Showing papers in "Journal of The Geological Society of India in 2013"
TL;DR: In this article, the landslide susceptibility in parts of the Darjeeling Himalayas using a relatively simple bivariate statistical technique is assessed using seven factor layers with 24 categories, responsible for landslide occurrences in this area, are prepared from Cartosat and Resourcesat - 1 LISS-IV MX data.
Abstract: Landslide susceptibility is the likelihood of a landslide occurrence in an area predicted on the basis of local terrain conditions. Since last few years, researchers have attempted to analyse the probability of landslide occurrences and introduced different methods of landslide susceptibility assessment. The objective of this paper is to assess the landslide susceptibility in parts of the Darjeeling Himalayas using a relatively simple bivariate statistical technique. Seven factor layers with 24 categories, responsible for landslide occurrences in this area, are prepared from Cartosat and Resourcesat - 1 LISS-IV MX data. Each category was given a weight using the Information Value Method. Weighted sum of these values were used to prepare a landslide susceptibility map. The result shows that 8% area was predicted for high, 32% for moderate and remaining 60% for low landslide susceptibility zones. The high value (0.89) of the area under the receiver operating characteristic curve showed the high accuracy of the prediction model.
80 citations
TL;DR: Roy et al. as discussed by the authors found a granitic basement below Deccan Traps Unearthed by Drilling in the Koyna Seismic Zone, Western India.
Abstract: Granitic Basement below Deccan Traps Unearthed by Drilling in the Koyna Seismic Zone, Western India — Sukanta Roy, N. P. Rao, Vyasulu V. Akkiraju, Deepjyoti Goswami, Mrinal Sen, CSIR-National Geophysical Research Institute, Hyderabad; Harsh Gupta, National Disaster Management Authority, Govt. of India, New Delhi and B.K. Bansal, Shailesh Nayak, Ministry of Earth Sciences, Govt. of India, New Delhi. (Email: sukantaroy@yahoo.com)
54 citations
TL;DR: In this paper, the authors consider the NE-SW trending quartz reefs and the NESW trending brittle-ductile shear system developed outside the quartz reefs to constitute a single tectonic fabric of the Bundelkhand massif.
Abstract: Quartz reefs that constitute the most spectacular feature of the Bundelkhand massif of Central India are as yet riddled with controversy. We consider the NE-SW trending quartz reefs and the NE-SW trending brittle-ductile shear system developed outside the quartz reefs to constitute a single tectonic fabric of the massif. The study of structural features of the quartz reefs and the associated NE-SW trending shear zones coupled with the mineralogical and structural features suggests that the quartz reefs represent strike-slip dominated vertical to subvertical shear zones with dominantly sinistral sense of shear. The loci of the quartz reefs constitute the large scale fractures developed as a consequence of extensional processes in this part of Central India. These fractures were the sites for later emplacement of siliceous magmatic melt, commonly known as quartz reef that was also responsible for the mineralization of some base metals as well as pyrophyllite and diaspore. The lithotectonic system of these quartz reefs thus developed was later on subjected to strike-slip movements. A generalized model of large scale extensional tectonics during the Proterozoic times has thus been suggested for the development of the NE-SW tectonic fabric of the Bundelkhand massif.
51 citations
TL;DR: In this paper, the authors evaluate and compare the consistency of GIS-based heuristic and bivariate landslide susceptibility mapping techniques in the Himalayan region, taking the Kulekhani watershed of central Nepal as an example.
Abstract: The goal of this paper is to evaluate and compare the consistency of GIS-based heuristic and bivariate landslide susceptibility mapping techniques in the Himalayan region, taking the Kulekhani watershed of central Nepal as an example. For this purpose, a heuristic and two statistical bivariate landslide susceptibility mapping methods are applied, and three separate landslide susceptibility zonation maps are produced. The maps are compared using three approaches: landslide density analysis, success rate analysis, and agreed area analysis. A comparison of the values obtained from landslide density analysis and the curves of success rate analysis indicate that the two bivariate methods produce almost identical results, whereas the map produced with the heuristic method differs significantly from the others. On the other hand, the agreed area analysis highlights significant spatial differences in the maps obtained from the three methods. Although the three approaches evaluate the consistency of susceptibility maps, only the agreed area analysis is capable of spatially comparing them. Hence, this approach proves to be more suitable for spatially and quantitatively evaluating the consistency of various landslide susceptibility zonation maps.
50 citations
TL;DR: In this paper, multivariate statistical analyses including factor analysis, cluster analysis and multidimensional scaling were applied to the hydrogeochemical data and the results show that a few factors adequately represent the traits that define water chemistry.
Abstract: The study area is located in the southwestern part of Bangladesh. Twenty-six groundwater samples were collected from both shallow and deep tube wells ranging in depth from 20 to 60 m. Multivariate statistical analyses including factor analysis, cluster analysis and multidimensional scaling were applied to the hydrogeochemical data. The results show that a few factors adequately represent the traits that define water chemistry. The first factor of Fe and HCO3 is strongly influenced by bacterial Fe (III) reduction which would raise both Fe and HCO3 concentrations in water. Na, Cl, Ca, Mg and PO4 are grouped under the second factor representing the salinity sources of waters. The third factor, represented by As, Mn, SO4 and K is related to As mobilization processes. Cluster analysis has been applied for the interpretation of the groundwater quality data. Initially Piper methods have been employed to obtain a first idea on the water types in the study area. Hierarchical cluster analysis was carried out for further classification of water types in the study area. Twelve components, namely, pH, Fe, Mn, As, Ca, Mg, Na, K, HCO3, Cl, SO4 and NO3 have been used for this purpose. With hierarchical clustering analysis the water samples have been classified into 3 clusters. They are very high, high and moderately As-enriched groundwater as well as groundwater with elevated SO4.
45 citations
TL;DR: In this paper, the authors show that large part of the current convergence across the central Himalayan arc is accommodated by lateral slip, and that this slip also continues unabated in densely populated foredeep for distances up to several tens of kilometers south of the Main Boundary Thrust (MBT).
Abstract: Two contemporary earthquakes originating in the central Himalayan arc and its foredeep (Sikkim earthquake of 18.09.2011, Mw 6.9, h: 10–60 (?) km and Bihar-Nepal earthquake of 20.08.1988, Mw 6.8, h: 57 km) are commonly associated with transverse lineaments/faults traversing the region. Such lineaments/faults form active seismic blocks defining promontories for the advancing Indian Craton. These actually produce conjugate shear faulting pattern suggestive of pervasive crustal interplay deep inside the mountains. Focal mechanism solutions allow inferring that large part of the current convergence across the central Himalayan arc is accommodated by lateral slip. Similar slip also continues unabated in the densely populated foredeep for distances up to several tens of kilometers south of the Main Boundary Thrust (MBT).
39 citations
TL;DR: A carbonatite plug-hosted rare earth oxide (REE) deposit has been discovered at Kamthai, Barmer district, Rajasthan as mentioned in this paper, and the resources have been estimated upto 84 m depth under Proved, Probable and Possible categories.
Abstract: Based on geological mapping and grid channel geochemical sampling, a carbonatite plug hosted REE deposit has been discovered at Kamthai, Barmer district, Rajasthan. The main REE minerals hosted by carbonatite plug are bastanesite (La), basnaesite (Ce), synchysite (Ce), carbocernaite (Ce), cerianite (Ce), ancylite and parisite. The highest value of LREE is 17.31%, whereas, mean works out 3.33% and weighted average is 2.97%. The carbonatite plug covers 19475 sq. meters and the resources have been estimated upto 84 m depth under Proved, Probable and Possible categories. The total resource estimation for carbonatite plug and other carbonate sills, dykes and veins is 4.91 million tons, making this as truly world class deposit. The TMC of individual LREO (lower rare earth oxide) calculated for carbonatite plug only are La=52196 tonnes, Ce =66026 tonnes, Nd = 13663 tonnes, Pr = 5415 tonnes, Sm = 920 tonnes and Eu = 207 tonnes. Besides these REE, the Kamthai resource will produce 551 tonnes of Ga, 44 tonnes of Ge and 1,12,830 tonnes of SrO during its mining life.
39 citations
TL;DR: In this paper, the authors applied fuzzy logic to landslide susceptibility mapping in the Ghurmi-Dhad Khola area, Eastern Nepal, where seven causative factors were considered: slope angle, slope aspect, distance from drainage, land use, geology and distance from faults and folds, soil and rock type.
Abstract: Landslides cause extensive loss of life and property in the Nepal Himalaya. Since the late 1980s, different mathematical models have been developed and applied for landslide susceptibility mapping and hazard assessment in Nepal. The main goal of this paper is to apply fuzzy logic to landslide susceptibility mapping in the Ghurmi-Dhad Khola area, Eastern Nepal. Seven causative factors are considered: slope angle, slope aspect, distance from drainage, land use, geology, distance from faults and folds, soil and rock type. Likelihood ratios are obtained for each class of causative factors by comparison with past landslide occurrences. The ratios are normalized between zero and one to obtain fuzzy membership values. Further, different fuzzy operators are applied to generate landslide susceptibility maps. Comparison with the landslide inventory map reveals that the fuzzy gamma operator with a γ-value of 0.60 yields the best prediction accuracy. Consequently, this operator is used to produce the final landslide susceptibility zonation map.
36 citations
TL;DR: A detailed hydrogeological investigation was carried out to have an overall idea of the aquifer system of the area as discussed by the authors, where the ground water occurs under shallow to moderately deep water table condition.
Abstract: Ground water levels and quality in Chhatna Block of West Bengal were studied based on different indices for irrigation and drinking purposes. A detailed hydrogeological investigation was carried out to have an overall idea of the aquifer system of the area. The ground water occurs under shallow to moderately deep water table condition. The groundwater is stored mostly in the weathered residuum and fractured — hard rock. Sodium absorption ratio (SAR), soluble sodium percentage (SSP), residual sodium bi-carbonate (RSBC), electrical conductance (EC), magnesium adsorption ratio (MAR) Kelly’s ratio (KR), total hardness (TH), permeability index (PI) were calculated as derived parameters, to investigate the ionic toxicity. From the results of chemical analysis, it was revealed that the values of Sodium Adsorption Ratio indicate that, ground water of the area falls under the category of low sodium hazard. So, there was neither salinity nor toxicity problem of irrigation water, and hence the ground water can safely be used for long-term irrigation. Plotting of analytical results of the groundwater collected from different areas in Piper’s trilinear diagram (1944) indicate that, the waters of the study area fall under fresh and sulphate rich region of the rhombus.
32 citations
TL;DR: In this paper, an integrated approach of remote sensing and Geographical Information System (GIS) to delineate groundwater prospective zones in Narava basin, Visakhapatnam region is presented.
Abstract: This paper mainly deals with the integrated approach of remote sensing and Geographical Information System (GIS) to delineate groundwater prospective zones in Narava basin, Visakhapatnam region. The various thematic maps generated for delineating groundwater potential zones are geomorphology, geology, lineament density, drainage density, slope and land use/land cover (LULC). Weighted index overlay (WIO) technique is used to investigate a number of choice possibilities and evaluate suitability according to the associated weight of each unit. The integrated map of the area shows different zones of groundwater prospects, viz. very good (18.9% of the area), good (26.4% of the area), moderate (17.1% of the area) and poor (37.6% of the area). The categorization of groundwater potential was in good agreement with the available water column in the basin area.
31 citations
TL;DR: The timing of glaciation is an important parameter that helps in the understanding of past climate change and provides valuable information for developing the predictive futuristic models as discussed by the authors, and there are evidences to suggest that during the late Quaternary, Himalayan glaciers fluctuated considerably thus implying their sensitivity to changes in past climatic conditions.
Abstract: The timing of glaciation is an important parameter that helps in the understanding of past climate change and provides valuable information for developing the predictive futuristic models. There are evidences to suggest that during the late Quaternary, Himalayan glaciers fluctuated considerably thus implying their sensitivity to changes in past climatic conditions. Although the Himalayan region is fed by two major weather systems viz. the southwest summer monsoon and the mid-latitude westerlies, however, the existing chronology (mostly exposure ages) indicates that irrespective of the geographical position, glaciers seem to grow during increased insolation and enhanced southwest summer monsoon including the mid-latitude westerly dominated north-western Himalayan glaciers (Ladakh and Karakoram). Considering the limited geographical coverage and the dating uncertainty, the above inferences should be treated as tentative.
TL;DR: The area adjoining the western part of the Archaean Nellore schist belt and the eastern margin of the Proterozoic Cuddapah basin in south Peninsular India is marked by emplacement of a number of granite plutons, intermittently extending over a stretch of 350 km from Vinukonda in the north to Sri Kalahasti in the south as mentioned in this paper.
Abstract: The area adjoining the western part of Archaean Nellore schist belt and the eastern margin of the Proterozoic Cuddapah basin in south Peninsular India is marked by emplacement of a number of granite plutons of Proterozoic age, intermittently extending over a stretch of 350 km from Vinukonda in the north to Sri Kalahasti in the south. Vinukonda, Darsi, Podili and Anumalakonda plutons are intensely deformed particularly along the margins, while development of crude deformational fabric is noticed in Kanigiri, Rapur and Kayyuru-Vendodu plutons. Petrographically majority of these granites vary from alkali feldspar granite to granite with the exception of Rapur granite which varies from granite to granodiorite. Geochemically they exhibit calc-alkaline trend and in A/NK-A/CNK plot they are positioned at the juncture of peraluminous-metaluminous-peralkaline field. Characteristically, majority of these granites are fluorite bearing. Biotite mineral chemistry suggests high FeOT contents (31.68 to 34.69 %) and very low MgO contents (0.49 to 2.41 %). Geochemically, these are charecterised by high SiO2 (69 to 74.5 %), Na2O+K2O (8.19 to 10.11%), Zr (280–660ppm), Y (70–340 ppm), Rb content (180–370 ppm) and high REE contents (except Eu); and low CaO (0.01 to 1.99), MgO (0.01 to 0.92%) and Sr (10 ppm to 85 ppm) contents. Rare earth element studies reveal a general enrichment of LREE, pronounced negative Eu anomaly; flat and depleted HREE. Enriched LILE and HFSE contents; presence of fluorite and interstitial biotite indicate that these granites are crystallized from a fluorine saturated magma derived from enriched crustal source. The field setup, distinct mineralogy and chemical characteristics suggest that these granite plutons are emplaced along a major tectonic zone i.e. terrane boundary shear zone (TBSZ) in a late-orogenic to anorogenic tectonic setup, close to the vicinity of a collision boundary zone; western margin of NSB and eastern margin of Nallamalai Fold Belt (NFB). The Proterozoic granite magmatism reported in the present studies represents a significant event of Precambrian crustal growth at the juncture of two tectonically contrasting terranes i.e. the Archaean Nellore schist belt and the Proterozoic Cuddapah basin in eastern Dharwar craton.
TL;DR: In this article, an integrated geophysical study with gravity, magnetic, radiometric, very low frequency electromagnetic (VLF) and gradient resistivity profiling methods around the known mineralized zones aimed at identifying the exact geophysical signatures and lateral extent of these uranium mineralization bands is presented.
Abstract: Beldih mine at the central part of the South Purulia Shear Zone (SPSZ) has been reported with low grade uranium-bearing formation within quartz-magnetite-apatite host in kaolinized formation. Therefore, the present integrated geophysical study with gravity, magnetic, radiometric, very low frequency electromagnetic (VLF) and gradient resistivity profiling methods around the known mineralized zones aimed at identifying the exact geophysical signatures and lateral extent of these uranium mineralization bands. The closely spaced gravity-magnetic contours over the low to high anomaly transition zones of Bouguer, reduced-to-pole magnetic, and trend surface separated residual gravity-magnetic anomaly maps indicate the possibility of high altered zone(s) along NW-SE direction at the central part of the study area. High current density plots of VLF method and the low resistive zones in gradient resistivity study depict the coincidence with low gravity, moderately high magnetic and low resistivity anomalies at the same locations. Moderate high radioactive zones have also been observed over these locations. This also suggests the existence of radioactive mineralization over this region. Along profile P2, drilled borehole data revealed the presence of uranium mineralization at a depth of ∼100 m. The vertical projection of this mineralization band also identified as low gravity, low resistivity and high magnetic anomaly zone. Thus, the application of integrated geophysical techniques supported by geological information successfully recognized the nature of geophysical signatures associated with the uranium mineralization of this region. This enhances the scope of further integrated geophysical investigations in the unexplored regions of SPSZ.
TL;DR: The Late Cretaceous (Cenomanian to Coniacian) marine sediments of central India prevalently known as Bagh Beds, have been deposited in the E-W extending Narmada Basin this paper.
Abstract: The Late Cretaceous (Cenomanian to Coniacian) marine sediments of central India prevalently known as ‘Bagh Beds,’ have been deposited in the E-W extending Narmada Basin. The stratigraphy of these Cenomanian — Coniacian sediments has been reviewed and summarized. The Bagh Beds have been found to consist of three formations: Nimar Sandstone, Nodular Limestone and Corallian Limestone in ascending order. Main emphasis has been given to Nodular Limestone Formation (Turonian), which is the most fossiliferous horizon of the Bagh Beds. Nodular Limestone Formation has more or less alternating bands of varying thickness of nodular limestone and marl. It yielded numerous ammonoid specimens, which have been found to belong to a morphologically highly variable ammoniod taxon Placenticeras mintoi Vredenburg.
TL;DR: In view of the recent reports of fluorosis in many parts of Bankura district, West Bengal, a detailed hydrogeochemical monitoring was carried out in the different blocks of bankura to find out the level and extent of affectation.
Abstract: In view of the recent reports of fluorosis in many parts of Bankura district, West Bengal, a detailed hydrogeochemical monitoring was carried out in the different blocks of Bankura to find out the level and extent of affectation. It is observed that the sub-surface environment of Bankura is appreciably contaminated with the deadly poison of fluoride. Out of the 3617 tube wells surveyed in 10 affected blocks, 612 sources are detected with fluoride above the desirable limit of 1 mg/l. In addition, down-the-hole rock drilling was performed at 15 different locations in 8 worst affected blocks of Bankura. Nearly 75% of the drill-hole rock chip samples and 62% of sub-surface water samples collected from different depths is found to have fluoride equal to or above 4000 mg/kg and 1 mg/l respectively. Detailed microscopic examination of drill chip samples has indicated diverse rock units in close succession, such as Chotanagpur Gneissic Complex, Singhbhum Group of rocks, anorthosite suite and unclassified metamorphics of Archaean-Proterozoic age. All these rocks have been intruded later by granitic fluids causing mineralization of fluoride to take place. Besides, fluoride is also found derived, to lesser extent, from Older Alluvium which bears different fluoride bearing minerals. Preliminary health surveys have revealed that dental and skeletal fluorosis are prevalent in the study area, which further corroborates with the analytical findings.
TL;DR: In this article, the authors present the control measures taken to manage aquifer recharge (MAR) and also to overcome the problem of seawater intrusion into the coastal aquifer along the Kalangi river, Nellore district of Andhra Pradesh, India having connectivity with Pulicat (saltwater) lake estuary.
Abstract: Overuse of groundwater in coastal areas, due to high population and agricultural activity results in seawater intrusion into the coastal aquifer. This paper presents the control measures taken to manage aquifer recharge (MAR) and also to overcome the problem of seawater intrusion into the coastal aquifer along the Kalangi river, Nellore district of Andhra Pradesh, India having connectivity with Pulicat (saltwater) lake estuary. Due to overexploitation of groundwater and less rainfall in past years, adjacent seawater has started intruding in the Kalangi river sub-surface and deteriorating groundwater quality up to 11.6 km from the confluence of the river with Pulicat lake. To prevent this situtation, subsurface dams were constructed in traditional manner using local earth material in three different places across the Kalangi river near Sullurpet town. The water storage capacities calculated after the sub-surface dams’ construction are 1.28 mcft at GK Engineering College, 6.23 mcft at Challamagudi and 3.143 mcft at Holy Cross School sites. The Holy Cross School sub-surface dam is the first full scale dam-cum-check dam constructed to prevent salt water intrusion in the Kalangi river at Sullurpet, Nellore district, Andhra Pradesh. At the Kalangi river estuary portion (at the mouth of sea) a groyne was reconstructed over old groyne site with the introduction of clay bed and wooden sheet piles at down stream. Apart from prevention of sea water entry into Kalangi river sub-surface (during seasons) the groyne top level was raised to prevent mixing of high sea water tides with fresh water and ensuring additional storage of fresh water at upstream side. The reconstructed groyne was serving the purpose of obstructing the surface seawater entry in the Kalangi river and water quality has improved in the river as well as in the wells. After construction of sub-surface dam, as per the Simpson ratio classification, there is substantial improvement of water quality in the SHAR infiltration well situated near the Holy Cross School sub-surface dam.
TL;DR: In this paper, a low resistivity body with an extremely high conductance of about 100,000 Siemens is delineated at the mid crustal depths beneath the exposed Bijawars south of Bundelkhand craton.
Abstract: Magnetotelluric studies over the Bundelkhand craton indicates a high resistivity sub-structure, typically observed in the Archean-Proterozoic regions The geoelectric section shows a single high resistivity layer in the northern part of the craton, extending from surface to a depth of about 60 km and a three layered resistivity structure overlying a conductive bottom in its southern part The geological studies reported earlier have delineated an EW trending zone of ultramafic rocks, called the Bundelkhand tectonic zone (BTZ), which marks the divide between the two electrical resistivity patterns The geoelectric structure is broadly indicative of a northward dipping tectonic fabric in this region which conforms to the Himalayan subduction, to the immediate north of this craton However this observation cannot explain the findings from geochemical, isotope analysis and geological studies, suggesting possible vertical block movements in the region, which are also indicated in the Bouguer gravity studies The geoelectric structure beneath the Vindhyan group to the south shows low resistivities even up to 60 km, suggesting that the Bundelkhand craton which is characterized by high resistivity rocks, does not extend to the south beneath the Vindhyans, as was believed by the earlier researchers A low resistivity body with an extremely high conductance of about 100,000 Siemens is delineated at the mid crustal depths beneath the exposed Bijawars south of Bundelkhand craton The causative factors behind this low resistivity are not immediately apparent, but some possibilities are discussed here
TL;DR: In this article, a detailed analysis of seismological data extending back to 1200 AD was presented, and it was shown that earthquake in Himalayan region may not be expected to be as large as those of subduction zones.
Abstract: The largest earthquake (Mw 8.4 to 8.6) in Himalaya reported so far occurred in Assam syntaxial bend in 1950. However, some recent studies have suggested for earthquake of magnitude Mw 9 or more in the Himalayan region. In this paper, we present a detailed analysis of seismological data extending back to 1200 AD, and show that earthquake in Himalayan region may not be expected to be as large as those of subduction zones. Also, there appears to be a lateral variation in the earthquake magnitude, being lesser in the western syntaxial bend when compared close to the eastern syntaxial bend. This is attributed to the difference in the plate boundary scenario; dominance of strike-slip and thrusting along the western syntaxis as against thrusting and remnant subduction along the eastern syntaxis.
TL;DR: In this paper, a study area is a one of the sub-basin of Vaigai River basin in the Theni and Madurai districts, Western Ghats of Tamil Nadu.
Abstract: The study area is a one of the sub-basin of Vaigai River basin in the Theni and Madurai districts, Western Ghats of Tamil Nadu. The Vaigai sub-basin extends approximately over 849 km2 and it has been sub-divided into 48 watersheds. It lies between 09°30′00″ and 10°00′00″N latitudes and 77°15′10″ and 77°45′00″ E longitudes in the western part of Tamil Nadu, India. It originates at an altitude of 1661m in the Western Ghats of Tamil Nadu in Theni district. The drainage pattern of these watersheds are delineated using geo-coded Indian remote sensing satellite (IRS) ID, linear image self-scanning (LISS) III of geo-coded false colour composites (FCC), generated from the bands 2, 3 and 4 on 1:50,000 scale in the present study. The Survey of India (SOI) toposheets 58G/5, 58 G/6, 58G/9 and 58G/10 on a scale of 1:50,000 scale was used as a base for the delineation of watershed. In the present study, the satellite remote sensing data has been used for updation of drainages and the updated drainages have been used for morphometric analysis. The morphometric parameters were divided in three categories: basic parameters, derived parameters and shape parameters. The data in the first category includes area, perimeter, basin length, stream order, stream length, maximum and minimum heights and slope. Those of the second category are bifurcation ratio, stream length ratio, RHO coefficient, stream frequency, drainage density, and drainage texture, constant of channel maintenance, basin relief and relief ratio. The shape parameters are elongation ratio, circularity index and form factor. The morphometric parameters are computed using ESRI’s ArcGIS package.
TL;DR: In this article, the applicability of Horton's Laws on Stream numbers, Stream lengths and Stream areas is tested by using the theory of regression by estimating theoretically bifurcation ratio, length ratio and area ratio.
Abstract: The morphometric analysis was carried out to determine the drainage characteristics of Panamaram watershed (PW) of Kabani river basin, Kerala, India with emphasis on fourth order sub-basins (FOSBs) using Geocoded imageries of IRS-IC LISS III FCCs (1997) of 1:50,000 scale, aerial photographs (1990) of 1:15,000 scale and Survey of India toposheets (1968) on 1: 50,000 scale. The main idea was to examine the stream properties based on the measurement of various stream attributes. The different drainage parameters studied and the measurements related to perimeter, area of sub-basins, basin length and number of rivers were determined by using Map Info 6.5 techniques. The drainage pattern of the PW is dendritic, a sixth order stream. There are 587, 135, 36 and 12 first, second, third and fourth order Hortonian streams, respectively in PW. The mean bifurcation ratio indicates that the drainage pattern is not much influenced by geological structures. The shape parameters reveal the elongation of the basin and sub-basins. The applicability of Horton’s Laws on Stream numbers, Stream lengths and Stream areas is tested by using the theory of regression by estimating theoretically bifurcation ratio, length ratio and area ratio. For the fourth order sub-basins of 1, 2, 4, 5 and 8 of PW, a second degree polynomial equation seems to be a better model than the Hortonian model.
TL;DR: In this paper, coal samples collected from four different sources in the Jaintia Hills of Meghalaya, northeast India, have been investigated for their sulfur content, mineral matter, and to assess their potential behavior upon beneficiation.
Abstract: Coal samples collected from four different sources in the Jaintia Hills of Meghalaya, northeast India, have been investigated for their sulfur content, mineral matter, and to assess their potential behavior upon beneficiation. These coals contain high sulfur which occurs both in organic and inorganic forms. The organic sulfur content is much higher than the inorganic sulfur. Studies on different size and gravity fractions indicated that the mineral phases are concentrated in higher density fractions (d > 1.8) and in general are fine grained (<50 μm). Data of reflected-light optical microscope and electron probe micro-analysis (EPMA) revealed that minerals in these coals are sulfides-pyrite, marcasite, sphalerite, pentlandite; sulfates-barite, jarosite; oxides-hematite, rutile; hydroxides-gibbsite, goethite; phosphate-monazite; carbonate-calcite, siderite and silicates-quartz, mica, chlorite, and kaolinitic clay. The disulfides of iron occur in two modes — mainly pyrite and occasionally marcasite with wide size ranges and in various forms, such as: framboid, colloidal precipitate, colloform-banded, fine disseminations, discrete grains, dendritic (feathery), recrystallized, nuggets, discoidal, massive, cavity-fracture- and cleat-fillings. Framboidal pyrite has formed primarily due to biological activities of sulfur reducing bacteria in the early stages of coalification. Massive and other varieties have formed at later stages due to coalescence and recrystallization of the earlier formed pyrites. Sulfur isotopic values indicate a biogenic origin for the pyrites. Association of trace metals, such as Ni, and Zn has been recorded in these pyrites. Given the large fractions of organic sulfur present, these coals can be upgraded only partially to reduce the sulfur content by beneficiation.
TL;DR: In this paper, spectral analysis of digital data of the Bouguer anomaly map of NW India suggests maximum depth of causative sources as 134 km that represents the regional field and coincides with the upwarped lithosphere boundary as inferred from seismic tomography.
Abstract: Spectral analysis of digital data of the Bouguer anomaly map of NW India suggests maximum depth of causative sources as 134 km that represents the regional field and coincides with the upwarped lithosphere — asthenosphere boundary as inferred from seismic tomography. This upwarping of the Indian plate in this section is related to the lithospheric flexure due to its down thrusting along the Himalayan front. The other causative layers are located at depths of 33, 17, and 6 km indicating depth to the sources along the Moho, lower crust and the basement under Ganga foredeep, the former two also appear to be upwarped as crustal bulge with respect to their depths in adjoining sections.
TL;DR: In this article, the impacts of change in land use, urbanisation and industrialisation on air, water and soil quality for Environmental Impact Assessment (EIA) were assessed in Maheshwaram watershed.
Abstract: Anthropogenic activities in Maheshwaram watershed have deteriorated water, air and soil quality during the last ten years due to rapid urbanisation and industrial development. Maheshwaram watershed experienced drastic changes in land use pattern, being very close to the Hyderabad city. Base-line data was collected during post monsoon season (October-November) of 2010 in Maheshwaram watershed to assess the impacts of change in land use, urbanisation and industrialisation on air, water and soil quality for Environmental Impact Assessment (EIA). Air samples were analysed for Suspended Particulate Matter (SPM) and Respirable Suspended Particulate Matter (RSPM). Groundwater samples were analysed for pH; EC; TDS; TH; cations, anions and heavy metals viz., Fe, Mn, Al, Si, V, Cr, As, Sr, Rb, Se, Ba, Li, B, Be, Co, Ni, Zn, Cd, and Pb using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Analysed data were compared with the National and International Standards and subjected to Factor Analysis (FA) for six chemical variables to assess and characterise hydro-chemical processes. A comparison of the results of groundwater samples with WHO and BIS guidelines show that most of the groundwater samples are heavily contaminated with heavy metals like lead, chromium, nickel, barium, aluminium, boron and selenium, which was quantified and presented in the form of spatial variation diagrams prepared using ArcGIS. 9.3.1. Similarly the results of air samples compared with the Central Pollution Control Board, Ministry of Environment and Forests, Government of India guidelines show that most of the air samples for residential, rural and industrial areas are contaminated by SPM and RSPM.
TL;DR: In this article, seasonal variation of ground water in Nayagarh district, Odisha is determined by analysing both pre and post monsoon water samples, which is largely due to chemical weathering of Eastern Ghats Mobile Belt rock types.
Abstract: Seasonal variation of ground water in Nayagarh district, Odisha is determined by analysing both pre and post monsoon water samples. The high fluoride content is an endemic problem in the area and special attention was attached to the point. The chemical compositions of the ground water of the area are dominated by CaCl, NaCl and mixed CaMgCl types in pre-monsoon and CaHCO3-mixed CaMgCl type in post-monsoon. This is largely due to chemical weathering of Eastern Ghats Mobile Belt rock types. Increasing alkalinity vis-a-vis F concentration in pre-monsoon is associated with sodium-bicarbonate water types having high pH (>7) and low calcium and magnesium contents. The percentage of total high fluoride containing water samples is nearly double in pre-monsoon than in post-monsoon. During both the seasons, pH values indicate mildly alkaline to weakly acidic nature of the water samples. Fluoride concentration has good correlation with pH in pre-monsoon whereas in post-monsoon it shows good correlation with Fe. Facies analysis indicates that water is becoming predominantly Ca-Na cation and Cl-SO4-HCO3 anion type in premonsoon than Ca-Mg type and HCO3-Cl-SO4 type in post-monsoon. The seasonal variations in concentrations of anthropogenic components demonstrate that the groundwater system is very less liable to pollution by human activities.
TL;DR: In this paper, the hydrochemical characteristics and quality of groundwater in Lokoja basement area have been evaluated based on different indices for assessing groundwater for drinking and irrigation purposes, which revealed that the groundwater is slightly alkaline, with little variations in chemical composition.
Abstract: The hydrochemical characteristics and quality of groundwater in Lokoja basement area have been evaluated based on different indices for assessing groundwater for drinking and irrigation purposes. Twenty groundwater samples were collected and analyzed for physicochemical parameters, major ions and heavy metals. The results revealed that the groundwater is slightly alkaline, with little variations in chemical composition. For example, electrical conductivity (EC) ranges from 242μS/cm to 1835μS/cm. The abundance of the major ions is in the order of Ca2+ >Na+>Mg2+>K+> Fe2+/3+ = HCO3 >Cl− >NO3 >SO4 >PO4. Based on the hydrochemical data, four hydrochemical facies were identified namely, Ca-Mg-HCO3, Na-K-HCO3, Na-K-Cl-SO4 and Ca-Mg-Cl-SO4 and these facies depict groundwater recharge zone, transition flow zone, deep flow zone and mixed water zone respectively. Groundwater from the area is unsuitable for drinking and domestic purposes as some of the ions and heavy metals of health concerns are well above the stipulated guideline values. Irrigation water quality indicators (salinity, Na % and Mg %), reveal that the groundwater is unsuitable for irrigation purposes. Interpreted statistical analysis reveals that the groundwater chemical compositions are controlled predominantly by weathering of litho units of the basement rocks and by drainage from domestic wastes.
TL;DR: In this article, the ages of 133 detrital zircon grains from a sample show that one grain is ca. 1880 Ma, another grain is c. 3300 Ma, and the remaining 131 grains fall between 2690 Ma and 2429 Ma, the population averaging 2522 ± 36 Ma.
Abstract: Felsic tuff beds with some presumed sedimentary components were reported from the Owk Shale (Kurnool Group; bearing Neoproterozoic fossils) in the upper part of the sedimentary succession in the Cuddapah basin in India by Saha and Tripathy (2012a). Our optical and SEM petrographic study of three thin sections, however, indicates that the parent samples are sandy mudstones with variable amounts of a felsic volcaniclastic component. New highquality U-Pb (SHRIMP and LA-MC-ICPMS) ages of 133 detrital zircon grains from a sample show that one grain is ca. 1880 Ma, one grain is ca. 3300 Ma, and the ages of the remaining 131 grains fall between 2690 Ma and 2429 Ma, the population averaging 2522 ± 36 Ma. The data indicate that the zircons are detrital grains derived from the ca. 2.5 Ga granitic/gneissic/greenstone basement of the Dharwar cratons that also host minor older Archean enclaves. The single 1880 Ma grain could have come from a ca. 1.9 Ga LIP. In the absence of any younger magmatic zircon, the absolute age of the Owk Shale remains elusive.
TL;DR: In this paper, a morphometric analysis of a terrain bounded by the E-W trending North Wagad Fault (NWF) and the Gedi Fault (GF) has been undertaken to ascertain the influence of seismicity in the evolution of the drainage basin.
Abstract: Recent studies suggest that the eastern Kachchh is a potential zone for major earthquakes in the near future. Particularly, the E-W trending faults are considered capable of generating large magnitude earthquakes is further indicated by the recent concentration of the earthquake shocks, which, show two prominent clustering around west and north of the Wagad upland. In view of this, the conventional morphometric analyses of a terrain bounded by the E-W trending North Wagad Fault (NWF) and the Gedi Fault (GF) has been undertaken to ascertain the influence of seismicity in the evolution of the drainage basin. The study suggests that the fifth order drainage basins responded to the seismicity associated with both the NWF and GF. However, compared to the GF, the NWF seems to be more active. In addition to this, based on the stream morphology, we could identify two lineaments trending N-S and E-W. The former appears to be associated with the activity along the Manfara Fault (MF), whereas, the later seems to be the splays of the NWF. Further, a preferential westward shift of the streams suggests left lateral displacement of the E-W trending faults. Overall it can be suggested that the terrain is in juvenile stage implying tectonic instability.
TL;DR: In this paper, the authors used Visual MODFLOW, pro 4.1 to simulate groundwater flow over an area of about 1345 km2 with a uniform grid size of 1000 m by 1000 m and contains three layers, 58 rows and 37 columns.
Abstract: The study area Hindon -Yamuna interfluve region is underlain by a thick pile of unconsolidated Quaternary alluvial deposits and host multiple aquifer system. Excessive pumping in the last few decades, mainly for irrigation, has resulted in a significant depletion of the aquifer. Therefore, proper groundwater management of Hindon-Yamuna interfluve region is necessary. For effective groundwater management of a basin it is essential that careful zone budget study should be carried out. Keeping this in view, groundwater flow modelling was attempted to simulate the behavior of flow system and evaluate zone budget. Visual MODFLOW, pro 4.1 is used in this study to simulate groundwater flow. The model simulates groundwater flow over an area of about 1345 km2 with a uniform grid size of 1000 m by 1000 m and contains three layers, 58 rows and 37 columns. The horizontal flows, seepage losses from unlined canals, recharge from rainfall and irrigation return flows were applied using different boundary packages available in Visual MODFLOW, pro 4.1. The river — aquifer interaction was simulated using the river boundary package. Simulated pumping rates of 500 m3/day, 1000 m3/day and 1500 m3/day were used in the pumping well package.The zone budget for the steady state condition of study area indicated that the total annual direct recharge is 416.10 MCM and the total annual groundwater draft through pumping is of the order of 416.63 MCM. Two scenarios were considered to predict aquifer system response under different conditions. Sensitivity analysis on model parameters was conducted to quantitatively evaluate the impact of varying model inputs. Based on the results obtained from the sensitivity analysis, it was found that the model is more sensitive to hydraulic conductivity and recharge parameter. Present study deals with importance of groundwater modelling for planning, design, implementation and management of groundwater resources.
TL;DR: In order to assess the impact of coal mining on groundwater quality in Talcher Coalfield area, seventeen groundwater samples for pre and post monsoon seasons were collected from borewells/dugwells and analysed for major ions and trace elements as discussed by the authors.
Abstract: In order to assess the impact of coal mining on groundwater quality in Talcher Coalfield area, seventeen groundwater samples for pre and post monsoon seasons were collected from borewells/dugwells and analysed for major ions and trace elements. Water quality analysis of major ions and trace elements shows elevated concentration in few groundwater samples. The water quality data was analysed using multivariate statistical techniques viz., factor analysis and cluster analysis. The result clearly shows that the variation in the season is due to recharge of rain water during monsoon. The factor and cluster analysis brought out impact of intensity by mining activity on groundwater regime. Discharge of mining seepage effluents and its interaction with the groundwater contaminate the surrounding groundwater regime. Multivariate statistical techniques are potential tools and provide greater precision for identifying contaminant parameters linkages with mining environment.
TL;DR: In this article, the opportunities and eco-environmental influences related to Hanjiang river's cascade hydropower development are explored and then recommendations are put forward to minimize the potential impacts.
Abstract: Hanjiang river is the longest river in Yangtze river basin, having high economic importance to China for its economically exploitable hydropower and potential water resources. In an attempt to satisfy China’s economic and social development needs, the Chinese government has established cascade dams and four relative water diversion projects in Hanjiang river, which aims at transferring water from south (Hanjiang river) to north (water-stricken areas). However, there are increasing eco-environmental concerns associated with the establishment and development of cascade hydropower. In this study, the opportunities and eco-environmental influences related to Hanjiang river’s cascade hydropower development are explored and then recommendations are put forward to minimize the potential impacts. The implementation of vigorous projects related to hydropower and water diversion has an important role to play in solving flood, energy and water shortage problems. In addition, the eco-environmental and socio-economic impacts on the middle and downstream and its diversion can be relieved to some degree in the area. However, the establishment of projects can cause several impacts on the local eco-environment. First, Danjiangkou reservoir construction can cause change in water flow, water bloom, soil erosion in the river basin. Second, it can directly lead to the decrease of 10.5 billion cubic meters of water in the middle- and downstream areas, threatening the local supply of drinking water and influencing farming irrigation and industrial production. Finally, the construction of cascade hydropower dams can change the water form and fish stocks may reduce threatening eco-environment security and environmental geology.