006867   Sarate O S (NO, Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow-226 007, Email: ossarate@yahoo.co.in) : Petroraphic composition and depositional environment of the coal from queen seam of Yellendu area, Godavari valley coalfield, Andhra Pradesh. J Geol Soc India 2010, 75(3), 488-94.

The study of coal succession from bore hole No. Q-448 of Yellendu area of the Godavari valley coalfield, Andhra Pradesh reveals that the coals of Queen seam are high volatile bituminous C in rank and have vitrinite reflectance (R₀ max %) varying between of 0.52 and 0.62%. The petrographic constitution however, suggests that the depositional site appears to be a slowly sinking and tectonically controlled basin, having received continuous supply of vegetal matter rich resource at regular intervals. The formation of inertinite rich coal suggests, oxidising environment of deposition. The dominance of vitrinite and liptinite constituents in these coals postulates the existence of alternating cold and humid spells. The present study indicates that these coals originated under an alternate oxic and anoxic moor condition.

6 illus, 3 tables, 39 ref

006866   Santosh Kumar;Raju S;Pathak M;Pandey A (Geology Dep, Kumaun Univ, Nainital-263 002, Email: skyadavan@yahoo.com) : Magnetic susceptibility mapping of felsic magmatic lithounits in the central part of Bundelkhand Massif, Central India. J Geol Soc India 2010, 75(3), 539-48.

Late Archaean to Palaeoproterozoic felsic magmatic lithounits exposed in the central part of the Bundelkhand massif have been mapped and their redox series (magnetite vs ilmenite series) evaluated based on magnetic susceptibility (MS) data. The central part of Bundelkhand massif comprises of multiple felsic magmatic pulses (<126>2600-2200 Ma), commonly represented by coarse grained granite (CGG-grey granite, CPG-pink granite), medium grained pink granite (MPG), fine grained pink granite (FPG), grey and pink rhyolites and granite porphyry (GP). However, the pink colour of these felsic rocks is the result of hydrothermal fluid-flushing leading to potassic alteration of grey granites. MS values of CGG vary from 0.058 to 14.75xlO^-3 SI with an average of 6.35xl0^-3 SI, which mostly represent oxidized type, magnetite series (73%) granites involving infracrustal (igneous) source materials. CPG (av. MS=3.95xl0^-3 SI) is indeed a pink variety of CGG, the original oxidizing nature of which must have been similar to the bulk of CGG, but has been moderately to strongly reduced because of distinctly more porphyritic nature together with partial assimilation of metapelitic (supracrustal) materials, surmicaceous enclaves, carbonaceous material included in the source materials, and to some extent, induced by hydrothermal and later deformational processes. MPG (av. MS= 1.15xl0^-3 SI) as lensoidal stock-like bodies intrudes the CPG and represent both magnetite series (18%) and ilmenite series (82%) granites, which are probably formed by heterogeneous (mixed) source rocks. GP (av. MS=6.26xlO^-3 SI) occur as dykes (mostly trending NE-SW) intrudes the MPG, CPG and migmatites and bears the nature similar to oxidized type, magnetite series granite. FPG (av. MS= 0.666xl0^-3 SI) trending NE-SW occur as lensoid bodies including a large outcrop, is intrusive into both CPG and MPG, and is moderately to very strongly reduced type, ilmenite series granites, which may be derived by the melting of metapelitic crustal sources. FPG hosting microgranular (mafic magmatic) enclaves commonly exhibit high MS values (7.31-10.22x10^-3 SI), which appear induced by the mixing and mingling of interacting felsic and mafic magmas prevailed in an open system. Grey (av. MS=10.30xl0^-3 SI) and pink (av. MS=6.72xl0^-3 SI) rhyolites represent oxidized type, magnetite series granites, which may have been derived from infracrustal (magmatic) protoliths. Granite series evaluation of felsic magmatic rocks of central part of Bundelkhand massif strongly suggests their varied redox conditions (differential oxygen fugacity) mostly intrinsic to magma source regions and partially modified by hydrothermal and tectonic processes acting upon them.

3 illus, 1 table, 28 ref

006865   Samaddar B (Geography Dep, Calcutta Univ, Kolkata) : Possibilities eco-tourism industry in the peripheral zone of Indian Sundarban. Indian J Landsc Syst ecol Stud 2009, 32(2), 345-52.

Sundarban is lying in the active zone of the Ganga delta along the coast of Bay of Bengal and is considered as the natural abode of West Bengal. Maze of innumerable small marshes, lakes, depressions and creeks have agglomerated within its purview. It is the breeding and feeding ground for multivariate aquatic species. Sundarban has been designated as "World Heritage" in 2001 for its exotic floral and faunal species and aesthetic natural beauty. All these have assembled together and attracted both domestic and foreign tourists promoting the growth of tourism industry. Keeping this fact in the mind, the Government with proper management and preservation of her rare species has paved the way towards the development of ecotourism industry within the periphery of Sundarban. The paper presents the fact that how ecotourism industry have supported and laid a strong foundation to the economic structure of the Heritage without affecting its ecological essence.

2 tables, 14 ref

006864   Sahu A S (Geography Dep, Kashipur M.M. Mahavidyalaya, Purulia, Pin-723 132, Email: abhaysankar@yahoo.co.in) : Geo-engineering features of brackish-water prawn fisheries and their physical performances A Geographical perspective. Indian J Landsc Syst ecol Stud 2009, 32(2), 173-80.

In India it is observed that brackish-water prawn fisheries acquire a major part in the contemporary land utilisations. Throughout the world it takes some specific role in economic development of coastal regions. In brackish-water fishery different types of embankments, canals and ponds are important to achieve their ultimate goal. In this paper an attempt is being made to evaluate the geo-engineering features of brackish-water prawn fisheries and their physical performances from the geographical perspective. Alampur brackish-water prawn farm is taken into consideration as a case study in the district of Purba Medinipur of West Bengal in India. Here we consider fishery-embankments, fishery-canals and fishery-ponds as the geo-engineering features. Number of ponds and canals are constructed to cultivate fishes in a prawn fishery. Generally, along these ponds and canals embankments are engaged to hold, and sometimes drain, the water for the very purpose of the fishery. Vulnerability of these embankments affects the fishery. And, good quality of embankments enhances the longevity as well. Location and conditions of these embankments, canals and ponds reflect to some extent the physical performances of them. Location of a brackish-water prawn fishery is space- and place- specific. Alampur farm is situated within the brackish-water environment. Fishery ponds get their brackish-water through the fishery canals. There embankments, canals and ponds are rightly constructed and well-maintained from the engineering point in view. Therefore, physical performance level of the geo-engineering features is satisfactory. It is an idiographic study based on field observation and there is nomothetic approach too in the analysis of geo-engineering features of the fishery. Primary and secondary data are taken into consideration for the present study as well.

6 illus, 3 tables, 8 ref

006863   Sahoo M;Gogoi K D (NO, Oil & Natural Gas Corporation Ltd, Nazira-785 685, Email: mayadhar2005@redifmail.com) : Depositional history, processes and mechanism of early miocene sediments of upper Assam basin. J Geol Soc India 2009, 73(4), 575-85.

A detailed analysis of depositional history of Miocene sediments and various effects which are governed for creation of accommodation space as well as the processes of sedimentation inherent to the depositional system at that period is described in this work. The early Miocene clastic sediments are deposited in prograding environment where sediment supply exceeds the accommodation space available. The accommodation space created due to basin subsidence and source area upliftment due to local and regional tectonic activity in the basin. In the early Miocene time, the Assam shelf major transgression occurred and several minor transgression followed. There was wide spread deposition of the fluvial Tipam sandstones. In Miocene time due to thrust loading and flexure subsidence, accommodation space was created for deposition of the sediments. The Tipam Sandstone is deposited by cyclic deposition of fining upward sequence in a fluvial to brackish water environment of braided river processes. The mechanism of braided rivers is also discussed in which it laterally expanded, leaving sheet like or wedge - shaped deposits of channel and bar complexes preserving only minor amounts of flood plain material.

15 illus, 33 ref

006862   Saha D K;Biswas S K;Biswas U K;Naskar D C;Das B;Roy Choudhury A K;Pal T (Geological Survey of India, Central Headquarters, Kolkata-700 016, Email: tn_pal@yahoo.com) : Integrated geological, hydrogeological, geochemical and geophysical study of arsenic pollution in groundwater of Gotra area, West Bengal part D: Geophysical survey and borehole logging. Indian J Geosci 2010, 64(1-4), 155-62.

Six Vertical Electrical Sounding (VES) and Resistivity Profiling have been conducted in and around Gotra area to delineate the near surface lithological variations for studying arsenic contamination in the area. The surveys reveal the presence of three-to five-layered sediments, in different parts of the area. The layers consist of sand, silt, clayey sand, sandy clay and clay with occasional intermixing. The results of electrical resistivity also reveal absence of saline/brackish-water zone in the study area. Experimental borehole logging, employing a digital multi-parametric geophysical logging unit has been conducted in eight shallow boreholes, with either metallic or PVC casing. The parameters like self-potential, high- and low-resolution densities, natural gamma, neutron, as well as temperature and fluid-conductivity characteristics of these boreholes have been determined. Analysis and interpretation of merged logs reveal the presence of single- or multiple-gaseous zones in five boreholes, suspected to be methane. Since methane is directly correlatable with high-arsenic zones, geophysical parameters may thus help in demarcating subsurface layers with high arsenic in groundwater.

6 illus, 4 tables, 6 ref

006861   Saha D;Chakraborti S;Tripathy V (Geological Studies Unit, Indian Statistical Institute, Kolkata-700 108, Email: dsaha@isical.ac.in) : Intracontinental thrusts and inclined transpression along eastern margin of the east Dharwar craton, India. J Geol Soc India 2010, 75(1), 323-37.

Recent works suggest Proterozoic plate convergence along the southeastern margin of India which led to amalgamation of the high grade Eastern Ghats belt (EGB) and adjoining fold-and-thrust belts to the East Dhrawar craton. Two major thrusts namely the Vellikonda thrust at the western margin of the Nellore Schist belt (NSB) and the Maidukuru thrust at the western margin of the Nallamalai fold belt (NFB) accommodate significant upper crustal shortening, which is indicated by juxtaposition of geological terranes with distinct tectonostratigraphy, varying deformation intensity, structural styles and metamorphic grade. Kinematic analysis of structures and fabric of the fault zone rocks in these intracontinental thrust zones and the hanging wall and footwall rocks suggest spatially heterogeneous partitioning of strain into various combinations of E-W shortening, top-to-west shear on stratum parallel subhorizontal detachments or on easterly dipping thrusts, and a strike slip component. Although relatively less prominent than the other two components of the strain triangle, non-orthogonal slickenfibres associated with flexural slip folds and mylonitic foliation-stretching lineation orientation geometry within the arcuate NSB and NFB indicate left lateral strike slip subparallel to the overall N-S trend. On the whole an inclined transpression is inferred to have controlled the spatially heterogeneous development of thrust related fabric in the terrane between the Eastern Ghats belt south of the Godavari graben and the East Dharwar craton.

11 illus, 39 ref

006860   Roy T B (Geography and Applied Geography, North Bengal Univ, West Bengal) : Irrigation system in Uttar Dinajpur district, W/B: a study on gaining importance of STW system. Indian J Landsc Syst ecol Stud 2009, 32(2), 431-6.

Irrigation plays a dominant role in influencing the regional variation in cropping pattern of a region. The following study concerned with the status of Different irrigation system and its temporal progressive analysis in Uttar Dinajpur district. Regional imbalances are prevalent in covering the land area under different mode of irrigation in different blocks of Uttar Dinajpur district and finding reason for emphasis given on using of STW system within the district.

6 illus, 7 tables, 6 ref

006859   Ranhotra P S;Bhattacharyya A (NO, Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow-226 007, Email: amalava@yahoo.com) : Holocene palaeoclimate and glacier fluctuations within Baspa valley, Kinnaur, Himachal Pradesh. J Geol Soc India 2010, 75(3), 527-32.

The study is an attempt to understand the tree line shift in relation to glacier fluctuations during Holocene based on the exploratory palynological studies from a 1.3 m deep sediment profile located at 3,100 meters above mean sea level (mamsl), Rukti valley, Kinnaur, Himachal Pradesh. The study reveals that during the early to middle Holocene, tree line taxa viz. Betula and Juniperus were well characterized in the site of investigation evident by higher percentage of their pollen grains in subsurface sediments than those recorded during the late Holocene. This variation in distribution of these taxa suggests that till middle Holocene tree line was close to the study site (3,100 mamsl) i.e. at lower altitude than its present day distribution between 3,800 to 3,900 mamsl. Accordingly, the glacier snout might also be at lower elevations (<126>3,500 mamsl) than its present day location at altitude (<126>4,300 mamsl).

3 illus, 22 ref

006858   Rameshwar Rao D;Rai H (NO, Wadia Institute of Himalayan Geology, General Mahadeo Singh Road, Dehradun-248 001, Email: raodr@wihg.res.in) : Geochemical studies of granitoids from Shyok tectonic zone of Khardung-Panamik section, Ladakh, India. J Geol Soc India 2009, 73(4), 552-66.

The Shyok tectonic zone lies to the north of Ladakh magmatic arc or the Ladakh batholith in the Trans-Himalaya of Ladakh district, J & K. Investigations were carried out on the granitoids exposed along Leh-Siachan highway between Khardung and Panamik villages. The granitoid bodies under study are: Khardung granite (KG), Tint granite (TG) and Panamik granite (PG) belonging to Ladakh batholith, Shyok ophiolitic melange and Karakoram batholith respectively. Though the granitoids belong to different litho-tectonic units, yet they have subduction related geochemical characters typical of Andean-type granitoids. Re-melting of crustal rocks of volcanic arc affinity has played an important role for the origin of KG rocks which are more evolved, while the TG and PG rocks represent transitional tectonic environment from primitive to mature arc.

8 illus, 3 tables, 41 ref

006857   Rai P K;Anurag N;Nathawat M S (Geography Dep, Banaras Hindu Univ, Varanasi-221 005, Email: rai.vns82@gmail.com) : Hydrogeomorhological mapping for ground water prospect evaluation using remote sensing data. Indian J Landsc Syst ecol Stud 2009, 32(2), 257-66.

Ground water is an important resource for survival of human beings. The ground water regime of an area basically depends upon lithology, geological structure, landforms and hydrological conditions. Hydrogcomorphological mapping by using high spatial resolution remote sensing data has truly emerged as a powerful tool for delineating ground water prospect zone. There are large numbers of variables includes hithology. structure, gcomorphology, drainage and recharge condition that are important in understanding the "round water condition in an area. The area under investigation covers Patna, Bhojpur and Buxar districts of Bihar State. The study area is located between 25°' to 25° 35 ' N latitude and 84°00 ' to 85° 10' E longitude covering an area of 8800 sq. km. forms a part of Ganga and Son river catchments, which also comprises of major drainage channels in the study area. Visual interpretation of IRS 1C L1SS 111 FCC of 22nd April 2006 has been carried out for mapping hydrogeomorphologically significant landforms like flood plain shallow, flood plain deep, alluvial plain deep, alluvial plain shallow, paleochannel and oxbow lakes based on the image characteristic like tone, texture, shape, color and association. Maps pertaining to drainage and surface water bodies were also interpreted on satellite images.

2 illus, 1 table, 7 ref

006856   Purohit M K;Prajapati K K (Applied Geology Dep, Dr. H.S. Gour Univ, Sagar-470 003, Email: mkp09@rediffmail.com) : Tectonic implications of the earthquakes in the Indian subcontinent. J Geol Soc India 2009, 73(5), 680-2.

The Bhuj earthquake (26 January 2001) in India and the Ghori earthquake (8 October 2005) in Pakistan, both occurred close to the Indian-Iranian plate boundary related to the activity along the intracontinental Chaman transform fault. It is suggested that the seismic activity along NNW to NNE trending weak zones or faults is more intense in the sub-continent than along the WNW trending zones, since the stress along the former is less compressive but more of the shear or translational type. The devastative Koyna (1967) and Latur (1993) earthquakes both occurred along faults or weak zones that were close to the meridional rather than the equatorial trend. The Indian plate is moving to the north or NNE or NNW, along a rotational trajectory and hence the force tends to be more compressive along the equatorial weak zones. In contrast, it tends to be less compressive and more of the shear or translational along the weak zones that are close to meridional trend. The seismic activity is therefore more intense along the weak zones with NNW to NNE trend than along the ENE to EW trending zones.

2 illus, 7 ref

006855   Prasannakumar V;Lloyd G E (Geology Dep, Kerala Univ, Kariavattom, Trivandrum-695 581) : Appliction os SEM-EBSD to regional scale shear zone analysis: a case study of the Bhavani shear zone, South India. J Geol Soc India 2010, 75(1), 183-201.

The Bhavani Shear Zone (BSZ), part of the Palghat-Cauvery shear system of southern India, comprises a number of subparallel shear zones ranging in width from a few centimetres to tens of metres. These shear zones are characterised by progressive mylonitisation and shear fabrics corresponding to increasing strain, as documented by grain size reduction, flattening, elongation and dimensional preferred orientation of constituent minerals (quartz, hornblende, biotite, plagioclase and orthoclase). However, SEM-EBSD measured crystal preferred orientations (CPO) of these minerals are more complex and indicate interchange of maximum (X) and intermediate (Y) tectonic axes during different phases of deformation, with the minimum axis (Z) remaining approximately constant. The tectonic evolution of the BSZ and the disposition of the surrounding Archaean and Pan-African granulites are interpreted therefore in terms of polyphase deformation involving both dip-slip and strike-slip movement events in a multiply reactivated setting. SEM-EBSD CPO analysis provides clearer indication of potentially conflicting movement directions that are otherwise poorly constrained by shear markers and shear sense indicators.

9 illus, 1 table, 77 ref

006854   Prasad B;Asher R;Borgohai B (KDM Institute of Petroleum Exploration, Oil and Natural Gas Corporation Limited, 9, Kaulagarh Road, Dehradun-248 195, Email: bijaiprasad@indiatimes.com) : Late neoproterozoic (Ediacaran)-early peleozoic (Cambrian) acritarchs from the Marwar supergroup, Bikaner-Nagaur basin, Rajasthan. J Geol Soc India 2010, 75(2), 415-31.

Characteristic latest Neoproterozoic and Early Paleozoic acritarchs and associated organic-walled microfossils are recorded from the sediments of Marwar Supergroup encountered in BGW-A well (Bikaner-Nagaur Basin) from 1123-481 m depth. Six distinct acritarch assemblages, broadly comparable with globally known Ediacaran (Vendian) and Cambrian assemblages are recognised. The recovered microfossils provide precise age for different units of the Marwar Supergroup whose ages, till now, were poorly understood due to absence or paucity of invertebrate and other mega and microfossils. Jodhpur Group (1123-1105 m), the basal unit of Marwar Supergroup, records abundant ornamented sphaeromorphs (Lophosphaeridium spp.) alongwith various species of Leiosphaeridia, suggesting Late Ediacaran age. Occurrence of small micrhystrids (Asteridium spp.) and appearance of Dictyotidium birvetense, Pterospermella solida and Annulum squamaceum in lower part of Bilara Group (1105-1081 m), suggests latest Ediacaran to early Early Cambrian age. Hanseran Evaporite Group (1068-907m) is marked by abundant Retisphaeridium dichamerum, Dictyotidium birvetense, Cristallinium cambriense, Comasphaeridium sp. cf. C. strigosum and Archaeodiscina umbonulata indicating late Early Cambrian to early Middle Cambrian age. Microfossil contents in Nagaur Group (907-727m) are very poor. The succeeding Upper Carbonate Sequence (727-481 m) shows abundant Cristallinium randomense, Cymatiosphaera crameri and Asteridium spp., along with other species of Cymatiosphaera and Cristallinium, and also includes the early Late Cambrian marker forms, such as Striatotheca loculifera and Dorsenidium (Veryhachium) minutum that suggest late Middle Cambrian to early Late Cambrian age. The recorded acritarch assemblages suggest Late Ediacaran to early Late Cambrian (ca 570-500 Ma) age for the Marwar Supergroup, with demarcation of Precambrian-Cambrian boundary within the lower part of Bilara Group. Associated microfossils indicate intertidal/foreshore depositional environment for Jodhpur and Nagaur groups, whereas inner neritic to subtidal for the Bilara, Hanseran and Upper Carbonate units. Occurrence of an Early Permian palynoflora in the succeeding sequence (481 -427 m depth) indicates a major hiatus of ca 200Ma between the Marwar and overlying Bap/Badhaura sequences which involves the absence of middle Late Cambrian to Late Carboniferous sediments in this basin. Latest biostratigraphic data from Ujhani (Ganga Basin) and Bhander (Vindhyan Basin) sediments suggest that the above two sequences are closely comparable with the Marwar Supergroup, and show the prospective exploration challenges as do the Marwar Supergroup.

4 illus, 1 table, 49 ref

006853   Prakasam C;Biswas B (Geography Dep, Burdwan Univ, Burdwan-713 104) : Land use land cover change study in Ausgram I & II Blocks, district Burdwan, West Bengal using remote sensing and GIS. Indian J Landsc Syst ecol Stud 2009, 32(2), 337-44.

Ausgram I & II blocks are located in the east-central part of Burdwan distract of West Bengal. The district in general and the blocks in particular, have under gone several land use changes in the past century. The changing land use land cover scenario of Ausgram 1&I1 Blocks were assessed using Remote Sensing and GIS techniques. The historic land use map was prepared from topographic maps of Survey of India, 1972. The land use and land cover maps of 2002 and 2008 were generated through the digital land use classification of Land Sat 5 and 7 satellite imageries supported by ground truths. The results for three time periods revealed that agriculture is main land use land cover in these blocks. From 49 percent land use land cover, agriculture increased marginally to 50.00 per cent in 2008. But forest and surface water bodies experienced decrease in the surface area coverage. As the forest and surface water bodies are two important ecologically sensitive land use land cover, specific care is necessary to prevent the decreasing trend of such resources to maintain the sustainability.

4 illus, 1 table, 10 ref

006852   Piazolo S;Jessell M W;Bons P D;Evans L;Becker J K (Geology and Geochemistry Dep, Stockholm Univ, 10961 Stockholm, Sweden, Email: sandra.piazolo@geo.su.se) : Numerical simulations of microstructures using the Elle platform: a modern research and teaching tool. J Geol Soc India 2010, 75(1), 110-27.

The last 20 years have seen a manifold increase in the application of numerical simulations in the earth sciences. This contribution aims to provide an overview of the possibilities of using numerical techniques, in particular the numerical simulation package Elle, as an aid in the training for microstructural interpretation in rocks. Three sets of experiments are described to illustrate the range of simulations currently possible, investigating the effects of grain growth, polyphase deformation and dynamic recrystallisation. Numerical simulations of static annealing of a pre-deformed natural sample show that Crystallographic Preferred Orientations can still be used for the interpretation of kinematic and deformation conditions, even after substantial post-deformational annealing. However, the grain network characteristics such as grain size, grain size distribution, boundary shapes and aspect ratios are rapidly altered during annealing, especially if the grains possessed highly contrasting internal strain energies. Experiments modelling two and three phase viscous deformation show that the rheology and microstructural evolution of a rock is largely determined by the linearity or non-linearity of viscous deformation; whereas the number of phases with differing viscosity is less important. Variations in strain in the same mineral phases can be used to infer flow properties. The spatial distribution of phases significantly influences the rheology at a specific point in time. During dynamic recrystallization the rates of the competing processes of grain size reduction and increase can have a systematic influence on the evolution of grain characteristics. Relatively high rates of grain size increasing processes result in larger grain sizes, lower aspect ratios, stabilization of grain size at lower strain and less strain localization. Numerical simulations can help to answer field related questions and to identify the number of significant active processes. They are also extremely useful as teaching tools as processes can easily be turned on or off, parameters can be changed and boundary conditions altered. Fortunately, numerical simulations have now matured to a point where users that do not want to spend time in coding a model can still perform and analyse numerical simulations.

16 illus, 48 ref

006851   Paul D;Kazy S K;Sar P;Pal T (Biotechnology Dep, Indian Institute of Technology, Kharagpur-721 302) : DGGE-based microbial community analysis of subsurface undisturbed sediments from arsenic-affected Gotra area, West Bengal. Indian J Geosci 2010, 64(1-4), 173-8.

The Gotra area in Nadia district is one of the worst arsenic-affected villages in West Bengal. Majority of the tubewells in this village yield groundwater with arsenic values above 10 ppb. Denaturing-Gradient-Gel-Electrophoresis (DGGE)-based microbial community analysis of subsurface undisturbed sediments has been carried out for varying lithoassemblages at different depths, with contrasting groundwater quality. The cluster analysis reveals highest similarity and possibly near similar type microbial diversity in S-44 (grey fine sand) and S-18 (grey soft silt) samples. Also similar type community structure exists in S-63 (orange-white coarse sand) and S-49 (orange sand) samples. Samples of S-34 (grey fine sand), S-33 (grey fine sand) and S-26 (grey fine sand) also share similar community structures. The DGGE banding pattern among the samples indicated an inversely proportional relation between the number bands and the arsenic content. The number of bands is indicative of number of bacteria species. Also the strong band intensities may be indicative of elevated number of predominant species. Detailed bacterial analysis of these subsurface samples would thus help as one of the tools in framing up a model for biogeochemical release of arsenic in specific microenvironments.

2 illus, 1 table, 16 ref

006850   Patra M C (Geography Dep, Calcutta Univ, Kolkata) : Quantitative geo-spatial analysis: an overview. Indian J Landsc Syst ecol Stud 2009, 32(2), 299-308.

Map or Statistical technique can not be separated from each other or in other words they must be combined together. Spatial analysis is of various types and flexible including both quantitative and qualitative technique. Though subjective analysis is very easy and traditional, objective analysis is essential. That is the reason why quantitative geo-spatial analysis is very important. The paper has tried to highlight the different quantitative geo-spatial techniques applied to different types of spatial data.

3 illus, 6 ref

006849   Patel D (J.J. Bajaj Nature Cure, Yoga, Training and Research Centre, At & Post-Randheja, District-Gandhinagar, Gujarat, Email: drdharmesh@rediffmail.com) : Fasting myths and scientivic approach. J Adv dev Res 2010, 1(2), 219-21.

006848   Passchier C W;Exner U (Earth Sciences Dep, Mainz Univ, D-550 99 Mainz, Germany) : Digital mapping in structural geology-examples from Namibia and Greece. J Geol Soc India 2010, 75(1), 32-42.

Many problems in geology, especially structural geology, can only be solved by detailed mapping. Presently, mapping is still mainly carried out on paper using techniques from the 19th Century. However, tools are now available to carry out most mapping tasks on microcomputers in the field without any need of paper. This speeds up geological mapping and reduces the errors involved in the mapping process. Digital mapping also allows work in featureless areas and areas of great structural complexity that would not be possible using paper maps. We present two practical examples of the new technology of digital mapping using microcomputers, from Namibia and Greece.

7 illus, 17 ref

006847   Pandey Y (Operation: Chhattisgarh, Central Region, Geological Survey of India, Raipur-492 013, Email: yogesh.pandey@gsi.gov.in) : High incidence of groundwater arsenic in relation to weathering of bedrocks in Rajnandgaon district, Chhattisgarh. Indian J Geosci 2010, 64(1-4), 9-14.

Arsenic contamination in groundwater and surface water in Rajnandgaon district and in limited areas of Kanker district of Chhattisgarh, shows isolated and patchy occurrence. It is restricted to the N-S trending Dongargarh-Kotri rift zone, which exposes mainly bimodal volcanics. The eastern part of the rift zone flanked by the Chhattisgarh sedimentary basin, is totally free from arsenic contamination. The villages Kaudikasa, Jadutola, Joratarai and Sonsyatola are severely affected. The highest value of arsenic recorded, is 2350 ppb in Sonsyatola (E80°42'05": N20°47'30"). In Gurwandi area of Kanker district, three boreholes under artesian condition are found to contain arsenic in the range of 10 ppb to 680 ppb. It is observed that the water samples collected during post-monsoon season contain more arsenic than samples collected during pre-monsoon season. Speciation studies reveal that the toxic As³⁺+ is predominant over non-toxic As⁵⁺ in most of the samples. The low SO₄ content (3-14 ppm) in most of the samples leads to the conclusion that the release of arsenic is not due to oxidation of pyrite and arsenopyrite occurring in rhyolite at rock-water-air interface. Arsenic is mainly released by alteration and weathering of acid magmatic rocks where it possibly lay adsorbed on Fe -Mn oxyhydroxide phases and is later mobilised into groundwater by the biomediated reductive desorption/dissolution.

1 illus, 2 tables, 10 ref

006846   Pandey O P;Chandrakala K;Reddy P R;Koti Reddy G (National Geophysical Research Institute, (Council of Scientific and Industrial Research), Hyderabad-500 007) : Structure, tectonics and thermal state of the lithosphere beneath intraplate seismic region of Latur, Central India: an appraisal. J Geol Soc India 2009, 73(4), 457-68.

Recent surge in intraplate seismicity has led to detailed geological and geophysical investigations, covering different continental segments of India including seismogenic region of Latur. A synthesis of such data sets to understand the prevailing tectonic and thermal state of the Lithosphcre beneath Latur region, that witnessed a large scale human loss due to 1993 seismic activity, has revealed shallow surfacing of denser deeper crustal segments which may have resulted due to ongoing active subsurface tectonic activity like uplift and erosion since geological past. Below this region, Mono temperature exceeds 500°C, heat flow input from the mantle is quite high (29-35 mW/m²) and the asthenosphere is shallow (<126>100±10 km). It is suggested that stress generated by ongoing upliftment and related subcrustal thermal anomaly is concentrating in this denser and stronger mafic crust within which earthquakes tend to nucleate. In all likelihood, the seismic activity witnessed in the region may stem from the deep crustal/lithospheric dynamics rather than the role of fluids at the hypocentral depth.

11 illus, 56 ref

006845   Pal T;Mukherjee P K;Shome S (Central Petrological Laboratories, Geological Survey of India, 15 Kyd Street, Kolkata-700 016, Email: tn_pal@yahoo.com) : Authigenic growth of siderite concretion in alluvial sediments of the arsenic-affected delta and its geobiological significance. Indian J Geosci 2010, 64(1-4), 163-6.

Siderite (FeCO₃) concretions from the subsurface unconsolidated sands of arsenic-affected areas in the Bengal delta have been studied by SEM, EDX and EPMA. The morphology of the concretions, as documented here, demonstrates the stages of progressive authigenic growth of the concretions during post-depositional diagenetic environment. Bacterial colony identified from the interior of the concretions indicates a geobiochemical role on its growth over substrates of iron-bearing mineral phases. Adsorption of arsenic on the growing surfaces of these concretions provides a clue in arriving at a geobioremedial measure for the hazardous problem of arsenic pollution in groundwater.

2 illus, 13 ref

006844   Pal T;Mukherjee P K;Mondal P K;Banerjee K; Tripathy S;Deepthy R (Central Petrological Laboratories, Central Headquarters, Geological Survey of Inida, 25 Kyd Street, Kolkata-700 016, Email: tn_pal@yahoo.com) : Characterisation of "orange-sand" vis-a-vis "grey-sand" from the arsenic-affected areas of West Bengal. Indian J Geosci 2010, 64(1-4), 167-72.

Groundwater in parts of West Bengal is contaminated with arsenic, resulting in health hazard to a large number of people. The aquifers consisting of "grey sand" mostly yield contaminated groundwater; whereas the aquifers consisting of "orange sand" yield arsenic-safe groundwater. This paper presents detailed characterisation of "orange sand" vis-a-vis "grey sand" to understand the distinction between these two sands, which yield contrasting levels of groundwater arsenic. The "orange sand", identified as silty sand, contains characteristic minerals like illite, siderite, Fe-coated grains, etc., and represents a deposit of oxidising condition. In contrast the "grey sand", identified as fine sand, characteristically contains muscovite, biotite, hornblende, tourmaline etc., along with carbonaceous matter, indicating the reducing nature of the "grey sand". Thus, any arsenic present in the environment gets adsorbed on the surfaces of "orange sand" grains and the associated groundwater thereby becomes arsenic-safe. Alternatively, the "grey sand" represents a reducing condition, where arsenic is reduced to its soluble form with consequent high arsenic in groundwater.

7 illus, 7 tables, 2 ref

006843   Nishant Kumar;Sarkar S;Mandal N (NO, Indian Institute of Science Education and Research, Kolkata, Email: shamiksarkar@gmail.com) : Numerical modeling of flow patterns around subducting slabs in a viscoelastic medium and its implications in the lithospheric stress analysis. J Geol Soc India 2010, 75(1), 98-109.

Presents results obtained from numerical model experiments to show different patterns of mantle flow produced by lithospheric movement in subduction zones. Using finite element models, based on Maxwell rheology (relaxation time <126> 10^II), we performed three types of experiments: Type 1, Type 2 and Type 3. In Type 1 experiments, the lithospheric slab subducts into the mantle by translational movement, maintaining a constant subduction angle. The experimental results show that tlie flow perturbations occur in the form of vortices in the mantle wedge, irrespective of subduction rate and angle. The mantle wedge vortex is coupled with another vortex below the subducting plate, which tends to be more conspicuous with decreasing subduction rate. Type 2 experiments take into account a flexural deformation of the plate, and reveal its effect on the flow patterns. The flexural motion induces a flow in the form of spiral pattern at the slab edge. Density-controlled lithospheric flexural motion produces a secondary flow convergence zone beneath the overriding plate. In many convergent zones the subducting lithospheric plate undergoes detachment, and moves down into the mantle freely. Type 3 experiments demonstrate flow perturbations resulting from such slab detachments. Using three-dimensional models we analyze lithospheric stresses in convergent zone, and map the belts of horizontal compression and tension as a function of subduction angle.

13 illus, 1 table, 30 ref

006842   Murthy B V S;Madhusudan Rao B;Dubey A K; Srinivasulu (Centre of Exploration Geophysics, Osmania Univ, Hyderabad-500 007) : Geophysical exploration for manganese-some first hand examples from Keonjhar district, Orissa. J Indian Geophys Union 2009, 13(3), 149-61.

Manganese ores in India are being exploited since the past hundred years. Continuous exploitation of shallower and massive deposits led to searching for further occurrences and also necessitated application of geophysical methods. Geological survey of India since 1940s, has been exploring for manganese deposits in various parts of the country employing different geophysical methods (Ganokar, Das & Srirama 2001). The authors of this paper had opportunity to conduct geophysical surveys comprising gravity, magnetic and electrical resistivity methods in some selected blocks in the JAMDA-KOIRA belt of Keonjhar District, Orissa. Manganese ore, mainly psilomelane and pyrolusite occur in this belt as small lenses/lumps discontinuously and, in general under cover of laterite. These ore occurrences appear to be confined to near NW-SE or N-S belts and associated with shales/phyllitic shales below which are occurring occasionally brecciated conglomerates with chert and cherty quartz. The basement is Banded Iron Formations, mainly BHJ and BHQs. In the first block, which is about 300 m x 300 m size, magnetic, gravity and electrical resistivity profiling and soundings were conducted. The geophysical signatures, though feeble, showed the trends and alignments of ore bodies and the intervening faults/ fractures associated with iron concentrations. Based on these results two more blocks (Block - II about 89 hectares and Block -III about 24 hectares) were covered by magnetic mapping, electrical resistivity profiling and sounding and gravity survey on selected traverses. The geophysical anomalies in these two blocks also are characteristic in delineating the probable alignments of manganese bodies. Critical analysis of, essentially, the magnetic contour maps and resistivity and magnetic profile data helped visualizing pockets of likely occurrence of manganese ore.

10 illus, 1 table, 10 ref

006841   Mukul M;Jade S;Bhattacharyya A K;Bhusan K (NO, CSIR Centre for Mathematical Modelling and Computer Simulation, Bangalore-560 037) : Crustal shortening in convergent orogens: insights from global positioning (GPS) measurements in Northeast India. J Geol Soc India 2010, 75(1), 302-12.

Deformation in active mountain belts like the Himalaya is manifested over several spatial and temporal scales and collation of information across these scales is crucial to an integrated understanding of the overall deformation process in mountain belts. Computation and integration of geological shortening rates from retrodeformable balanced cross-sections and present-day convergent rates from deforming mountain belts is one way of integrating information across time-scales. The results from GPS measurements carried out in NE India indicate that about 15-20 mm/yr of convergence is being accommodated there. Balanced-cross sections from the NE Himalaya indicate about 350-500 km of shortening south of the South Tibet Detachment (STD). Geothermobarometry suggest that the rocks south of the STD deformed under peak metamorphic conditions at<126> 22 Ma. This indicates a geological convergence rate of <126> 16-22 mm/ yr which appears to be fairly consistent with the GPS derived convergence rates. Approximately 1.5 to 3.5 mm/yr (<126> 10-20%) of the total N-S of the present-day convergence in the NE Himalaya is accommodated in the Shillong Plateau. In addition,<126> 8-9 mm/yr of E-W convergence is observed in the eastern and central parts of the Shillong Plateau relative to the Indo-Burman fold-thrust belt. Balanced cross-sections in the Indo-Burman wedge together with higher resolution GPS measurements are required in the future to build on the first-order results presented here.

6 illus, 2 tables, 42 ref

006840   Mukhopadhyay S C (Geography Dep, Calcutta Univ, Kolkata) : Fluvial processes with special reference to avulsion in the flood plains of the unstable Mahananda-Sankosh interfluvial areas, West Bengal. Indian J Landsc Syst ecol Stud 2009, 32(2), 521-38.

This is an attempt to elucidate the fluvial processes especially in the floodplains and the related modification by avulsions in the valleys of neo-tectonically unstable Mahanda-Sankosh interfluve with climate changes Lower Ganga-Brahmaputra basin, West Bengal, It has been based on advanced techniques of measurement, the variation of typical depositional landforms evolved in the area etc., both qualitatively and quantitatively.

14 illus, 18 ref

006839   Mukhopadhyay E;Basak K (Geology Dep, Calcutta Univ, Kolkata-700 019, Email: dhruba_38@yahoo.co.uk) : Eastern ghats belt-a polycyclic granulite terrain. J Geol Soc India 2009, 73(4), 489-518.

The Eastern Ghats Belt is a polycyclic granulite terrain along the east coast of India whose western boundary marked by a shear zone along which the granulites are thrusted over the cratonic units of the Indian shield, and its northern margin is marked by the presence of a number of fault-bounded blocks. Recent work has convincingly brought out that there are domains within the belt having different evolutionary histories. The segment south of the Godavari Rift went through a high grade thermo-tectonic event at <126>1.6-1.7 Ga. North of the Godavari Rift in a narrow zone along the western boundary the last high-grade metamorphic event is of late Archaean age. A series of alkaline plutons along the western boundary zone testifies to a rifting episode at <126>1.3-1.5 Ga. In the major part of the EGB the metamorphism is broadly of Grenvillian age, with two major thermo-tectonic pulses at <126>1.1-1.2 Ga and <126>0.95-1.0 Ga. But high grade conditions persisted for a long period and younger thermal events of <126>0.65 Ga to <126>0.80 Ga are locally recorded, There are differences in the tectonometamorphic histories of different domains, but the tectonic significance of these differences remains uncertain. Pan-African (0.50-0.55) thermal overprints are common and become conspicuous along the western boundary zone. The thrusting of the Eastern Ghats granulites in a hot state over the cratons to the west is of Pan-African age. In the Rodinia assembly (<126>0.9 Ga) the Eastern Ghats and the Rayner-Napier Complexes of Antarctica were contiguous, but the pre-Rodinia configuration of these terrains remains unclear. At <126>0.8 Ga during the Rodinia break up Greater India rifted apart from East Antarctica, and only later it docked with Australia-East Antarctica at 530-550 Ma. The continuation of the East Antarctic Pan-African erogenic belts into the Eastern Ghats is yet to be ascertained.

7 illus, 2 tables, 15 ref

006838   Mukhopadhyay D;Chattopadhyay N;Bhattacharyya T (Geology Dep, Calcutta Univ, 35 Ballygunge Circular Road, Kolkata-700 032, Email: dhruba_38@yahoo.co.uk) : Structural evolution of a gneiss dome in the axial zone of the Proterozoic south Delhi fold belt in central Rajasthan. J Geol Soc India 2010, 75(1), 18-31.

The structural geometry of the Anasagar gneiss dome in the axial zone of the South Delhi Fold Belt is controlled by polyphase folding. It is classified as a thrust-related gneiss dome and not as a metamorphic core complex. Four phases of deformation have affected both the gneiss and the enveloping supracrustal rocks. D₂ and D₃ deformations probably represent early and late stages of a progressive deformation episode in a simple shear regime combined with compression. The contact between the gneiss and the supracrustal rocks is a dislocation plane (thrust) with top-to-east sense of movement which is consistent with the vergence of the D₂ folds. The thrust had a ramp-and-flat geometry at depth. At the present level of exposure it is a footwall flat (that is, parallel to the gneissosity in the footwall), but it truncates the bedding of the hanging wall at some places and is parallel at others. The thrusting was probably broadly coeval with the D₂ folds and the thrust plane is locally folded by D₂. D₂ and D₃ folds have similar style and orientation as the first and second phases respectively of major folds in the Delhi Supergroup of the South Delhi Fold Belt and these are mutually correlatable. It is suggested that Dj may be Pre-Delhi in age. Available geochronological data indicate that the emplacement of the Anasagar gneiss predated the formation of volcanic rocks in the Delhi Supergroup and also predated the main crust forming event in the fold belt. The Anasagar gneiss and its enveloping supracrustal rocks are probably older than the Delhi Supergroup.

13 illus, 1 table, 35 ref

006837   Mukherjee S (NO, Baripur College, 24 Pargans (S), West Bengal) : Effect of soil salinity on agriculture productivity in costal area of block Ramnagar-1 Purba Midnapur. Indian J Landsc Syst ecol Stud 2009, 32(2), 287-92.

Deals about affect of soil salinity on agriculture productivity at Block Ramnagar-1, Purba Midnapur. This place bordered by Bay of Bengal in south. The problem of soil salinity in costal areas is a national problem. The fanners of costal area near Bay of Bengal faced very much problem eases of soil salinity in agricultural land. Mainly seawater is responsible for greater salinity of soil. Dwellers of this costal area trying to change their occupation for decreasing of agricultural productivity. After examining salinity with the help of salinity meter it is established that salinity is very high near sea shore and back side of sea dykes, the range of salinity in this area is 0.25mmhos/cm. to 2.60 mmhos/cm.

1 illus, 2 tables, 10 ref

006836   Mondal A;Das D N (Centre for the Study of Regional Development, Jawaharlal Nehru Univ, New Delhi) : Flood damage assessment using radarsat data in Orissa, 2006. Indian J Landsc Syst ecol Stud 2009, 32(2), 29-40.

Floods are the most common and widespread natural disasters and statistically more than half of the world ' population lives near to the sea coast or river delta or along the rivers. India is one of the worst flood affected countries in the world and is placed second after Bangladesh. In India, particularly in Orissa, most of the flood events happen during the Monsoon period (June to September). The authors have mate suggestions for the assessment of flood damages specially using the radder set deta in the rivers of Orissa - a case study with suitable illestrations and example.

5 illus, 5 tables, 17 ref

006835   Mitra G;Bhattacharyya K;Mukul M (Earth and Environmental Sciences Dep, Rochester Univ, Rochester, NY 14627, USA, Email: mitr@ur.rochester.edu) : Lesser Himalayan duplex in Sikkim: implications for variations in Himalayan shortening. J Geol Soc India 2010, 75(1), 289-301.

Thrust duplexes account for large fractions of the total shortening in most fold-thrust belts (FTBs). They also provide an efficient mechanism for transferring slip upward from the basal decollement and for transporting roof thrust sheets over long distances. The Lesser Himalayan duplex (LHD) plays a prominent role in the overall evolution of the Himalayan FTB and has been described from Garhwal-Kumaon to Bhutan. In Sikkim the LHD shows unique structural geometry and has been responsible for transporting crystalline thrust sheets (MCT 1 and MCT 2) farther southward than other parts of the Himalaya. Such lateral variations in LHD geometry imply variations in the kinematic history of the Lesser Himalaya and variations in shortening and shortening history along the length of the Himalayan arc, and these are reflected in observable large scale structural patterns.

9 illus, 39 ref

006834   Mishra D;Biswas S K (Geology Dep, Banaras Hindu Univ, Varanasi-221 005, Email: d_mishra5@yahoo.co.in) : Sedimentology, sequence stratigraphy and Synrift model of younger part of Washtawa formation and early part of Kanthkot formation, Wagad, Kachchh basin, Gujarat. J Geol Soc India 2009, 73(4), 519-27.

The 600 m thick prograding sedimentary succession of Wagad ranging in age from Callovian to Early Kimmeridgian has been divided into three formations namely, Washtawa, Kanthkot and Gamdau. Present study is confined to younger part of the Washtawa Formation and early part of the Kanthkot Formation exposed around Kanthkot, Washtawa, Chitrod and Rapar. The depositional architecture and sedimentation processes of these deposits have been studied applying sequence stratigraphic context. Facies studies have led to identification of five upward stacking fades associations (A, B, C, D, and E) which reflect that deposition was controlled by one single transgressive - regressive cycle. The transgressive deposit is characterized by fining and thinning upward succession of facies consisting of two facies associations: (1) Association A: medium - to coarse-grained calcareous sandstone - mudrocks alternations (2) Association B: fine-grained calcareous sandstone -mudrocks alternations. The top of this association marks maximum flooding surface as identified by bioturbational fabrics and abundance of deep marine fauna (ammonites). Association A is interpreted as high energy transgressive deposit deposited during relative sea level rise. Whereas, facies association B indicates its deposition in low energy marine environment deposited during stand-still period with low supply of sediments. Regressive sedimentary package has been divided into three facies associations consisting of: (1) Association C: gypsiferous mudstone-siltstone/fine sandstone (2) Association D: laminated, medium-grained sandstone - siltstone (3) Association E: well laminated (coarse and fine mode) sandstone interbedded with coarse grained sandstone with trough cross stratification. Regressive succession of facies association C, D and E is interpreted as wave dominated shoreface, foreshore to backshore and dune environment respectively. Sequence stratigraphic concepts have been applied to subdivide these deposits into two genetic sequences: (i) the lower carbonate dominated (25 m) transgressive deposits (TST) include facies association A and B and the upper thick (75m) regressive deposits (HST) include facies association C, D and E. The two sequences are separated by maximum flooding surface (MFS) identified by sudden shift in facies association from B to C. The transgressive facies association A and B represent the sediments deposited during the syn-rift climax followed by regressive sediments comprising association C, D and E deposited during late syn-rift stage.

3 illus, 1 table, 28 ref

006833   Mehrotra N C;Venkatachala B S;Kapoor P N (NO, Birbal Sahni Institute of Palaeobotany, 53, University Road, Lucknow-226 007) : Palynology in hydrocarbon exploration: high impact palynological studies in western offshore and Krishna-Godavari basins. J Geol Soc India 2010, 75(2), 364-79.

Presents an updated account of palynostratigraphic, source rock evaluation and palaeoenvironment data on Western Offshore and Krishna Godavari (K-G) Basins. Forty three dinoflagellate biohorizons have been identified in the Tertiary subsurface of Mumbai Offshore, facilitating a high resolution correlation of Oil bearing horizons. In K-G Basin integrated palynostratigraphic data and the composite general lithologies for the Mesozoic and Cenozoic have been presented in a tabular form; Eighty two dinoflagellate biohorizons have been identified. A very fine dinoflagellate based stratigraphic resolution has been achieved at most levels making it useful in geological modelling for hydrocarbon exploration in both Western Offshore and K-G Basin. Useful information on matured organic matter facies distribution in Panna Formation (Western Offshore) and Cretaceous of K-G Basin has been summarized. Recently, potential source rock facies have been identified in Panna Formation in Western Offshore. Limitations of present studies and future areas of focus have been outlined.

10 illus, 2 tables, 27 ref

006832   Mandal S P;Jana N C (Geography Dep, Burdwan Univ, Burdwan-713 104) : Valuating land degradation : a case study of Khatra block in Bankuir district. Indian J Landsc Syst ecol Stud 2009, 32(2), 127-35.

Land is aproduct of nature and a three dimensional dynamic body. It is that part of the earth which supports life offering agricultural commodities and where human beings build dwelling for the protection from natural calamities. Land degradation refers to a decline in the overall quality of soil, water or vegetation condition commonly caused by human activities. The current trend of economic and industrial development coupled with growing human as well as livestock population has been the major reasons behind the incidence of land degradation in Khatra Block. These factors exert pressure on limited land resources of the study area for agricultural, industrial and housing needs of the growing population. It is the land under cultivation, which face biggest challenge of land degradation in Khatra Block. The present paper deals with the land degradation of Khatra Block in Bankura District, West Bengal and suggests measures towards the protection of land and its sustainable utilization.

3 illus, 5 tables, 19 ref

006831   Mandal B U (NO, Calcutta Univ, Kolkata, Email: ujjwal_rv@rediffmail.com) : Impact of fluvial geomorphology on land utilization strategies of Kalej Khola basin, Sikkim. Indian J Landsc Syst ecol Stud 2009, 32(2), 319-26.

Deals with the comprehensive study on the impact of fluvial geomorphology on land utilization strategies of the Kalej Khola basin, West district, Sikkim (India). It is a micro river basin consisting of approximately 500 sq km area under the Tista drainage basin and embodies some fluvial activities under an unstable zone of this basin which influence the development of land use patterns over different fluvial landforms being processed by both endogenetic and exogenetic forces with distinct expansion of time and space. KEY WORDS: Kalej Khola Basin, Fluvial Geomorphology, Mountainous Terrain, Land Utilization Strategies.

2 tables, 7 ref

006830   Mamtani M A (Geology and Geophysics Dep, Indian Institute of Technology, Kharagpur-721 302, Email: mamtani@gg.iitkgp.ernet.in) : Strain-rate estimation using fractal analysis of quartz grains in naturally deformed rocks. J Geol Soc India 2010, 75(1), 202-9.

The area-perimeter fractal dimension (D) of quartz grains has earlier been proposed as a strain-rate gauge based on experimental deformation of quartz aggregates. To test the application in naturally deformed rocks, D is calculated in (a) three quartzites belonging to the Lunavada Group of rocks (Aravalli Mountain Belt, NW India) that developed textures between 420-600°C and (b) one quartz reef sample from the Malanjkhand Granite (Central India), which underwent dynamic recrystallization between 250-400°C. Using the above T ranges and calculated D values, strain-rates are calculated for the two sets of samples. A 10^-12.7 s^-1 strain rate at 250°C is calculated for the quartz reef sample. However, at higher temperatures the calculated strain-rate is >10¹⁰ s^-1 for the quartz reef and the quartzite samples. The quartzites show evidence of dynamic recrystallization by grain boundary migration (GBM) and subgrain rotation (SGR), while the quartz reef is replete with evidence of bulging (BLG) recrystallization. T and calculated strain-rates are plotted on available recrystallization map of quartz. It is demonstrated that whilst the T/strain-rate of the quartzites does not fall in the region of GBM and SGR, the T/strain-rate of the quartz reef falls in the BLG region. The problems with strain-rate calculations using area perimeter fractal dimension are discussed. It is concluded that the method of strain-rate calculation can be used only for lower T.

6 illus, 1 table, 33 ref

006829   Majumder A;Sivaramakrishnan L (Geography Dep, Burdwan Univ, West Bengal) : Land acquisition and its impact on the farmers: a case study of Ulhas township, Burdwan. Indian J Landsc Syst ecol Stud 2009, 32(2), 496-500.

With the increasing population pressure and spread of urbanisation the land use pattern has been changing continously in the recent decades. In order to accommodate the huge population of the urban centers and in a view to decentralise the congestion caused by the immigrants in the urban centers- the satellite towns are on rise. Thus to provide space for the housing complexes the agricultural fields are being continously converted to build up area. But this type of conversion of agricultural land to build up space is creating problems to the cultivators and the agricultural labourers and also to the environment. In this paper an attempt has been made to study the plight of agriculturalists who have given up their land holdings to Burdwan Development Authority for the development of a township called 'Ulhas'.

2 tables, ref

006828   Lohani A K;Chatterjee C;Kumar R;Singh R D (NO, National Insitute of Hydrology, Roorkee-247 667) : Management model for waterlogging and drainage congestion problem of Mokama tal area. J Instn Engrs-Pt CI 2009, 90(May), 28-33.

Surface waterlogging and drainage congestion are usual phenomenon during the monsoo period over a depressed land of 1062 km² (Mokama group of Tals) in Bihar. The case study presented herein addresses development of a management model aimed at minimization of the waterlogged area under the constraints of check over inflows (control monsoon runoffs from tributaries) entering the Tal and provides strategic solutions for different rainfall situations. A non-linear optimization problem developed earlier has been envisaged and solved setting revised constraints of available water for different rainfall varying from below average to above average both for kharif and rabi seasons. Various scenarios of check over inflows and corresponding benefits have also been analyzed in order to verify the suitability of the management strategy for most frequent rainfall patterns of the region.

5 illus, 2 tables, 8 ref

006827   Krishnamurthy N S;Ananda Rao;Dewashish Kumar (NO, National Geophysical Research Institute, Hyderabad-500 606, Email: dew_kumar@yahoo.co.uk) : Electrical resistivity imaging technique to delineate coal seam barrier thickness and demarcate water filled voids. J Geol Soc India 2009, 73(5), 639-50.

Exploration and exploitation of coal seams is one of the major resources for the energy sector in any country but at the same time water filled voids/water logged areas in the old workings of these seams are very critical problems for the coal mining industry. In such situations, disasters like inundation, landslides, collapsing of the old seams may occur. In this regard, it is necessary to find out the water saturated/water filled voids and zones in the mining areas. Since no established technique is available to find such zones, an experimental study using Electrical Resistivity Imaging (ERI) has been carried out in one of the coal mining areas near Dhanbad, to find out the feasibility of finding the barrier thickness and the water logged area in underground coal mines. The area under study forms part of Jharia coalfield in Dhanbad district, Jharkhand state. The coal bearing rocks of Barakar Formation of Lower Permian age (Gondwana period) occur in the area under a thin cover (10 m to 15 m) of soil and or alluvium. Coal bearing Barakar Formations consist mainly of sandstone of varying grain size, intercalation of shale and sandstone, grey and carbonaceous-shale and coal seams. Since the water saturation reduces the resistivity of a formation to a large extent, water filled voids and old coal workings are expected to have significant resistivity contrast with the surrounding host rock. Hence, ERI technique was applied in such an environment as this technique uses high-density data acquisition both laterally and vertically by using multiple number of electrodes. Along with ERI, mise-a-la-masse (also called charged body) technique was also employed at one of the promising sites to find out the connectivity of water logged areas and also detection of these old workings from the surface measurements was analyzed. The interpreted 2D resistivity sections have clearly indicated the water bearing zone(s) along the profile which was well confirmed with the existing water level in the nearby borewells. On the other hand, this technique did not identify the size of the coal pillar and gallery (air filled voids), which might be due to the small size of the voids (i.e. about 2 m x 2 m) below a depth of 15m and more but have indicated altogether as a high resistive zone ranging from 600-1000 Ohm-m.

14 illus, 27 ref

006826   Kratinova Z;Machek M;Kusbach V (Geophysical Institute, Czech Academy of Sciences, Bocni II/1401, 14131 Praha 4, Czech Republic, Email: kratinova@ig.cas.cz) : Fabric transpositions in granite plutons-an insight from non-scaled analogue modelling. J Geol Soc India 2010, 75(1), 267-77.

Investigations on a set of experimental models of highly viscous intrusions were carried out in order to study the internal strain pattern during vertical ascent and emplacement of granite intrusions. The strain pattern was determined by means of anisotropy of magnetic susceptibility (AMS) resulting from the orientation of magnetite particles in a liquid plaster medium. The modelled intrusions show distinct fabrics reflecting the flow of a Theologically complex, non-Newtonian material. During the vertical growth of the intrusion, constrictional vertical fabrics are transposed into flattening fabrics, and along with the development of low-intensity fabric domains are passively transported upwards. Vertical growth takes place along subvertical thrust shear zones that satisfactorily explain the discordant magmatic fabrics in granites along intrusion sides. The resulting complex fabric patterns suggest that the vertical movement of material in ascending intrusions is accommodated by various flow mechanisms operating simultaneously.

6 illus, 50 ref

006825   Khosla S C;Nagori M L;Jakhar S R;Rathore A S (Geology Dep, Mohanlal Sukhadia Univ, Udaipur-313 002, Email: sckhoslal@yahoo.com) : Mixed marine, brackish water and non-marine microfaunal association in the inter-trappean bed (early palaeocene) of Jhilmili, Chhindwara District, Madhya Pradesh. J Geol Soc India 2009, 73(5), 724-32.

Except for the east coast of Andhra Pradesh, the Deccan Inter-trappean sedimentary beds of Peninsular India have beentong known to yield non-marine microfauna, mainly ostracods. These have been extensively described from different localities of Madhya Pradesh, Maharashtra, Karnataka, Andhra Pradesh, Gujarat and Rajasthan states. Occurrence of mixed microfaunal association of marine, brackish water and non-marine foraminifers and ostracods is being recorded from these beds from Jhilmili, Chhindwara district, Madhya Pradesh. It comprises at least two or more planktonic foraminifer species, and one brackish water and 17 non-marine ostracod species. The brackish water ostracod, Neocyprideis raoi (Jain, 1978) has been previously recorded in great profusion from the Inter-trappean beds of Duddukuru, West Godavari District, Andhra Pradesh, which have been assigned Early Palaeocene age (Khosla and Nagori, 2002). Presence of molt stages of the bulk of non-marine and brackish water ostracods in the Inter-trappean beds of Jhilmili is suggestive that they were inhabitants of low mesohaline inland pool/lake. The planktonic foraminifers were carried to this pool/lake by a marine transgression probably from the east coast of India through the Trans Deccan Straits.

2 illus, 1 table, 70 ref

006824   Khilnani M (SERC, DST, JNV Univ, Jodhpur) : Palaeodrainage and palaeoclimate of north-west India. J Hydrol 2009, 32(1), 21-9.

Geological records point out to a period of aridity 10,000 years ago, at the end stage of Pleistocene glaciation, which gradually changed to a wet phase. Copious rainfall in the Himalayan region gave rise to innumerable rivers, mainly Sarasvati river along with six other rivers which flowed down in cascades bringing enormous amounts of water in the plains of Punjab, Rajasthan and north Gujarat. During this period ( 6000 BC to 3000 EC), Aryan Vedic civilization developed along Sarasvati river. Aryans worked on Vedas and Rigveda contains 75 hymns in praise of Sarasvati river. Sarasvati river desiccated due to head ward erosion of Yamuna and west ward flow of Satadru (Sutlej, earlier a tributary of the Sarasvati) meeting Indus river where Indus civilization developed during 3000 BC to 1900 BC. The existence and desiccation of Sarasvati river had led many scientists during last 150 years to work on its migratory course and some have even suggested its shift from base of Aravail to Anupgarh and attributed all fresh water found in older formations in Thar desert to have been recharged by Sarasvati river. There are also Vedic references of another river, named as Drishadvati river, originating in Siwaliks and flowing south of Sarasavti river and Kurukhestra and ultimately merging in Runn of Kutch of Kutch. Earlier workers regarded Drishadvati river as one of the tributaries of Sarasvati river meeting it near Hanmangarh. Many workers advocated that Drishadvati river had independent catchment area in Siwaliks, took the course of present Chautang river till Sirsa after which it southern course was not traced. The author, after studying the satellite images of the area between Sirsa and Merta, traced its existence marked by saline lakes of Tal Chhapar, Didwana and Khatu which were formed as local depression after Drishadvati river stopped flowing. Based on the findings of the study of satellite images, author finds Drishadvati river as an independent river flowing on the northern side of Aravail, taking the present course of Luni river and ultimately merging in Runn of Kutch of Kutch with independent delta.

1 illus, 21 ref

006823   Keller G;Sahni A;Bajpai S (Geosciences, Princeton Univ, Princeton. NJ 08544, USA, Email: gkeller@princeton.edu) : Deccan volcanism, the KT mass extinction and binosaurs. J Biosci, Bangalore 2009, 34(5), 709-28.

Recent advances in Deccan volcanic studies indicate three volcanic phases with the phase-1 at 67.5 Ma followed by a 2 m.y. period of quiescence. Phase-2 marks the main Deccan volcanic eruptions in Chron 29r near the end of the Maastrichtian and accounts for <126> 80% of the entire 3500 m thick Deccan lava pile. At least four of the world's longest lava flows spanning 1000 km across India and out into the Gulf of Bengal mark phase-2. The final phase-3 was smaller, coincided with the early Danian Chron 29n and also witnessed several of the longest lava flows. The K.T boundary and mass extinction was first discovered based on planktic foraminifera from shallow marine mtertrappean sediments exposed in Rajahmundry quarries between the longest lava flows of the main volcanic phase-2 and smaller phase-3. At this locality early Danian (zone PI a) planktic foraminiferal assemblages directly overlie the top of phase-2 eruptions and indicate that the masse extinction coincided with the end of this volcanic phase. Planktic foraminiferal assemblages also mark the KT boundary in intertrappean sediments at Jhilmili, Chhindwara, where freshwater to estuarine conditions prevailed during the early Danian and indicate the presence of a marine seaway across India at KT time. Dinosaur bones, nesting sites with complete eggs and abundant eggshells are known from central India surrounding the hypothesized seaway through the Narmada-Tapti rift zone. A Maastrichtian age is generally assigned to these dinosaur remains. Age control may now be improved based on marine microfossils from sequences deposited in the seaway and correlating these strata to nearby terrestrial sequences with dinosaur remains.

12 illus,139 ref

006822   Kaur S;Aggarwal R;Thaman S;Manish Kumar (Soil and Water Engineering Dep, Punjab Agricultural Univ, Ludhiana) : Micro level assessment of water resources-a case study. J Indian Wat Resour Soc 2009, 29(1), 17-21.

Water is most vital input in agriculture and has made a significant contribution in providing stability to food grain production. This resource can be optimally used and sustained only when quantity and quality of water is assessed. Efficient management of water resources relies on a comprehensive database. Thus, the present study was aimed to assess the total available water resources at the block level during Kharif and Rabi season in Ludhiana district and it was calculated that the total available water resource in the district was 619734.0 ha-m out of which 446813.7 ha-m (72%) in Kharif season and 170866.5 ha m (28%) in Rabi season. The maximum water availability is in Jagraon (2.09 m) followed by Ludhiana (1.88 m) and Dehlon (1.76 m) and minimum water availability is in Mangat (1.37 m) followed by Pakhowal (1.46 m) and Sudhar (1.48 m). In Ludhiana district rainfall and ground-water contributes 40% and 50% respectively to the total water resources while the remaining 10% is contributed by canal water.

4 illus, 4 tables, 4 ref

006821   Karmalkar N R;Duraiswami R A;Chalapathi Rao N V;Paul D K (Geology Dep, Pune Univ, Pune-411 005, Email: nrkarmal@unipune.ernet.in) : Mantle-derived mafic-ultramafic xenoiths and the nature of Indian sub-continental lithosphere. J Geol Soc India 2009, 73(5), 657-79.

Mantle derived xenoliths in India are known to occur in the Proterozoic ultrapotassic rocks like kimberlites from Dharwar and Bastar craton and Mesozoic alkali igneous rocks like lamrophyres, nephelinites and basanites. The xenoliths in kimberlites are represented by garnet harzburgites, Iherzolites, wehrlite, oil vine clinopyroxenites and kyanite-eclogite varieties. The PT conditions estimated for xenoliths from the Dharwar craton suggest that the lithosphere was at least 185 km thick during the Mid-Proterozoic period. The ultrabasic and eclogite xenoliths have been derived from depths of 100-180 km and 75-150 km respectively. The Kalyandurg and Brahmanpalle clusters have sampled the typical Archaean subcontinental lithospheric mantle (SCLM) with a low geotherm (35 mW/rn²) and harzburgitic to Iherzolitic rocks with median X _mg^olivin<62> 0.93. The base of the depleted lithosphere at 185-195 km depth is marked by a 10-15 km layer of strongly metasomatised peridotites (X_mg^olivine<62> <126>0.88). The Anampalle and Wajrakarur clusters 60 km to the NW show a distinctly different SCLM; it has a higher geotherm (37.5 to 40 mW/m²) and contains few sub-calcic harzburgites, and has a median X_mg^olivine<62> = 0.925, In contrast, the kimberlites of the Uravakonda and WK-7 clusters sampled quite fertile (median X_mg^olivine<62> <126>0.915) SCLM with an elevated geotherm (<62> 40 mW/m² ). The lamrophyres, basanites and melanephelinites associated with the Deccan Volcanic Province entrain both ultramafic and mafic xenoliths. The ultramafic group is represented by (i) spinel Iherzolites, harzburgites, and (ii) pyroxenites. Single pyroxene granulite and two pyroxene granulites constitutes the mafic group. Temperature estimates for the West Coast xenoliths indicate equilibration temperatures of 500-900°C while the pressure estimates vary between 6-11 kbar corresponding to depths of 20-35 km. This elevated geotherm implies that the region is characterized by abnormally high heat flow, which is also supported by the presence of linear array of hot springs along the West Coast. Spinel peridotite xenoliths entrained in the basanites and melanephelinites from the Kutch show low equilibrium temperatures (884-972°C). The estimated pressures obtained on the basis of the absence of both plagioclase and garnet in the xenoliths and by referring the temperatures to the West Coast geotherm is <126> 15 kbar (40-45 km depth). The minimum heat flow of 60 to 70 mW/m² has been computed for the Kutch xenolith (Bhujia hill), which is closely comparable to the oceanic geotherm. Xenolith studies from the West Coast and Kutch indicate that the SCLM beneath is strongly metasomatised although the style of metasomatism is different from that below the Dharwar Craton.

6 illus, 5 tables, 110 ref

006820   Jothiprakash V;Mohan S (Civil Engineering Dep, Indian Institute of Technology Bombay, Powai, Mumbai-400 076) : Effect of length of inflow data in explicit stochastic modeling approach. J Hydrol 2009, 32(1), 38-58.

An explicit stochastic model (ESM) has been developed for seasonal planning of an irrigation system and was applied to a case study to find the length of inflow data at which the steady state polices stabilizes. The seasonal operational plan for the case study has been derived in two steps (1) generation of synthetic stream flow data (2) derivation of operational policies using stochastic dynamic programming (SDP) model with the transition probabilities estimated from the generated inflow data as well as historical inflow data. The main objective is to find the length of inflow data after which the derived policies stabilizes and become independent of length of inflow data. A comprehensive simulation model was also constructed to evaluate the performance of the policies derived from the optimization model. It is found that the operational policies inferred from the model reached steady state when the length of inflow data used is 60 years or more.

7 illus, 4 tables, 22 ref

006819   Joshi K C;Sengupta S;Kandpal G C (NO, Geological Survey of India, Northern Region, Lucknow-226 024) : Macroseismic study of 20th may 2007 Sikkim earthquake its seismotectonic implications for the region. J Geol Soc India 2010, 75(2), 383-92.

An earthquake of magnitude 5.0 with its epicenter in the West Sikkim district occurred on the evening of 20th May 2007. The macroseismic study revealed an ENE-WSW isoseismal pattern indicating a trend conforming to that of the major tectonic discontinuities in this part of the Himalaya. The relatively moderate event, felt even at far away places like, Siliguri, Darjeeling, etc induced a maximum intensity of VI (MSK) in the form of development of cracks in the walls, fall of thick chunks of plaster in Type A or even Type B-C structures at localities like Tashiding, Ralang, Rabang, Keozing, Sakyong, etc. The study also revealed that the NW-SE trending Tista lineament is playing an important role in the release of the tectonics strain in this region and that the rupture initiated under the influence of the northward directed tectonic stresses at an asperity formed at one of the deeollements within the crust by the intersection of this tectonic discontinuity was interpreted to be responsible for this seismic event.

7 illus, 2 tables, 22 ref

006818   Joshi A;Mohanty M;Teotia S S;Bansal A R;Dimri V P;Chadha R K (Science and Technology Dep, Government of India, New Delhi-110 016) : Crustal attenuation of shearwaves in Pithoragarh region. J Indian Geophys Union 2009, 13(3), 121-32.

The region of Kurnaon Himalaya is one of the seismically active regions of Himalaya. Frequent seismic activities in this region demonstrate the seismotectonic nature of the region. In this paper, necessary efforts are being made to study the attenuation properties of shear wave in Pithoragarh region using the data from strong motion network of eight stations installed in Kumaon Himalaya. In the present work, data of eight events recorded at Dharchula station have been utilized for inversion. The input to the algorithm used in the present work is simply the S phase of acceleration record and the hypocentral distance. The raw data have been processed using different steps like instrumental scaling, baseline correction and filtering. In the present work all records have been filtered using band passed Butter worth filter within ranges. Since the strong motion sites are located in weathered rock terrains, necessary efforts have been made to apply site amplification estimated by H/V spectral ratio techniques of Nakamura (1988) to noise data. Site amplification curves have been prepared which show less amplification at low frequencies compared to high frequencies. Using the inversion algorithm developed by Joshi (2006), the frequency dependent Quality factor(Q) has been calculated which gives Q_β (f) = 63 f^1.25 in frequency range. Stress drop for different events has been calculated using corner frequencies obtained from inversion. The stress drop of events ranges from very low to high value indicating highly unstable tectonic activity. Low value of coefficient (<60> 200) and high frequency dependence (<62>0. 8) in the Q_β (f) relationship suggest that the region is seismically and tectonically active and is characterized by large number of heterogeneities.

7 illus, 3 tables, 36 ref