005686   Dey S;Paul S;Debbarma C;Sarkar P (Geography and Disaster Management Dep, Tripura Univ, Suryamaninagar-799 130, Email: sudip_geo@rediffmail.com) : Experiment on imaging and visualising for assessing late-tertiary microstructural evidences of depositional changes in gajalia fold, South Tripura. J Geol Soc India 2011, 77(4), 367-76.

The present work concentrates on microstructure imaging for visualising the changes of depositional environment during Tertiary period. For that purpose Tipam layers of Gajalia fold area in southern Tripura was selected which was deposited during late Tertiary period under marine-coastal environment. Thin sections of eleven selected samples of the study area were prepared in the laboratory for microstructure analysis. For visualising the crystalline particles or quartz brightness and contrast of the image was increased up to maximum level. Surface conditions of the samples were analysed within RGB combination. The grain size and shapes of the eleven samples tested prove that the depositional environment remained very dynamic through Tertiary period in the study area. The microstructure and surface conditions also strongly support this view.

5 illus, 1 table, 36 ref

005685   Dey R C ('Greenwood' D-7, 315-B Upen Banerjee Road, Kolkata-700 060, Email: raneshdey@gmail.com) : Framework analysis of outer limestone belt(wedges) in Himachal and Haryana Sub-Himalayas. Indian J Geosci 2011, 65(1), 23-38.

The characteristics of a series of detached lensoid outcrops of Proterozoic limestone along the Main Boundary Fault sensu stricto/Main Boundary Thrust (MBF/MBT) in the Sub-Himalayas of Himachal Pradesh (Sataun-Kansar-Nahan sector) and Haryana (Malla-Tundapathar sector), christened the 'Outer Limestone Belt', have been dealt with, particularly the stratigraphic, structural and tectonic aspects. This limestone, as distinguished from the 'Outer Carbonate Belt' (Krol Belt) and the 'Inner Carbonate Belt' (Shali Belt) of the Simla Lesser Himalaya, is coeval with the 'Jammu Limestone' (Proterozoic). The 'Outer Limestone' is an autochthon, sandwiched between the autochthonous Neogene sequence (Lower Siwalik - Nahan) to the south and the para-autochthonous Palaeogene sequence (Lower Tertiary - Subathu) to the north. This limestone formed the basement rock/basin floor for the Subathu sedimentation, and the unconformable relationship between the two is evident from conglomerate at Kansar and pisolitic horizon at Sataun. The Subathu sea gradually narrowing down towards east was restricted, in the-then (palaeo-) topography, by the positives of the basement rock (i.e. 'Outer Limestone') around Sataun and the subsurface Delhi-Hardwar-Harsil (Aravalli-Delhi) Ridge to the east at Kalsi (Uttarakhand). Additionally, the frontal outcrops of the Krol Thrust (KT) (<126> 0.20 Ma) sheet advancing from the north and gradually overriding the Subathu rocks, as also the Chail Thrust (CT), in turn, tectonically overlapping the Krol Thrust, eliminated any possibility of Subathu and 'Outer Limestone' outcrops further east of Bhatrog (Sataun). The active tectonic phase of the MBT (<126> 5.23-4.8 Ma) eliminated parts of the peripheral 'Outer Limestone Belt', thereby rendering discontinuous nature of outcrops (wedge-shaped) in the present-day landscape. Prevalence of basic intrusions within the 'Outer Limestone' and the Subathu sequence around Sataun-Kyari is considered owing to intense shearing, fracturing and faulting in the constricted (MBT-KT/MBT-CT) inter-thrust zone in this part. Some interesting tectonic features are folding of the MBF/MBT, gliding tectonics and 'relief thrust', nano-klippen, nano-outlier, etc. particularly at Malla. Possibility of the 'Outer Limestone' being related to and linked with the Trans-Aravalli Vindhyan (TAV) carbonate sequence (= Bilara Group), west of the Aravalli-Delhi Ridge in northwest Rajasthan, has been touched upon. This aspect, as also the area between Sataun (H.P.) and Kalsi (Uttarakhand), deserves critical attention from different streams of earth science to fill in the gaps in our knowledge.

5 illus, 1 table, 38 ref

005684   Das D P;Pramanik K (Map and Cartographic Div, Central Headquarters, Geological Survey of India, 29, J.L. Nehru Road, Kolkata-700 016, Email: dasdp@hotmail.com) : Evaluation of impact of earthquake and tsunami on the coastal morphology of Andaman-Nicobar Island using multisensor temporal satellite data. Indian J Geosci 2011, 65(1), 9-22.

The giant earthquake of 26 December 2004 triggered large-scale tsunami around the western coast of Sumatra Island has brought about significant morphological changes around Andaman-Nicobar group of islands. The islands located between latitudes 06° 30'N to 13° 45' N and longitudes 92° 10' to 94° E 00' E instantly suffered submergence or emergence of landmass, erosion, deposition and inundation and other shock-induced changes. Study of multisensor temporal satellite data of pre- and post-earthquake period of six months revealed that northwestern part of the Island Belt experienced emergence of landmass while major parts of South Andaman, part of Little Andaman and islands of Nicobar Group suffered submergence. Geomorphological changes associated with emergence include raised reef with appearance of new beach or increase in the width of existing beach, appearance of new islands and drying up of creeks while the changes due to submergence include subsidence of reef with narrowing of beach, disappearance of islands and previously existing land bridges / straits, widening of bays and inundation of low-lying areas and large-scale tsunami deposition of sand. Two curvilinear pivotal zones of 'no-change', sub-parallel to Sunda Trench were delineated across the Island Belt in between the zones of emergence and submergence. Further study for a period of six months following the main shock, established that the uplifted northwestern part of the Andaman-Nicobar Island Belt experienced reverse changes and the southeastern part suffered further submergence due to post-earthquake readjustment while the central part of the belt remained stable.

12 illus, 6 tables, 8 ref

005683   Das A K;Majumdar D (Geology Dep, Asutosh College, 92 S.P. Mukherjee Road, Kolkata-700 026, Email: dipanjan07@gmail.com) : Reappraisal of magnetic susceptibility anisotropy of the precambrian banded haematite jasper rocks of Bonai synclinorium, Orissa to unravel the deformation history. Indian J Geosci 2011, 65(1), 65-78.

Anisotropy of magnetic susceptibility (AMS) of banded haematite jasper (BHJ) of Bonai Synclinorium has been studied to decipher the deformation history and to understand the strain variation in different parts of the synclinorium. AMS and rock-magnetic data from 54 oriented, cylindrical cores drilled at 14 sites and collected from the western and eastern limbs of the synclinorium and hinge portion are documented. Two distinct tectonic fabrics have been identified trending NNE-SSW and WNW-ESE indicating first (Dl) and second order (D2) of deformation respectively. An increase in tectonic contribution to the rock-magnetic fabric of BHJ is observed towards the inner part of the regional synclinorium indicating a higher state of strain development. Principal eigenvectors of maximum and intermediate susceptibility axes are found to align respectively with the northerly-plunging and westerly-plunging folds related to Dl and D2 deformation respectively.

18 illus, 2 tables, 43 ref

005682   Chatterjee A;Bhattacharya A;Mukherjee A; Pramanik T (Geology Dep, Presidency Univ, (Formerly Presidency College), 86/1, College Street, Kolkata-700 073, Email: alokesh@yahoo.com) : Delineation of fire-affected coal mines in Damodar valley, India using thermal remote sensing techniques. Indian J Geosci 2011, 65(3), 229-34.

The Jharia Coalfield of India, one of the famous coking-coal deposits of the Damodar Valley, is well known for its surface and subsurface coal mine fire. As the coal deposits of Damodar Valley are of equivalent geological age and almost similar in composition, there may be a possibility that the other coalfields of Damodar Valley may also be vulnerable to coal mine fires. Hence, the aim of the present study is to find out whether coal fires exist in other coal fields, hitherto unknown, applying space- borne thermal infrared (TIR) remote sensing techniques. Daytime band 6 (both low and high gain) image (thermal band with spectral resolution of 10.40 μm to 12.50 μm) of Landsat Enhanced Thematic Mapper (ETM) has been analysed to identify the coal mine fire. After determining the threshold temperature for the fire and non-fire pixels, it is found that apart from Jharia Coalfield, other important coalfields like Raniganj, East and West Bokaro, North and South Karanpura, and Ramgarh of Damodar Valley are also affected by coal mine fires. Thus, all the coalfields of Damodar Valley, which were deposited under the similar depositional environment at the same time, are also affected by coal-mine fires.

3 illus, 5 tables, 16 ref

005681   Bhattacharya H N;Bhattacharya B (Geology Dep, Presidency Univ, 86/1, College Street, Kolkata-700 073) : Sole marks in storm beds from a glacially influenced late palaeozoic shallow sea, Talchir formation, Talchir basin, India. Indian J Geosci 2011, 65(3), 175-88.

Gutter casts on sandstone bedding undersurfaces of storm-laid sandstone-mudstone heterolithic facies within the Talchir Formation (Permo-Carboniferous), Talchir Basin, India, are oriented perpendicular to the wave ripple crest lines, and are commonly associated with flute casts and different tool marks. Three distinct sets of tool marks are identified based on their mutual orientation with the gutter axis. Type-1 tool marks include gutter-parallel fine groove marks, oriented perpendicular to major wave ripple crest lines. Type-2 tool marks are represented by an association of straight, parallel, sinuous, cross-cutting, recurved and turnabout groove marks, along with bi-directional prod marks, bounce marks, brush marks and chevron marks, which are oriented sub-parallel to the major gutter axis. Type-3 tool marks, dominated by shorter groove marks with a few prod marks, are distinctly gutter-normal and thus, trend sub-parallel to the wave ripple crests. Sole marks trending sub-parallel to wave ripple crests were formed by shore-parallel geostrophic flow in initial storm phases. During intensification of storms, oscillation-dominated shore-normal currents produced gutters, grooves and bipolar-bimodal prod marks and bounce marks at nearly perpendicular or at high angle to the axis of major wave ripple crests. Superposition of shore-normal oscillatory flow on shore-parallel geostrophic currents during peak storms is evident from curvilinear, cross-cutting (and converging) and turnabout groove marks. Hydrodynamic interpretation of these sole marks, interrelationship between palaeogeographic constraints governing the overall sediment dispersal pattern, and the stratification architecture in storm event beds signify complex interplay of mutually perpendicular shore-parallel and shore-normal components of storm current in shallow marine settings.

7 illus, 45 ref

005680   Bagchi J;Kumar R;Sharma S (LHIM and EPE Div, Geological Survey of India, A-II, Pushpa Bhawan, Madangir Road, New Delhi-110 062, Email: bagchij@yahoo.com) : Variability of landslide incidences in India. Indian J Geosci 2011, 65(3), 223-8.

Landslide occurrences are widespread and prolific in India and cover more than 15% of the total area spread over twenty-two states and two union territories. These are mostly concentrated in Himalayas, Arakan-Yoma Belt of northeastern India, parts of Meghalaya Plateau, Nilgiri Hills and Western and Eastern Ghats. An effort has been made through this paper to understand the landslide distribution and evolve a relationship between landslides and rainfall. Database showing spatial and temporal distributions of hazardous landslide events have been taken as the basic input for assessing the impacts of landslides. In the present evaluation, data for two years, from April 2007 to March 2009 has been considered. The data has been collected from investigation reports of Geological Survey of India, media reports and information from some Central and State agencies. There were 445 landslide incidences in 2007-08 and 59 in 2008-09 -maximum of which are rainfall-triggered. The human fatalities for 2007-08 and 2008-09 were 236 and 84 respectively. Analyses revealed that the density of landslide incidences follows the susceptibility zone based on geological and geomorphological parameters. It was also observable that the intensity of landslide and its temporal distribution is correlatable with the progress and intensity of southwest monsoon.

6 illus, 6 ref

005679   Babu Lal (Geological Survey of India, Western Region, Jaipur-302 004, Email: babulal_gsi1@indiatimes.com) : Geophysical characterisation of aquifer and minimisation of impact of urban environment in Vidyadhar Nagar township of Jaipur, India. Indian J Geosci 2011, 65(1), 79-86.

Resistivity surveys in about 3.5 sq km barren land of Vidyadhar Nagar area in Jaipur. Rajasthan (India) in year 1985 produced some interesting results leading to the development of glorious township having high-rise housing complex, multiplex, civil structures, etc. Resistivity survey revealed the presence of potential aquifer saturated with good quality drinking water in the study area. Isopach map of aquifer thickness obtained by resistivity sounding exhibits a nala-type structure along Vdak-Raniji Ki Bavri-Ambabari with increasing thickness towards the south. The cross-section of this nodal zone of aquifer shows that its thickness is about 95m in header side in Udak area in the north. Its thickness increases to about 127m and the span is narrowed in its footer side in Ambabari area in the south. Thereafter it appears to be merged with the Amanishah-Ka-Nala. This nala-type feature in aquifer appears to be an ancient branch which has turned its course towards east in Udak area and joins with the Amanishah-Ka-Nala to the north of Vidyadhar RHB colony, as it exists today. Impact of urban environment causes imbalance of groundwater budget due to cementing of ground surface vis-avis decrease in percolation and simultaneous increase in pumping of groundwater due to urbanisation. Check-dam at header position of nodal zone of aquifer at Udak branch of nala for harvesting of rainwater drained from adjacent hill and harvesting of rainwater flowing from roof, road, other cemented grounds, etc. would help in balancing the recharge and discharge of groundwater in the area.

6 illus, 1 table, 4 ref

005678   Armstrong-Altrin J S;Madhavaraju J;Sial A N; Kasper-Zubillaga J J;Nagarajan R;Flores-Castro K;Rodriguez J L (NO, Instituto de Ciencias del Mar y Limnologia, Mexico, Email: john_arms@yahoo.com) : Petrography and stable isotope geochemistry of the cretaceous EI abra limestone (actopan), Mexico: implication on diagenesis. J Geol Soc India 2011, 77(4), 349-59.

Petrography and stable isotopes (carbon and oxygen) geochemistry of limestones from the El Abra Formation, Actopan, were studied to identify their digenetic environments. The major petrographic types identified are mudstone, wackestone, grainstone, and boundstone. Most of the studied samples show positive δ¹³C values, except two samples (2 and 28), which are slightly negative values (-0.27% and -0.02%o). The organic remains identified in foraminiferal wackestone type can be responsible for the negative δ¹³C values. The δ¹⁸O values range from -12.41%o to -4.02%o and indicate meteoric diagenesis.

8 illus, 1 table, 65 ref

004622   Uniyal A;Ravindran K V;Prasad C (NO, Remote Sensing Applications Centre-UP, Sector-G, Jankipuram, Lucknow-226 021, Email: aniruddhauniyal@yahoo.com) : Tectonic control on alluvial fans, piedmont streams and Ganga river in Western Ganga Plain (India) using satellite remote sensing data. Curr Sci 2010, 99(1), 91-7.

Study pertains to a segment of the western Ganga Plain drained by the River Ganga and its tributaries in the area between Haridwar, Roorkee and Bijnor. Various geomorphic surfaces were identified on the basis of satellite remote sensing data aided by field investigations. The dominant geomorphic surfaces identified are megafan surface (MF), older flood plain (T₁), piedmont fan surfaces, viz. PF₂ (older) and PF₁ (younger), and active flood plain (T₀). The disposition of these geomorphic surfaces and the trends of streams are interrelated and tectonically controlled. Upland terrace surface (T₂), which is the oldest depositional surface of Ganga Plain, is not exposed in this area and it is the reworked MF on which all other surfaces are superposed. The large sized coalescing fans of PF₂ and superposed PF₁ evolved by the deposition of sediments derived from the rising Himalayan and Siwalik ranges. The narrow widths of T₁ and T₀ terrace surfaces of the Ganga and its tributaries are the result of deep incision by these rivers owing to their tectonic control. There are evidences of progressive lateral migrations of the Ganga channel to both directions. The study also indicates that presently the processes of deposition are active mainly on T₀ and upper part of the PF₁.

4 illus, 1 table, 14 ref

004621   Pandey Y;Imtiyaz M;Dhan D (Agricultural Engineering Div, University of Agricultural Sciences and Technology-K, Shalimar-191 121, Email: yogeshpandey2007@gmail.com) : Prediction of runoff and sediment yield of Ninga watershed sone catchment. Envir Ecol 2011, 29(2A), 739-44.

Deterministic geomorphic modeling is the basic tools for prediction of any hydrological behavior of a basin. The magnitude of sediment transported by rivers in major concern for the water resources planning and management. Proper scientific planning and management require detailed data to make reliable predictions. Multivariate statistical technique was applied to develop dimensionally homogeneous and statistically optimal models for predicting the annual runoff and sediment production rate from a small watershed of Sone catchment. The parameters of model ware calculated by multiple regression method using measured runoffs and sediment yield data. The model parameters were determined by five years (1999-2003) data. The performance of model was evaluated by performing the quantitative tests on measured and estimated data. The developed models can be conveniently used to predict the runoff and SPR of small ungauged watershed of Sone catchment and also other region having similar physiographic characteristics.

4 illus, 2 tables, 5 ref

004620   Dutta S K;Prasad V S (NO, National Centre for Medium Range Weather Forecasting, Noida-201 307, Email: surya@ncmrw.gov.in) : Assessment of WRF-Var assimilation for cyclonic storm - Nisha. Curr Sci 2010, 99(1), 86-91.

Study is a case study of cyclonic storm Nisha to assess the impact of cold and cyclic mode assimilation schemes. The results from both the assimilation modes were compared with the results of Weather Research and Forecasting (WRF) simulations initiated with the initial conditions prepared from the global model forecast fields interpolated over the mesoscale model grid. So, the impact of WRF-3DVar assimilation over the numerical simulation of the cyclonic storm Nisha is also highlighted. WRF-3DVar simulations in cyclic mode have produced more intense cyclonic storms with stronger circulations and winds over 850 hPa pressure level and surface. The genesis, intensification and dissipation of the cyclone are better represented by the cyclic runs. The simulation and advection of higher quantity of moisture by WRF analyses in cyclic mode is one of the probable reasons for the over-intensification of the storm. The impact of assimilation is also well highlighted. It is quite evident that the initial conditions prepared through assimilation is superior to the initial conditions directly accepted from the global model forecasts.

7 illus, 6 ref

003566   Unnikrishnan Warrier C;Praveen Babu M (Isotope Hydrology Div, Centre for Water Resources Development and Man, , Kunnamangalam P.O., Kozhikode-673 571, Email: warrier@cwrdm.org) : Comparative study on isotopic composition of precipitation in wet tropic and semi-arid stations across southern India. J Earth Syst Sci 2011, 120(6), 1085-94.

Isotopic composition of monthly composite precipitation samples from Kozhikode (n = 31), a wet tropic station and Hyderabad (n = 25), a semi-arid station across southern India were studied for a period of four years from 2005 to 2008. During the study period, the Kozhikode station recorded an average rainfall of 3500 mm while the Hyderabad station showed an average rainfall of 790 mm. The average stable isotope values in precipitation at the Kozhikode station were δ18O= -3.52%, d-excess = 13.72%; δ18O = -2.94%, d-excess = 10.57%; and δ18O = -7.53%, d-excess = 13.79%, respectively during the pre-monsoon (March-May), monsoon (June-September) and post-monsoon (October-February) seasons. For the Hyderabad station, the average stable isotope values were δ18O = -5.88, d-excess = 2.34%; δ18O = -4.39%, d-excess = 9.21%; and δ18O = -8.69%, d-excess = 14.29%, respectively for the three seasons. The precipitation at the two stations showed distinctive isotopic signatures. The stable isotopic composition of precipitation at the Hyderabad station showed significant variations from the global trend while the Kozhikode station almost followed the global value. These differences are mainly attributed to the latitudinal differences of the two stations coupled with the differences in climatic conditions.

4 illus, 2 tables, 32 ref

003565   Thakur O P;Singh A;Singh B D (NO, Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow-226 007, Email: singhbd.bsip@gmail.com) : Petrogeraphic characterization of Khadsaliya lignites,Bhavnagar district, Gujarat. J Geol Soc India 2010, 76(1), 40-6.

The petrological studies on Khadsaliya lignites from Bhavnagar district have been carried out for their microconstituents characterization. Quantitative estimation of macerals reveal, due to high amount of macerals of huminite group, that this lignite deposits has formed from forest dominated vegetation in a fast subsiding basin, experiencing almost uniform environmental conditions, with slight intermittent fluctuations. The rank based on R_o.max 37 values indicates that lignites are less mature and have not reached the sub-bituminous stage of coalification as those of the lignites from Panandhro (Gujarat) and Neyveli (Tamil Nadu) fields. High pyrite content in the Khadsaliya lignite makes it not much suitable for combustion purpose.

2 illus, 2 tables, 24 ref

003564   Tamilenthi S;Punithavathi J;Baskaran R; Chandramohan K (Earth Science Dep, Tamil University, Thanavur) : Dynamics of urban sprawl, changing direction and mapping: a case study of Salem city, Tamil Nadu, India. Archiv appl Sci Res 2011, 3(1), 277-86.

Urban sprawl refers to the extent of urbanisation, which is a global phenomenon mainly driven by population growth and large scale migration. In developing countries like India, where the population is over one billion, one-sixth of the world's population, urban sprawl is taking its toll on the natural resources at an alarming place.Urban planners require information related to the rate of growth, pattern and extent of sprawl to provide basic amenities such as water, sanitation, electricity, etc. In the absence of such information, most of the sprawl areas lack basic infrastructure facilities. Pattern and extent of sprawl could be dectected with the help of statelite images and temporal data. This is used to analysing the growth, pattern and extent of sprawl. This paper brings out the extent of sprawls directions taking place for the period of nearly three decades using GIS and Remote Sensing.

12 illus, 22 ref

003563   Singh R (NO, SRMS College of Engineering and Technology, Bareilly) : Quality of drinking water in India. Archiv appl Sci Res 2011, 3(1), 444-9.

This review article gives the summary of the available data on the following:- Requirement of water for Indian masses as per Indian Constitution. Contaminants and their limiting values. Toxic limits of contaminants Health risks of contaminants.

3 tables, 8 ref

003562   Singh K N (School of Studies in Earth Science, Vikram University, Ujjain-456 010, Email: singhkn_vikram@yahoo.com) : Coal bed methane potentiality - case studies from Umaria, Korba and Ib-valley coal,s son-Mahanadi basin. J Geol Soc India 2010, 76(1), 33-9.

The Coal Bed Methane (CBM), a dreadful mining hazard, became eco-friendly clean gas for the third world country w en humanity is facing challenges against pollution and energy crisis. It is observed from the studies that the Korba and Ib valley coals have potential for CBM exploration whereas Umaria coals have negligible potential. Though, the Sohagpur coalfields (east of Umaria coalfield) have ample scope of CBM exploration. In the absence of enough desorption data on gas content, the in situ gas content has been determined here following the theoretical interpretation of adsorption curve, taking into account of the moisture, ash, volatile matter, fixed carbon, depth of coal bed and the geothermal gradient. Data generation on gas content, gas saturation and gas sorption characteristics is vital for better definition of high quality coal prospects.

3 illus, 4 tables, 27 ref

003561   Santosh Kumar (Geology Dep, Kumaun University, Nainital-263-002, Email: skyadavan@yahoo.com) : Mafic to hybrid microgranular enclaves in the Ladakh batholith, Northwest Himalaya: implications on calc-alkaline magma chamber processes. J Geol Soc India 2010, 76(1), 5-25.

Felsic magmatisms in the north of Indus-Tsangpo Suture Zone (ITSZ) in Ladakh range of northwest Indian Himalaya, referred herein Ladakh granitoids (LG), and associated magmatic rocks constitute the bulk of the Ladakh batholith. They have been characterized as Andean-type, calc-alkaline, largely metaluminous (I-type) to a few peraluminous (S-type) granitoids derived from partial melting of subducting materials. The LG can be broadly classified into coarseªgrained facies with abundant mafics (hbl-bt), medium-grained facies with low content of mafics, and fine-grained leucocratic facies with very low amount of mafics. Mesocratic to melanocratic, rounded to elliptical, fine to medium grained, mafic to hybrid microgranular enclaves (ME) are ubiquitous in medium to coarse-grained LG. ME are absent or rare in the leucocratic variety of LG. In this paper different types of ME, and their field relation and microstructures with respect to felsic host LG are documented from northwestern, central, southeastern parts of the Ladakh batholith. Rounded to elongate ME of variable sizes (a few cm to metres across, mostly d<60>30 cm) commonly having sharp, crenulate, and occasionally diffuse contacts of ME with felsic host LG suggest that several pulses of crystal-charged mafic and felsic magmas coexisted, hybridized, and co-mingled into subvolcanic settings. Occurrence of composite ME (several small mafic ME enclosed into large porphyritic ME) strongly point to multiple mafic to hybrid magma intrusions into partly crystalline LG magma chambers. Synplutonic mafic dykes disrupted to form subrounded to angular (brecciated) mafic ME swarms commonly disposed in strike-length suggest mafic magma injections at waning stage of felsic magma evolution with large rheological contrasts. Pillowing of mafic melt against leucocratic (aplitic) residual melt strongly suggests mafic magma intrusion in nearly-crystallized condition of pluton. Although common mineral asemblages (hblªbt-pl-kfs-qtz-ap-zrn-mt±ilm) of ME (diorite, quartzdiorite) and host LG (granodiorite, monzogranite) may relate to their cogenetic relation, fine to medium grained porphyritic (hybrid) nature and lack of cumulate texture of ME strongly oppose cognate origin for ME. Presence of plagioclase xenocrysts, quartz ocelli and accicular apatite in porphyritic ME strongly indicate mingling and undercooling of hybridized ME globules into relatively crystal-charged cooler host LG magma. Grain size differences of some ME, except to those of porphyritic ones, appear related to varying degrees of undercooling of ME most likely controlled by their variable sizes. Several smaller ME, however, lack fine-grained chilled margin probably because of their likely disaggregation from a large size ME during the course of progressive hybridization (mingling to mixing) leaving behind trails of mafic schlieren. Field and microstructural evidences at least suggest that Ladakh granitoids and their microgranular enclaves are products of multistage magma mingling and mixing processes concomitant fractional differentiation of several batches of mafic and felsic magmas formed in open magma chamber(s) of subduction setting.

12 illus, 82 ref

003560   Saha A;Ganguly S;Ray J;Dhang A (Geology Dep, University of Calcutta, 35, Ballygunge Circular Road, Kolkata-700 019, Email: jsray65@hotmail.com) : Vanadium bearing titaniferous magnetite ore bodies of Ganjang, Karbi-anglong District, Northeastern India. J Geol Soc India 2010, 76(1), 26-32.

A new occurrence of (syenite-hosted) Vanadium bearing titaniferous magnetite ore body has been reported from Ganjang (26°0935 N 93°20 E), Karbi-Anglong, Northeastern India. The magnetite ore bodies have lumpy and sporadic occurrences within the host syenite pluton intrusive into gneissic country rocks. Ore microscopic studies reveal that magnetite is often associated with haematite and ilmenite depicting different textural patterns. Critical consideration of several elemental patterns suggests magmatic differentiation to be main ore-forming process. The ore body is suggested to have been formed as late stage segregation from a differentiating alkaline magma in a fluid enriched milieu.

7 illus, 2 tables, 32 ref

003559   Odeyemi A T;Ojo M A (Microbiology Dep, University of Ado Ekiti, Ekiti State, Nigeria) : Microbiological, physicochemical and mineral studies of fadama soil in Ekiti state of Nigeria. Archiv appl Sci Res 2011, 3(1), 192-202.

The bacteriological and mineral analysis of fadama (wetland) soil samples from Ado-Ekiti, Ifaki-Ekiti and Ikere-Ekiti in Ekiti State were determined. Total bacterial counts were determined using pour plating method while the mineral content was known using Atomic Absorption Spectrophotometry. Total bacterial count ranged between 1.71 x 10¹⁰ 2.96 x 10¹¹ cfu/ml. The percentage distribution revealed Escherichia coli with 28.6% of soil sample from Ado-Ekiti having the highest frequency while Pseudomonas spp (5.7%) of the same sample and Salmonella spp (5.7%) of soil sample from Ikere-Ekiti having the lowest frequency. The mineral parameters had the following values: sodium (62.4 to 91.98mg/l), potassium (64.88 to 93.12mg/l), calcium (62.53 to 71.49mg/l), magnesium (70.53 to 85.6mg/l), zinc (1.40 to 3.15mg/l), iron (1.73 to 3. 05mg/l), lead (0.02 to 0.03mg/l), copper (0.1 to 0.65mg/l), manganese (0.8 to 1.33mg/l). Unwanted substances may be deposited on fadama soil as a result of environmental pollution due to run off of heavy rainfall. Soil depth does not have significant effect (at 0.05) on the mineral composition of the fadama soil samples analyzed. There are significant differences (at 0.05) in correlation between the bacteria count and some minerals such as sodium, potassium and manganese with respect to the location of sample collection. Though the presence of some minerals in higher amount in the fadama soil may lead to increase in bacterial load and help the organisms in degrading wide variety of organic material which will eventually lead to high yield productivity of agricultural products from fadama soil.

4 illus, 6 tables, 13 ref

003558   Niyogi A;Pati J K;Patel S C;Panda D;Patil S K (Earth and Planetary Sciences Dep, University of Allahabad, Allahabad-211 002, Email: jkpati@yahoo.co.in) : Anthropogenic and impact spherules: Morphological similarity and chemical distinction - A case study from India and its implications. J Earth Syst Sci 2011, 120(6), 1043-54.

Provides first report of silica-rich anthropogenic spherules of varying colour, shape, size, surface texture and chemical composition found in road-deposited sediments (RDS) of Allahabad city, Uttar Pradesh, India. Morphological details and lithophile elemental composition of the silica-rich spherules are compared to microtektites and impact spherules from India to demonstrate their striking morphological similarities and chemical variability. This study suggests the need to use spherule data carefully while assigning an impact origin to spherule-finds or spherule-bearing lithological horizons.

4 illus, 2 tables, 46 ref

003557   Nedelea A;Comanescu L (Faculty of Geography, Geomorphology-Pedology Dep, Bucharest University, 010041, No. 1, N. Balcescu Avenue, Bucharest, Romania, Email: lauracomanescu@yahoo.com) : Present day relief-shaping systems acting on the southern slope of the Fagaras Mountains (Romania). J Earth Syst Sci 2011, 120(6), 1023-32.

The present topography of the Fagaras Mountains is a snapshot of the long-term evolution that brought about significant alterations of the landscape, and especially of the relief, which has acquired different features depending on the intensity of the relationship between the exogenous and endogenous agents. At present, relief shaping in the study area is controlled by the orographic and climatic features. However, the climate of the high and middle-height mountains is the main cause that determines the mechanism, the intensity and the spatial distribution of the shaping processes. The considerable height of the Fagaras Mountains, which exceeds 2500 m altitude is responsible for the vertical zonation of climate and vegetation which implicitly induce the setting of the systems of relief modelling, too.

7 illus, 31 ref

003556   Mousavi S M;Alavi A H;Gandomi A H;mollahasani A (Geography and Urban Planning Dep, Faculty of Humanities and Social Sci, Islamic Azad University, Tehran, Iran, Email: ah_alavi@hotmail.com) : Nonlinear genetic-based simulation of soil shear strength parameters. J Earth Syst Sci 2011, 120(6), 1001-22.

New nonlinear solutions were developed to estimate the soil shear strength parameters utilizing linear genetic programming (LGP). The soil cohesion intercept (c) and angle of shearing resistance (φ) were formulated in terms of the basic soil physical properties. The best models were selected after developing and controlling several models with different combinations of influencing parameters. Comprehensive experimental database used for developing the models was established upon a series of unconsolidated, undrained, and unsaturated triaxial tests conducted in this study. Further, sensitivity and parametric analyses were carried out. c and φ were found to be mostly influenced by the soil unit weight and liquid limit. In order to benchmark the proposed models, a multiple least squares regression (MLSR) analysis was performed. The validity of the models was proved on portions of laboratory results that were not included in the modelling process. The developed models are able to effectively learn the complex relationship between the soil strength parameters and their contributing factors. The LGP models provide a significantly better prediction performance than the regression models.

16 illus, 6 tables, 54 ref

003555   Mathur V S;Chaturvedi D D (NO, Tata Chemicals Ltd., Babrala) : Water footprint assessment-TCL Babrala. Indian J Fertil 2011, 7(6), 26-34.

Global water scarcity is an emerging risk that all industries need to focus on and all stakeholders need to be informed. The rising global population, rapid economic growth in developing countrie and climate change combined together is triggering enormous water availability challenges for the world. Power plants, fertilise industries, and other water-intensive industries are especially vulnerable, both in their operations and their extensive supply chains. It is believed that wasteful uses of water are likely to become increasingly questioned and subjected to increased regulatory intervention. There appear to be growing expectations on the par of shareholders and other key stakeholders that industries and business should handle environmental, social and governance (ESG) issues proactively, and water availability in right quality and quantity is a sustainability issue for the humanity. Tata Chemicals at Babrala plant has adopted a focused approach on conservation of natural resources, particularly water and natural gas. A process based environment management system with proper measurements, monitoring and reviews has resulted into sustained and improved water footprint.

7 illus, 1 table, ref

003554   Maitra M;David J S;Bhaduri S (Central Petrological Laboratories, Geological Survey of India, , Kolkata-700 016) : Melanite garnet-bearing nepheline syenite minor intrusion in Mawpyut ultramafic-mafic complex, Jaintia Hills, Meghalaya. J Earth Syst Sci 2011, 120(6), 1033-41.

Mawpyut igneous suite in Jaintia Hills of Meghalaya plateau comprises differentiated suite of ultramafic-mafic rocks. The complex differs from other ultramafic-alkaline-carbonatite igneous emplacements of Shillong plateau and Mikir Hills like Jesra, Sung, Samchampi complexes, by the absence of alkaline-carbonatite rocks as major litho-units. Melanite garnet-bearing nepheline syenite, occurs as late phase minor intrusion in Mawpyut igneous complex, posseses alkaline character and shows inubiquitous relation with the host ultramafic-mafic rocks. On the other hand, this alkaline intrusive bodies of the Mawpyut igneous complex shows chemico-mineralogical resemblance with garnet-bearing nepheline syenite, ijolite litho-members of Jesra, Sung, Samchampi complexes of the region. It is interpreted that melanite garnet-bearing nepheline syenite intrusion in Mawpyut is contemporaneous with Jesra, Sung, Samchampi ultramafic-alkaline-carbonatite complexes and the host rocks of Mawpyut complex is an earlier magmatic activity possibly from a comparatively least enriched source.

7 illus, 5 tables, 38 ref

003553   Kathal P K;Singh V K (Centre of Advanced Study in Geology, Dr. H.S. Gour University, Sagar-470 003, Email: pkkathal@rediffmail.com) : First report of some ecent benthic foraminifera from the east coast of India. J Geol Soc India 2010, 76(1), 69-74.

Twelve Recent benthic foraminiferal species hitherto not reported from the east and west coasts of India are presented and illustrated. They are, namely- Bolivina semicostata, Elphidium subgranulosum, Hanzawaia nipponica, Planorbulina variabilis, Pseudononion japponicum, Reussella haizwnensis, Rosalina bradyi, Adelosina sp., Lagina sp. A, Lagina sp. B, Uvigerina sp. A and Uvigerina sp. B.

1 illus, 1 table, 22 ref

003552   Humane S K;Chaurpaga S N;Humane S S;Kundal P (Postgraduate Geology Dep, RTM Nagpur University, Law College Square, Nagpur-440 001, Email: sumed.humane@gmail.com) : Dasycladalean algae and their depositional environments in the Sylhet limestone formation (Lower-middle eocene), Bengal basin. J Geol Soc India 2010, 76(1), 75-85.

Avery rich and diversified dasycladalean algal assemblage has been discovered from the Sylhet Limestone Formation (lower-middle Eocene) of the Bengal Basin of India for the first time. The depositional environments of the Sylhet Limestone Formation have been discussed based on the presence of the 11 species of the dasycladalean algae belonging to the three families Dasycladaceae (Cymopolia inflataramosa Segonzac, C. mayaenese Johnson and Kaska, C. paronai Raineri, Cymopolia sp.), Triploporaceae (Dissocladella lunata Segonzac, Dissocladella sp., lodotella sloveniaensis Deloffre and Radoicic) and Acetabulariaceae (Clypeina socanensis Deloffre and Radoicic, Clypeina sp., Terquemella sp., Neomeris sp.). The lower Eocene Sylhet Limestone Formation revealed predominance of dasycladalean algal assemblage with the halimedacean and udoteacean algae and rare occurrence of coralline algae. This suggests their luxuriant growth in the open lagoonal to shelf environment at the depth of 5-6 m in the warm waters. There is a gradual decrease in the dasycladalean species and genera in the middle Eocene Sylhet Limestone Formation. The predominance of coralline algae associated with the Sporolithon indicates that the limestone of middle Eocene Sylhet Limestone Formation have been deposited at the littoral to shallow, high energy open shelf marine environments at a depth of about 40-60 m in warm tropical waters.

1 illus, 1 tables, 34 ref

003551   Chowksey V;Maurya D M;Joshi P;Khonde N;Das A; Chamyal L S (Geology Dep, The M. S. University of Baroda, Vadodara-390 002, Email: lschamyal@yahoo.com) : Lithostratigraphic development and neotectonic significance of the Quaternary sediments along the Kachchh Mainland Fault (KMF) zone, western India. J Earth Syst Sci 2011, 120(6), 979-99.

The Kachchh Mainland Fault (KMF) is a major E-W trending seismically active fault of the Kachchh palaeorift basin whose neotectonic evolution is not known. The present study deals with the eastern part of the KMF zone where the fault is morphologically expressed as steep north facing scarps and is divisible into five morphotectonic segments. The Quaternary sediments occurring in a narrow zone between the E-W trending KMF scarps and the flat Banni plain to the north are documented. The sediments show considerable heterogeneity vertically as well as laterally along the KMF zone. (The Quaternary sediments for a northward sloping and are exposed along the north flowing streams which also show rapid decrease in the depth of incision in the same direction.) The deposits, in general, comprise coarse as well as finer gravelly deposits, sands and aeolian and fluvial miliolites. The Quaternary sediments of the KMF zone show three major aggradation phases. The oldest phase includes the colluvio-fluvial sediments occurring below the miliolites. These deposits are strikingly coarse grained and show poor sorting and large angular clasts of Mesozoic rocks. The sedimentary characteristics indicate deposition, dominantly by debris flows and sediment gravity flows, as small coalescing alluvial fans in front of the scarps. These deposits suggest pre-miliolite neotectonic activity along the KMF. The second aggradation phase comprises aeolian miliolites and fluvially reworked miliolites that have been previously dated from middle to late Pleistocene. The youngest phase is the post-miliolite phase that includes all deposits younger than miliolite. These are represented by comparatively finer sandy gravels, gravelly sands and sand. The sediment characteristics suggest deposition in shallow braided stream channels under reduced level of neotectonic activity along the KMF during post-miliolite time evidenced by vertical dips of miliolites and tilting of gravels near the scarps. The tectonically controlled incision and dissection of the Quaternary deposits is the result of neotectonic activity that continues at present day. The overall nature, sedimentary characteristics and geomorphic setting of the sediments suggest that the KMF remained neotectonically active throughout the Quaternary period.

11 illus, 38 ref

003550   Chaurasia S (Earth, Ocean, Atmosphere, Planetary Sciences and Applications Area, Sp, , ) : Development of regional wheat VI-LAI models using resourcesat-1 AWiFS data. J Earth Syst Sci 2011, 120(6), 1113-25.

Time of forcing of spatial LAI to crop models at single or multiple stages is important to simulate crop biomass and yield in varying agro-climatic conditions and scales. The high temporal resolution (5-day) by Advanced Wide Field Sensor (AWiFS) on-board Resourcesat-1 Satellite IRS-P6 with 56 m spatial resolution and large swath (740 km) has substantially increased the availability of regional clear sky optical remote sensing data. The present study aimed at developing empirical vegetation index VI-LAI models for wheat using AWiFS optical data in four bands and in-situ measurements sampled over five different agro-climatic regions (ACRs) during 2005-2006 followed by validation during 2006-2007. While nonlinear relations exist for all the three normalized indices such as normalized difference vegetation index (NDVI), normalized difference water index (NDWI) and Green NDVI, linear relation was the best fit for ratio vegetation index (RVI). Both NDVI and RVI models generally showed better correlation ranges (0.65-0.84 for NDVI and 0.37-0.76 for RVI) than other indices. The common NDVI-LAI model was found to produce lower root mean square errors (RMSE) between 0.5 and 1.1 from pooled model than those between 0.5 and 1.32 from regional models. The rate of substantial increase in errors from NDVILAI model (RMSE of modelled LAI: 0.85 to 1.28) as compared to RVI-LAI model (RMSE of modeled LAI: 1.12 to 1.17) at LAI greater than 3, than below 3 revealed the early saturation of NDVI than RVI. It is therefore recommended that LAI estimates can be used to force crop simulation model up to early vegetative stage based on NDVI and maximum vegetative to reproductive stages based on RVI.

8 illus, 5 tables, 37 ref

002302   Zaidi F K (SGS Chair on Natural Hazards, Geology and Geophysics Dep, College of Science, King Saud Univ, P.O.Box 2455, Riyadh-11451, Saudi Arabia, Email: fzaidi@ksu.edu.sa) : Drainage basin morphometry for identifying zones for artifical recharge: a case study from the Gagas river basin, India. J Geol Soc India 2011, 77(2), 160-6.

Drainage basin morphometry is a quantitative way of describing the characteristics of the surface form of a drainage basin and provides important information about the region's topography and underlying geological structures. It plays an important role in hydrogeological investigations for delineating zones of adequate groundwater potential and selecting sites for construction of artificial recharge structures. In the present study an attempt was made to discover the stream properties in the Gagas River Basin of Almora district in the state of Uttarakhand using the various stream attributes. Based on the study the potential zones for the construction of artificial recharge structures in the basin were identified.

3 illus, 5 tables, 18 ref

002301   Sinha K K;Pandey P;Bhairam C L;Parihar P S (NO, Atomic Minerals Directorate for Exploration and Research, West Block VII, R.K. Puram, New Delhi-110 067, Email: sinhakk63@gmail.com) : Peperite occurrence and its implications on origin and temporal development of the proterozoic Dhala basin, Mohar area, Shivpuri district, Madhya Pradesh. J Geol Soc India 2011, 77(2), 183-9.

In the western part of Bundelkhand massif, a caldera with intra-caldera sediments, known as Dhala Formation, occurs as an outlier in and around Mohar village of Shivpuri district, Madhya Pradesh. For the first time, occurrence of peperite is being reported from the basal part of the Dhala sediment. Two types of peperites have been recognized: blocky and fluidal or globular with variable morphology. In peperitic zones, features like soft sediment deformations, presence of sediment into the rhyolite along cracks, vesiculation of the sediments and other evidences suggestive of sediment fluidization are some definite characteristics of interaction of hot magma with wet sediments forming peperite. The occurrence of peperites reflects the contemporaniety of deposition of the Dhala sediments and volcanism, which is well in accordance to the volcanic origin of Dhala structure. Further, the nature of unconformity between the Dhala and overlying Kaimur which is characterized by merely a few centimeter thick pebbly/conglomeratic bed does not appear to represent a large hiatus as expected between the Semri and Kaimur of Vindhyan Supergroup. So, the contemporaniety of the Dhala Formation (at least the lower part) as reflected by occurrence of peperites, coupled with the available age of the rhyolite and the nature of the unconformity between the Dhala and overlying Kaimur provide convincing evidence to correlate the Dhala Formation with the Lower part of the Kaimur and unlikely with the Semri Group or Bijawar as proposed earlier.

3 illus, 20 ref

002300   Singh T;Sharma U;Awasthi A K;Virdi N S; Ravindra Kumar (NO, CSIR-Centre for Mathematical Modelling and Computer Simulation, Bangalore-560 037, Email: tejpal@cmmacs.ernet.in) : Geomorphic and structural evidences of neotectonic activity in the sub-Himalayan belt of Nahan salient, NW India. J Geol Soc India 2011, 77(2), 175-82.

Neotectonism in the Sub-Himalayan belt is not new. Moreover, the word' Sub-Himalaya' is almost synonymous with 'neotectonic activity'. In the present paper, we report some of the most convincing geomorphic and structural evidences of neotectonic activity from the Sub-Himalayan belt in the Nahan Salient. The geomorphic evidences mainly include the four geomorphic surfaces identified from the transverse topographic profiles drawn parallel to the Himalayan front. These surfaces are commonly covered with terrace deposits that are tilted as well as faulted at a number of places. A number of faults, directly observable in the field, are normal in nature and they are oriented at high angles to the Himalayan Frontal Thrust (HFT). These faults are similar to the E-W extension in southern Tibet in response to the oblique convergence of India at <126> N20°E in the NW Himalaya. They are attributable to the kinematics of neotectonic compression along the HFT, the frontal ramp-oblique ramp-frontal ramp geometry of the thrust fault and related adjustments.

5 illus, 1 table, 17 ref

002299   Singh B P;Srivastava A K (Geology Dep, Banaras Hindu Univ, Varanasi-221 005, Email: bpsingh_in@yahoo.com) : Storm activities during the sedimentation of late paleocene-middle eocene subathu formation, Western Himalayan foreland basin. J Geol Soc India 2011, 77(2), 130-6.

Late Paleocene-middle Eocene Subathu Formation represents the earliest deposits of the western Himalayan foreland basin. A large part of this formation is comprised of impure limestone and grey shale intercalations. The limestones contain sole marks, intraformational conglomerates, hummocky cross stratification and wave ripples. The occurrence of sole marks suggests that they are developed by the unidirectional currents at the initial phase of the storm that resulted erosion and subsequent deposition. The intraformational limestone conglomearate also suggests erosion of the earlier deposited limestone hardgrounds as a consequence of storm associated transgression. The hummocky cross stratification formed by the oscillatory flows during the long-shore littoral drift. The depth of formation of the hummocky cross stratified limestone facies was less than 40 m and most likely deposited between shore-face to backshore regions of the gulf similar to present day Persian Gulf. The identification of deeper facies (shelf facies) from Pakistan and coastal facies from India suggest that the gulf was open from the west and closed from the east.

4 illus, 37 ref

002298   Singh B P (Center for Advanced Study in Geology, Panjab Univ, Chandigarh-160 014, Email: v_ruh@rediffmail.com) : Paleobiogeography, paleoecology and paleoenvironmental significance of the cambrian trilobites from the Zanskar region (Zanskar-Spiti-Kinnaur basin), Northwest Himalaya. J Geol Soc India 2011, 77(3), 219-26.

In study the newly recorded latest Middle Cambrian trilobite fauna from the Cambrian succession of the Zanskar region of Zanskar-Spiti-Kinnaur Basin (Tethyan Himalaya) is analyzed critically to assess relationships with other Cambrian faunal elements of equatorial peri-Gondwanaland. The identification of genus Neoanomocarella, Parablackwelderia, Kunmingaspis, Fuchouia, Damesella and Dorypyge from the Cambrian of the Zanskar region and their comparison with those of South China and Australia is significant. It constitutes the basis for assessing the paleobiogeographic affinities during the Cambrian. The latest Middle Cambrian trilobite fauna from Zanskar shows proximity of Indian margin with that of southwest China "outboard" micro-continent. The recovery of analogous Middle Cambrian species i.e., Dorypyge perconvexlis, Fuchouia bulba, Fuchouia cf. oratolimba, Parablackwelderia sp. and Damesella sp. from the Zanskar region (Tethyan Himalaya) suggests a contiguous close proximity with south China and Australia during the latest Middle Cambrian, which supports the model of Meert and Van der Voo (1997) for assembly of Gondwanaland. The presence of Kunmingaspis in Zanskar and similar reports from northwestern Yunnan-Tibetan region, northern Henan, central and southeastern Hubei, north China, western Xinjiang and Yangtze platform reveal a close affinity between the Indian margin and the Yangtze platform during the Middle Cambrian. The trilobite fauna indicates the deeper shelf-shallow slope environment of deposition under fluctuating conditions of relative sea-level. The faunal elements of the Lejopyge acantha and Proagnostus bulbus zones indicate that the sea inundated the nortnern margin of Zanskar region during the latest Middle Cambrian time (Teta transgression) which is synchronous with globally recognized eustatic events during Lejopyge laevigata Zone.

2 illus, 1 table, 71 ref

002297   Seshunarayana T;Rajendra Prasad B;Prasad A S S S R S;Mysaiah D (National Geophysical Research Institute (CSIR), , Uppal Road, Hyderabad-500 007, Email: rajbitragunta@yahoo.com) : Subsurface structure derived from detailed gravity and magnetic investigations along the Pala-Maneri traverse of the main central thrust, NW Himalaya. J Geol Soc India 2011, 77(3), 213-18.

Detailed, integrated gravity and magnetic study across the Main Central Thrust (MCT) along the Pala-Maneri traverse in Uttaranchal, NW Himalaya was carried out. The gravity data was acquired using a CG-3 gravity meter with an accuracy of 0.005 mGal, while magnetic data was acquired using a proton precession magnetometer with a station interval of 20 m. Data was collected along a 11.7 km, NE-SW traverse from Pala to Maneri along the proposed route of a hydroelectric headrace tunnel. The measured variation in the gravity field was approximately 70 mGal, with two prominent highs recorded at distances of 0.5 km, 7.5 km and lows at 3.0 km, 10.5 km from Maneri. The gravity highs can be attributed to presence of high-density rocks along the thrust planes. The sharp gravity low recorded at 10.5 km distance possibly indicates a sympathetic fault of the MCT that is highly saturated with fluids (water). The broad gravity low between 2.5 km and 4.0 km distance is likely to represent the gravity signature of the MCT itself. The measured variation in the magnetic field was approximately 285 nT. The associated gravity and magnetic signatures located several faults along the traverse including presence of the MCT at Kumaltigad.

4 illus, 9 ref

002296   Saikia C;Ahmad A H M;Wasim S M (Geology Dep, Aligarh Muslim Univ, Aligarh-202 002, Email: aligsyed@gmail.com) : Facies controlled diagenetic evolution of the Delhi group sandstones, Bayana basin, Rajasthan. J Geol Soc India 2011, 77(3), 261-8.

The Bayana Basin forms the eastern most limit of north Delhi fold belt covering parts of northeastern Rajasthan. The deposition of sediments took place during middle Proterozoic in fluvial and shallow marine environments. The rocks are mainly elastics and include conglomerate, sandstone and shale. During mechanical compaction rearrangement of grains took place and point and long contacts were formed. The sandstones are cemented by iron oxide, silica, carbonate and barite. The porosity has developed due to dissolution of iron, carbonate cement and feldspar grains. Dissolution of quartz along grain boundaries and silica rich compaction pore water seems to be the main source of silica. These observations suggest progressive compaction which initiated at the sediment water interface and continued till deep burial diagenesis in a rapidly subsiding basin.

6 illus, 1 table, 17 ref

002295   Ravikant V;Golani P R (Institute Instrumentation Center, Indian Institute of Technology, Roorkee-247 667, Email: ravikant.vadlamani@gmail.com) : Rb-Sr direct dating of pyrite from the pipela VMS Zn-Cu prospect, Rajasthan, NW India. J Geol Soc India 2011, 77(2), 149-59.

In unaltered volcanogenic massive sulfide (VMS) ore deposits, variable Rb/Sr ratios in the ore mineral permits application of the Rb-Sr isotopic method to directly date the time of ore formation. In contrast, post-crystallization deformation and metamorphism would open the system to metamorphic fluids that would alter elemental ratios. To test whether the Rb-Sr isotopic systematics in the ore minerals had preserved the formation time in the <126> 800 Ma metamorphosed VMS ores within the <126> 1 Ga Ambaji-Sendra arc terrain, Rajasthan, NW India, common sulfides, pyrite and sphalerite from the Pipela Cu-Zn prospect, were analyzed for their geochemistry and Rb-Sr isotopic systematics. Trace and rare earth elements in these minerals are resident probably at crystal defects, whereas all inclusions (including those from metamorphic fluids) were removed by a simple crush leach method. Results of direct dating by the Rb-Sr method to the hydrothermal pyrite yielded an isochron age of 1025 ± 76 Ma with an initial Sr ratio of 0.7051±0.0006, similar to previously determined zircon U-Pb age of 987 Ma from associated rhyolites. This suggests the applicability of the crush leach method to date formation time of metamorphosed pyrite ores.

5 illus, 3 tables, 36 ref

002294   Pawar B A;Pandarkar A K;Shendge A N (Zoology Dep, P.V.P. College, Pravaranagar, Tal.Rahata, Ahmednagar-413 713) : Water quality of Pravara river in relation to pisciculture, Ahmednagar district, Maharashtra. J expl Zool 2011, 14(2), 651-5.

The present work deals with the water quality of Pravara river In Ahmednagar district, Maharashtra during July 2008 to June 2009 in order to assess its suitability for pisciculture. Various physico-chemical parameters determined reveals that seasonal fluctuations in water temperature, dissolved oxygen, pH and nitrite in all the season were within the favourable limits for fish and fisheries practices. However, very low level of alkalinity during winter to summer at station-I, chloride during all the season at station-I and III and during winter and monsoon at station-II, hardness during summer at station-I, calcium in all the season at all the stations and magnesium during all the season at station-I and III and during monsoon at station-II and high level of alkalinity during post-monsoon at station-II, chloride during summer at station-II, hardness during post-monsoon and summer at station-II and phosphate during winter to monsoon at all the stations were recorded. These parameters need to be modifying in order to favour the fish culture.

1 illus, 1 table, 19 ref

002293   Naithani N P;Bhatt M (Geology Dep, H.N.B. Garhwal Campus Univ, Badshahi Thaul, Tehri-Garhwal-249 199, Email: naithaninp60@rediffmail.com) : Drainage basin morphometric analysis and its relationship with altitude of Uttarkashi district. J appl nat Sci 2012, 4(2), 167-71.

Area of investigation lies between Maneri and Gangnani along the Bhagirathi river in the lesser and central Himalayan block of Garhwal Himalayas. The rocks of Garhwal group are represented by quartzites, sericite quartzite's and talc chlorite schist intruded by metabasics, whereas the Central crystallines are constituted by gneisses, schists, migmatites and amphibolites. For the purpose of drainage basin morphometric analysis 100 third order drainage basins were marked. Drainage basin morphometric parameters of 100 basins were calculated. On the basis of lithology and tectonic setup, the area was divided into three morphogenetic units viz Central crystallines, Thrust zone and Garhwal group. The basins which were situated below 2500 mts are categorized under low altitudes and above 2500 as basins: of higher altitudes. The relationship between deainage basinmorphometric parameters and altitude suggest that basins situated at higher altitude have higher value of stream frequency, number of first and second order streams, fine texture and low drainage density.

2 illus, 2 tables, 19 ref

002292   Mukhopadhyay S;Ray J;Chattopadhyay B;Sengupta S;Ghosh B;Mukhopadhyay S (Geology Dep, Calcutta Univ, 35, Ballygunge Circular Road, Kolkata-700 019, Email: jsray65@hotmail.com) : Significance of mineral chemistry of syenites and associated rocks of Elagiri complex, southern granulite terrane of the Indian shield. J Geol Soc India 2011, 77(2), 113-29.

The Elagiri complex (12°31' N: 78°35' E) represents one of the important silica - oversaturated syenite plutons of the Southern Granulite Terrane of the Indian shield. This article for the first time reports the mineral chemistry of the Elagiri complex and brings out important petrogenetic significance. The litho-members of Elagiri complex are intrusive into high grade country rocks viz. granite gneiss, amphibolite and pyroxene granulite. The country rocks are foliated bearing evidences of multiple folding and deformation. On the other hand, the constituent litho members of the Elagiri complex (syenites, gabbro and later intrusives marked by lamprophyre and carbonatite) show preservation of igneous layering in terms of discernible parallelism of the constituent minerals. The Elagiri complex shows presence of sharp contacts among litho members and marked absence of chilled facies peripheral to the margin. Electron microprobe data have been critically used to systematize the constituent mineral-phases of the different lithomembers of the complex. Geothermobarometric data indicate a temperature of equilibration in the range of <126> 700° to 500°C at <126> 2.0 to 5.2 kb which corresponds to shallow level (cf. 18.2 km) equilibration-depth of the complex. Field observations and mineral chemistry data suggest that liquid immiscibility plays an important role during the evolution of the Elagiri complex.

11 illus, 8 tables, 91 ref

002291   Mahesh P;Bansal A;Kundu B;Catherine J K; Gahalaut V K (National Geophysical Research Institute, Council of Scientific and Industrial Research, Hyderabad-500 007, Email: vkgahalaut@yahoo.com) : Mw 7.5 2009 Coco earthquake, North Andaman region. J Geol Soc India 2011, 77(3), 243-51.

The recent 10 August 2009 Coco earthquake (Mw 7.5), the largest aftershock of the giant 2004 Sumatra Andaman earthquake, occurred within the subducting India plate under the Burma plate. The Coco earthquake nucleated near the northwestern edge of the 2004 Sumatra-Andaman earthquake rupture under the unruptured updip segment of the plate boundary interface. The earthquake with predominant normal motion on approximately north-south to northeast-southwest oriented plane is very similar to the 27 June 2008 Little Andaman earthquake which occurred in the South Andaman region near the trench. We provide the only available estimate of coseismic offset due to the 2009 Coco earthquake at a survey-mode GPS site in the north Andaman, located about 60 km south of the Coco earthquake epicentre. The not so large coseismic displacement of about 2 cm in the ESE direction is consistent with the earthquake focal mechanism and its magnitude. We suggest that, like the 2008 Little Andaman earthquake, this earthquake too occurred on one of the approximately north-south to northeast-southwest oriented steep planes of the obliquely subducting 90°E ridge which was reactivated in normal motion after subduction, under the favourable influence of coseismic and ongoing postseismic deformation due to the 2004 Sumatra-Andaman earthquake. Another notable feature of this earthquake is its relatively low aftershock productivity. We suggest that the earthquake occurred very close to the aseismic region of the Irrawaddy frontal arc of very low seismicity where pre-existing faults are not so critically stressed and because of which the earthquake could trigger only a few aftershocks in its immediate vicinity.

6 illus, 2 tables, 21 ref

002290   Lokho K;Raju D S N;Azmi R J (NO, Wadia Institute of HImalayan Geology, 33 GMS Road, Dehra Dun-248 001, Email: kapesa@wihg.res.in) : Paleoenvironmental and biostratigraphic significance of uvigerinids and other foraminifera from the Bhuban formation, Assam-Arakan basin, Mizoram. J Geol Soc India 2011, 77(3), 252-60.

Planktic and benthic foraminifera including uvigerinids are documented from the Upper Bhuban Formation, exposed at Thingdawl village, Kolasib district, Mizoram. The foraminiferal assemblage is poorly preserved and consists of index fossils useful for precise biochronology and interpretation of the depositional environment. A total of ten benthic and six planktic foraminiferal species are described. Six species belong to the genus Uvigerina, four to Ammonia, one species each of Globorotalia, Globigerinoides, Clavatorella, Praeorbulina and two species of the genus Orbulina. Based on lithological and foraminiferal assemblage, middle neritic to upper part of outer neritic paleobathymetry is inferred for the deposition of this part of the Upper Bhuban Formation. The foraminiferal assemblage suggests late Early Miocene to early Middle Miocene, (<126> 16 Ma) equivalent to planktic foraminiferal zones N8-N9 for the Upper Bhuban Formation.

3 illus, 41 ref

002289   Jha N;Pauline Sabina K;Tewari R;Mehrotra N C (NO, Birbal Sahni Institute of Palaeobotany, 53, Road Univ, Lucknow-226 007, Email: paulinesabina@gmail.com) : Palynological dating and correlation of surface and subsurface sediments from Wardha valley coalfield, Maharashtra. J Geol Soc India 2011, 77(2), 137-48.

42 genera of palynomorphs have been reported from the qualitative and quantitative analysis of the palynoflora from both open cast mine and bore holes viz., Ballarpur open cast mine, Durgapur open cast mine and Bore hole CMWNM-57 on barrier between Kawadi/Majri open cast and Hindustan Lalpeth Colliery from the Wardha valley coalfield of Wardha basin. Two palynoassemblages have been recorded i.e., an Upper Karharbari palynoassemblage comprising dominance of radial monosaccate genus Parasaccites and subdominance of nonstriate disaccate genus Scheuringipollenites and a Lower Barakar palynoassemblage consisting of dominance of Scheuringipollenites and subdominance of striate disaccates chiefly Faunipollenites, suggesting an Early Permian age (Late Sakmarian to Early Artinskian) to the sediments. It is further authenticated by the occurrence of palynotaxa viz., Crucisaccites, Caheniasaccites, Indotriradites and Tiwariasporis. Upper Karharbari Formation has been demarcated for the first time in lithologically designated Barakar Formations in Ballarpur, Durgapur, Majri and Hindustan Lalpeth Colliery while the sample 57/2 of bore hole CMWNM from Kawadi area may belong to the Kamthi Formation on the basis of pinkish yellowish coarse grained to medium grained sandstone. An attempt has been made to correlate these palynoassemblages with other Lower Gondwana basins of Early Permian affinity.

5 illus, 49 ref

002288   Gupta M C;Singh B K;Singh K N (NO, Water Resources Dep, Narmada-Tapti, Indore-452 001) : Engineering geological rock mass classificayion of Punasa tunnel site, Khandwa district, Madhya Pradesh. J Geol Soc India 2011, 77(3), 269-72.

Systematic rock mass characterization is an integral part of rock engineering practices. In the present scenario several classifications are in used for rock mass characterization for tunnelling. The present paper discusses engineering geological investigations carried out for Punasa tunnel, a part of Narmada Sagar project. The horse shoe shaped tunnel is 3675.25 m long and 9 m in diameter. This straight and free flow tunnel has been constructed in basaltic lava flows erupted during Cretaceous to Eocene age, belonging to poor to fair rock mass rating (RMR) and extremely poor to good in tunnel quality (Q-system). The values of RMR and Q-system ranges from 29 to 74 and 0.0825 to 13.33 respectively.

4 tables, 12 ref

002287   Duarah B P;Phukan S (Geological Sciences Dep, Gauhati Univ, Guwahati-781 014, Email: bpduarah@yahoo.com) : Understanding the tectonic behaviour of the Shillong plateau, India using remote sensing data. J Geol Soc India 2011, 77(2), 105-12.

Shillong Plateau in India is tectonically and geologically interesting entity in the subducted front of Indian Plate below Burmese Plate to the southeast and Tibetan Plate to the north and associated with thrusts and shears along the plate boundaries. Horse-tail geometry in the foothills of the Arunachal Himalaya, east of Jia Bhareli river, associated with south-convex foothill ranges in the eastern Himalaya and exactly similar structural geometry in the eastern part of Shillong Plateau in Meghalaya seems to develop due to resistance received by the plateau in its eastward journey. Wide separation of Karbi Anglong Plateau and Shillong Plateau to the southeast as compared to northwestern part defines the shape of Kopili graben. Low seismic activity in southeastern part of Shillong Plateau might be related to stress released field generated by its clockwise rotation. Satellite derived images and digital elevation data from Landsat ETM+ and SRTM data shows that the central part of Shillong Plateau possesses young topography with strong structural fabrics along with relatively high topography aligning NE-SW following Kolkota-Pabna-Mymansingh High and if extended passes through western part of Arunachal Pradesh in eastern Himalayas. This alignment has been observed in Precambrian gneissic complex west of the Proterozoic intracratonic Shillong Basin. The epicentral plot for the period 1918 to 2009 shows their high concentration within the Shillong Plateau aligning along this trend. The active geodynamics of Shillong Plateau is reflected in its seismic activity pattern in relation with the structural fabrics, northward migration of the Brahmaputra in the north front of the Plateau and by shrinking pattern of Chandubi Lake in the Kulsi river catchment, a north-flowing tributary of the Brahmaputra in the north-central part of the plateau.

7 illus, 17 ref

002286   Debala Devi L;Ibotombi Singh N (Geology Dep, D.M. College of Science, Imphal-795 001, Email: debala_lois@yahoo.com) : Geochemical study of peridotites from the Manipur ophiolite complex, Northeast India with special reference to their PGE concentration. J Geol Soc India 2011, 77(3), 273-9.

The peridotites of the Manipur Ophiolite Complex (MOC) have been examined based on mineral chemistry, major elements and PGE contents. They represent high-magnesian cumulates with Mg<35> <62> 0.90 (Mg/Mg+Fe) in olivine and Cr<35> <62> 0.12 (Cr/Cr+Al) in spinel. High Mg* contents of the olivine show that these rocks are most likely derived from partial melting of the residual upper mantle. The peridotites contain higher concentration of Palladium Group PGE (PPGE) (Rh=4.4-6.6ppb; Pd=336-458ppb and Pt=14.6-36.4ppb) than the Iridium Group PGE (IPGE) (Os=2.4-5.8ppb; Ir=3.2-4.16ppb and Ru=5.2-7ppb). These are characterized by overall enrichment of PGE concentration (Σ PGE=365.8 - 516.6 ppb) and high ratio of (Pt+Pd)/(Os+Ir+Ru). This suggests that the rocks are formed by partial melting and crystal fractionation of olivine-rich (picritic) magma.

3 illus, 4 tables, 27 ref

002285   Choudhary A K;Jain A K;Singh S;Manickavasagam R;Chandra K (Institute Instrumentation Centre, Indian Institute of Technology Roorkee, Roorkee-247 667, Email: akc.iitr@gmail.com) : Crustal accretion and metamorphism of mesoarchean granulites in Palghat-Cauvery shear zone, Southern India. J Geol Soc India 2011, 77(3), 227-38.

This work provides unequivocal evidence of the existence of Mesoarchean granulite facies metamorphic event in the Palghat-Cauvery Shear Zone (PCSZ) of South India. Charnockite samples from two prominent hills at Kollaimalai (KM) and Pachchaimalai (PM) as well as from two quarries within the Bhavani Shear Zone (BSZ) have been analyzed for their Sm-Nd and Rb-Sr ages to investigate the existence or otherwise of the Archean granulite facies events within the PCSZ. The Rb-Sr whole-rock isochron ages for massive charnockites from both the hills appear to be contemporaneous at 2.9 Ga with the initial Sr isotopic ratios of 0.7012 and 0.7014, respectively. However, the Rb-Sr data for whole-rock samples of basic granulites from one of the quarries within the BSZ indicate open system behavior, while the charnockites from the other quarry have insufficient spread in ⁸⁷Rb/⁸⁶ Sr ratios and do not yield any isochron. The Sm-Nd data, on the other hand, do not distinguish between the massive charnockite and the lowland charnockite and yield Depleted Mantle model ages in the range 2.98±0.3 Ga for all of them. The ε ^T CHUR for all of these rocks are highly positive. Both the Sr isotopic ratios and positive ε ^T CHUR values for these rocks strongly suggest a mantle source for all of them. An upper age limit of<126> 3.28 Ga may be assigned to the crustal accretion of the protolith of all these rocks on the basis of their Nd model ages. The Rb-Sr isochron ages of 2.9 Ga for the two massifs could be the age of granulite facies metamorphism. Thus, the metamorphism in the KM and PM Hills took place within <126> 100 Ma of crustal accretion of these rocks and probably was part of the same geological event of crust formation and metamorphism. The open system behavior with respect to Rb-Sr isotopes in the basic granulite from Bhavani is possibly due to the migration of Sr isotopes, triggered during the later shearing of these rocks.

6 illus, 2 tables, 53 ref

001520   Zume J T;Tarhule A A (Geography and Earth Science Dep, Shippensburg Univ, 1871 Old Main Drive, Shippensburg, PA 17257, USA, Email: jtzume@ship.edu) : Modelling the response of an alluvial aquifer to anthropogenic and recharge stresses in the United States Southern great pains. J Earth Syst Sci 2011, 120(4), 557-72.

Used Visual MODFLOW to simulate potential impacts of anthropogenic pumping and recharge variability on an alluvial aquifer in semi-arid northwestern Oklahoma. Groundwater withdrawal from the aquifer is projected to increase by more than 50% (relative to 1990) by the year 2050. In contrast, climate projections indicate declining regional precipitation over the next several decades, creating a potential problem of demand and supply. The following scenarios were simulated: (1) projected groundwater withdrawal, (2) a severe drought, (3) a prolonged wet period, and (4) a human adjustment scenario, which assumes future improvements in water conservation measures. Results indicate that the combined impacts of anthropogenic pumping and droughts would create drawdown of greater than 12 m in the aquifer. Spatially, however, areas of severe drawdown will be localized around large-capacity well clusters. The worst impacts of both pumping and droughts will be on stream-aquifer interaction. For example, the projected aquifer pumpage would lead to a total streamflow loss of 40%, creating losing stream system regionally. Similarly, a severe drought would lead to a total streamflow loss of <62>80%. A post-audit of the model was also carried out to evaluate model performance. By simulating various stress scenarios on the alluvial aquifer, this study provides important information for evaluating management options for alluvial aquifers.

8 illus, 2 tables, 48 ref

001519   Westaway R;Mishra S;Deo S;Bridgland D R (MCT, The Open Univ, Abbots Hill, Gateshead NE8 3DF, United Kingdom) : Methods for determination of the age of pleistocene tephra, derived from eruption of Toba, in Central India. J Earth Syst Sci 2011, 120(3), 503-530.

Tephra, emplaced as a result of Pleistocene eruption of the Indonesian 'supervolcano' Toba, occurs at many localities in India. However, the ages of these deposits have hitherto been contentious; some workers have argued that these deposits mark the most recent eruption (eruption A, ca 75 ka), although at some sites they are stratigraphically associated with Acheulian (Lower Palaeolithic) artefacts. Careful examination of the geochemical composition of the tephras, which are composed predominantly of shards of rhyolitic glass, indicates that discrimination between the products of eruption A and eruption D (ca 790 ka) of Toba is difficult. Nonetheless, this comparison favours eruption D as the source of the tephra deposits at some sites in India, supporting the long-held view that the Lower Palaeolithic of India spans the late Early Pleistocene. In principle, these tephra deposits should be dateable using the K-Ar system; however, previous experience indicates contamination by a small proportion of ancient material, resulting in apparent ages that exceed the true ages of the tephras. We have established the optimum size-fraction in which the material from Toba is concentrated, 53-61 μm. and have considered possible origins for the observed contamination. Also demonstrate that Ar-Ar analysis of four out of five of our samples has yielded material with an apparent age similar to that expected for eruption D. These numerical ages, of 809 ± 51, 714 ± 62, 797 ± 45 and 827 ± 39 ka for the tephras at Morgaon, Bori, Gandhigram and Simbhora, provide a weighted mean age for this eruption of 799 ± 24 ka (plus-or-minus two standard deviations). However, these numerical ages are each derived from no more than 10-20% of the argon release in each sample, which is not ideal. Nonetheless, our results demonstrate that it is feasible, in principle, to date this difficult material using the Ar-Ar technique; future follow-up studies will therefore be able to refine our preparation and analysis procedures to better optimize the dating.

11 illus, 6 tables, 114 ref

001518   Venkatesh B;Nandagiri L;Purandara B K;Reddy V B (NO, National Institute of Hydrology, Hanuman Nagar, Belgaum-590 001, Email: bvenki30@yahoo.com) : Modelling soil moisture under different land covers in a sub-humid environment of western ghats, India. J Earth Syst Sci 2011, 120(3), 387-98.

Objective of this study is to apply and test a simple parametric water balance model for prediction of soil moisture regime in the presence of vegetation. The intention was to evaluate the differences in model parameterization and performance when applied to small watersheds under three different types of land covers (Acacia, degraded forest and natural forest). The watersheds selected for this purpose are located in the sub-humid climate within the Western Ghats, Karnataka, India. Model calibration and validation were performed using a dataset comprising depth-averaged soil moisture content measurements made at weekly time steps from October 2004 to December 2008. In addition to this, a sensitivity analysis was carried out with respect to the water-holding capacity of the soils with the aim of explaining the suitability and adaptation of exotic vegetation types under the prevailing climatic conditions. Results indicated reasonably good performance of the model in simulating the pattern and magnitude of weekly average soil moisture content in 150 cm deep soil layer under all three land covers. This study demonstrates that a simple, robust and parametrically parsimonious model is capable of simulating the temporal dynamics of soil moisture content under distinctly different land covers. Also, results of sensitivity analysis revealed that exotic plant species such as Acacia have adapted themselves effectively to the local climate.

8 illus, 4 tables, 32 ref