006304   Marathe A (NO, Deccan Coll Postgrad and Res Inst, Pune-411 006, Email: pranav@pn2.vsnl.net.in) : Acheulian cave at Susrondi, Konkan, Maharashtra. Curr Sci 2006, 90(11), 1538-44.

Discovery of a Late Acheulian cave occupation at Susrondi in Palshet near Guhagar, on the banks of a small perennial stream, near a waterfall, at a height of 85 m amsl and 2 km inland is the first of its kind on the more than 7500 km long coastline or on the Deccan plateau. On the basis of observations made on tool typology, geomorphology and lithostratigraphy it is shown that early man occupied the cave during early Late Pleistocene.

7 illus, 37 ref

006303   Luirei K;Pant P D;Kothyari G C (NO, Wadia Inst of Himalayan Geol North East Unit, Izatnagar-791 113, Email: ashing_luirei@rediffmail.com) : Geomorphic evidences of neotectronic movements in Dharchula area, Northeast Kumaun : a perspective of the recent tectonic activity. J Geol Soc India 2006, 67(1), 92-100.

The northeastern Kumaun part of Kumaun Lesser Himalaya is seismotectonically one of the most active segments of the Central Himalaya. The major as well as minor thrusts and faults in Dharchula and its environs are neotectonically quite active and as such their movements have made this region vulnerable to landslides. Dharchula and its environs have been affected by number of eartquakes. The recent tectonic movements along these thrusts and faults are expressed in the geomorphic rejuvenation of the terrain such as entrenched meandering, river courses characterized by deep gorges, unusual widening of the river valleys, formatkion of the palaeolakes, deflection of rivers, and offsetting of the river terraces. Abrupt deflection of Kali river course from general flowage i.e. NNE-SSW to E-W is observed, which reflect the rejuvenated movements of the faults. Reactivation of the fault has resulted in the formation of six levels of terraces in Gathibagar. Relicts of lacustrine deposits formed due to abrupt changes in the drainage regime are also observed along Jauljibi-Dharchula section.

7 illus, 19 ref

006302   Krishnamurti T N;Biswas M K (Meteorology Dep, The Fla St Univ, Tallahassee, FL 32306, USA, Email: tnk@io.met.fsu.edu ) : Transitions in the surface energy balance during the life cycle of a monsoon season. J Earth Syst Sci 2006, 115(2), 185-201.

In this observational/ diagnostic study, illustrated the time history of some important parameters of the surface energy balance during the life cycle of a single monsoon season. This chronology of the surface energy balance portrays the differential equilibrium state from the preonset phase to the withdrawal phase. This includes an analysis of the time history of base variables such as soil moisture, ground temperature, cloud cover, precipitation and humidity. This is followed by an analysis of the components of the surface energy balance where noted subtle changes in the overall balances as proceed from one epoch of the monsoon to the next. Of interest here is the transition sequence: preonset, onset, break, revival, break, revival and withdrawal during the year 2001. Computations are all illustrated for a box over central India where the coastal effects were small, data coverage was not sparse and where the semi-arid land mass changes drastically to a lush green area. This region exhibited large changes in the components of surface energy balance. The prinicpal results pertain to what balances the difference among the incoming short wave radiation (at the earth's surface) and the long wave radiation exhibited by the ground. That difference is balanced by a dominant sensible heat flux and the reflected short wave radiation in the preonset stage. A sudden change in the Bowen ratio going from <62> 1 to <60> 1 is noted soon after the onset of monsoon. Thereafter the latent heat flux from the land surface takes an important role and the sensible heat flux acquires a diminishing role. Also examined the subtle changes that occur in the components of surface energy balance between the break and the active phases. The break phase are seen to be quite different from the preonset phases. The study is aimed to illustrate the major importance of moisture and clouds in the radiative transfer computations that are central to the surface energy balance during each epoch. These sensitivities (of moisture and clouds) have major consequences for weather and climate forecasts.

21 illus, 19 ref

006301   Jadhav S S;Surve P R;Biradar R G;Ambore N E (NO, , ) : Seasonal variation of physico-chemical characteristics of Sonkhed Dam water. Aquacult 2006, 7(1), 117-22.

Sonkhed dam is a minor irrigation dam. The water in Sonkhed dam isused for irrigation, fish culture, drinking and domestic purposes. The investigation deals with the study of seasonal variations of physico-chemical characteristics of Sonkhed dam water. The study was carried out during the year 1999 for a period of 12 months. The parameters such as atmospheric temperature, water temperature, pH, free carbon dioxide, carbonate alkalinity and dissolved oxygen were studied. The pH shows allcaline trend.

6 illus, 16 ref

006300   Immaculate Mary M;Senthamarai Kannan K; Suyambulingom C (NO, N.I. Coll of Engng, Kumaracoil-629 180) : Monthly rainfall forecasting using harmonic analysis. Ultra Scient phys Sci 2006, 18(1), 77-82.

An attempt is made to predict rainfall using Fourier series for the estimation of monthly rainfall forecast based on the monthly average rainfall computed for 56 years from 1945 to 2000 in the south end of Tamilnadu. Fourier series was developed by taking different harmonics: The results obtained with the eighth harmonic gave the minimum non-significant chi-square value with the observed values.

2 illus, 4 tables, 7 ref

006299   Ghosh B;Praveen M N;Shrivastava H S (NO, Geol Surv of India, E-5 Area Colony, Bhopal-462 016, Email: bghosh_geol@hotmail.com) : Gahnite chemistry from metamorphosed Zn-Pb-Cu sulphide occurrences of Betul Belt, Central India. J Geol Soc India 2006, 67(1), 17-20.

Gahnite Chemistry from metamorphosed Zn-Pb-Cu sulphide occurrences of Betul Belt, Central India has been presented. Gahnites of this Belt are suggested to be a product of desulphidation of sphalerite during metamorphism. Although the very presence of zincian spinels in rocks may appear to constitute an exploration guide for metamorphosed massive sulphide (MMS) deposits, spinels that are likely to to be spatially associated with sulphides appear to have characteristic Zn-rich, Mg-poor compositions.

^ssc3 illus, 1 table, 20 ref

006298   Devaraju T C;Kaukonen R J;Sudhakara T L; Alapieti T T (Dep of Appl Geol, Kuvempu Univ, Jnanasahyadri, Shankaraghatta, Shimoga-577 451, Email: devraj63@sancharnet.in) : Tremolite-olivine-phlogopite-bearing ultramafic enclaves in the archean migmatite gneiss near Naregal, Gadag District, Karnataka. J Geol Soc India 2006, 67(3), 312-16.

Polyphase migmatite gneiss exposed in the vicinity of Naregal contains unusual ultramafic enclaves with the modal composition of 50% tremolite, 21% olivine, 16% phlogopite, 10%- Cr-magnetite (with 5.6 wt% Cr₂O₃) and 2% anthophyllite. Geochemically the enclaves resemble 'Barherton komatiite' in respect of high MgO, Ni, Cr and Low Al₂O₃ and TiO₂ and one of 'Wajrakarur kimberlite' plug rocks with reference to high K₂O₂ Rb, Zr and Ba. The finding suggests the possible existence of pristine crust in the northern part of the Western Dharwar Craton.

^ssc3 illus, 2 tables, 8 ref

006297   Chetty T R K (NO, Natn Geophys Res Inst, Hyderabad-500 007, Email: chettytrk@yahoo.co.in) : Contrasting deformational systems and associated seismic patterns in precambrian peninsular India. Curr Sci 2006, 90(7), 942-51.

Distinct geodynamic settings of the precambrian peninsular India exhibit contrasting deformational systems and associated seismic patterns. The architecture of Archaean Dharwar craton, characterized by a mosaic of block structure evident from various geological features, suggests continued tectonic activity since the Precambrian, making the region vulnerable to seismic activity. Block rotation seems to be a plausible model for explaining the mechanism of the Latur earthquake considering its structural fabric and associated geo-morphic features. The role of shear zone dynamics appears to be significant in understanding the seismic patterns in the Precambrian mobile belts like the Southern Granulite Terrain (SGT). The interface between the Dharwar craton and the SGT is marked by a crustal-scale shear zone system, namely the Cauvery Shear Zone (CSZ) with prolonged deformational history. The role of the CSZ in understanding the major geomorphic ridge, which lies just north of the CSZ, and associated seismicity, is examined. A new tectonic hypothesis is proposed involving a north-verging blind thrust emanating from the base of the CSZ, which would be responsible in generating the geomorphic ridge, and associated seismic activity. Northward movement of the Indian plate seems to be the root cause of continued tectonic activity in the Indian shield, but differs in the deformational systems depending on their crustal architecture of distinct geodynamic settings.

9 illus, 44 ref

006296   Chaujar R K (NO, Wadia Inst of Himalaya Geol, Dehra Dun-248 001, Email: r_chaujar@hotmail.com) : Lichenometry of yellow Rhizocarpon geographicum as database for the recent geological activities in Himachal Pradesh. Curr Sci 2006, 90(11), 1552-4.

Growth rate and colonization delay of yellow Rhizocarpon geographicum species of lichen are recorded to date recent geological activities at four different localities in Himachal Pradesh. The study involved the measurement of the largest sized specimen growing on the well-dated monuments. Correlation of size with age, by plotting the measurements on a graph and finding the best fit line, gives the rate of growth of lichens (per year) and colonization delay, the time taken by the lichen to grow on a surface after its exposure to the atmosphere. It has been found that colonization delay and growth rate in the four localities namely Sanjoli, Kanlog (both in Shimla), Dharamshala and Dalhousie are 24, 68, 50, 86 yrs and 0.73, 0.79, 0.56, and 0.54 mm/yr respectively. Colonization period was also confirmed by the absence of lichens on the recent monuments prior to the calculated dates. The database will be useful to date the recent geological activities in the region.

2 illus, 14 ref

006295   Changkakoti A;Pandalai H S;Gray J;Ahmad S; Perasud E R (Earth Sci Dep, The Univ of Melbourne, Parkville, Victoria, Australia, 3052) : Origin of fluorite mineralisation and hydrothermal alteration at the Chandidiongri deposit, Rajnandgaon district, Central India - evidence from oxygen and hydrogen isotopes. J Geol Soc India 2006, 67(1), 33-40.

Economic mineralization relatable to the early-Proterozoic Dongargarh granite that forms part of a large volcano-plutonic complex of Central India includes the Chandidongri fluorite deposit located on the granite, a few small deposits of uranium in sheared rhyolites and basic rocks in close proximity to the granite, and minor Cu±Pb mineralisation within sheared rhyolitess. In the fault-controlled fluorite deposit at Chandidongri, the δ¹⁸O values of fluorite-bearing quartz range from 11.4 to 13.8 per mil, whereas δ¹⁸O values of quartz from intensely altered granites range from 13.0 to 14.4 per mil. The δD values of fluid inclusion waters extracted from vein-quartz, fluorite and quartz from altered granites range from -32 to -52, -38 to -40 and -48 to -60 per mil respectively. The δ¹⁸O values and measured δD values indicate a dominantly meteoric source for the fluorite and alteration fluids that may have undergone slight mixing with magmatic water.

3 illus, 2 tables, 33 ref

006294   Chakraborty D;Chakraborty A;Santra P;Tomar R K;Garg R N;Sahoo R N;Ghosal Choudhury S;Bhavanarayana M;Kalra N (Div of Agric Phys, Indian Agric Res Inst, New Delhi-110 012, Email: cdebashis@rediffmail.com) : Prediction of hydraulic conductivity of soils from particle-size distribution. Curr Sci 2006, 90(11), 1526-31.

Study deals with the prediction of hydraulic conductivity, K, as a function of water content (θ) of 12 soils of Andaman Islands, India, three each in clay loam, sandy clay loam, sandy clay and clay textures, from their particle-size distribution (PSD) data using the Arya-Paris model. Pore-size distribution of soils was derived from PSD data using the model and K(θ) was determined by the horizontal infiltration method. Twenty soils, five each with the above-mentioned textural classes were used to relate the pore flow rate (q) and the pore radius (r) using the parameters c and x as obtained from the Hagen-Poiseuille equation for an idealized porous medium, log(c) varied from -5.58 to 0.17 and x varied from 2.41 to 3.95, but no systematic trends were observed for the textural classes, except the value of x approaching 4 as the sand content in the samples increased. The model predicted unsaturated hydraulic conductivity with reasonable accuracy. The root mean square residuals (RMSR) of the log-transformed K(θ) for all textures ranged from 0.107 to 0.879. The intra- and inter-textural uncertainties in the prediction could be attributed to the heterogeneity in the observed (experimental) data, which originated from the difference in hydrophysical behaviour of the soils.

4 illus, 2 tables, 19 ref

006293   Beyarslan M;Kali B (Dep of Geol Engng, Firat Univ, Elazig, Turkey, Email: mbeyarslan@firat.edu.tr) : Geology of the region between Darica-Asagiulupinar villages and origin of the Kepezdagi volcanics, Malatya, Turkey. J Geol Soc India 2006, 67(3), 387-93.

The Kepezdagi volcanics of Middle-Upper Miocene age occur between Kozluca and Balaban in the western part of Maratya (in the Eastern Taurus Orogenic Belt). These unconformably overlie Yenice and Balaban Formations of Eocene age and constitute one of the youngest volcanics of the Eastern and Southeast Anatolian Regions. These units are composed of basalt and andesite lava flows and pyroclastic rocks. The petrographic and geochemical data presented in the paper indicates that the Kepezdagi volcanics are formed from magmas derived in the mantle. These magmas are effected by subduction enrichment, assimilation and contamination during their ascent through the crust.

10 illus, 1 table, 22 ref

006292   Anbazhagan S;Ramasamy S M (Earth Sci Dep, Indian Inst of Technol Bombay, Mumbai-400 076, Email: anban@iitb.ac.in) : Evaluation of areas for artificial groundwater recharge in Ayyar basin, Tamil Nadu, India through statistical terrain analysis. J Geol Soc India 2006, 67(1), 59-68.

Approach of selecting suitable areas for artificial groundwater recarhge structures through remote sensing and integrated terrain analysis by statistical method has been presented. The study area "Ayyar basin" is an aquifer system of gneisses and charnockite litho-units in Tiruchirappalli district, Tamil Nadu. The area has witnessed a steady decline in groundwater table. Hence, the scope for artificial groundwater recharge was studied in this area with the help of Tamil Nadu State Council for Science and Technology (TNSCS&T). Numerical database was generated for water level, lineament density, slope, drainage density, soil type, thickness of soil, thickness of weathered zone, thickness of fractured zone and depth to bedrock through remote sensing and hydrogeological study. These nine variabels were used as input parameters and factor analysis with varimax rotation was carried out. In the factor analysis, the factor in which the variabels loaded significantly were considered for further analysis. Using factor scores, the domains where the water level was deeper with decrease of slope and drainage density, and increase of lineament density, thickness of soil, thickness of weathered zone, thickness of fractured zone and depth to bedrock were buffered out. The buffered domains derived from each factor were finally integrated and thus the entire study area was fragmented into a number of domains suitable for artificial recharge. Such statistical output has not only helped to identify the suitable locations for artificial recharge but also indicated their controlling terrain characteristics, thus leading to the prioritization of area for specific method of cost effective recharge.

4 illus, 5 tables, 23 ref

005226   Verma N;Mishra D D;Dixit S (Dep of Chem, Govt Geetanjali Girls P.G. Coll, Bhopal-462 016, Email: savitadixitl@yahoo.com) : Effectiveness of aeration units in improving water quality of Lower lake, Bhopal, India. Asian J expl Sci 2006, 20(1), 87-95.

Effectiveness of aeration units, have been studied in the Lower Lake, which is situated in Bhopal, the capital city of Madhya Pradesh, India. The Lower lake (Lat 23° 16' 00" N and Long 77° 25' 00" E ) is an artificial lake. It is situated towards the east end of the Upper lake and is an integral part of the latter. It has a small catchment area 9.60 sq.km. and water spread of 1.29 sq.km. The extent of water pollution has been found to minimize by aeration units. The physico- chemical parameters like pH, Dissolved Oxygen, Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD) nitrate, phosphate and bacteriological status have studied to ascertain the effectiveness of aeration unit. The floating fountain cum ozonizer installed at Neelam park station is more effective unit as it increases Dissolved Oxygen Concentration, reduces Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) and the ozonizer installed at Khatlapura is also effective to increase Dissolved Oxygen concentration in the hypolimnion and control total coliform (MPN). Study indicates the aeration units especially dual systems are very effective in improving the water quality of a degraded water body.

7 illus, 15 ref

005225   Valdes-Lozano D S;Real E (Centro de Investigacion y de Estudios Avanzados Km. 6 Antigua Carreter, , C.P. 97310, Merida, Yucatan, Mexico, Email: dvaldes@mda.cinvestav.mx) : Sediment oxygen consumption in a development coastal lagoon of the Mexican Caribbean. Indian J Mar Sci 2006, 35(3), 227-34.

Nichupte is estuarine lagoon connected to the Caribbean Sea by two channels with very high levels of organic carbon in sediments, which ranged from 1.56 to 9.29%, with the maximum concentration at the northeastern zone, known as Bojorquez, a section with high greater anthropogenic impacts. The rate of sediment oxygen consumption (measured in the laboratory) during summer (July) was 292 mmol O₂ m^-2 d^-1 at Bojorquez, with a mean value of 70 mmol O₂m^-2d^-1. During winter (January), at the same site, the rate increased to 309 mmol O₂m^-2d^-1 (average 125 mmol O₂ m^-2 d^-1). The total average for both seasons (summer and winter) was 97 mmol O₂ m^-2 d^-1. For the whole lagoon system (48.3 km²), the total oxygen consumption by sediments was 4.6 x 10⁶ mol O₂ d^-1. During summer, the net input of oxygen from the sea to the lagoon was 1.6 x 10⁵ mol 0₂ d^-1, decreasing towards winter (1.5 x 10⁵ mol O₂ d^-1). The oxygen input from sea to lagoon, represented only 3% of the oxygen consumed by sediments, indicating that, if some of the oxygen sources like photosynthesis or wind re-aeration are interrupted or diminished, hypoxia might occur, particularly at Bojorquez zone.

3 illus, 3 tables, 45 ref

005224   Tripathi K C;Das I M L;Sahai A K (K.Banerjee Cent of Atmospheric & Ocean Stud, Univ of Allahabad, Allahabad-211 002, Email: drimldas@yahoo.com) : Predictability of sea surface temperature anomalies in the Indian Ocean using artificial neural networks. Indian J Mar Sci 2006, 35(3), 210-20.

Artificial Neural Networks (ANN) have been used to access the predictability of sea surface temperature (SST) anomalies for the small area of Indian Ocean Region (27° to 35° S and 96° to 104° E). Twelve networks, corresponding to each month, have been trained on the area average SST values. The performance of the networks has been evaluated and found that the models have been able to predict the anomalies with a reasonably good accuracy. The performance of ANN models has been compared with the Linear Multivariate Regression model to justify the use of a nonlinear model. It has been found that whenever the dependence of present anomalies on the past anomalies show a nonlinear relationship, the linear model such as regression models fails to make any forecast. These are the months of June, September, October and November. In such cases the nonlinear ANN models have been proved to be fairly useful and make relatively better forecasts. When the dependence is linear, the performance of the ANN models is similar to the regression models. In such cases, use of ANN models only leads to increase in complexity without significant improvement in the performance.

5 illus, 3 tables, 26 ref

005223   Thomas J V;Sreedevi C;Kurup B M (Sch of Industrial Fish, Cochin Univ of Sci and Technol Fine Arts Avenue, Kochi-682 016, Email: madhukurup@hotmail.com) : Variations on the infaunal polychaetes due to bottom trawling along the inshore waters of Kerala (south-west coast of India). Indian J Mar Sci 2006, 35(3), 249-56.

Variations of the infaunal polychates populations due to bottom trawling were studied during December 2000 to November 2002 at depth ranging from 0-50 m along Cochin-Munambam area (Kerala, long.76°10'94''to 75°56' and lat. 9°58'to 10°10''), in the southwest coast of India. Infaunal polychaetes from the sediment samples were collected both before and after experimental trawling in order to assess the variations on their abundance (no.m^-2), biomass (g.m^-2) and diversity due to bottom trawling. Highest variations in polychaetes were recorded at station 9 in May 2002 where polychaete abundance increased to 20710 no.m^-2 after trawling from 2787 no.m^-2 before trawling. Biomass showed highest variations at station 3 in December 2000 where biomass increased from 7.16 g.m^-2 recorded before trawling to 34.53 g.m^-2 in the samples collected after trawling. Multivariate community analysis carried out based on both species abundance and biomass of polychaetes also confirm the wide variations in the similarities of the stations comparing both before and after trawling.

6 illus, 2 tables, 33 ref

005222   Subrahmanyam V;Subrahmanyam A S;Murthy K S R; Murty G P S;Sarma K V L N S;Suneeta Rani P;Anuradha A (Regional Cent, Natn Inst of Oceanography, 176-Lawson's Bay Colony, Visakhapatnam-530 017, Email: svan@nio.org) : Precambrian mega lineaments across the Indian sub-continent - preliminary evidence from offshore magnetic data. Curr Sci 2006, 90(4), 578-81.

Marine and airborne magnetic data over south Indian continent including the western and eastern continental margins between latitudes l2°30'N and 10°N were studied and interpreted. The total intensity magnetic anomalies over the south Indian continental block between 10°45'N and l2°30'N exhibit distinct character compared to the adjoining northern and southern blocks. The study revealed the presence of two Precambrian mega lineaments over a stretch of 750-800 km running in east-west direction. They were mapped approximately from the isobath of 1500 m in the western continental margin, across the south Indian Peninsula and through the eastern continental margin up to a water depth more than 3000 In. These mega lineaments may be acting as a crustal junction/contact between two major geological provinces, viz. the Southern Granulite Terrain (SGT) and the Dharwar Craton. In addition to these two mega lineaments, major faults have been inferred, which acted as controlling parameters to create a bulge/bite in the coastline off Cuddalore. The continent-ocean boundary/transition on the Eastern Continental Margin of India (ECMI). may be the offshore boundary for these two Precambrian mega lineaments.

2 illus, 9 ref

005221   Sridhar A R;Pradeep Kumar A;Uma Shankar; Thakur N K (NO, Natn Geophys Res Inst, Uppal Road, Hyderabad-500 007) : Presence of illites in Bay of Bengal - an analysis of the sample obtained from GEODROME. Curr Sci 2006, 90(4), 574-8.

GEODROME stands for Geophysical Deep-water Research Observatory for Multidisciplinary Experiment. The instrument can withstand up to a depth of 6000 m with its full operational conditions. GEODROME is a benthic station measurement consisting of several modular structures for research of geophysical and geochemical processes at the sea bottom. The multi-parameter geophysical and geochemical measurements from the instrument would provide knowledge about earthquake processes taking place in the marine environment. It may also provide insight about the ongoing physical and chemical processes in the subsurface. The stand-alone recording has facilities to record data for long periods. In the study author has analysed the sample collected during GEODROME experiment and some results are also presented.

4 illus, 1 table, 9 ref

005220   Sinha D K (NO, , 69/A, Ekdalia Road) : On recent Tsunamis : an analytic approach. Sci Cult 2006, 72(3-4), 107-14.

The tsunami on December 26, 2004 has rightly raked up a variety of issues, dominantly conceptual; also there are consequential upshots which need to be considered in terms of futurities on such phenomena. Deals with a brief critique of developments in this direction. With this as part of the layout, it seeks to pose some relevant problems that need to be addressed. Then it proceeds to set forth a model approach with its raison d'etre adn salients. The societal foci are not dispensed with. The basic objective here of presenting an analytical approach has been set forth against the backdrop of globality of concerns and the vulnerability of the areas of occurrence. That a synergy of culture and sicentific temper is called for permeates throughout the paper.

2 illus, 6 ref

005219   Singh U K;Tiwari R K;Singh S B;Rajan S (Natn Cent for Antarctic & Ocean Res, , Vasco, Goa-403 804, Email: upendra_ngri@rediffmail.cElectrical resistivity) : Prediction of electrical resistivity structures using artificial neural networks. J Geol Soc India 2006, 67(2), 234-42.

Artificial neural network (ANN) technique is, at present, most efficient and modern tool for parameter estimation and inversion of geophysical data. With the application of ANN technique for the inversion of vertical electrical resistivity sounding (VES) data obtained from the NNW-SSE part of Banner district, Rajasthan. The efficiency of ANN technique is tested first on synthetic resistivity data generated from the numerical model and then trained on the actual VES field data. The analyses predict sediment thickness of the order of 172m at Rawtra (S-15), and indicate that there is possibility of fresh aquifers at all sounding locations along the profile except at Sonadi (S-1). These results match with the depth-resistivity structure obtained by the conventional method. However, the high accuracy and faster ANN imaging system seems to have highly correlated with that of conventional method for mapping the complex subsurface resistivity structures with less ambiguity. These finding also correlate remarkably well with known drilling results and geologic boundaries.

7 illus, 20 ref

005218   Rai S P;Vijay Kumar;Singh O;Bhishm Kumar;Jain S K (Natn Inst of Hydrology Western Himalayan Regional Cent, , Satwari Jammu Cantt-180 003, Email: spr@nih.ernet.in) : Bathymetry, sedimentation rate and physico-chemical characteristics of Mansar lake in the Himalayan foothills, Jammu and Kashmir, India. J Geol Soc India 2006, 67(2), 211-20.

An attempt has been made to workout the bathymetry, determine the rate of sedimentation and the physico-chemical characteristics of the Mansar lake of Jammu region. The bathymetric survey conducted using Range-line method shows present lake surface area is 0.59x10⁶ m² and volume to be 11.57xl0⁶ m³. The rate of sedimentation determined using ¹³⁷Cs and ²¹⁰Pb radiometric dating technique in the lake varies between 0.14 cm/y to 0.37 cm/y with a mean rate of 0.23 cm/y±0.002 cm/y. The variation of temperature, pH, electrical conductivity, dissolved oxygen, hardness and alkalinity suggest that Mansar lake undergoes two distinct stages, viz. complete mixing stage in the months of January and February and stratified stage in other months. The catchment lithology contributes a large part of the major constituents in lake water; Ca and Mg account 70 to 85% of the cations and HCO₃ accounts for 77 to 91% of the total anion, and equivalent ratio of Ca:Mg varies from 0.45 to 6.40. The average (Ca+Mg)/HCO₃ equivalent ratio of 1.04, major contribution of (Ca+Mg) to total cations and high (Ca+Mg)/(Na+K) ratio indicate that weathering of calcareous sandstones and mudstones of the Siwalik Group could be the primary source of major ions in the lake water. Results of phosphorous show that Mansar lake has entered the eutrophic stage.

8 illus, 1 table, 19 ref

005217   Raghu V;Sastry D V J;Mruthyunjaya Reddy K (A.P. St Remote Sens Applics Cent (Apsrac) 2nd Floor, , DES Campus, Email: raghuvangeepuram@rediffmail.com) : Oozing of water in wells and agricultural fields of certain villages in Ranga Reddy and Mahabubnagar districts, Andhra Pradesh. J Geol Soc India 2006, 67(2), 151-8.

A devastating mega thrust earthquake of magnitude 9.3 occurred on 26th December 2004 at the interface of India and Burma Plates. This triggered a tsunami that lashed south coastal Andhra Pradesh causing damage to life and property. This event was followed by a strange phenomenon of sudden rise in groundwater levels at some villages in Ranga Reddy and Mahabubnagar Districts. Unusual rise in water levels was observed in old, dried and abandoned wells and in some agricultural fields, which created a flutter among local population. A preliminary investigation carried out in parts of Ranga Reddy and Mahabubnagar Districts reveals that all the villages where oozing of water was observed, are located adjacent to structurally controlled streams. Except Pirampalli all the villages are located in WNW-ESE direction and located between two major faults trending in the same direction. Detailed further investigations could reveal the underlying cause for such strange occurrences.

^ssc6 illus, 1 table, 19 ref

005216   Rabinowitz C;Douek J;Weisz R;Shabtay A; Rinkevich B (Natn Inst of Oceanography Israel Oceanographic & Limnological Res, , Tel Shikmona, P.O. Box 8030, Haifa 31080, Israel, Email: buki@ocean.org.il) : Isolation and characterization of four novel thraustochytrid strains from a colonial tunicate. Indian J Mar Sci 2006, 35(4), 341-50.

Thraustochytrids, a common group of marine eukaryotic protists, are the major contaminants of invertebrate primary cell cultures. Attempted to isolate thraustochytrid species from primary cultures of extirpated buds of the colonial tunicate Botryllus schlosseri. Four new strains (termed BS3-BS6) were isolated. Cells of these strains subjected to three media conditions, showed different growth patterns and cellular morphologies. Phylogenetic (18S rDNA) and AFLP analyses revealed two-band patterns, one characteristic to strains BS3 and BS5 and the other to strains BS4 and BS6. A Sequence analysis showed 98% identity between strains BS3 and BS5, and 100% identity between strains BS4 and BS6. Distance analysis tree showed that the four new strains were primarily related to two other thraustochytrids strains, independently isolated from the same tunicate species a few years ago. It is suggested that the six closely related thraustochytrid strains isolated from Botryllus schlosseri reveal a biological association between the tunicate and a clade of species/cryptic species of thraustochytrids, which can be identified by molecular markers, growth patterns and cellular characterizations.

6 illus, 1 table, 31 ref

005215   Prakash Narasimha K N;Krishnaveni ;Prasad P S R;Ramalingaiah H;Venu Gopal J S (Dep of Geol, Univ of Mysore, Mysore-570 007, Email: prakashnarasimha@yahoo.com) : Vermiculite in the Gopalpura area, Karnataka-A mineralogical study. J Geol Soc India 2006, 67(2), 159-63.

Vermiculite mineralization in the Gopalpura area, Karnataka in the Archean supracrustal rocks of the Sargur Group occurs as discontinuous lenses and pockets within the ultramafic rock and at the contact with acid intrusives. Detailed mineralogy as studied using microscopy, X-ray diffraction, infrared spectroscopy, differential thermal analyses, and electron microprobe analyses are presented. The probable origin of the vermiculite from biotite through hydrobiotite has been discussed.

^ssc4 illus, 1 table, 21 ref

005214   Panchang R;Nigam R;Linshy V;Rana S S;Ingole B (NO, Natn Inst of Oceanography, Dona, Paula, Goa-403 004, Email: prajani@nio.org) : Effect of oxygen manipulations on benthic foraminifera: A Preliminary experiment. Indian J Mar Sci 2006, 35(3), 235-9.

Three sediment cores were collected at 50 m water depth on the west coast of India, off Ratnagiri, and were subjected oxygen manipulations maintaining natural temperature and salinity. The objective was to understand foraminiferal response to changed oxygen conditions. After a fortnight, the experimental cores were sub-sectioned and analyzed for their live foraminiferal content. This data was compared with background field data obtained from the non-experimental core. The data indicate that any change in natural oxygen conditions causes lowering of foraminiferal numbers. It is clearly evident that Fursenkoina and Nonions are more adaptive to changed oxygen conditions in contrast to Bolivinids and Rotalids, which quickly die out. This study clearly demonstrates the change in foraminiferal distribution in response to oxygen changes. This experimental study further can help develop foraminifera as a proxy to decipher the past fluctuations in the OMZ in the past, including assessment of their anthropogenic origin.

2 illus, 14 ref

005213   Nair K M;Padmalal D;Kumaran K P N (LBS Cent for Sci and Technol, , Thiruvananthapuram-695 033) : Quaternary geology of south Kerala sedimentary basin. J Geol Soc India 2006, 67(2), 165-79.

The South Kerala Sedimentary Basin (SKSB), extending along the coast between Kollam and Kodungallur, is the landward extension of the offshore Kerala-Konkan Basin (KKB). The SKSB has a fill of about 700 m of sediments, of which <62> 80 m are made up of Quaternary sediments, the rest being Miocene formations. Data from over 120 bore holes drilled for groundwater extraction from Tertiary aquifers, geotechnical investigations and stratigraphic studies form the basis of this paper. Based on sediment characteristics and tectonic setting, the SKSB can be divided into three separate blocks: (a) Southern Block (uplifted during Pleistocene end), (b) Central Depression (undergoing subsidence from Early Miocene to Present) and (c) Northern Block (uplifted during Pleistocene-Holocene transition but undergoing subsidence during Holocene). The Late Pleistocene sedimentary sections, indicate continental environments at the bottom. The marine influence during Pleistocene predates 42 ky BP. Ecology and environment deduced from sedimentology, palynology-micropalaentology and geochemistry suggest climatic variations from higher-than-present to low rainfall rates during deposition of Pleistocene sediments. Holocene sedimentation also started in continental environments. The marine transgression giving rise to littoral-lagoonal environments dates back to 7-6 ky BP. The high precipitation in Holocene gradually got reduced and by ca 3.5 ky BP the area witnessed prolonged exposure and development of ferruginous palaeosols. Within the constraints imposed by insufficient samples and inadequate geochronological data, the paper gives a broad picture of the structural framework, stratigraphy, palynology and depositional environments of SKSB. From these, inferences on sea level oscillations, palaeoclimatic variations and depositional environments are made.

8 illus, 3 tables, 35 ref

005212   Mishra D C;Rajasekhar R P (NO, Natn Geophys Res Inst, Hyderabad-500 007, Email: dcm_ngri@yahoo.co.in) : Bhuj earthquake of 26 January 2001: tectonic inversion, lithospheric flexure and plate motion and comparison with Shillong and New Madrid earthquakes. Curr Sci 2006, 90(4), 504-6.

3 illus, 30 ref

005211   Khare N;Chaturvedi S K (Natn Cent for Antarctic and Ocean Res, (Ministry of Earth Sciences) Headland Sada, Vasco-da-Gama, Goa-403 804, Email: nkhare@ncaor.org) : Size variations of planktonic foraminiferal population in the Indian Ocean sector of Southern Ocean. Indian J Mar Sci 2006, 35(3), 221-6.

Twenty five surface sediment samples (comprising Peterson Grab, Piston, Gravity and Spade core top samples) were collected along a north-south transect (between 9.69° N and 55.01° S latitude and 80° E and 40° E longitude). On the basis of overall size, the total planktonic population has been divided into two groups (<62> 120 μm sized population and <60>120 μm sized population). The results show an apparent interrelationship between shell size and variations in hydrographic conditions such as food availability/nutrition (phosphate) of ambient water masses. It is apparent that nutrients play a significant role in determining the size of the foraminiferal population and an increase in the nutrient supply is conducive for the growth of the planktonic population.

3 illus, 3 tables, 31 ref

005210   Kar R K;Ambwani K;Dutta D;Kar R (NO, Bribal Sahni Inst of Palaeobotany, 53, University Road, Lucknow-226 007, Email: ratankar@yahoo.com) : Major floral turnover at mahadeo-langpar formational boundary above K/T Iridium layer: Is it facies controlled. J Geol Soc India 2006, 67(2), 180-8.

The Um Sohryngkew river section at Therriaghat, Meghalaya, exposes Mahadeo (Maastrichtian) and Langpar (Danian) Formations extensively. The palynological investigation of the topmost Mahadeo and lowermost Langpar reveals an abrupt change in palynoflora at the formational boundary. The Maastrichtian index palynofossils viz. Azolla cretacea, Ariadnaesporites ariadnae, Mulleripollis bolpurensis etc. disappear at the uppermost Mahadeo. At the basal Langpar the assemblage is dominated by fungal and algal elements. On this basis the palynofacies turnover is demarcated within a 40 cm thick calcareous sandy shale underlain by the 3 cm thick highly carbonized shale. The palynological boundary corresponds with the lithological one demarcated by Pandey (1978, 1981), and is located 10 m above the foraminiferal, nannofossil, dinoflagellate boundary approximating the iridium rich level. The palynological data suggest no major catastrophic event at the iridium level with the major taxa continuing through. The major palynological break reported in the paper is at formational boundary and may be facies controlled as well.

6 illus, 1 table, 35 ref

005209   Kandpal G C;Joshi K C;Joshi D D;Singh B K; Singh J (Geol Surv of India, , Lucknow-226 024) : Signature of quaternary tectonics in a part of Dehradun valley, Uttaranchal. J Geol Soc India 2006, 67(2), 147-50.

Signatures of active tectonics have been observed in the eastern part of Doon valley in proximity to a lineament (fault?) cutting across the Himalayan grain. A normal fault has been observed over the Doon sediments represented by a sequence of silty clay, gravel and clay exposed in a quarry section. The fault displaces the litho sequence with a vertical throw of 1.5 m. This suggests tectonic movement along the fault during Quaternary period.

^ssc4 illus, 10 ref

005208   Kakade S B;Dugam S S (Div of Forecasting Res, Indian Inst of Trop Meteorology, Pune-411 008, Email: kakade@tropmet.res.in) : North Atlantic Oscillation and northern hemispheric warming. Indian J Mar Sci 2006, 35(3), 205-9.

Effect of Winter-NAO on northern hemispheric temperature and snow-cover is studied because North Atlantic Oscillation (NAO) fluctuations are strongest in the winter season. The correlation analysis, for the period 1973-2003, suggests that winter-NAO is inversely associated with Northern hemispheric snow-cover from winter through summer and the correlation coefficients are significant at 5% level. Moreover, NAO is showing direct relationship with northern hemispheric temperature during winter season. This relationship is also significant at 5% level. The stability of this relationship is tested and found to be stable. The correlation analysis further suggests that winter-NAO and global temperature difference between land and ocean have direct association, which is significant at 5% level. The effect of rising trend in winter-NAO may have resulted in decreasing northern hemispheric snow-cover, which ultimately results in warming of northern hemispheric temperature. The study suggests that NAO plays an important role in warming of northern hemisphere through decreasing northern hemispheric snow-cover extent.

4 illus, 17 ref

005207   Joshi A (Earth Sci Dep, Kurukshetra Univ, Kurukshetra-136 119, Email: anushijos@yahoo.co.in) : Three dimensional attenuation structure of the central seismic gap region of Himalaya obtained from inversion of seismic intensity data. Curr Sci 2006, 90(4), 581-5.

Central gap region of the Himalaya, which lies in the noorthern part of the Indian subcontinent, is exposed to a great seismic hazard. Due to paucity of existing seismic instrumentation we. have less digital data of past earthquakes in this region. With isoseismal data have used damped least square inversion scheme to get three-dimensional attenuation structure of the region based on Q value. The obtained Q structure explains the aerial distribution of isoseismals of major earthquakes in the recent past. The studied area covers the Tehri town, which is the locale of one of the biggest earth-fill dams of height 260 m. The surface distribution of Q value suggests that the region around Tehri is surrounded by comparatively less attenuating medium and hence is a region of potential seismic hazard. The obtained Q structure explains the surface distribution of isoseismals of major earthquakes and provides important inputs for the purpose of seismic hazard zonation.

4 illus, 24 ref

005206   Goutham M R;Raghubabu K;Prasad C V R K; Subbarao K V;Damodara Reddy V (Dep of Geophysics, Osmania Univ, Tirupati-517 502) : A Neoproterozoic geomagnetic field reversal from the Kurnool group, India: implication for stratigraphic correlation and formation of Gondwana. J Geol Soc India 2006, 67(2), 221-33.

The Proterozoic Cuddapah Supergroup is predominantly of normal magnetization but has a reversely magnetized level coinciding with the Srisailam Quartzite at the top of the succession. The Kurnool Group overlies the Cuddapah Supergroup with an unconformity and presented palaeomagnetic results from the Kurnool Group members comprising the Banganapalli Quartzite and the Narji Limestone. The Neoproterozoic Banganapalli Quartzite carries stable normal and reverse magnetizations suggesting a geomagnetic field reversal at the time of its formation. The Narji Limestone is normally magnetized. A similar magnetization to that in the Banganapalli Quartzite is reported <126>1000 km away in the Baghain Sandstone of the Vindhyan Supergroup. A possible correlation is made between Cuddapah Supergroup and Kurnool Group with the Vindhyan Supergroup. Based on palaeomagnetic poles, palaeolatitudes, palaeoclimatic and structural evidence it is suggested that India and Australia collided possibly during Neo-proterozoic times in an attempt to form larger Gondwana.

8 illus, 3 tables, 56 ref

005205   Gahalaut V K (NO, Natn Geophys Res Inst, Hyderabad-500 007, Email: vkgahalaut@yahoo.com) : 2005 Kashmir earthquake: not a Kashmir Himalaya seismic gap event. Curr Sci 2006, 90(4), 507-8.

1 illus, 14 ref

005204   Dwivedi A K;Hegde G N;Umamaheswar K (Dep of Atom Energy Atom Miner Directorate for Explor and Res, , Jamshedpur-831 002, Email: ak_dwivedi2003@yahoo.co.in) : Uranium mineralisation in the Gulcheru quartsite of Cuddapah basin, in the Tipparajupalle and Cheruvula bodu area, Cuddapah district Andhra Pradesh. J Geol Soc India 2006, 67(2), 197-200.

New occurrences of uranium mineralisation have been discovered in quartzite and siltstone/shale units of the Gulcheru Quartzite Formation in the area to the north of E-W trending Idupulapaya fault around Idupulapaya, Malayalamma Bhavi, Tipparajupalle and Cheruvula Bodu. Mineralisation occurs in the form of lensoid bodies of 5m x 0.5m to 50m x 1.5m and is traced intermittently over an extent of 2000 m. Physical assay result of rock samples (n=66) has indicated values from 0.011% to 1.769% eU₃O₈, 0.017% to 1.868% U₃O₈ and <60>0.01% ThO₂. Samples (n=21) also analysed higher concentration of Cu (<60>25 ppm to 3202 ppm), Mo (<60>25 ppm to 472 ppm), Pb (<60>25 ppm to 2015 ppm), V (<60>25 ppm to 1010 ppm), Ag (<60>0.25 ppm to 3.92 ppm) and Au (<60>0.25 ppm to 1.40 ppm). Uranium minerals identified are uranophane, autunite, uraninite, pitchblende and U-Ti complex in association with pyrite, chalcopyrite, specular haematite and limonite. The above findings have opened up new potential target areas to look for uranium in the southwestern margin of Cuddapah basin.

1 illus, 2 tables, 11 ref

005203   Diju S;Thamban M (Dep of Geol, Govt Coll Kasaragod, Vidyanagar, Kasaragod-671 123, Email: meloth@ncaor.org) : Clay mineral and textural variations in the sediments of Chandragiri river, estuary and shallow marine realms off Kasaragod, Kerala. J Geol Soc India 2006, 67(2), 189-96.

X-ray diffraction and textural studies were carried out on 25 surficial sediments collected from Chandragiri River, estuary and shallow marine areas off the river located in Kasaragod district, Kerala for understanding the provenance of the clay minerals. The riverine sediments are dominated by sandy silt to silty sand, whereas the estuarine sediments consist of clayey silt to silty sand and the shallow marine sediments are dominated by clayey silt. Kaolinite and gibbsite dominate the sediments with minor amounts of illite and smectite with the complete absence of chlorite in all depositional environments, supporting the intense chemical weathering occurring in the study area. Illite is relatively higher in the shallow marine sediments compared to the estuarine and riverine sediments, suggesting the influence of morphological characteristics of clay minerals and hydrodynamic conditions in their lateral distribution. Smectite is subtly and systematically higher in shallow marine environment, which is attributed to the fine size nature of this mineral. Although various processes may redistribute clay minerals within the aquatic systems, it is possible to identify the source rocks and weathering characteristics from the detrital clay mineral studies. The major source rocks contributing towards the clay mineral distribution in the study area are the Precambrian crystalline rocks, laterites and the Tertiary sedimentary formations exposed along the coastal belt.

2 illus, 1 table, 43 ref

005202   Deeba F;Hossain D (Bangladesh Atom Energy Commn, BSMEC, Cox's Bazar-4700, Bangladesh, Email: fdeeba_geoaec@yahoo.com) : Subsurface mapping of the beani bazar anticlinal structure of Surma basin Bangladesh. J Geol Soc India 2006, 67(2), 201-10.

The Beani Bazar structure is located along the eastern margin of the Surma basin, Bangladesh. Results of interpretation of seismic and well data from this structure has been presented. Based on the analysis of seismic data and their correlation with well information, seven reflecting horizons could have been identified, viz. top of the Bhuban Formation (Middle Miocene), the lower gas sand, the upper gas sand, the Bokabil Formation (Upper Miocene), the Tipam Sandstone Formation, the Girujan Clay Formation and the Dupi Tila Formation (Plio-Pleistocene). Structural analysis shows that the Beani Bazar is a N-S trending unfaulted anticlinal structure with eastern flank slightly steeper than the western one. The gas producing sands of the Beani Bazar structure belong to Bokabil Formation. The seismo-stratigraphic study of this area allows to resolve all the formations in the section.

7 illus, 3 tables, 13 ref

005201   Cheng Y;Liu Y;Xu Q (Phys Oceanography Lab, Ocean Univ of China, Qingdao-266 003, Email: yugliu@mail.ouc.edu.en) : New wind wave spectrum model for deep water. Indian J Mar Sci 2006, 35(3), 181-94.

With the statistical relationships and equations, a new wind wave spectrum model for deep water is proposed in this study. In the new model, the total spectral energy level, the location of the maximum spectral energy (represented by location of spectral peak), and the width character of energy distribution (represented by the spectral steepness) at high frequencies located to the right of spectral peak of wind waves are all determined by the two basic parameters, i.e., the wind speed and the inverse wave age. The statistical relationships also show that with the same wind speed and wave age, the steepness of the wind wave spectrum at high frequencies located to the right of the spectral peak for field case is different from that for laboratory case. This is the main difference between field wind wave spectrum and laboratory spectrum. With the inverse spectral width, the new model is more appropriate to describe the real wind wave status. Compared with measurements in the Black Sea, the model calculated zeroth spectral moment m₀ and the spectral width are in both good agreements with measured data. Furthermore, the new model can match elevation spectrum data obtained by four-frequency microwave radar and other field measurements fairly well. The new model can describe better and explain the influence of the wind speed and wave age on the energy distribution of developing wind waves generated in open ocean, also it plays a significant role in the study of oceanic microwave remote sensing, especially for understanding the uncertainty of retrieved ocean environment variables.

13 illus, 3 tables, 31 ref

005200   Chamoli A;Srivastava R P;Dimri V P (NO, Natn Geophys Res Inst, Hyderabad-500 007, Email: chamoli_jp@rediffmail.com ) : Source depth characterization of potential field data of Bay of Bengal by continuous wavelet transform. Indian J Mar Sci 2006, 35(3), 195-204.

Wavelet transform is an efficient technique to interpret the potential field data. The continuous wavelet transform is used to locate and characterize the source of the potential field by transferring the data into an auxiliary space. The technique has been tested on several synthetic source anomalies and applied to potential field data from Bay of Bengal. Using free air gravity and magnetic data the mean depth to causative sources indicates presence of lithospheric flexure at the central part of profile across 85°E ridge. Using free air gravity data, it is inferred that mean depth to causative sources decreases from west to east across 90°E ridge along MAN-01 profile which indicates increase of sediment thickness across the ridge from east to west. The technique gives mean depth of the causative sources without any a priori information which can be used as a initial model in any inversion algorithm.

8 illus, 3 tables, 13 ref

005199   Ahmad A H M;Bhat G M;Khan A F;Saikia C (Dep of Geol, Aligarh Muslim Univ, Aligarh-202 002, Email: bhatgm@Indiatimes.com) : Petrography, diagenesis, provenance and tectonic setting of the sandstones of upper Katrol formation (Kimmeridgian) Nakhtarana area, Kachchh, Gujarat. J Geol Soc India 2006, 67(2), 243-53.

The sandstones of the Upper Katrol Formation were studied with a view to understand the nature of Kachchh basin in relation to provenance and tectonic setting in the vicinity of Nakhtarana area. These Upper Katrol sandstones are fine to coarse grained, moderately to poorly sorted, sub-angular to sub-rounded and of moderate sphericity. These sandstones are composed of several varieties of quartz, feldspar, rock fragments, micas and a suite of heavy minerals derived from the Aravalli Range and Nagarparkar massif. Study reveals that these sediments were derived from the continental block orogen provenance characterized by collision suture and fold thrust belts. Three types of cement encountered in this study include iron oxide, calcite and silica. Evidence of diagenetic modifications suggests an early stage of burial to a depth of 748 to 932 m for these sandstones. Porosity reduction is mainly due to early stage mechanical compaction and subsequent pervasive calcite and Fe - calcite cementation, which was followed by the late stage authigenic kaolinization in the secondary pore space.

11 illus, 5 tables, 27 ref

005198   Achuthan C;Rejish Kumar V J;Manju N J;Philip R;Bright Singh I S (Natn Cent for Aqu Anim Hlth, Cochin Univ of Sci and Technol Fine Arts Avenue, Cochin-682 016) : Development of nitrifying bacterial consortia for immobilizing in nitrifying bioreactors designed for penaeid and non-penaeid larval rearing systems in the tropics. Indian J Mar Sci 2006, 35(3), 240-8.

Two ammonia oxidizing (AMOPCU-1 and AMONPCU-1) and two nitrite oxidizing (NIOPCU-1 and NIONPCU-1) consortia for activating nitrifying bioreactors and thereby establishing nitrification in penaeid and non-penaeid hatchery systems were developed by enrichment. For further amplification of the consortia a simple medium having seawater (either salinity 30% or 15%) as base, supplemented with NH₄+-N/NO₂-N and PO₄ and pH adjusted to 8 was identified. During the amplification in a fermentor the consortia exhibited excessive wall growth and diminished their yield coefficient posing difficulty in harvesting the cells completely. The consortia consisted of both Gram negative and Gram-positive bacterial cells embedded in a mucilaginous matrix of glycocalyx - like material presumably composed of polysaccharides. The consortia besides being useful in activating nitrifying bioreactors developed for shrimp/prawn hatchery systems can also be used as bioaugmentors in the bioremediation of ammonia and nitrite toxicity in aquaculture systems.

6 illus, 2 tables, 33 ref

004321   Yadav R P;Samra J S;Aggarwal R K;Agnihotri Y (NO, Cent Soil and Wat Conserv Res and Training Inst Res Cent, Chandigarh) : Effect of soil and water conservation measure on soil quality of degraded lands in Shivaliks. Int J Trop Agric 2006, 24(1-2), 165-75.

Soils of the Shivalik region are subjected to severe land degradation due to its fragile geology, land slope and sparse vegetation. Relmajra watershed in Nawanshahar district of Punjab was experiencing severest form of degradation and heavy silt load was getting deposited in agricultural fields down slope. An earth filled dam was constructed in 1992 to store rainwater for supplemental irrigations and save the fields from inundation and sand deposition. Suitable soil conservation measures were taken to rehabilitate the degraded lands of various types. Evaluation after eight years of its implementation revealed that severely eroded upstream site of dam was stabilized by establishing vegetative barrier of Saccharum munja on contour trenches. The silt retained behind these barriers had 20 and 6 times more available K than eroded portion in 0-5 and 5-15 cm depths, respectively. While annual silt deposited at surface had same organic carbon contents, sub-surface had its four times more accumulation. Jamun plantation with gypsum application in basins and poplar based silvi-pastoral systems reclaimed the alkali and waterlogged saline soils, respectively. Different alternative land uses with conservation measures decreased salt contents and pH and increased organic carbon.

5 tables, 8 ref

004320   Yadav D N;Chauhan M S;Sarin M M (Bhabha Atom Res Cent, , Trombay, Mumbai-400 085, Email: dny@apsara.barc.ernet.in) : Geochemical and pollen proxy records from Northeastern Madhya Pradesh: An appraisal of late-quaternary vegetation and climate change. J Geol Soc India 2006, 68(1), 95-102.

A 1.5 m deep sedimentary core from Jagmotha swamp in northeastern Madhya Pradesh has been analyzed for reconstruction of Late-Quaternary vegetation and climate change based on distribution of major/trace elements, organic carbon, nitrogen and pollen grains contained in the sediments. The combined geochemical and palynological results indicate a cool and dry climate between 6000 to 5000 yrs BP representing a tree savannah type vegetation followed by warm and moist climate between 5000 to 3000 yrs BP. Such a drastic change in climate promoted tropical mixed deciduous forests in the region. Subsequently, between 3000 to 1200 yrs BP, the climatic condition got further improved with enhanced precipitation in the region marked by the advent of sal tree in the forest floristics. Since then, the climate has been inferred conducive for development of modern sal forests in the region.

3 illus, 4 tables, 21 ref

004319   Thakur V C;Jayangondaperumal R;Champatiray P K;Bhat M I;Malik M A (Wadia Inst of Himalayan Geol, , Dehra Dun-248 001, Email: thakurvc@wihg.res.in) : 8 October, 2005 Muzaffarabad earthquake and seismic hazard assessment of Kashmir gap in Northwestern Himalaya. J Geol Soc India 2006, 68(2), 187-200.

The 8 October 2005 Muzaffarabad earthquake was the deadliest earthquake in the history of Indian subcontinent. Its epicenter located 10 km northeast of Muzaffarabad lies in the Indus Kohistan Seismic Zone (IKSZ), which represents northwestern continuation of the microseismicity and moderate earthquakes belt of Garhwal, Kumaun and Nepal. A multi-institutional team undertook post-earthquake studies along the LOC and adjoining areas in Tangdhar, Uri and Poonch sectors of Kashmir, India. The Tangdhar area lying on the hanging wall and the Uri area close to the rupture zone have suffered much more damage in comparision to the Poonch region located on the footwall. An isoseismal map of the earthquake affected region has been prepared on the basis of observations and website data. The opened-up cracks and lateral spreads mapped in the Tangdhar and Uri region show both right-lateral as well as left-lateral strike-slip and vertical motions of a few cm to 30 cm. The Mw 7.6 Muzaffarabad earthquake has ruptured a segment -80 km x 50 km west of the closure of Kashmir Valley. An earlier mapped active fault of en echelon nature, trending NW-SE and extending from Balakot to Muzaffarabad and further southeast along the eastern bank of river Jhelum, coincides with linear-trend of the aftershocks belt and the rupture plane of the earthquake. The knowledge gained through this earthquake implies that a seismic gap of a similar size of unruptured segment that lies between the 1555 Kashmir (Mw 7.5) and 1905 Kangra (Mw 7.8) earthquakes, where there is no historical record of a large earthquake for more than 500 years, may be ripe for a large event.

10 illus, 18 ref

004318   Sreenivasan G;Majumdar T J (NO, Regional Remote Sens Serv Cent, Nagpur-440 010, Email: tjmajumdar@sac.isro.gov.in) : Mapping of antarctic sea ice in the depletion phase: an indicator of climatic change. Curr Sci 2006, 90(6), 851-7.

The mapping and monitoring of the sea ice variability in the polar regions is of prime importance for global climate modelling. Apart from sea ice, spatial snow cover variability and depth estimates are needed for accurate assessment of many climate parameters required in the ice-ocean models. Mapping and analysing the spatial and temporal variability of Antarctic sea ice and snow cover are therefore highly important for polar ice-pack studies in the global climate cycle. The present study has been carried out mainly for sea ice mapping surrounding Antarctica using Special Sensor Microwave Imager (SSM/I) passive microwave data during its depletion phase (November 2001 to January 2002). Sea ice concentrations and snow depths over the Antarctic sea ice have been calculated and their temporal variation patterns studied. The overall extents under all ice concentration categories during different months over the study period have decreased in the order of 1 to 3 million km² in comparison to the sea ice concentration categories during 1978-87 period. The thermal conductivity of snow is about an order of magnitude less than the sea ice. Hence the presence of small amount of snow on sea ice can greatly affect the heat flux between the sea surface and atmosphere. Depletion in snow depths over sea ice (from 1988-94 to 2001-02) could be observed particularly in December, though not much change has been observed in November and January. These changes (shrinking ice covers/depletion in sea ice concentration) can be attributed to some locally changing weather patterns in the Antarctic continent as well as due to regional phenomenon like global warming.

5 illus, 1 table, 23 ref

004317   Somani R L (Dep of Geol, Univ of Raj, Jaipur-302 004, Email: rlsomani@sancharnet.in) : Genesis of granite hosted tungsten mineralization at Balda, Rajasthan: constrains from granite geochemistry and fluid inclusions. J Geol Soc India 2006, 68(2), 239-50.

The Balda Granite is spatially associated with tungsten mineralization that owes its genesis to the associated magmatic hydrothermal system. The wolframite mineralization is confined to quartz veins and greisenized pegmatites located along the shear zones in the Balda Granite. Balda Granite is intruded into the Erinpura Granite. Balda Granite is characterized by high SiO₂, K₂O, W, Sn, Rb, Nb, Rb/Sr and low TiO₂, Ba/Rb, and K/Rb ratio indicating its highly fractionated nature and as a result was enriched in aqueous volatile constituents. Fluid inclusion studies indicate that hydrothermal activity involved three types of fluids. A high salinity fluid 45-58 eq.wt% NaCl of probably magmatic origin and homogenization temperature up to 430°C was associated with greisenization of granite. A low salinity (5.4 to 9.0 eq.wt.% NaCl) carbonic fluids containing variable amount of CO₂ with temperature of homogenization between 255° to 355°C was associated with most of the wolframite mineralization in shear zones in the granite. This lower salinity carbonic fluid was derived from mixing of fluids. Third low salinity aqueous fluid (4.92 to 12.2 eq.wt.% NaCl) having homogenization temperature between 360° to 170°C was associated with deposition of fluorite and possibly derived from meteoric sources. B and F were introduced and Na was depleted during hydrothermal alterations. The presence of tourmaline and fluorite suggest that various B and F complexes partition W from melt phase. W was transported mainly as H₂WO₄°, HWP₄^- and WO4^2- and alkali tungustate ion complexes. Various P, Cl complexes and CO₂ also favor W transportation and precipitation in many ways.

7 illus, 2 tables, 45 ref

004316   Singh L N;Lal T;Agrawal A K;Singh S L;Singh N (Geol Surv of India Nth Region, , Lucknow-226 020) : Induced polarisation in search of lead-zinc mineralisation in Sawar belt, Ajmer district, Rajasthan. J Geol Soc India 2006, 68(2), 213-24.

Lead-zinc mineralisation in Sawar metasedimentary belt is essentially sediment-hosted type. It is of Proterozoic age and occurs in the two-carbonate members of Sawar group. Induced Polarisation cum resistivity survey has delineated 22 anomaly zones located in lower marble, lower schist and upper marble and at the mutual contacts formed by these different litho-units of Sawar group. Out of these, eight zones have been drill tested proving mineralisation and the remaining 14 zones in the area are yet to be tested. Drilling results in the area have clearly indicated that there is a fair correlation between induced polarisation cum resistivity anomalies and mineralised zones intersected in the different boreholes. Induced Polarisation cum resistivity pseudo depth sections constructed in few zones located over different rock units have established depth persistence of inferred shallow conductors. The resistivity survey has demarcated the contact of different litho-units of Sawar group occurring in the area even under soil cover. The lithocontacts inferred from resistivity data coincide fairly accurate with extrapolated geological contacts. The interpretation of induced polarisation and resistivity pseudo sections by inversion technique has brought the model and its geometry, which compares well with the subsurface geology. The resistivity model correlates the measured and calculated apparent resistivity pseudo sections. The chargeability model also corroborates these inferences.

9 illus, 2 tables, 27 ref

004315   Singh K J;Goswami S;Chandra S (Birbal Sahni Inst of Palaeobotany, , 53, University Road, Lucknow-226 007, Email: kamaljeet31@hotmail.com) : Megafloral assemblage similar to Karharbari biozone from Talchir coalfield of Mahanadi basin, Orissa. J Geol Soc India 2006, 68(2), 277-87.

A rich collection of plant megafossils have been studied from the rocks of Karharbari Formation (Early Permian=Lower Artinskian) at South Balanda Colliery (Latitude 20° 56' Longitude 85° 14'), Talchir Coalfield, Angul district, Orissa. The lower Gondwana rocks in this coalfield have been represented by Talchir, Karharbari, Barakar, Barren Measures and the Kamthi Formations (in ascending order) representing earliest Permian to Late Permian. Palaeobotanical studies have been extensively carried out in the past by a number of workers in almost all the Lower Gondwana formations except the Karharbari Formation. Megafloral assemblage has been recovered for the first time from Karharbari sediments of the Lower Gondwana deposits in this coalfield. The specimens are preserved as impressions and compressions on blackish grey fine-grained shales of the South Balanda Colliery exposed just above the carbonaceous shales. The lowermost coal seam i.e. seam no. 1/Karharbari seam of this coalfield exists below the above-mentioned two shale bands. The megafloral assemblage consists of Phyllotheca westensis, Noeggerathiopsis hislopii, Euryphyllum whittianum, E. maithyi, Macrotaeniopteris feddeni, Buriadia heterophylla, Glossopteris browniana, G. communis, Gangamopteris cyclopteroides and Surangephyllum elongatum. The genus Buriadia dominates the total assemblage (about 80%). The assemblage has been compared thoroughly with the known megafloral assemblages of Karharbari Formation.

2 illus, 1 table, 64 ref

004314   Shaw R (Grad Sch of Global Enviromental Stud, Kyoto Univ, Kyoto, Japan, Email: shaw@global.mbox.media.kyoto-u.ac.ip) : Critical issues of community based flood mitigation: examples from Bangladesh and Vietnam. Sci Cult 2006, 72(1-2), 62-71.

River flooding is regarded as a natural, although chronic, disaster in many parts of Asia. A combination of soft and hard measures is required for flood mitigation. However, due to resource constraints, the efforts are mostly restricted to soft measures. Community-based initiatives are more effective in most of the developing countries in Asia, especially if they have a focus on the empowerment of local communities and link community based activities to local development policies. Community based flood mitigation programs are often faced with two critical questions: issues of sustainability and issues of scaling-up. Analyzes community-based approaches to flood mitigation in Bangladesh and Vietnam, two countries which have contrasting sociopolitical systems. The common findings in this regard are: 1) local institutions (both formal and informal) play a critical role in sustaining flood mitigation efforts, 2) integration of community initiatives into government policies and practices is important to scale-up the efforts, 3) local change agents play crucial roles in grassroots implementation, and 4) synergy of grassroots efforts with development policy is regarded as the measure of success of a project's implementation.

5 illus, 30 ref