Amit K. Bhattacharya

Groundwater assessment through an integrated approach using remote sensing, GIS and resistivity techniques: a case study from a hard rock terrain

Satellite data have been widely used in conjunction with Geographic Information System (GIS) techniques in groundwater resource management. Satellite data are useful for extracting various thematic maps required for groundwater assessment. In this study, Indian Remote Sensing (IRS) 1D LISS III and Landsat Thematic Mapper (TM)/Enhanced TM (ETM+) digital data, and digital elevation models (DEMs) from the Shuttle Radar Topography Mission (SRTM) along with other collateral data were analysed to create various thematic maps (geomorphology, landuse, lithology, lineament, soil, drainage density, river gradient and slope maps) required for groundwater modelling in a hard rock terrain of Bargarh district, Orissa, India. These thematic maps were assigned suitable weights and different rankings to the individual classes within each thematic map using Saatys Analytical Hierarchy Process (AHP). A raster‐based empirical GIS model was developed for integrating the thematic maps to locate suitable groundwater prospective zones. The integrated thematic maps were in turn used to compute the Groundwater Potential Index (GWPI). GWPI values calculated in the study area were found to vary from 0.175 to 0.940. These GWPI values have been classified into various classes: very poor (<0.4), poor (0.4–0.5), moderate (0.5–0.6), good (0.6–0.7), very good (0.7–0.8) and excellent (>0.8). A final map showing very poor to excellent groundwater prospective zones was prepared. The results thus obtained were subsequently cross‐checked with resistivity survey and pumping test data. Very poor GWPI zones show low yields of 0.5 lps from weathered granite of resistivity 20–100 Ω m and thickness 0.5–6 m, while excellent GWPI zones show high yields of 5–7 lps from highly fractured granite of resistivity 100–300 Ω m and thickness 14–31 m. The results obtained from integration of the various thematic maps on the GIS platform produced a good match with the resistivity and pumping test data.

Delineation of ground water potential zones in a hard Rock Terrain of Bargarh District, Orissa using IRS data

In the present paper, various groundwater potential zones for the assessment of groundwater availability in a hard rock terrain have been delineated with the help of hydrogeological parameters using satellite IRS- 1B-LISS-II digital data. Area selected for this study is a part of Bargarh district, Orissa, India covering an area of about 680 square km. Satellite data has been used to prepare geological-cum-lineaments, geomorphological, landuse and drainage maps. The various thematic maps have been integrated with the help of Geographic Information System to demarcate the poor to excellent groundwater potential zones. Weightage has been given to various groundwater controlling factors to the total groundwater potential in each segment of study area. Subsequently, several sites were selected and pumping tests carded out in the area. The results show that among others, lineaments as well as drainage density are the most important contributory factors in the groundwater potential of various geomorphic units in the area of investigation.

Extraction of linear and anomalous features using ERS SAR data over Singhbhum Shear zone, Jharkhand using fast Fourier transform

Digital filtering of ERS‐2 SAR data using the fast Fourier transform (FFT) has been attempted over Singhbhum shear zone (SSZ) and its surroundings for extraction of linear and anomalous patterns. The results show that numerous lineaments as well as drainage patterns could be identified and demarcated by FFT digital filtering method. Major as well as several minor drainage patterns are easily detectable from the filtered image, which are structurally controlled and not observed in the original map. Comparison of the present interpretation of the study area to existing geological map/earlier interpretation has been done effectively. This technique was found to be more effective in identifying the lineaments using ERS SAR data compared with using Landsat imagery over the study area. The present study reveals that maximum lineaments occurring in the north of SSZ are NNE, NNW and NW trending, while maximum lineaments occurring in the south of SSZ are NE, ENE, WNW, and NW trending. The demarcated geological structures may have a great significance to locate the hidden ore/mineral occurrences. The existences of various mines, such as Baharagora, Mosaboni, Surda, Narwa, Bhatin, Jadugoda, Rakha, and Tatanagar along the shear zone, correlate well with the interpreted results.

A HFSE- and REE-enriched ferrodiorite suite from the Bolangir Anorthosite Complex, Eastern Ghats Belt, India

AbstractThe massif-type anorthosite complex at Bolangir in the northern part of the Eastern Ghats belt occurs in a milieu of predominantly supracrustal granulite-grade rocks. The massif is separated from the host gneisses by coarse-grained garnetiferous granitoid gneisses which are interpreted as coeval crustallyderived melts. Melanocratic ferrodiorite rocks occur at the immediate contact with the anorthosite massif which they intrude in cross-cutting dikes and sheets. The emplacement age of the anorthosite diapir and the associated igneous suites is deemed to be pre-D2. Recrystallization of the igneous assemblages of the ferrodiorite suite (750–800°C, 7–8kbar,

The Turkei anorthosite complex revisited

a_{H_2 O}< 0.25, logf_{O_2 }< - 18 bar

Mapping geological features of the Jharia coalfield from Landsat-5 TM data

) during a period of near-isobaric cooling from the igneous crystallization stage to the regionalP-T regime led to extensive development of coronitic garnet at the interface of plagioclase phenocrysts with the mafic matrix assemblage (opx + fay + cpx + ilm ± amph, bio). Abundant accessory phases are zircon, apatite and thorite. The mafic phases have extremely ferrous compositions (XFe gar: 0.93-0.87, fay: 0.90-0.87, opx: 0.80-0.60, cpx: 0.70-0.47, amph: 0.81-0.71) reflecting the low Mg-number (16-8) of the rocks. Compared to worldwide occurrences of similar rocks, the Bolangir ferrodiorites (SiO2 36–58 wt.%, FeO*: 39-10 wt.%) are characterized by exceptionally high concentrations of HFSE and REE (TiO2: 4.8-1.0 wt.%, P2O5: 1.7-0.5 wt.%, Zr: 5900-1300 ppm, Y: 240-80 ppm, La: 540-100 ppm, Ce: 1100-200 ppm, Yb: 22-10 ppm, Th: 195-65 ppm). Well defined linear variation trends for major and trace elements reflect progressive plagioclase accumulation towards the felsic members of the suite. The ferrodiorites are interpreted to represent residual liquids of anorthosite crystallization which after segregation and extraction from the ascending diapir became enriched in HFSE and REE through selective assimilation of accessory phases (zircon, monazite, apatite) from crustal felsic melts. Ferromonzodioritic rock presumably formed through hybridization between the ferrodiorite and overlying felsic melts.

Usage of ERS SAR data over the Singhbhum Shear Zone, India for structural mapping and tectonic studies

Shoreline is one of the rapidly changing linear features of the coastal zone which is dynamic in nature. The issue of shoreline changes due to sea level rise over the next century has increasingly become a major social, economic and environmental concern to a large number of countries along the coast, where it poses a serious problem to the environment and human settlements. As a consequence, some coastal scientists have advocated analyzing and predicting coastal changes on a more local scale. The present study demonstrates the potential of remote sensing, geospatial and statistical techniques for monitoring the shoreline changes and sea level rise along Digha coast, the eastern India. In the present study, multi-resolution and multi temporal satellite images of Landsat have been utilized to demarcate shoreline positions during 1972, 1980, 1990, 2000, and 2010. The statistical techniques, linear regression, end-point rate and regression coefficient (R2) have been used to find out the shoreline change rates and sea level change during the periods of 1972–2010. Monthly and annual mean sea level data for three nearby station viz., Haldia, Paradip and Gangra from 1972 to 2006 have been used to this study. Finally, an attempt has been made to find out interactive relationship between the sea level rise and shoreline change of the study area. The results of the present study show that combined use of satellite imagery, sea level data and statistical methods can be a reliable method in correlating shoreline changes with sea level rise.

Generation of emissivity and land surface temperature maps using MODIS TIR data for lithological mapping over the Singhbhum-Orissa Craton

Geological investigation in recent years reveals that the anorthosite-leuconorite massif (81 sq km) is much larger than known from previous studies. The massif is bordered by a suite of garnetiferous felsic rocks comprising quartz monzonite gneiss, granite gneiss and megacrystic K-feldspar-bearing granite. Ferrodiorites, hitherto unknown from this area, occur as veins at the massif-felsic suite interface, and as rare apophyses within leuconorites at the massif margin. The massif and the bordering felsic rocks were presumably emplaced during the earliest of the three phases of folding documented by the metasedimentary gneisses that host the massif.The petrographic and geochemical characteristics suggest that the low-K anorthosite-leuconoriteferrodiorite suite does not share a common parentage with the bordering high-K felsic intrusives. The anorthosites and leuconorites were derived by polybaric fractionation of mantle-derived melts. The ferrodiorites are anorthosite residual melts that were not entirely segregated from the host solids. By contrast, the granite gneisses and granites originated by incongruent melting of crustal rocks. The chemical differences between quartz monzonite and granite gneisses point to their derivation from different crustal precursors.