008015   Prakasa Rao B S;VasudevaRao P H;Jaisankar G; Amminedu E;Satyakumar M;Kotewsara Rao P (Geo-Engineering Dep, College of Engineering, Andhra Univ, Visakhapatnam-530 003) : Interlinking of river basins: a mega harvesting plan. J Indian Geophys Union 2010, 14(1), 31-46.

Water availability is becoming dearer and dearer day by day in India due to monsoon vagaries and increasing population propulsion. Linking of basins through canals is not a new concept, but has been in practice since times immemorial. Inter-basin water transfer was primarily envisaged by Rao and Dastur in 1970s. The President of India, Abdul Kalam gave a shot in the arm early in 2003 to the issue of linking of rivers. Ultimately the National Water Development Authority (NWDA) made thorough study, which indicated that Himalayan Rivers, have exceedingly surplus quantum of water and hence, proposed transfer of water from these surplus basins to deficit basins in peninsular region. We opine that the areas of dry land to be converted into a wetland, and the areas of unproductive land to be converted into agriculture land are far more than the land to be lost due to canals and reservoirs. Moreover, increase in the number of crops per year or the cropping intensity also increases along the link canals and the rivers to be linked. It is an environmentally sound and sustainable, technically feasible and socially acceptable measure, also to control inundation and floods through dense afforestation of the river banks. It reduces siltation too. Thus, the economic and ecological benefits far outweigh the feared losses.

^iia38 ref

008014   Patel R P;Patel K;Singh A K;Singh R P (Physics Dep, M.M.H. College, Ghaziabad-201 009, Email: abhay_s@rediffmail.com) : Simultaneous observation of VLF and VHF wave in the presence of ionospheric irregularities. J Indian Geophys Union 2010, 14(1), 139-18.

The propagation of electromagnetic waves through the ionosphere in the presence of irregularities is differently affected in different frequency ranges. Very high frequency waves are scattered whereas very low frequency waves are guided through the ducts formed by the irregularities under suitable conditions. To study these effects, we have analyzed VLF and VHF waves recorded at Varanasi during the period January 1991 to December 1999. VLF waves from natural lightning discharges and VHF amplitude scintillations of signals at 250 MHz transmitted from FLEETSAT geostationary satellites have been used. The occurrence rate of VLF waves is low and sporadic and they are generally observed during nighttimes. The VHF scintillations at Varanasi are also generally observed during nighttimes. The whistler waves generally propagated along the magnetic field lines, which is dipolar and lies in the ionosphere for the Varanasi station. A correlation study of these two simultaneously recorded signals has been carried out. The recorded events of VLF whistlers/emissions and VHF scintillations are largely uncorrelated. However, there are a number of days when these two events are simultaneously observed. Analysis of these correlated events show that at time and under certain suitable conditions, the ionospheric irregularities may help VLF wave propagation and also cause scattering of VHF signals resulting into either weak or strong scintillations.

4 illus, 1 table, 29 ref

008013   Panda G;Jain S K;Vijay S K;Gwal A K (Physics Dep, Space Science Laboratory, Barkatullah Univ, Bhopal-462 026, Email: gopal_panda007@yahoo.com) : Study of ionospheric perturbations during turkey-central earthquake of December 20, 2007. J Indian Geophys Union 2010, 14(2), 133-8.

Deals with variation of foF2 (critical frequency) in F-region of ionosphere before seismic shock of Turkey-Central earthquake on December 20, 2007. A statistical analysis of variation in foF2 before earthquake has been presented. We analyzed foF2 data using bound method. The observed anomalous changes related to geomagnetic disturbances are filtered out (using Dst index). Assuming the remaining disturbances are due to earthquake which may be used as an earthquake precursor.

6 illus, 2 tables, 25 ref

008012   Onkari Prasad;Singh O P;Subramanian S K (NO, , 43 Ritu Apartments, A-4 Paschim Vihar, New Delhi-110 063, Email: onkariprasad06@yahoo.com) : Seasonal forecast of southwest monsoon rainfall district level. J Indian Geophys Union 2010, 14(2), 93-113.

An empirical model has been proposed for district level seasonal forecast of rainfall during southwest monsoon season. Results relating to meteorological subdivision of Tamilnadu and Pondicherry are discussed. Cloud and rainfall data for a period of 36 years (1972-2008 except 1978) have been used in the study. It has been shown that different features of cloudiness over near equatorial regions of Indian Ocean during pre-monsoon months of April and May contain signals indicating likely performance of subsequent southwest monsoon. These features have been quantified by assigning an index called South Indian Convergence Zone ( SICZ ) Activity Index ( SAI ). SAI varies from 1 to 20. Verification of the forecasts has shown that the proposed model is capable of producing 'Useful' forecasts of seasonal rainfall for meteorological sub-division of Tamilnadu and Pondicherry and its districts.

8 illus, 11 tables, 24 ref

008011   Murthy D V N S;Sarma D D (NO, Bankatlal Badruka College for Information Technology, Kachiguda, Hyderabad, Email: donepudi_murthy@yahoo.co.in) : Estimation of parameters of a stationary stochastic process and sample optimization with special reference to gold mineralisation at shallow depths. J appl Geochem 2009, 11(2), 166-82.

Formation of mineral deposits by geological process(es) may be thought of as a discrete stochastic process Z(x): x e D, which may either be stationary or non-stationary. In the case of gold mineralization process, samples drawn at regular interval may be considered as a discrete stochastic process. Estimation of mineral value properties can be performed employing statistical methods, time-series analysis or by carrying out geostatistical structural analysis. In geostatistical structural analysis, a suitable semi-variogram model fit is first obtained and then, utilizing these estimated parameters of the fitted function, estimation of either point or block value is carried out employing kriging - an optimal estimation procedure.

9 illus, 10 tables, 19 ref

008010   Mohanty P R (Applied Geophysics Dep, Indian School of Mines, Dhanbad-826 004, Email: priyamohanty@hotmail.com) : Imaging subsurface geological features with seismic migration-a numerical study. J Indian Geophys Union 2010, 14(1), 15-20.

The seismic data recorded at the surface are processed in a complex sequence of steps among which seismic migration plays an important role. This paper presents an overview of the Phase Shift (PS) and Phase Shift Plus Interpolation (PSPI) wave equation migration methods applied to various geological models. PS time migration and PSPI depth migration schemes are applied to a syncline, anticline, graben and complex salt dome structures. It is observed that the PSPI migration method works well for all the structures in terms imaging and accuracy as compared to PS migration.

4 illus, 4 ref

008009   Manikyamba C;Khanna T C;Prachiti P K;Raju K (NO, National Geophysical Research Institute, Uppal Road, Hyderabad-500 606, Email: cmaningri@yahoo.com) : High-Mg magmas of diverse diverse tectonic settings-examples from the greenstone belts of Dharwar craton, India. J appl Geochem 2009, 11(2), 315-27.

Komatiites and boninites are two distinct types of high-Mg magmas generated at diverse tectonic settings and are common at different times in the geological time scale. Though both these rock types have similar high-Mg content komatiites exhibit unique spinifex texture whereas boninites lack it. Their source, depth of melting, pressure, temperature, fluid pressure and associated rock types are different which ultimately reflect on their diverse geodynamic setting and origin. They exhibit diverse geochemical characteristics except elevated Mg<35>. Komatiites of both Al-depleted and undepleted types are present in different greenstone belts all over the world. They exhibit chondritic Al/Ti <126>20, high Mg<35>, (Gd/Yb)_N ≥ 1 and depleted to flat LREE relative to HREE with negative to positive anomalies of Nb (Ta) and Zr (Hf). They are inferred to have been generated by high degree dry melting of a plume source at greater depth in the majorite stability field. Unlike komatiites, boninites have distinctive geochemical composition with high Al₂O₃/TiO₂ (30-60), high Mg<35>, low CaO/Al₂O₃, characteristic U-shaped REE patterns with low concentration of MREE and negative anomalies of Nb, Ta, Ti. They are formed by low pressure fluid fluxed melting of metasomatized refractory peridotitic mantle wedge in a subduction zone complex. The greenstone belts of western Dharwar craton have predominant occurrence of high-Mg basalts and komatiites whereas in the eastern Dharwar craton, boninites represent high-Mg magmas at some places. The presence of these two distinct rock types in Meso - Neoarchean greenstone belts reflects on the geothermal conditions prevalent during the Archean. It is widely recognized that Archean mantle was hotter than modern mantle and underwent extensive melting (mantle plume activity) which resulted in faster generation of oceanic crust. Due to faster spreading of the oceanic crust, its consumption also took considerably less time (20-60 Ma). These conditions favored the generation of boninites at late Archean convergent margins. Due to high temperature, the subducting slab melted, provided fluids/ melts to the mantle wedge that eventually melted at shallow depth to generate boninites. Therefore, it is suggested that hotter Archean mantle was subjected to frequent plume activity that gave rise to komatiites and Oceanic Island Basalts (OIB) in intraplate setting, while the thick oceanic lithosphere which got subducted (at low angle) produced boninites and calc-alkaline sequences in intraoceanic arc environment.

5 illus, 1 table, 35 ref

008008   Malik R;Sarkar S;Mukherjee S;Gwal A K (Physics Dep, Space Science Laboratory, Barkatullah Univ, Bhopal-462 026, Email: sslakg@gmail.com) : Ionospheric variability during geomagnetic storms. J Indian Geophys Union 2010, 14(1), 47-56.

The dual frequency Global Positioning System (GPS) receivers provide an opportunity to determine Total Electron Content (TEC) over the crest of equatorial ionization anomaly region Bhopal by taking advantage of the dispersive nature of the ionospheric medium. The TEC values observed for eight geomagnetic storms of the period 2004-2005 is used in this paper to discuss the behaviour of ionospheric total electron content (TEC) during geomagnetically disturbed periods. Variation of TEC is studied in correlation with the geomagnetic index Dst and southward component of interplanetary magnetic field Bz. The main purpose of this study is to know how TEC varies from its average values with geomagnetic storms. The TEC variability is found to vary between 49%-104% with the maximum negative excursion of Dst index during the geomagnetic storms days. Positive phases are observed for all the storms studied. Maximum TEC variability is observed during the recovery phase of the storms. The study of storm time TEC behaviour is very important due to recent increase in satellite-based navigation applications.

5 illus, 1 table, 32 ref

008007   Lisha P A;Kumar P K Pradeep;Jayakumar K V (NO, Centre for Water Resources Development and Management, P.O. Kunnamangalam, Kozhikode-673 571) : Rainfall pattern in northern Kerala. J Indian Wat Resour Soc 2010, 30(1), 10-20.

Available daily rainfall data for 81 years (1901 - 1969, 1990 - 1996 and 2001 - 2005) of five stations Kannur, Kozhikode, Quilandy, Vythiri and Vadakara in northern Kerala have been transformed into annual, southwest monsoon, northeast monsoon and non monsoon components for each year and analyzed for a study of the rainfall behaviour. Regression analysis of southwest monsoon rainfall and annual rainfall showed a variation in intercept from 734.60 to 1153.86 and in slope from 0.87 to 1.07 with standard error of estimate varies from 282.93 to 389.82. Correlation analysis shows the variation in coefficient from 0.80 to 0.95. Maximum values of annual and southwest monsoon rainfall yield a parallel behaviour. Average annual and southwest monsoon rainfall values also yield a parallel behaviour. Overall southwest monsoon rainfall is 76.99% of annual rainfall in the area of study. The variation of annual and southwest monsoon rainfall show a regular pattern in increase or decrease.

12 illus, 8 tables, 13 ref

008006   Li X;Zhao T (School of Mathematical Science, Soochow Univ, Suzhou, Jiangsu-215006, People's Republic of China, Email: xhli@suda.edu.cn) : Weakly normal subrgoups of finite groups. Indian J pure appl Math 2010, 41(6), 745-53.

A subgroup H of a group G is weakly normal in G if H^g ≤ N_G(H) implies that g ∈ N_GH. In this paper, authors shall obtain some characterizations about the supersolvability and nilpotency of G by assuming that some subgroups of prime power order of G are weakly normal in G.

10 ref

008005   Kumar T J R;Balasubramanian A;Kumar R S; Manokaran K (Earth Sciences Dep, Annamalai Univ, Annamalainagar-608 002, Email: tjeyavel@rediffmail.com) : Hydrogeochemical study on deeper aquifers of Chittar, Chittar-Uppodai subbasin, Tambaraparani river basin, Tirunelveli district, Tamil Nadu. J appl Geochem 2009, 11(2), 266-75.

Chittar-Uppodai is a sub-basin of Tarnbaraparani river basin of Tirunelveli District, Tamil Nadu. To evaluate the groundwater quality of the deeper aquifers, 53 ground water samples were collected from bore wells during June 2004. The important physical parameters like pli, EC, and major cations and anions were analysed for the present study. The study shows that the average ionic concentration of different parameters like pH, EC, TDS and TH are 7,1779 microsiemens/cm, 1246 mg/l and 447 mg/l respectively. Similarly, the average ionic concentration of cations Ca., Mg, Na, K and anions Cl. SO₄, HCO₃, NO₃ are 122 mg/l, 35 mg/l, 74 mg/l, 4 mg/l and 369 mg/l, 63 mg/l, 278 ma/1, 7 mg/l respectively. According to the Scholar classification, all the 53 samples come under the water type III (rCl <62> rSO₄ <62> r HCO₃). According to Stuyfzand classification, about 35%, 28%, 17%, 18%, and 2% samples have been identified with the fresh, brackish- chloride, Oligohaline. Fresh-Brackish and Brackish-Salt chloride types category respectively. About 11% of samples are above the maximum permissible limit which described in the drinking water quality standard of ISI. Further, the groundwater samples were interpreted with the U.S. Salinity Laboratory diagram. It falls with C₁S₁, C₂S₁ C₃S₁ C₃S_n and C₄S₂ category respectively. In the study area, apart from the present level of ionic concentration from natural sources such as host rock, sewage tank and improper human waste disposal, agricultural practice and application of fertilizers also could have contributed certain extent.

5 illus, 2 tables, 31 ref

008004   Khatri T B;Shah D N;Mishra N (Conservation and Sustainable Use of Wetlands in Nepal (CSUWN), Training Section Building, Second floor, Forestry Complex, Babar Mahal, Kathmandu, Nepal) : Post-flood status of the endangered Ganges river dolphin Platanista gangetica gangetica (Cetartiodactyla: Platanistidae) in the Koshi river, Nepal. J Threatened Taxa 2010, 2(13), 1365-71.

The breach of the eastern embankment of the Koshi Barrage at Paschim Kusaha Village of Sunsari District on 18 August 2008, created havoc for wildlife and their habitats, as well as people's livelihood and welfare. The Koshi River flowed through the breach for five months. Following the breach, a population assessment survey of the Endangered Ganges River Dolphin Platanista gangetica gangetica was made between March and November 2009 in the Koshi River main channel starting from Chatara to 2km south of Koshi Barrage to ascertain their status. A direct count survey was conducted by two teams of researchers simultaneously searching for animals by boat from Chatara to the Koshi Barrage including the Triyuga River and on foot along the river banks downstream of Koshi Barrage and along the Mariya River. Standard protocols were followed to record the number of sighted dolphins. A total of 11 dolphins were recorded in the entire 49-km river stretch with an encounter rate of 0.23 dolphins per km. The current result showed an encouraging population of dolphins in the Koshi Tappu Wildlife Reserve and its buffer zone but the threats for conservation still remain challenging. Close monitoring of dolphins and their habitats involving local communities are required for long term conservation of the river dolphins in Nepal.

008003   Khanna T C;Manikyamba C;Subba Rao D V; Prachiti P K;Raju K (NO, National Geophysical Research Institute, Uppal Road, Hyderabad-500 606, Email: cmaningri@yahoo.com) : Geochemistry and petrogenesis of gadwal kimberlites, eastern Dharwar cration, India. J appl Geochem 2009, 11(2), 328-46.

Siddanpalli kimberlites occur within the granites that surround the Neoarchean Gadwal greenstone belt. Fresh samples have been analysed from three pipes of this area for estimation of bulk-rock major and trace element geochemistry. Olivine is predominantly present as macrophenocrysts, microphenocrysts and groundmass. Groundmass is essentially serpentene and carbonates in which calcite. ilmenite, perovskite, apatite, spinel and other opaques are present. These kimberlites are rich in MgO (24-28 wt.%.) at 30-36 wt.%. SiO₂ with a range of CaO between 9.5 - 15.2 wt.%. The presence of perovskite and ilmenite is reflected in high concentration of TiO₂ Given the high Mg<35> (83-85), the concentration of Ni, Cr, Co, Sc and V remains very low while the large ion lithophile elements (LILE; Ba. Sr) are enriched relative to high field strength elements (HFSE; Zr, Nb). Though there are slight differences in LILE and HFSE contents, the samples from these three distinct pipes display unique coherence and have highly fractionated chondrite normalized REE patterns (La/Yb <61> 106-119); their trace element patterns exhibit significant negative Rb, U, Sr, Zr, Hf and Ti anomalies that are interpreted to be a characteristic feature of the primary magma despite the mobile nature of Rb and Sr. Contamination Index for Siddanpalli kimberlites ranges from 1.13-1.42 ruling out the probability of any significant crustal contamination during the ascent of kimberlite magma to the surface. Whole-rock Rb-Sr isochron gave an emplacement age of 1093 ± 4 My for Siddanpalli kimberlites. Even though the kimberlite occurrence in this area is exposed in three different locations, their chemical compositions indicate melting of a similar/same source. Their coherent behaviour in terms of LILE, HFSE and REE and their resemblance to Group I kimberlites is consistent with their derivation from the melting of a deeper mantle source. The Neoarchean subducted lithospheric slabs, evidenced by the predominance of island arc volcanic rocks in the greenstone belts of Eastern Dharwar craton (EDC), appear to have mixed with the asthenospheric mantle at the transition zone and their geochemical signatures are identified in the Siddanpalli kimberlites of EDC.

7 illus, 1 table, 58 ref

008002   Jha D K;Dass A;Saravanane N;Abdul Nazar A K; Kirubagaran R (National Institute of Ocean Technology, Ministry of Earth Sciences, Port Blair-744 103, Email: dilipjha75@yahoo.com) : Sensitivity of GIS-based interpolation techniques in assessing water quality parameters of Port Blair bay, Andaman. J Mar Biol Ass India 2010, 52(1), 55-6.

The surface water parameters such as temperature, salinity, conductivity, dissolved oxygen, pH and turbidity of Port Blair bay, Andaman & Nicobar Islands were measured in situ over 104 sampling points using a digital multi-parameter water quality instrument and a Global Positioning System (GPS) during high tide. These parameters were subsequently interpolated over the entire bay using three methods, viz., Inverse Distance Weighted (IDW), Spline and Kriging. The interpolated values over the sampling points were compared with the corresponding measured values by means of three statistical indices: Mean Absolute Error (MAE), Root Mean Square Error (RMSE) and Index of Agreement (d). It was found that among the three interpolation methods, IDW method showed better matching between the measured and interpolated values for four out of six parameters whereas Kriging method showed better results for the remaining two parameters with lower MAE and RMSE values, and higher values of 'd'. This paper describes the details of interpolation methods and its suitability to assess water quality parameters in the bay. In addition, it also highlights the capability of GIS as a tool to model spatial changes in environmental systems.

3 illus, 1 table, 9 ref

008001   Jena S K;Tiwari K N;Pandey A (NO, Directorate of Water Management, (Formerly WTCER) (ICAR), Chandrasekharpur, Bhubaneswar-751 023) : Runoff estimation by distributed curve number technique using remote sensing and GIS. J Indian Wat Resour Soc 2010, 30(1), 31-8.

A study was undertaken to compare composited and distributed Curve Number (CN) techniques for estimation of runoff from a medium size agricultural watershed namely Tarafeni (West Bengal). Indian remote sensing satellite digital images were used for classifying the land use/ land cover of the study watershed. The study watershed was divided into grids and weighted CN was calculated for individual grids by intersecting the grid with CN coverage. Using distributed CN technique runoff was simulated at each grid and averaged at the outlet of the watershed and finally compared with the values obtained from traditional compositing technique. The different initial abstractions (IJ of 0.2S and O.BS (S is the maximum potential retention) have also been taken in different simulations and results were compared with the observed runoff. The study revealed that there is definite increase in runoff value estimated by distributed CN technique over composited technique. The amount of increase in runoff value calculated is more for the case of I_a=0.3S than I_a-0.2S. The percent increase in runoff is very high for small events, moderate for medium and low for high rainfall events. The results from statistical analysis, which includes percent deviation, model efficiency, coefficient of determination, coefficient of residual mass, root mean square error and student's t-test for significant difference, show that distributed CN with I_a=0.2S estimated runoff values are closely matching the observed runoff.

3 illus, 23 tables, 19 ref

008000   Jayabalan M;Gowthaman A T;Mohan C;Suresh R; Thamaraichelvi S (Geology Dep, Government Arts College, Salem-636 007) : Petrological and geochemical characteristics of ultramafic rocks of Salem and Dharmapuri districts, Tamil Nadu. J appl Geochem 2009, 11(2), 183-98.

Petrological and geochemical characteristics along with the platinum group element (PGE) content of the ultramafic rocks (dunite, peridotite, and pyroxenite) from the lineament controlled Chalk Hills, Kanjamalai, Pakkanadu, Kanjanur and Tippampatti of Samalpatti Complex of Salem and Dharmapuri districts have been discussed. The compatible trace element contents suggest an enriched mantle protolith. The incompatible trace element plots display both a primitive character and an insignificant contamination. The REE of the sampled rocks display the mantle residue character for dunite and a derived character for the others. The sampled dunite displays a higher PGE value (14.4 to 17.4 ppb) compared to the peridotites and pyroxenites. The IrPGE values range from 1.4 to 9.6 ppb and the PdPGE from 4.8 to 11.6 ppb. The total PGE content is above that of the bulk crust, MORB, and the upper crust values but the below primitive mantle range suggesting poor fractionation from a depleted source.

7 illus, 2 tables, 18 ref

007999   Jain R C;Sinha A K (Geology Dep, Rajasthan Univ, Jaipur) : Sustainable management of the water stressed aquifers in Sabarmati basin Gujarat, India. J Indian Wat Resour Soc 2010, 30(1), 21-30.

The Sabarmati basin is underlain by a multi-aquifer system, with prolific yields but the excessive groundwater pumping over many years has resulted in de-watering of a substantial aquifer thickness and reduction in pressure heads as reflected in long term decline in ground water levels. The ground water use in the basin being practiced currently is considered unsustainable as the ground water draft far exceeds the replenishable recharge. For providing sustainability to ground water withdrawal structures and keeping in view the increasing thrust on development of ground water resources, there is an urgent need to address the problem of ground water depletion through both supply side as well as demand side management interventions. Based on the in depth analysis of hydrogeology, long term water level trends, aquifer parameters and the availability of surplus runoff a strategy for managed aquifer recharge (MAR) has been formulated to augment the ground water resources of the water stressed aquifers. Typical designs of different types of structures suitable for artificial recharge have been included based on the lessons learnt. The paper presents a matrix of recommendations for implementing MAR in the basin through various stakeholders. For demand side management it is essential that ground water development is controlled and regulated through appropriate legal and administrative measures in view of the fast emerging aquifer depletion in large part of Basing.

11 illus, 2 tables, 22 ref

007998   Goyal S K;Chaudhary and B S (Geophysics Dep, Kurukshetra Univ, Kurukshetra-136 119, Email: sanjayktl@gmail.com) : GIS based study of spatio-temporal changes in groundwater depth and quality in Kaithal district of Haryana, India. J Indian Geophys Union 2010, 14(2), 75-87.

The study has analyzed the spatio-temporal changes in groundwater depth and quality from 1992 to 2007 in Kaithal district of Haryana state to understand the hydrological behavior and status of the area. Pre- and post- monsoon depth to water level below ground level (bgl), electrical conductivity (EC) and Landsat remote sensing data were used in the study. Spatial distribution of depth and EC in the study area were mapped and classified into standard zones in GIS environment for 1992, 1997, 2002 and 2007. Change detection maps, seasonal fluctuation maps and groundwater prospects maps were generated using cross and difference operations in Integrated Land and Water Information System (ILWIS 3.6) to identify critical as well as potential groundwater zones in the district. The study revealed a decline in average groundwater depth from 9 m bgl in 1992 to 16 m bgl in 2007. Average EC of groundwater in the district was also found to degrade from 1722 μS/cm to 2267 μS/cm in the corresponding period. The changes in depth and quality were more prominent in two-third part of the district (upland plains) under Gulha, Siwan, Kaithal and Pundri blocks. In the remaining low lying part in southern region, depth and EC were almost stable in 3-10m and 2500-9000 μS/cm range respectively. Due to high EC (<62>4000 μ,S/cm), the groundwater in a part of Rajaund block was found unsuitable for irrigation. Also, it had low public acceptability for drinking. Entire Pundri block along with a part of the adjoining Kaithal block (about 32% of total area) was identified as the zone of good groundwater prospects. Western part in Siwan block (about 8% of total area) was found critical due to fast depleting groundwater levels. The depletion of levels and worsening of groundwater quality in general, can be attributed to over-exploitation of groundwater and excessive use of agrochemicals in addition to natural factors. High EC (2500-9000 μS/cm) and a nearly shallow water table observed in Rajaund and Kalayat blocks can be understood to be a combined effect of inadequate groundwater withdrawal, poor drainage conditions, effect of leaching, and geohydrological setting of the area.

8 illus, 6 tables, 21 ref

007997   Goutham M R;Sandhya R;Madhusudhan Rao B;Patil S K;Murthy B V S (Center of Exploration Geophysics, Osmania Univ, Hyderabad-500 007) : Rock magnetic and palaeomagnetic study of the Archaean granites from Hyderabad, India. J Indian Geophys Union 2010, 14(1), 67-74.

Samples from Hyderabad granitic region are studied for their rock magnetic and palaeomagnetic behaviour. There are considerable differences between the pink and gery granites in the rock magnetic properties such as Intensity of natural remanent magnetization (J_n, magnetic susceptibility (χ) and Koenigsberger's ratios (Q_n and indicates that these granites are of two different origins. Average values of NRM intensity, % and Q_n are found to be 488 and 637 Am¹-, 1689 and 1780; and 9 and 19.7 for pink and gray granites respectively. Two different mean palaeomagnetic directions were obtained for these rocks after af demagnetization which are D/I = 159°/-25° and 268°/-40°. The corresponding palaeomagnetic poles lie at 69S/160E and 8S/327E respectively. Based on the statistics former direction 159°/-25° is considered as the palaeomagnetic direction of Hyderabad granitic region.

4 illus, 2 tables, 23 ref

007996   Ghosh G K;Basha S K;Salim M;Kulshreshth V K (NEF Project, Oil India Limited, Duliajan-786 602, Email: gk_ghosh@yahoo.com) : Integrated interpretation of seismic, gravity, magnetic and magneto-telluric data in geologically complex thrust belt areas of Manabum, Arunachal Pradesh. J Indian Geophys Union 2010, 14(1), 1-14.

Subsurface heterogeneity delineation in the geologically complex and logistically hostile terrain of the Assam-Arakan basin near fore deep of Himalayan foot hills is one of the key factors for hydrocarbon exploration among the Geoscientists. The area of study primarily falls close to the foot hills of Himalaya i.e. fore deep region in the North-East and partly in Belt of Schuppen (thrust belt) to the south-east, facing the Upper Assam foreland shelf in India. In such a complex mountainous and thrusted terrain, the seismic method has its own limitation to map the deeper geological basement configuration, because energy transmission is very meager and most part of the energies engrossed at boulder-sandstone formation. To overcome this problem it is always recommended to utilize some passive geophysical methods to supplement some value added constraints information to seismic data. Oil India Limited (OIL) decided to acquire ground Gravity-Magnetic (GM) as well as Magneto-Telluric (MT) data acquisition simultaneously in the fringe of Seismic lines where few profiles fall on the vicinity area to map the deeper subsurface information and also to make out the potentially hydrocarbon prospect zone. Additional quantitative spectral analysis technique has been used to map the top sedimentary layer and basement structure. This paper describes the correlation between GM, MT and Seismic data to map the different sedimentary layers and the basement configuration.

13 illus, 1 table, 8 ref

007995   Gewal A K;Jain S K;Panda G;Vijay S K (Physics Dep, Space Science Laboratory, Barkatullah Univ, Bhopal-462 026, Email: ak_gwl@yahoo.co.in) : Ionospheric precursors observed during some earthquakes. J Indian Geophys Union 2010, 14(2), 115-31.

Ionospheric anomalies in association with earthquakes were derived using foF2 records from ionospheric stations. The present study reports the ionospheric perturbations, if any, observed over the related ionospheric station prior to occurrences of five earthquakes during last three years at various locations. Initially, foF2 data were analyzed with upper and lower bound and the observed anomalous changes related to geomagnetic disturbances were filtered out. Then the remaining perturbations were analyzed in relation to the occurrence of seismic activities. Hence period considered in this study comes under the quiet geomagnetic conditions. The results of the study showed some unusual perturbations. These anomalies are strongly time dependent and appeared some days before the main shock. The possible mechanism to explain these anomalies is the effect of seismogenic electric field generated just above the surface of the earth within the earthquake preparation zone well before the earthquake.

30 illus, 2 tables, 24 ref

007994   Dudeja D;Biyani A K (Geology Dep, DBS College, Dehradun, Email: divyadudeja@yahoo.co.in) : Hydrogeochemical and quality assessment of spring water of Doon Valley, Uttarakhand. Int J Envir Dev 2009, 6(2), 93-115.

Deals with the analysis of chemical composition of spring water of Doon Valley and assessment of its suitability for drinking, irrigational and industrial purposes. For the study, major ion analysis of about 29 springwater samples is done. pH is found to be slightly acidic to slightly alkaline in nature varying from 5 in Lakshmansidh spring to 8.09 in Maldeota spring.. Calcium and magnesium are the most dominant cations while the most dominant anion is bicarbonate. Very hard spring water is found in Sahastradhara, Maldeota, near Neelkanth and in kemptyfall while springs of Laklwar. Bairagiwala, Gram Kandoli Uparli, Suarna riverbed, Manduwalci village and Lakshman Sidh temple have soft water. Concentration of major cations and anions when compared with drinking water standards set by Bureau of Indian Standards, suggests that very hard water springs of northern side of valley are not suitable for drinking purpose and can pose problems of scaling also. Their encrustation tendency is verified by positive values of Langelier Saturation Index. Various indices for analyzing their suitability for irrigational purpose are also computed such as sodium absorption ratio, sodium percentage, permeability index, magnesium ratio etc. These indices suggest that spring water of Doon Valley is free from any sodium hazard and is of excellent water class with SAR below 2 and sodium percent less than 20 except in Manduwala village. But USSL diagram predicts high salinity zone and C₃-S₁ (high salinity-low sodium hazard) category for about 31% of springs.

6 illus, 11 tables, 20 ref

007993   Dhananjaya Rao E N;Aruna Kumar P;Rao A T (Geology Dep, Andhra Univ, Visakhapatnam-530 003) : Petrology and geochemistry of amphiboites from Kandra Nellore schist belt, Andhra Pradesh. J appl Geochem 2009, 11(2), 199-211.

The Kandra Volcanic Belt (Nellore Schist Belt, NSB) consists of quartzites, mica schists, amphibolites, gabbroic rocks, granitic gneisses, granites, pegmatites and dolerites with predominant amphibolites and gabbroic rocks. The amphibolites, gabbros and dolerites constitute the 'Kandra volcanics'. Gabbros are emplaced in amphibolites (occasionally amygdaloidal) and are in turn intruded by dolerites. Adjoining the Kandra volcanics in the NE and SW, migmatitic gneisses with alternating distinct amphibolite layers are exposed. Apart from these, amphibolites also occur in the fractures of dolerites. The major and trace element compositions of all these three types of amphibolites suggest that they.are ortho-amphibolites. REE abundance in the amphibolites associated with the granitic gneisses have low œ REE, while higher 2 REE, is observed in amygdaloidal types. Chondrite normalized REE patterns show an overall similarity of distribution patterns in amphibolites derived from basalts/dolerites suggesting their formation from same or similar source. Moderate to light REE enrichment in these amphibolites, suggest their source to be theoleiitic and found in back-arc or marginal basin tectonic setting.

1 illus, 4 tables

007992   Deshpande S M;Aher K R (Post Graduate Geology Dep, Institute of Science, Caves Road, Aurangabad-431 004, Email: dr_smd@rediffmail.com) : Hydrogeochemistry and quality assessment of groundwater in Chikalthana industrial area of Aurangabad, Maharashtra, India. Bionano Front 2011, 4(1), 157-61.

One of the most important crises of twenty first century is the scarcity of water for domestic, agricultural and industrial use. The accelerated growth of industries and the discharge of the industrial waste water around the Chikalthana area causing heavy damage to the groundwater quality. In the present study an atteinpt is made to evaluate the chemistry of groundwater in and around Chikalthana industrial area. Groundwater samples from 45 different locations in and around Chikalthana industrial area were collected randomly in the month of May 2008. The determination of Physico-chemical parameters of groundwater samples were carried out by adopting standard method given by APHA (2002) and Trivedi and Gocl (1984). The study reveled that the most of the groundwater samples in the study area are heavily polluted. The majority of parameter exceeding permissible limit given by BIS (1991) and WHO (1993) are total dissolved solids, total hardness, Calcium, Magnesium and Chloride. Discussion held by the author with the Farmers of the study area noted that a lot of people in the area are suffering from health problems like skin, throats infection using this water. Based on these studies recommendation can be made to the local authorities to take suitable control measures to reduce pollution level of groundwater sources before it becomes unmanageable.

1 table, 26 ref

007991   Dashore N;Upadhyaya G;Vyas K (Physics Dep, B.M. College of Technology, Indore-452 012) : Fuzzy logic based model for predicting volcanic activity. Indian J Sci Technol 2010, 3(7), 759-63.

This paper describes a fuzzy logic based system to predict volcanic eruption. Meaningful prediction requires careful monitoring of a volcano's vital signs. Seismometers can be used to pinpoint earthquakes which track the rise of magma and its movement along fissures. Measurements of the tilt of the entire mountain provide additional information about the 'breathing' of the volcano as magma moves inside it. Instruments that sniff SO², CO² and other gases also can signal changes in the volcano. At some volcanoes the seismic information seems most reliable; at others the tilt tells the story. But the best predictions come from the combination of all of these methods into a volcano monitoring and prediction system.

5 illus, 5 tables, 8 ref

007990   Bhowinick P K (KDMIPE, ONGC, Kaulagarh Road, Dehradun-248 195, Email: pkbhowmick@yahoo.co.in) : Petroleum geochemistry in hydrocarbon exploration: past, present and future. J appl Geochem 2009, 11(2), 276-89.

Energy is the most vital input for economic and social development of any society. The economy is highly dependent upon the availability of energy. The sustainable, environmental-friendly and socially responsible management of energy resources forms an integral component of any economic activity. To maintain our economic growth rate of 8-10%, India needs all the energy it can get. Our focus is to develop our economy through efficient utilization of available energy resources while preserving the ecology and be instrumental in giving social and economic equity to the one billion population of India. Globally, oil and gas constitute 37% and 23% of the fuel share. Oil (Petroelum) remains the dominant energy source. The oil (petroleum) share in energy balance is set to grow from current level of 37% to 44% by 2010. Out of Global Proven Hydrocarbon Reserves of 1300 billion bbl, India has proven reserves of 6.3 billion bbl, globally in 20^th position. The first major event in the history of petroleum geochemistry was the concept that hydrocarbons were generated from organic matter buried along with fine-grained sediments (source rocks). The importance of thermal stress and time in the generation process was recognized, leading to the concept of the oil window, according to which organic matter first generates gas, followed by liquid hydrocarbon and minor amounts of gas and eventually dry gas in the over-mature zone. These understandings gave rise to the 'hydrocarbon kitchen concept', which postulates that reservoirs adjacent to or in communication with hydrocarbon generative kitchens are more likely to be oil-gas bearing. In the initial stages of exploration, Surface Geochemical Exploration (SGE) tools have emerged as powerful indicators of the presence of hydrocarbons. Identification and characterization of effective source rocks and maturity modeling has led to identification of 'hydrocarbon kitchen' in every producing/ prospective basin. High resolution molecular level geochemical studies using state of the art analytical techniques led to precise oil-oil and oil-source correlations to define petroleum systems. Reservoir geochemistry is effectively utilized to understand reservoir heterogeneities in many producing oil fields to optimize reservoir management through identification of fairways of migration within the trap. Chemostratigraphy is one of the methods developed to address the stratigraphic problems associated with biostratigraphically barren sequences. In addition, geochemical studies are being utilized in the field of Coal bed methane, Gas Hydrate exploration, Basin Centered and Biogenic Gas exploration. Kinetic based Multi 1-D thermal maturation modeling of organic matter involving burial and thermal reconstruction led to the modeling of hydrocarbon generation and expulsion as well as timing of generation and expulsion from identified source rocks. The role of geochemistry in hydrocarbon exploration was realized globally by 1955 and its role in E and P business increased at a faster pace due to rapid advancements in analytical tools and techniques. These state-of-the-art technologies and expertise has enabled the identification and characterization of petroleum source rocks and hydrocarbon generation and exploration modeling leading to prioritization of prospect to ensure the risk reduction in petroleum exploration and maximization of value creation. The future of geochemical technology belongs to synergy of all branches of geosciences and synthesis of knowledge derived from it. The application of more refined, sophisticated and robust analytical tools and technologies will lead to identification of new petroleum systems, fine-tuning occurrence models and establishing petroleum systems and the extents of their generative basins, delineating crude oil and natural gas compositional occurrence trends and reconstructing migration and post accumulation alteration histories and thus providing more optimism and opportunity for further hydrocarbon exploration.

9 illus, 11 ref

007989   Ansari M (Mathematics Dep, North-Eastern Hill Univ, NEHU Campus, Shillong-793 022, Email: mansari@nehu.ac.in) : Dirac equation in a 5-dimensional Kaluza-Klein theory. Indian J pure appl Math 2010, 41(6), 715-36.

Dirac equation is discussed in 5-dimensional space time having topology M⁴ x T¹, where M⁴ and T¹ both are curved. It is shown that 4-dimensional fermion can be obtained from 5-dimensional fermion, as a result of com-pactification of extra dimension. It is found that the realistic 4-dimensional fermions are possible in higher modes earlier than those in lower modes during the course of expansion of 4-dimensional universe. 4-dimensional Dirac equation, obtained from 5-dimensional Dirac equation after compactification, is solved for an arbitrary mode for superheavy as well as light (realistic) fermions. Time-dependence of polarization vector and magnetization density, as a result of Gordon-decomposition of the current vector for 4-dimensional spin-1/2 field (with arbitrary mode), is exhibited.

14 ref

006890   Wall H D;Schobel S;Pandit M K;Sharma K K;Just J (Geozentrum Nordhayern, Erlangen-Nurnberg Univ, Schlossgarten 5, D-91054 Erlangen, Germany, Email: dewall@geo.uni-erlangen.de) : Record of ductile syn-intrusional fabrics to post solidification cataclasis: magnetic fabric analysis of neoproterozoic Mirpur and Mt. Abu granitoids, NW India. J Geol Soc India 2010, 75(1), 239-53.

The Mirpur granite body represents a relatively small (10 km²) pluton intruded along the northern margin of the adjacent Mt. Abu batholith (-125 km²) in NW India. It is a visibly undeformed alkali feldspar rich pink granite; in contrast, the Mt. Abu is a composite granitoid body and variably deformed. Both are intruded by rhyolitic dykes and the terminal magmatic events in both the cases are mafic dykes. The AMS (Anisotropy of Magnetic Susceptibility) data identify the Mt. Abu with SE-dipping foliations and subvertical lineations as a single structural domain while the Mirpur granite body shows two domains characterized by predominantly E - W trend of magnetic foliation in the eastern part (domain I) and N - S orientations in the western part (domain II). The domain I shows magmatic fabrics, typical for the peraluminous granites of Malani Igneous Suite (MIS). Change in fabric orientation in the domain II has resulted from cataclasis wherein the samples show destruction of the original E - W fabric and complete transposition by N - S trends. The foliations in the Mt. Abu granites have been related to SE orientation of maximum horizontal stress. The same maximum stress direction can be inferred from dyke orientation in the Mirpur granite, which is interpreted as continuation of the tectonic imprint in this region during emplacement of both the granites. Age of the cataclastic overprint with a predominant N - S orientation is not yet constrained but corresponds with the trend of the nearby Sindreth basin within the Malani Igneous Suite. The Neoproterozoic tectonic scenario for the region has been interpreted in terms of an ongoing crustal convergence and granitic magma emplacement against the back stop offered by the rigid Delhi Fold Belt.

11 illus, 2 tables 49 ref

006889   Vivekanandan N (NO, Central Water and Research Station, Pune-411 024) : Comparison of T-year rainfall using frequency analysis approach. J Indian Wat Resour Soc 2009, 29(1), 22-7.

Estimation of rainfall for a desired return period is one of the pre-requisite for planning and operation of various hydraulic structures. Frequency analysis approach is the effective and expedient tool for estimation of rainfall. This paper gives details of a study involving the use of frequency analysis approach adopting six statistical distributions for estimation of rainfall for different return periods for Kakrapar, Roha and Sudhagad sites. Goodness-of-Fit tests like Chi-square and Kolmogorov-Smirnov are used for checking the adequacy of fitting of the distributions to the recorded annual daily maximum rainfall data. Diagnostic test involving D-index is used for selection of appropriate distribution for rainfall estimation. The paper presents the 2-parameter Gamma distribution is found to be suitable among six distributions for estimation of rainfall for the data under study.

6 illus, 8 tables, 8 ref

006888   Viladkar S G;Bismayer U (NO, Carbonatite Research Centre, Amba Dongar, Kadipani, Dist. Baroda-390 117) : Compositional variation in pyrochlores of Amba Dongar carbonatite complex, Gujarat. J Geol Soc India 2010, 75(3), 495-502.

Pyrochlore is interpreted as a primary magmatic mineral that appeared in early carbonatite phases at Amba Dongar. Later intrusive phases incorporated this early pyrochlore and caused compositional modification, particularly around the rims, in response to changing magma chemistry. Consequently pyrochlore compositions show wide ranges in Nb, Ta, Ca, Ba, Ti and Ce. The final carbonatite phase was ankeritic and rich in hydrothermal fluids, giving rise to extreme compositional zoning and introduction of diverse elements (Si, U, Sr, Th, Fe), in the contained pyrochlore. Enrichment in radioelements such as U lead to metamictization, alteration and A-site vacancy.

7 illus, 3 tables, 19 ref

006887   Venkata Ramana R;Chakravorty B;Pandey N G; Mani P (NO, NIH, Phulwarishrif, Patna-801 505) : Development of intensity duration frequency relationship for short duration rainfall. J Hydrol 2009, 32(1), 59-75.

The rainfall Intensity Duration Frequency (IDF) relationship is one of the most commonly used tools in water resources engineering for planning, designing and operation of water resources projects. In the present paper rainfall data of 14 raingauge stations of Punpun basin located in Bihar was used for regional rainfall frequency analysis based on L-moment approach facilitated to find the robust distribution for these daily raingauge stations having data availability of 9-17 years. The robust distribution was used to find the IDF relationship and curves for short duration rainfall for Punpun basin. From the IDF curves parameters of empirical equations for the gauged locations were determined and contour maps were generated. IDF curves for ungauged locations were developed form the generated contour maps using GIS and finally a generalized IDF curve incorporating return period and the duration of rainfall for particular a station was developed.

5 illus, 6 tables, 10 ref

006886   Tewari H C;Surya Prakasa Rao G;Rajendra Prasad B (NO, National Geophysical Research Institute, Hyderabad-500 007) : Uplifted crust in parts of western India. J Geol Soc India 2009, 73(4), 579-88.

During northward movement of the Indian sub-continent, after its breakup from the Gondwanaland in the Late Cretaceous, the western part of India traversed over the Reunion plume. The Saurashtra peninsula and the Cambay Basin are two important geological regions in this part. Two and half dimensional density models, based on the crustal seismic structure, were generated to establish a relationship between these two regions. These models indicate that the crust is 32-33 km thick in the eastern Saurashtra and the northern part of the Cambay Basin. The shallower crust is in a triangular region formed by the extension of the western limb of the Proterozoic Aravalli trend in Saurashtra, its eastern limb and the Narmada fault in the south. Compared to 36-37 km thick crust to the west and 38-40 km to the east of this region the crust in the above triangular region is uplifted by 4 to 6 km. This uplift took place either after the deposition of Mesozoic sediments or was concomitant with the rise of Reunion plume prior to the extrusion of the Deccan volcanics as the region was close to the axis of the plume.

7 illus, 3 ref

006885   Surwade K B;Ramesh C;Kshirsagar M M;Govindan S (NO, Central Water and Power Research Station, Khadakwasla, Pune-411 024) : Assessment of peak maximum rainfall for estimation of peak flood for ungauged lakya catchment-a case study. J Hydrol 2009, 32(1), 1-20.

In water resources planning and management many problems are faced in estimation of flood flows in ungauged catchments. Researchers have been adopting different techniques in estimating flows from ungauged catchments for design and risk analysis of hydraulic structures. The important aspect in such situations is an assessment of Peak Maximum Rainfall (PMR). This PMR is derived through statistical methods. The PMR for big catchments is estimated using scientific tools and is widely known as Probable Maximum Precipitation (PMP). The paper presents one such case study of Lakya catchment in Bhadra head water reach for which the peak flood has been estimated with the extreme precipitation derived. Extreme Value Type-l probability distribution was selected for PMR estimation. Various methods exist for determining the parameter estimates of probability distribution from a given sample of daily maximum rainfall. In this paper, the method of self-determined probability weighted moments (SD-PWM) is included as an alternative method for parameter estimation for extreme value distribution. In all, about seven methods including the SD-PWM for the extreme value estimation have been studied. To examine the relative performance of the SD-PWM estimations, parameters and extreme rainfalls were also estimated with MOM, MLM, PWM, L' Mom., POME and MLE. The goodness of fit for the results obtained using SD-PWM has been determined.

7 illus, 9 tables, 19 ref

006884   Suresh M;Gurugnanam B;Vasudevan S; Dharanirajan K;Jawahar Raj N (Earth Sciences Dep, Annamalai Univ, Annamalai Nagar-608 002) : Drinking and irrigational feasibility of groundwater, GIS spatial mapping in uppper Thirumanimuthar sub-basin, Cauvery river, Tamil Nadu. J Geol Soc India 2010, 75(3), 518-26.

In the study, the chemical characteristics of groundwater with respect to drinking and Irrigation water quality in upper Thirumanimuthar sub-basin, Cauvery River, have been studied. 51 groundwater samples were collected and analysed for pH, conductance, total dissolved solids, total hardness, calcium, magnesium, carbonate, bicarbonate, total alkalinity, chloride, sodium, potassium, sulphate etc. The values analyzed were evaluated in detail and compared with WHO water quality standards. It is observed that, for most of the groundwater quality parameters, the values are not potable for drinking and irrigational use. To understand the spatial distribution of unsuitable zones, ArcGIS was employed. Attributes were linked and spatial interpolation mapping was done. Inverse distance weighted interpolation technique was followed for raster and vector mapping. Finally the overlay analyses were also carried out to locate the worst quality zone.

7 illus, 6 tables, 21 ref

006883   Surajit;Swades Pal (Visva-Bharati, Santiketan, West Bengal, Email: surajitgeo@gmail.com) : Flood trend analysis in lower Mayurakshi river basin of West Bengal : an attempt towards flood forecasting. Indian J Landsc Syst ecol Stud 2009, 32(2), 89-98.

Flood is a part and partial event of the river basin. Lower Mayurakshi River basin of the West Bengal is highly flood prone. So flood trend tracking is very necessary because entire basin now under the punch of human habitation. So to get avoidance from flood situation, obvious necessity is to predict flood in right direction. Some simple statistical analysis namely probability analysis, relative probability analysis, time series analysis, chi-square test etc. are employed to infer the nature of flood tendency and casual consequences in future. It is very evident fact that flood frequency is gradually increasing with time. Human interference is largely responsible for ground degradation of drainage network as well as flood situation.

5 illus, 9 tables, 6 ref

006882   Subba Rao N;Srinivasa Rao K V;Surya Rao P; Venkat Rao C;Arjunudu K;Madhusudhana Reddy P;Subrahmanyam A (Geology Dep, Andhra Univ, Visakhapatnam-530 003, Email: Srnandipati@rediffmail.com) : Geochemistry of carbonate precipitation from the groundwater in a coastal region. J Geol Soc India 2009, 73(5), 651-6.

Groundwater samples were collected from a coastal region of Andhra Pradesh to assess the possible conditions of the formation of carbonates. The area experiences a semi-arid climate and is underlain by khondalites, over which the Quaternary sediments occur. The study of the geochemistry of groundwater indicates that groundwater is mostly of fresh, with alkaline nature. The study further suggest that the breakdown of feldspars as kaolinite during rock-water interaction, releases Ca²⁺. Soils/weathered products contribute high CO₂ under the open system. The Ca²⁺ and CO₂ are added to the groundwater through the infiltrating recharge water. They subsequently precipitate as fine-grained carbonates in the weathering profile due to evapotranspiration under a freshwater environment.

4 illus, 3 tables, 19 ref

006881   Srivastava R P;Vedanti N;Pandey O P;Dimri V P (National Geophysical Research Institue, Council of Scientific and Industrial Research, Hyderabad-500 007, Email: nimisha@ngri.res.in) : Detailed gravity studies over Jabera - Damoh region of the Vindhyan basin (Central India) and crustal evolution. J Geol Soc India 2009, 73(5), 715-23.

Vindhyan Basin of Central India situated just north of SONATA rift zone, forms one of the major geotectonic segment of the Indian subcontinent which is associated with complex thermo-tectonic history. Southern part of this basin is known to contain favorable conditions for hydrocarbon entrapment. Keeping this in view, a detailed gravity survey network comprising 40 gravity bases and 1500 data points in an area of about 110 x 100 km² was planned in and around Jabera-Damoh region. Analysis of Bouguer and free air gravity anomaly maps, prepared using fractal based gridding method, indicates presence of two sedimentary basins (Jabera and Damoh) faulted on either sides beside ridge like features. However, well-known Jabera domal structure appeared to be a shallow feature only. Inversion of gravity data further reveals presence of 5 to 6 km thick Vindhyan sediments in the Jabera basin which are underlain by Mahakoshal/ Bijawar group of rocks, resting directly over the lower crust, thereby indicating almost total absence of granitic crust from this region. It appears that due to an underlying thermal anomaly, the entire region may have been subjected to sustained uplift, deformation, erosion and consequent crustal extension during early to mid Proterozoics which brought high velocity mafic crust to such shallow levels.

10 illus, 22 ref

006880   Srivastava H B;Srivastava V (Geology Dep, Banaras Hindu Univ, Varanasi-221 005, Email: hbsrivastava@gmail.com) : Mylonitic microfabrics from the rocks of MCT zone in Alakhnanda valley, Garhwal Himalaya. J Geol Soc India 2010, 75(1), 152-9.

MCT Zone of Alakhnanda valley is a major ductile shear zone in Garhwal Himalaya, which is characterised by different types of mylonite rocks. On the basis of grain size and the percentage of matrix in the rock, zones comprising protomylonite, augen mylonite, mylonite and ultramylonite have been identified. The study of microstructures, grain size and crystallographic preferred orientation of quartz oaxis fabric reveals that the rocks of the MCT zone were deformed by a combination of intracrystalline creep (power law creep) and grain boundary migration (sliding super plasticity).

6 illus, 1 table, 34 ref

006879   Srivastava A K;Khare N (Geology Dep, SGB Amravati Univ, Amravati-444 003, Email: ashokamt2000@hotmail.com) : Granulometric analysis of glacial sediments, Schirmacher oasis, East Antarctica. J Geol Soc India 2009, 73(5), 609-20.

Granulometric analysis of nineteen sediment samples has been carried out for their statistical and textural parameters. The samples are collected from the northern and southern margins of Schirmacher Oasis extending below the polar ice sheet and grading to coastal area respectively and main rocky land of Schirmacher including lakes. The analysis shows that most of the sediments are of medium grain size and fall in poor to very poor sorted category. An attempt has been made to interpret the depositional set-up by plotting the scatter patterns between various textural parameters, including C-M plot and arithmetic log-probability curves. The influence of physical parameters viz. low to high velocity winds, ice and meltwater on sediment characteristics has been discussed.

7 illus, 2 tables, 40 ref

006878   Srivastava A K;Ingle P S;Khare N (Geology Dep, SGB Amravati Univ, Amravati, Maharashtra-444 602, Email: ashokamt2000@hotmail.com) : Textrural characteristics, distribution pattern and provenance of heavy minerals in glacial sediments of Schirmacher oasis, east Antarctica. J Geol Soc India 2010, 75(2), 393-402.

Heavy minerals of twenty sediment samples, belonging to polar ice sheet, lake, mainland area and shelf region of Schirmacher Oasis, east Antarctica, have been studied for their textural characteristics, abundance and provenance determination. The heavy crop is represented by zircon, tourmaline, rutile, garnet, hypersthene, hornblende, chlorite, enstatite, lawsonite, kyanite, sillimanite, zoisite, andalusite, spinel, topaz and opaques. The assemblage, in general, is dominated by hornblende-hypersthene-garnet assemblage, followed by kyanite-sillimanite-andalusite and zircon-tourmaline-rutile. The high concentration of specific minerals of metamorphic origin reveals high-grade metamorphic terrain as the primary source. The ZTR ratio is low showing low mineralogical maturity. An attempt has also been made to compare the trends of heavy minerals of various sub glacial regions with those of the average values of entire area.

8 illus, 2 tables, 23 ref

006877   Srilatha Indira Dutt V B S;Rao G S B;Swapna Rani S;Swarana Ravindra Babu;Goswami R K (Electronic & Communication Engineering Dep, Andhra College of Engineering Univ, Visakhapatnam-530 003, Email: srilatha06.vemuri@gmail.com) : Investigation of GDOP for precise user position computation with all satellites in view and optimum four satellite configurations. J Indian Geophys Union 2009, 13(3), 139-48.

The advent of Global Positioning System (GPS) has revolutionized the field of navigation particularly in the field of civil aviation sector. The accuracy of GPS system is affected by several factors. One such factor is satellite Geometry, which represents the geometric locations of the GPS satellites as seen by GPS receiver. This plays a very important role in determining the total positioning accuracy. Better the geometry better the position accuracy. The Satellite Geometry effect can be measured by a single dimensionless number called Geometric Dilution of Precision (GDOP). Lower the GDOP value, better the satellite Geometry. GPS requires minimum of four satellites to compute user position. When more number of satellites are in view, best four satellites are taken in order to reduce the redundancy. With four satellites, best geometry is obtained when one of the satellites is at the zenith and remaining three forms an equilateral triangle and all the four together forms a tetrahedron structure. The larger the volume of the tetrahedron, the better is the value of GDOP. Similarly, greater the number of satellites, better the value of GDOP. Practically, GDOP ranges from 2 to 6. Monitoring of GDOP is also an important aspect for high-precision applications such as surveying and Integrity monitoring in the GPS receivers. For making use of GPS for en-route and Precision Approach (PA) aircraft landings over the Indian subcontinent, the aspect of best GDOP value to be used in the user position computation is investigated which is obtained due to all the satellites in view or best four satellites in this paper. A new algorithm is proposed to compute various GDOP. Analysis is made by computing the best GDOP due to four optimum satellites as well as for all the satellites in view. The dual frequency GPS receiver data of IISC, Bangalore (13.02° /77.57" Lat./Long.) is used for investigation of best GDOP configuration to be used in user position determination over the Indian subcontinent.

8 illus, 5 tables, 4 ref

006876   Sreenivasa A;Jayasheela H M;Nagesh C P (Geology Dep, Karnataka Univ, Dharwad) : Factor analysis of hydrochemical data of Kumadvathi river sub-basin in Karnataka, India. J Hydrol 2009, 32(1), 30-7.

Statistical factor analysis (FA) technique has been applied to chemical data of 125 bore well water samples from Kumadvathi river sub-basin to assess the un usefulness of such techniques for interpretation of the hydro chemical data. FA technique identified three factors, which account for 60% of the major ion variations observed in the sub-basin, namely, TDS, carbonate and bicarbonate. The comparison between unrelated and rotated communalily values and rotated matrix led to the similar interpretations. Spatial variations of factor scores have been contoured and found that it could be directly correlated with the lithological units.

2 tables, 9 ref

006875   Sreedevi P D;Owais S;Khan H H;Ahmed S (NO, National Geophysical Reserach Institute, Uppal Road, Hyderabad-500 007, Email: pd_sreedevi@yahoo.co.in) : Morphometric analysis of a watershed of south India using SRTM data and GIS. J Geol Soc India 2009, 73(4), 543-52.

An attempt has been made to study drainage morphometry and its influence on hydrology of Wailapalli watershed, South India. For detailed study used Shuttle Radar Topographic Mission (SRTM) data for preparing Digital Elevation Model (DEM), aspect grid and slope maps, Geographical information system (GIS) was used in evaluation of linear, areal and relief aspects of morphometric parameters. The study reveals that the elongated shape of the basin is mainly due to the guiding effect of thrusting and faulting. The lower order streams are mostly dominating the basin. The development of stream segments in the basin area is more or less affected by rainfall. The mean Rb of the entire basin is 3.89 which indicate that the drainage pattern is not much influenced by geological structures. Relief ratio indicates that the discharge capability of these watersheds is very high and the groundwater potential is meager. These studies are very useful for planning rainwater harvesting and watershed management.

5 illus, 5 tables, 32 ref

006874   Soundranayagam J P;Sivasubramanian P; Chandrasekar N;Rajamanikam G V (Centre for Geo Technology, Manonmaniam Sundaranar Univ, Tirunelveli-627 012, Email: johnprince06@gmail.com) : Remote sensing and GIS application in urban expansion and its impact on sea water intrusion in Thoothukudi, Tamil Nadu. Indian J Landsc Syst ecol Stud 2009, 32(2), 1-10.

Detailed geomorphologies and land use/land cover studies have been carried out for Thoothukudi, Tamilnadu by using remote sensing data of IRS ID and L1SS III data of 2003 and Survey of India topomaps published in 1969, During the 43 years in Thoothukudi, the area of settlement and salt pans were increased by 19.45 sq.km and 9.4 sq.km respectively. The total area of waste land and Agriculture land were decreased by 47.45 sq.km. The increases in the settlements and salt pans have caused serious damages on coastal sand dunes. Exponential growth in population in the present study area has amplified the consumption of ground water resource also. This leads to seawater intrusion in the coastal aquifers. The present paper provided the detail impact of industrialization and urbanization on land use of the Thoothukudi.

6 illus, 4 tables, 9 ref

006873   Sonwane B G;Achole P B;Govindrao G S (Geography Dep, Mahatma Gandhi College, Ahmedpur, Dist Latur, (Maharshtra State)) : Spatio-temporal changes in general land use in Osmanabad district 1984-89 to 1999-2004. Indian J Landsc Syst ecol Stud 2009, 32(2), 327-36.

This is an important investigation on the problems of spatio-temporal changes occurring in the land utilisation in Osmanabad District (1984-89 to 1999-2004) based on modern methods and extensive field work. In fine the authors have presented some suggestions for the development in terms of optimal land utilisation after discussing in details the results of the main finding and sobservations in the area under consideration.

10 illus, 2 tables, 11 ref

006872   Solaimani K (GIS & RS Centre, Sari Agriculture & Natural Resourcees Univ, P.Box 737, Sari, Iran, Email: solainani2001@yahoo.co.uk) : Flood forecasting based on GIS and Hydraulic model. J Adv dev Res 2010, 1(2), 125-31.

Flood plains and the area near to the rivers channels, because of their special circumstances such as fertility and water resources are appropriate situations for the social and agricultural activities, but due to morphological characteristics usually, these area are affected by different flood hazards. Interaction between some river hydrologic models and geographical information systems (GIS) cause some gains and methods, which are reasonable to the planners. This study was carried out with the purpose of using hydraulic model of HEC-RAS with Arc View software to estimate the flood zone of 5-km distance on Neka River in Northern part of Iran, where during the last decade we had different flood events with a high magnitude damages. Topography maps at 1:1000 scales were used for the flood zonation for different periods of 2, 5, 10, 25, 50, 100 and 200 years. The results obtained attest to the fact that the combination of GIS and HEC-RAS model used in this study is useful and efficient in delineating the flood zonation. Finally the flood zone of 25 years is predicted to be more hazardous than the other periods for the selected areas.

7 illus, 2 tables, 23 ref

006871   Sharma M;Ahmad Z;Sharma N (Irrigation Dep, , Nepal) : Runoff and sediment yield modeling using ANN: Kankaimai watershed, Nepal. J Indian Wat Resour Soc 2009, 29(1), 28-37.

Deals with the prediction of daily runoff and sediment yield from Kankaimai watershed at Mainachuli, Nepal using ANN and regression models. Vegetational and geomorphologic analysis of the watershed reveals that Kankaimai watershed is fairly good watershed with moderately peak flow of shorter duration. The basin is predominantly covered by sparse and medium vegetation and have moderately high rate of soil erosion. The land area covered by dense vegetation is comparatively less, which results in the formation of more numbers of streams. ANN and regression models were developed to predict daily runoff and sediment yield from the Kankaimai watershed using daily runoff and sediment yield data for the years 2001-2003 for the monsoon season. ANN runoff model consisting of concurrent rainfall of three rain gauges and past one and two days runoff performs better than the other models in the terms of statistical and graphical indicators. Like wise ANN sediment yield model of the input parameter concurrent runoff is better than the other models. Regression runoff and sediment yield models were also developed using the same input vectors used in ANN models.

8 illus, 5 tables, 28 ref

006870   Sharma B K;Amod Kumar;Murthy V M (NO, Central Scientific Instruments Organisation, Chandigarh-160 030, Email: erbks@yahoo.com) : Evaluation of seismic events detection algorithms. J Geol Soc India 2010, 75(3), 533-8.

Identification of seismic events from continuously recorded seismic data in real-time through a Digital Seismic Data Recording system is a difficult task. Despite the vast amount of research in this field, the signal processing and event parameters discrimination algorithms have not yet fully come of age. Presently, we have a wide spectrum of trigger algorithms, ranging from a very simple amplitude threshold type to the sophisticated ones based on pattern recognition approaches. Some of the other approaches use adaptive technique and neural network methods. Researchers are continuously making efforts for the development of algorithms using various techniques, which produce minimum false trigger. Some approaches have been reported which are accurate for detecting first phase of events and take minimum possible computational time. In this paper several approaches for detecting event signals in background noise are presented and their precision evaluation is discussed.

24 ref

006869   Shah J;Srivastava D C;Rastogi V;Ghosh R;Pal A (NO, Schlumberger Asia Services Limited, Goregaon(E), Mumbai-400 067, Email: dpkesfes@gmail.com) : Strain estimation from single forms of distorted fossils-a computer graphics and MATLAB approach. J Geol Soc India 2010, 75(1), 89-97.

Most of the existing methods of strain analysis can estimate strain in a single form of distorted brachiopod, or trilobite provided independent evidence, such as the association of the fossil with cleavage and/or stretching lineation is available for inferring the direction of maximum principal strain. This article proposes a simple computer graphics based method and its MATLAB code that determine the minimum amount of strain in a single distorted fossil form even if data for inferring the maximum principal strain direction are lacking. Our method is a rapid computer-graphics alternative to some of the existing analytical methods. In a distorted fossil form of original bilateral symmetry, the relative senses of angular shears along the hinge line and the median line are mutually opposite to each other. It follows, therefore, that the maximum principal strain direction lies within the acute angle between the hinge and the median lines in the plane of the fossil. Using this principle, our method performs several simulations such that each simulation retrodeforms the distorted fossil by assuming a particular orientation, lying within the acute angle between the hinge line and the median line, as the potential direction of the maximum principal strain. Each simulation of retrodeformation yields a potential strain ratio. The distribution of all the potential strain ratios, obtained by assuming different orientations as the potential directions of the maximum strain, is typically a parabola-like curve with a distinct vertex that corresponds to the minimum amount of strain in the distorted fossil. An entirely computer graphical approach is somewhat time-intensive because it involves a large number of retrodeformational simulations. We, therefore, give a MATLAB code, namely, the Minstrain, that rapidly retrodeforms the fossil and determines the minimum strain with precision.

8 illus, 2 tables, 20 ref

006868   Sarkar P K;Mude S N (Geology Dep, Fergusson College, Pune-411 004, Email: pksarkar123@yahoo.com) : Remnants of vertical and lateral migration of the entrapped volatiles and gases in the Deccan trap basalts at Bhaja, Maval taluka of Pune district, Maharashtra. J Geol Soc India 2010, 75(3), 560-62.

The paper records some of the remnant vertical and horizontal to sub-horizontal gas migration channels in the Deccan Trap basalts from the vertical escarpment face at Bhaja Caves. These could have developed during the eruption, migration, inflation and overriding of the basaltic lava flows. The accumulated entrapped gases and volatiles of the lower flows migrated vertically and laterally into offshoots along the upper contacts or within the flow itself. In most cases, the vesicles are found to be empty as well as filled with the secondary minerals.

4 illus, 7 ref