as CALC, GMS, NE-SWlineament corridor maps, Pb, and Cu geochemical maps have been integrated to obtain thefinal potential map showing four classes of favorability index.     

Petrographic characteristics and depositional conditions of Eocene coals of platform basins, Meghalaya, India

The coal deposits of Meghalaya occur in the Lakadong Sandstone (25–250 m thick) of Eocene age. The coal-bearing formations are understood to have been deposited over platform areas in estuarine and lagoonal environments and subjected to recurrent marine transgressions and regressions during the Eocene period. There are three major groups of coalfields in Meghalaya, viz. Garo Hills (West Daranggiri and Siju Coalfields), Khasi Hills (Langrin and Mawlong–Shella Coalfields) and minor coalfields (Laitryngew, Cherrapunji and Bapung Coalfields). Pillar coal samples have been collected from 10 seams at 15 locations and have been subjected to a detailed petrographic examination for their characterization. An effort has been made to trace the path of their evolution based on coal petrography-based models. The quantitative petrographic analysis shows that these coals are vitrinite rich (45.0–92.9%, mean 73.4% mmf basis) with low concentration of inertinite (0.0–13.8%, mean 3.0% mmf basis), whereas the liptinite occurs in appreciable concentration (5.5–53.1%, mean 22.5% mmf basis). Further, these coals are rich in vitrite (51.6–100%, mean 78.3% mmf basis). The volatile matter (from 38.5% to 70.0%, d.a.f.) and vitrinite reflectance (Rom from 0.37% to 0.68%) characterize these coals, as per German (DIN) and North American classification, approximately as sub-bituminous ‘C' to high volatile ‘C' bituminous. The occurrence of teleutospore (single, double and triple celled) suggests that these coals have originated from a characteristic Tertiary flora. The maceral and microlithotype composition in the coal petrography-based depositional models suggest that the coals of Garo Hills were formed in reed to open water swamps in telmatic to limnic conditions. The coals of Khasi Hills were dominated by forest swamps and telmatic to limno-telmatic conditions. In addition, the occurrence of large-size resins suggests prolific growth of conifers in the swamps.     

Remote sensing applications in the study of landuse and soils of aeolian cover op the western part of Haryana State

Multispectral and multitemporal landsat-FCC of 1:250,000 and transparancies on 1:1000,000 scales of bands 4, 5, 6 and 7 were interepreted to identify and delineate the areas under varying intensities of dunal activity in the western part of Haryana State comprising an area of 12610 sq. km. CCTs of some representative areas were also interpreted on the Multispectral Interactive Data Analysis System. Field checks were made to correlate the laboratory interpretation and the ground truth. The study areas were differentiated into the following units: (1) Sandy desert zone: No cultivation on dune tops except some shrubs, (2) Aeolian cover with sandy hummocks: low intensity cultivation, (3) Plain with aeolian cover: moderately cultivated, (4) Plain: Moderately to intensively cultivated. The major soils in association were Typic Torripsamments/Ustipsamments/Ustorthents/Ustifluvents/Calciorthids and Natric Camborthids.