011943   Kumar c P;Mittal S;Srivastava S L (Hard Rock Regional Centre, National Institute of Hydrology, Belgaum-590 001) : Soil moisture retention characteristics at RD 838 of I.G.N.P. State-II. J appl Hydrol 2001, 14(2-3), 17-21.

Mathematical models of hydrologic and agricultural systems require knowledge of the relationship between soil moisture content (θ), soil water pressure (h) and unsaturated hydraulic conductivity (K). Hence, a sustained research effort towards the parameterisation of K(H) and h(θ) has resulted in the development of several laboratory, field and theoretical methods. Presents the soil moisture retention characteristics at RD 838 of Indira Gandhi Nahar Pariyojana, Stage - II. A total of 15 soil samples were collected from 4 locations at different depths. Extensive laboratory measurements were made for each soil sample collected. Soil bulk density, particle density and porosity were measured for each soil sample. Saturated hydraulic conductivity was measured through Permeameter. Retention data was obtained through pressure plate apparatus. Parameters of water retention function of the van Genuchten model were determined through non-linear regression analysis.

1 illus, 1 table, 2 ref

011942   Kalantari N (Geology Department, Chamran University, Ahwaz, Iran) : Chemistry of spring water in carbonate rock of the fariab area in southern Iran. J appl Hydrol 2001, 14(2-3), 43-8.

Occurrence, movement, and chemical characteristics of groundwater are controlled by lithology and permeability distribution of aquifer that make up the groundwater system. It is also generally accepted that characteristic of groundwater in carbonate rocks is almost determined from saturation status of water in relation to carbonate minerals. But saturation indices of carbonate system depend on several parameters, such as recharge, discharge, distance between recharge and discharge and deposition of calcite in aquifer before issuing from water bearing formation. Collected data from two springs in the study area indicate direct interdependence between fracture density, recharge, partial pressure of CO2 and saturation indices of carbonate mineral in fracture zone, whereas such relationship is not observed in other springs. Describes relation between fracture density, discharge and saturation index in spring water in carbonate rock of Fariab area.

2 illus, 4 tables, 8 ref

011941   Jain C K;Bhatia K K S;Kumar S R (National Institute of Hydrology, , Jal Vigyan Bhawan, Roorkee-247 667) : Ground water contamination in greater Guwahati, Assam. Indian J envir Prot 2000, 20(9), 641-8.

Ground water quality of Greater Guwahati is presented with reference to trace element contamlnation. The various elements analysed include Cu, Co, Cd, Fe, Zn and Pb. The trace element analysis of ground water samples has revealed that the concentration of iron in ground water is much higher than the tolerance limit prescribed for drinking water. The maximum concentration recorded was 3.58 mg/L. The presence of iron above acceptable limit in drinking water often imparts alien taste and inky flavour. It can also discolour cloths, plumbing fixture and cause scaling which encrusts pipes. Excessive concentration of iron may promote bacterial activities in pipes and cause objectionable odours and red - rod disease in water.

1 illus, 1 table, 32 ref

011940   Gangadhara Rao M;Subbarao C;Prasad N V B S S; Eswara Rao K S;Murthy D N (Department of Geophysics, Andhra University, Visakhapatnam) : Impact of intensive agriculture on the distribution of potassium in the groundwater of lower Godavari deltaic basin. J appl Hydrol 2001, 14(2-3), 59-67.

Chemical analyses are carried out on groundwater samples collected from dugwells as part of a hydrogeological survey from different parts of lower - Godawari Deltaic region. The area of investigation covers 1657.5 Sq.Km. bounded between latitudes 16°22' and 16°45'N and longitudes 81°45' and 82°15'E. The results indicate higher concentrations of potassium in ground water. The content of potassium in dugwell waters of this area is ranging from 2 ppm to 150 ppm, with an average value of 68 ppm Potassium fertilizers are extensively used in this area for increasing the crop yield. Potassium content of these waters crossing 50 ppm is considered as a indicating of pollution. This may be due to intense water logging nature of the area which poses a threat to the hydrological environment of this area. Deals with a identification of high concentrations of potassium in study area in both pre and post monsoon periods due to impact of intensive agriculture and Coastal environmental on groundwater quality. The studies of mole fraction K/Na, correaltion between conductivity and total dissolved solids and relation of potassium with depth to the water level are indicating the degree of pollution due to higher salinity.

5 illus, 5 tables, 6 ref

011939   Dwivedi S;Tiwari I C;Bhargava D S (NO, , D - 1/2, River Bank Colony, Lucknow) : Classification of water quality of river Ganga at Varanasi. Indian J envir Prot 2000, 20(9), 688-97.

Variations in water quality are discussed with regard to the several water quality variables and a water quality index (WQI) respresenting the integrated effect of the concentrations and relative importance of the variables is used to denote degradation of the river quality. WQI values indicate a deterioration in water quality towards the downstream side due to additional discharge of sewage at successive downstream points and bathing ghats all along the river. Results also show relatively constant water quality conditions down the years from 1985 - 88. Significance of coliforms for assessing the sanitary water quality conditions is highlighted. A comprehensive strategy is presented for improving the water quality of the river.

4 illus, 6 tables, 8 ref

011938   Dasgupta Adak M;Purohit K M (Department of Chemistry, Regional Engineering College, Rourkela-769 008) : Correlation coefficient of some physico - chemical characteristics of surface and ground waters of Rajgangpur - I. Indian J envir Prot 2000, 20(9), 681-7.

Twenty nine physico - chemical parameters of water from 8 sampling points to Rajgangpur municipal area were monitored from March 1999 to February 2000 and the values obtained were compared with standards prescribed by Bureau of Indian Standards (BIS), Indian Council of Medical Research (ICMR), and World Health Organisation (WHO). Then corresponding water quality Index (WQI) and correlation coefficient were worked out for the observed water quality parameters. Analysis of results showed that the experimental waters are suitable for drinking purpose except pond water.

5 tables, 5 ref

010852   Vijaya S V;Rao Y R S;Rao S V N;Ramasastri K S (NO, National Institute of Hydrology, Deltaic Regional Centre, Kakinada-533 003) : Base flow characteristics of three rivers of subzone 4(A) along east coast of India. J appl Hydrol 2001, 14(4), 37-44.

Rainfall -runoff process is an important part of land phase of hydrological cycle. Depending upon the catchment geomorphology surface runoff, interflow, sub-surface runoff or baseflow combine to form total runoff. As the low flows are the contributions from the discharges of the aquifers to the rivers, they depend on the drainage and the geotechnical properties of the formations of river basin. The amount of baseflow increases after the recharge of ground water and it gradually diminishes during periods of no recharge. If low flows are successfully to be predicted at a site indexing hydrogeology of the catchment is very important. Base flow indices (BFI's) are estimated for three east flowing rivers of sub-zone 4A, namely the Rishikulya at Purushottampur in Orissa, the Nagavali at Narayanapuram Anicut and the Sarada at Anakapalli in Andhra Pradesh using the daily mean discharges at the four sites.

6 illus, 6 ref

010851   Valdiya K S;Kotlia B S (NO, Geodynamics Unit, Jawaharlal Nehru Centre for Advanced Scientific Rese, Bangalore-560 064) : Fluvial geomorphic evidence for late quaternary reactivation of a synclinally folded nappe in Kumaun Lesser Himalaya. J Geol Soc India 2001, 58(4), 303-17.

In parts of Kumaun Lesser Himalaya terrane that is defined by the very active Main Boundary Thrust and Main Central Thrust, tectonic strain is progressively building up due to horizontal compression with resultant crustal shortening. Consequently, the thrust that bounds a synclinal nappe of Precambrian crystalline rocks has been reactivated in the Late Pleistocene and Holocene times. The neotectonic movements along the nappe-bounding thrust and associated faults within the nappe and in the adjacent autochthonous terrane are manifest in the pronounced geomorphic rejuvenation of the landscape, the development of rugged mountain barriers along the active thrusts and the dismemberment and dislocation of Late Quarternary fluvial terraces, lacustrine flats and colluvial cones. The resultant stream ponding culminated in the formation of lakes behind recently uplifted blocks upstream of active faults. Formed within the fluvial regimes and stretching 7 to 11 km upstream of the neotectonic impediments, the lakes are represented by 10 to 13 m thick succession of clays and muds. Radiocarbon dates of the lacustrine clay and mud in eastern Kumaun indicate the timings of the reactivation of these faults of the synclinal Almora Nappa at <128><62> 35 ka and 9 ka. Several other palaeolakes in the Himalayan province originated in the temporal interval of 35 to 40 ka.

11 illus, 36 ref

010850   Sitaram M V D;Yadav D K;Goswami K (Geoscience Division, Regional Research Laboratory, Jorhat-785 006) : Study on crustal structure beneath Arunachal Himalaya and Assam. J Geol Soc India 2001, 58(4), 285-301.

A study of travel times for Pg, P^* and Pn waves is conducted for the three profiles along the Main Central Thrust (MCT) and Main Boundary Fault (MBF) in Arunachal Himalaya and the Bramaputra Lineament (BPL) in Assam, in order to obtain seismic velocities and the thicknesses of the upper and lower crust and the depth to Moho. These profiles roughly pass through the locations of seismic stations and the epicentres of the earthquakes used in this study. 143 earthquakes with magnitudes 2 to 5.5 and depths of 10 to 20 km during the period 1985-1997 were used to carry out the study. Velocities 6.01±0.15, 6.57±0.13, 8.31±0.07 km/sec along the MCT, 6.0±0.1, 6.54±0.13 and 8.24±0.14 km/sec along the MBF and 5.90±0.04, 6.37±0.08 and 8.01±0.07 km/sec along the BPL for Pg, P^* and Pn waves were obtained. The corresponding thickness of upper and lower crust are 28±1.6, 23.8±0.2 km for the MCT; 25.1±1.4, 23.8±0.2 km for the MBF and 21.5±1.5, 23.8±0.2 km along the BPL (ig 2). A 6.5 km thickening of upper crust from Assam towards Arunachal Himalaya is visualised.

10 illus, 6 tables, 46 ref

010849   Sharma J C;Jitendra Prasad;Saha S K;Pande L M (Department of Soil Science and Water Management, University of Horticulture and Forestry, Solan-173 230) : Watershed prioritisation based on sediment yield index in eastern part of Doon valley using remote sensing (RS) and geographic information system (GIS). Indian J Soil Conserv 2001, 29(1), 7-13.

Determines the priority categories of sub-watersheds of Song river watershed, eastern Doon valley, based on Sediment Yield Index (SYI). Landuse/landcover, physiography cum soils information obtained from IRS-IC LISS-III data and terrain slope information from topographiy maps were integrated to generate composite erosion intensity units (CEIUs). The delivery ratio and weightage values assigned to CEIUs were used as the inputs to SYI model. The SYI for each sub-watershed was computed using GIS techniques and priority categories were determined. Results indicated that out of the 25 sub-watershed 3, 5, 4, 9 and 4 numbers of sub-watersheds covering 12.36, 17.65, 11.63, 38.04 and 20.31 per cent area fell in very high, high, medium low and very low priority categories, respectively. Priority classification also exhibited that the sub-watersheds having high to very low SYI (priority categories I and II) were located in hills and mountainous areas, whereas, those belonging to medium to very low priority categories (III, IV and V) were mostly located in piedmont areas and in terraces (Ganga and Song terraces). Out of the total area of 1034.35 sq km, 310.31 sq km constituting about 30 percent fell under high to very high priority categories demanding immediate attention for soil and water conservation measures.

1 illus, 2 tables, 9 ref

010848   Sharma H C;Shiv Kumar;Ashok Kumar;Sharma S N (Department of Irrigation and Drainage Engineering, College of Technology, G.B. Pant University of Agriculture and Technol, Pantnagar-263 145) : Ground water quality of phreatic aquifer in Tarai belt of Udham Singh Nagar district. J appl Hydrol 2001, 14(4), 10-15.

Study was undertaken to assess the quality of ground water for its suitability for irrigation, industrial, human and livestock consumptions. Revealed that the ground water of the phreatic aquifer, in the Tarai belt of Udham Singh Nagar district, is not safe for human consumption due to high concentration of coliform bacteria. The ground water taken from hand pumps should not be consumed without proper treatment. The physico-chemical properties of the ground water show that it is mostly suitable for irrigation and industrial uses except at few places where the ground water was of bad quality as far as irrigation was concerned. It may be due to the presence of highly polluted effluents coming out of the paper mills, sugar mills and other industries located in the area.

2 tables, 6 ref

010847   Sankar K (Centre for Remote Sensing, Bharatidasan University, Tiruchirapalli) : Remote sensing study of groundwater occurrence in Kanyakumari district, Tamil Nadu, India. J appl Hydrol 2001, 14(4), 16-26.

Remote sensing techniques provide an effective modern tool employed for identifying groundwater potential zones. Geomorphological investigations have been carried out using IRS-IB LISS-II false color composites in the scale of 1 : 50,000 scale by visual interpretation techniques. Different geomorphic units such as shallow pediments, buried pediments, bajada zones, structural hills, residual hills and denudational hills were identified. Lineaments exist in the direction of N-S, E-W and NE-SW. Collateral data such as rainfall, watertable contour map, depth of weathered zone map, fractured zone map, water level fluctuations and bore well lithology are integrated and hydrogeomorphology map was prepared. Bajada zone, buried pediments and flood plains are most prospective zones for groundwater targeting. Occurrence of lineaments in such zones is also a favourable indicator.

10 illus, 15 ref

010846   Sangode S J;Suresh N;Bagati T N;Bloemendal J; Rohtash Kumar;Thakur V C (NO, Wadia Institute of Himalayan Geology, 33, G.M.S. Road, Dehradun-248 001) : Discovery of an aborted reversal (geomagnetic excursion) in the late pleistocene sediments of Pinjor Dun, NW Himalaya. Curr Sci 2002, 82(2), 210-15.

Reports the occurrence of an aborted reversal (geomagnetic excursion) in the Late Pleistocene sediments of Pinjor Dun near Chandigarh, NW Himalaya. The event discovered at <126> 697.5 cm level from the base of Kiratpur section corresponds to the OSL date of 40 ± 5 Ka coinciding with the Laschamp excursion¹ and palaeointensity minima² elsewhere. The Pinjor Dun sediments are deposited at a high rate of sedimentation that enables quite enlarged records of remanent geomagnetic field, hence suitable for further high resolution study of the excursion (under progress) to extend its utility as a stratigraphic marker in the Quaternary sediments at the foothills of the Himalaya.

6 illus, 22 ref

010845   Rao D M (Dept of Geo-Engineering and Resource Development Technology, College of Engineering, Visakhapatnam-530 003) : Groundwater resources in basaltic terrain of Jalana of Maharashtra state. J appl Hydrol 2001, 14(4), 55-9.

Development of groundwater resources in hard rock area, the basalitic terrain of Jalana District, is a complicated task. Hence, an interdisciplinary methodology has been adopted for the delineation of groundwater aquifers. The methodology utilises data inputs from aerial photographing thematic mapper products of Landsat, and surface drainage information from topographic maps. Geo-electrical surveys are conducted in the selected sites to arrive at the extent and occurrence of fracture zones and to compute possible yields. The fundamental objective of the methodology is to locate aquifers capable of giving better yields to fulfill the domestic needs.

3 tables, 6 ref

010844   Ramadass G;Ramaprasada Rao I B;Himabindu D; Srinivasulu N (Centre of Exploration Geophysics, Osmania University, Hyderabad-500 007) : Pseudo-surface velocities (densities) and pseudo-depth densities (velocities) along selected profiles in the Dharwar craton, India. Curr Sci 2002, 82(2), 197-202.

Pseudo-surface velocities were obtained from the density studies conducted along the Jadcharla-Panaji substransect that cuts across the northern part of the Dharwar cration, via an empirical velocity-density relationship. Velocities in the range of 3.62-4.43 km/s, 3.51-5.24 km/s and 3.68-9.73 km/s were computed for the three major constituents of the Dharwar craton-granites, peninsular gneisses and schists, respectively. Further, a pseudo-depth density graph was also obtained from the established depth-velocity functions along the Kavali-Udipi DSS profile and also in the Dharwar craton. The Kolmogorov-Smirnov statistical test was applied to these two data sets - to the pseudo-velocities along the Jadcharla-Panaji subtransect and the pseudo-densities along the Kavali-Udipi profile - to determine whether any difference existed in the lateral and/or vertical variation, between the eastern and western blocks of the Dharwar craton. Results from both the tests indicated that the samples belonged to different population distributions, implying a surface as well as depth variation between the eastern and western blocks of the craton, thus reinforcing their separate nature.

5 illus, 2 tables, 21 ref

010843   Rakesh kumar;Lohani A K;Sanjay Kumar;Nema R K (NO, National Institute of Hydrology, Roorkee-247 667) : GIS based morphometric analysis of Ajay river basin upto Sarath gauging site of South Bihar. J appl Hydrol 2001, 14(4), 45-54.

Geomorphological characteristics of a basin are very commonly used for developing the regional hydrological models for solving the various hydrologic problems of the ungauged basins or inadequate data situations. A number of hydrological studies have been carried out, wherein, various geomorphological and physical characteristics of the basins have been employed. Some of these studies include development of the regional flood formulas, regional unit hydrograph derivation, regional flood frequency analysis, geomorphological instantaneous unit hydrograph derivation and development of regional flow duration curves etc. Presents evaluation of some of the pertinent geomorphological characteristics which are commonly adopted for regionalization of the hydrological variables and time area diagram for the Ajay river basin upto Sarath gauging site of South Bihar, using geographical information system (GIS). For this purpose the GIS package, Integrated Land and Water Information System (ILWIS) has been used.

7 illus, 1 table, 11 ref

010842   Parvez I A;Panza G F;Gusev A A;Vaccari (NO, CSIR Centre for Mathematical Modelling and Computer Simulation, NAL B, Bangalore-560 037) : Strong-motion amplitudes in Himalayas and a pilot study for the deterministic first-order microzonation in a part of Delhi city. Curr Sci 2002, 82(2), 158-66.

Interdependence among the strong-motion amplitude, earthquake magnitude and hypocentral distance has been established¹ for the Himalayan region using the data set of six earthquakes, two from the Western Himalayas (WH) and four from the Eastern Himalaya (WH) (Mw = 5.2-7.2) recorded by strong-motion networks in the Himalayas. The level of the peak strong-motion amplitudes in the EH is three-fold larger than that in the WH, in terms of both peak acceleration and peak velocities. Includes the strong-motion data of Chamoli earthquake (Mw = 6.5) of 1999 from the western sub-region, to see whether this event supports the regional effect. The minimum estimates of peak acceleration (Apeak) for the epicentral zone of Mw = 7.5-8.5 events is 0.25-0.4 g for the WH and 1.0-1.6 g for the EH. Similarly, the expected minimum epicentral values of peak velocity (Vpeak) for Mw = 8 are 35 cm/s for WH and 112 cm/s for EH, respectively. The presence of unusually high levels of epicentral amplitudes for the eastern sub-region also agrees well with the macroseismic evidence¹. Therefore, these results represent systematic regional effects, and may be considered as a basis for future regionalized seismic hazard assessment in the Himalayan region.

6 illus, 1 table, 43 ref

010841   Mudholkar A V (NO, National Institute of Oceanography, Dona Paula, Goa-403 004) : Magmatic evolution of the fresh basalts from the ridge axis near Egaria Fracture Zone, Central Indian Ridge. J Geol Soc India 2001, 58(4), 329-39.

Fresh Mid-Ocean Ridge Basalts (MORBs) from the Central Indian Ridge (CIR) 20<128><144>12'S: 66<128><144>53'E), located north of the Rodriguez Triple Junction (RTI) are studied for their petrography and bulk composition along with mineral chemistry of plagioclase, olivine and spinels. Melt inclusions from plagioclases and olivines show post-entrapment depletion of oxides with the host mineral. Plagioclases and olivines show gradual changes in the anorthitic and forsteritic content (An=89 to 78; Fo=90 to 85) from the basalts under study. These gradual changes in the olivines and plagioclase point to a simple evolution of the basaltic magma by differentiating mineral phases from the parental basalt. The resorption features observed in high forsteritic olivines (<128><126> 89.90) and zoning in the high anorthitic plagioclases (<128><126> 90, 94) in fractionated host basalt indicate that these olivines and the plagioclases are xenocrystic to the host viz., evolved basalts. One basalt sample from a set of basalts has a near primitive composition (MgO <128><126> 9.50<128>%) and from this the remaining basalts seem to have fractionated. Major and trace element data reveal low-pressure crystal fractionation in a shallow level magma chamber within the crust. The chemical data of the basalts under study was run through a computer programme of the least square and mass balance calculations for understanding the evolutionary path by differentiating minerals present in these basalts. The results indicate that the basalts under study represent a set of basalts, with a parental basalt which is near primitive in its composition, and remaining have differentiated from this parental basalts. The chemical data of basalts under study has been compared with two published basalt data sets from the CIR for understanding the possible evolutionary sequences of basalts from CIR.

4 illus, 6 tables, 33 ref

010840   Mohanty S;Marathe R A;Shyam Singh (NO, National Research Centre for Citrus, Amravati Road, Nagpur-440 010) : Rainfall characteristics of Vidarbha region. Indian J Soil Conserv 2001, 29(1), 18-21.

Frequency analysis of the daily ranfall data of 33 years (1966 to 1998) collected at Nagpur, was carried out. Expected monthly, seasonal and annual rainfall values at different probability levels were determined. At 80 per cent probability, enough rainfall is available for growing kharif crops. The annual maximum daily rainfall value, which is important for design of hydraulic structures and soil conservation measures, was determined for 50 and 100 years of return period and found as 252.1 and 282.6 mm day^-1, respectively. The depth - duration - frequency relations of rainfall of Nagpur was developed which may prove handy for drainage planning of different crops with varying degrees of crop tolerance to excess water.

1 illus, 1 table, 12 ref

010839   Lee B S (Department of Earth Science Education, Chonuk National University, Jeonju, 561-756) : Conodonts from the Cambrian succession of South Korea. J Geol Soc India 2001, 58(4), 319-28.

The lower Paleozoic Choseon Supergroup is widely distributed in the northeastern part of Ogcheon Zone, mid-eastern Korea, including the well-known sequences of Duwibong and Yeongweol. Since 1970, conodonts have been intensely studied to arrive at a precise biostratigraphic framework for the Cambro-Ordovician succession of Korea. Conodonts from the Middle Cambrian Daegi Formation of Duwibong sequence and Sambangsan Formation of Yeongweol sequence are very low in abundance and diversity and are poorly preserved. Six Late Cambrian conodont zones are recognized in Duwibong area, while two faunal assemblages are indentified in Yeongweol area. The conodont zones and assemblages are defined and briefly discussed. Conodont faunas between the two areas are correlated and their biostratigraphic implications are evaluated in terms of correlation with equivalent global zonal schemes.

5 illus, 2 tables, 38 ref

010838   Kumar C P;Vijay Kumar;Vivekanand Singh (Hard Rock Regional Centre, National Institute of Hydrology, Belgaum-590 001) : Soil moisture characteristics in upper part of Hindon river catchment. J appl Hydrol 2001, 14(4), 1-9.

Presents the field and laboratory determination of soil moisture characteristics and their variation along the Hindon river in its upstream reach. A total of 38 soil samples were collected from 14 sites in Aurangabad, Kamalpur, Budhakhera, Gagalheri and Dudhil Bukhara comprising around 24 km reach, upstream of Hindon river. Extensive laboratory measurements were made for each soil sample collected. Porosity was obtained for each soil sample. Saturated hydraulic conductivity was measured through ICW Permeameter in the laboratory. Retention curve data was obtained through presure plate apparatus. Unsaturated hydraulic conductivity function was indirectly derived through van Genuchten retention parameters by non-linear regression analysis.

1 illus, 3 tables, 4 ref

010837   Khadri S F R;Wagh T M (Deptt. of Geology, Amravati University, Amravati-444 602) : Nature of groundwater regime of Uma river basin exposed near Murtizapu region, Akola district Maharashtra, India. J appl Hydrol 2001, 14(4), 60-65.

^ssc3 illus, 4 tables, 3 ref

010836   Karisiddaiah S M;Veerayya M (NO, National Institute of Oceanography, Dona Paula, Goa-403 004) : Occurrence of pockmarks and gas seepages along the central western continental margin of India. Curr Sci 2002, 82(1), 52-7.

High-resolution seismic reflection profiling has revealed the occurrence of acoustic masking, pockmarks, gas seepages and plumes on the inner shelf, middle shelf and upper continental slope of western India, Between 20 and 50 m, 60 and 75 m, and 170 and 260 m water depths, respectively. A typical 40-km long seismic section trending in a NW-SE direction - from the upper slope is characterized by anticline-syncline structure and culminates toward the NW. In some places fluid or gas escape features and plumes appear 2-12 m above the seafloor. Active and relict-type pockmarks are noticed. Out of thirty well-recognized pockmarks along the section, six are buried. In general, the pockmarks are 80-130 m in diameter and 0.75-2.5 m deep. Biogenic gas due to organic-rich sediments in the slope or thermogenic gas emanating from deep-seated faults, fractures and lineaments in the region may have given rise to these features.

5 illus, 36 ref

010835   Kar G (NO, Water Technology Centre for Eastern Region (I C A R), Bhubaneswar-751 023) : Remote sensing and GIS techniques for land use planning - a case study in Yachram watershed, Andhra Pradesh. Indian J Soil Conserv 2001, 29(1), 77-81.

1 illus, 1 tables, 6 ref

010834   Jana S K;Das S S (Department of Geological Sciences, Jadavpur University, Kolkata-700 032) : Report of a 157.8 m.y.-old dinosaur bone from the Jurassic marine chari formation, Kutch, Gujarat and its taphonomic significance. Curr Sci 2002, 82(1), 85-8.

Describes the proximal part of hindlimb bone of a sauropod from the Middle Callovian horizon of Kutch, Gujarat. It was found in shallow marine shelf facies, associated with steno-haline faunas, e.g. brachiopods and ammonites. Co-occurrence of dinosaurs and ammonites is a rare phenomenon and specific identification of time-diagnostic ammonite species thus provides a precise 157.8 million years, when the present dinosaur lived. The bone is supposed to have been derived from a floating carcass and its marine association has taphonomic implications.

4 illus, 36 ref

010833   Hadda M S;Sur H S;Sandhu B S (Department of Soil, Punjab Agricultural University, Ludhiana-141 004) : Runoff and soil loss in foothills of Shiwaliks. Indian J Soil Conserv 2001, 29(1), 14-17.

The hydrologic response of micro-watershed to rainfall events was assessed through the analysis of hydrograph time parameters. The peak runoff rate per unit area and time to peak runoff is more in untreated microwatershed than that in treated microwatershed. The large coefficient of variation in runoff occurred from storm to storm in untreated micro-watershed (131.0%) than that in treated microwatershed (112.2%). The high values of land characteristics viz., drainage texture, lamniscate ratio and length of overland flow are observed in untreated microwatershed than that in treated microwatershed. The applied treatments and land characteristics played an important role in relation to runoff and soil loss in the area.

1 illus, 5 tables, 7 ref

010832   Gupta H K;Mandal P;Rastogi B K (NO, National Geophysical Research Institute, Hyderabad-500 007) : How long will triggered earthquakes at Koyna, India continue. Curr Sci 2002, 82(2), 202-10.

Continued occurrence of triggered earthquakes in the vicinity of the artificial water reservoir at Koyna, India over the past 39 years is comprehended in terms of Kaiser effect (water level exceeding the previous maxima), rate of loading and duration of retention of high water levels. It is inferred that the increase in heterogeneity of the media due to mechanical changes caused by the impoundment of the reservoirs may not permit occurrence of another M 6.3 earthquake. However, smaller (M <126> 5) earth-quakes will continue for another 3 to 4 decades.

4 illus, 3 tables, 24 ref

010831   Bhatt N Y;Shringarpure D M;Patel S J (Department of Geology, M G Science Institute, Ahmedabad-380 009) : Occurrence and palaeoenvironmental significance of sand domes and sand holes in sandstone of Chari formation near Bhuj, Kachchh, Gujarat. J Geol Soc India 2001, 58(4), 361-3.

Structures such as sand domes, sand holes and bubble/cavernous sand found in the Chari Sandstone of Kachchh owe their origin to trapping and escaping of air between two water saturated layers of sand in fluctuating tidal conditions.

^ssc3 illus, 11 ref

010830   Ballukraya P N (Dept of Applied Geology, University of Madras, Chennai-600 025) : Over-exploitation of groundwater: consequences and remedial measures. J appl Hydrol 2001, 14(4), 27-36.

Over-exploitation of groundwater in the area around Singalandapuram in Namakkal district of Tamil Nadu has caused serious decline in groundwater levels there resulting in the drying up of wells and borewells. The average depth of borewells here is about 175m at present and is likely to be around 240m by the year 2020. The groundwater levels in some pockets have declined to 60m below ground level. Drying up of wells has lead to a decrease in irrigated crop area in some of the villages, which has a serious impact on the development of the nation due to reduced agricultural production in the years to come. Construction of recharge structures seems to have resulted in decline of groundwater levels in areas slightly away from such structures, due to cessation of surface runoff. A scheme is suggested for conserving groundwater, which will help restore normal groundwater levels.

5 illus, 1 table, 6 ref

010829   Ashalatha B;Singh R N (NO, National Geophysical Research Institute, Hyderabad-500 007) : Effect of fluid circulation on the thermal structure of evolving lithosphere: application to Carlsberg Ridge. J Geol Soc India 2001, 58(4), 351-9.

The thermal structure of Carlsberg Ridge in the northwest Indian Ocean is discussed using the plate model with realistic thermal boundary condition at the ridge axis, which includes the effects of adiabatic cooling, magmatic crystallization and solidification. The elastic and brittle layer boundaries as predicted by the model are shallower when compared with results from earlier studies using gravity-bathymetry data across the ridge and seismicity at the axis of the ridge. In order to explain the observed anomalous structure, considers hydrothermal circulation as resulting in additional heat loss. This is incorporated in the thermal model by presenting lower temperature in the shallow regions at the axis where fluid flows could occur. The resulting thermal structure explains the observed elastic thickness and brittle layer thickness.

6 illus, 3 tables, 39 ref

010828   Anbarasu K (Centre for Geosciences and Engineering, Anna University, Chennai-600 025) : Facies variation and depositional environment of mesoproterozoic Vindhyan sediments of Chitrakut area, Central India. J Geol Soc India 2001, 58(4), 341-50.

Chitrakut Formation of the Mesoproterozoic Semi Group is exposed in and around Chitrakut Town, Banda District, Uttar Pradesh and Satna District, Madhya Pradesh. The normal stratigraphic sequence of Semri Group is interrupted at Lodhwara, Sangrampur-Kamtanath and Muradpur hill sections in the Chitrakut subbasin due to vertical and lateral facies variation. Inpact of relative sea-level fluctuations, low clastic sediment imput and uneven topography have controlled the deposition of these lithounits in shallow subtidal - peritidal environmental complexes, dominantly in intertidal settings.

3 illus, 3 tables, 51 ref

009882   Vijaya Kumar K;Ratnakar J (NO, School of Earth Sciences, Swami Ramanand Teerth Marathwada University, Vishnupuri, Nanded-431 606) : Petrogenesis of the Ravipadu Gabbro pluton, Prakasam province, Andhra Pradesh. J Geol Soc India 2001, 57(2), 112-40.

Ravipadu gabbroic rocks are primarily hypersthene and olivine normative; they do not contain quartz or nepheline in the norm. Textures, mineral assemblages and mineral- and whole-rock chemistry indicate that the Ravipadu gabbros could be formed by crystal-liquid fractionation of subalkaline tholeiitic magma under reducing (anhydrous) conditions. The tholeiitic nature is also re-affirmed by Fe-enrichment as the parental magma evolved. The chondrite normalized REE patterns show enriched LREE, convex downward MREE and almost flat HREE trends with positive Eu anomalies for all the rocks. Petrographic features and geochemical traits accord cumulative status to the rocks and they do not represent melt compositions. Parental melt REE concentrations are calculated by utilising exploratory geochemical inversion techniques. The calculated parental liquids display enriched LREE and flat HREE trends. The variation in the concentrations of REE calculated from different cumulate rocks represents progressive evolution of a parental magma by fractional crystallization. Petrogenetic modelling suggests that the parental liquids are derived by 5 to 10% melting of an LREE enriched komatiite/tholeiite source in the deep crust. This source could be an underplated Late Archaean crust and this deep crustal melting might have been induced by the heat released from a mantle plume.

14 illus, 10 tables, 67 ref

009881   Vasanthi A;Mallick K (NO, National Geophysical Research Institute, Hyderabad-500 007) : Patterns of occurrence of Kimberlite pipes based on gravity and magnetic anomalies in Wajrakarur-Lattavaram region, Andhra Pradesh. J Geol Soc India 2001, 58(3), 251-9.

Kimberlite pipes of Wajrakarur-Lattavaram region in Andhra Pradesh follow some definite depending on regional geology, structure and tectonics. The lithotectonic units with contrasting physical properties often find expression in geophysical measurements. Although direct detection of buried kimberlite pipes by geophysical methods is often difficult, judicious integration of geology, tectonics, and geophysics may suggest favourable zones for detailed investigations. Based on the distribution of 13 kimberlite pipes discovered so far in the Wajrakarur-Lattavaram region, and on the regional and residual Bouguer gravity and residual magnetic maps derived by a finite element approach, authors has attempted to recognize patterns of occurrence of kimberlite pipes. A few potential regions are identified mainly at the intersections of the NE-SW trending faults and the contacts of granites and country rocks.

5 illus, 17 ref

009880   Valdiya L (Geodynamic Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore-560 064) : River response to continuing movements and the scrap development in central Sahyadri and adjoining coastal belt. J Geol Soc India 2001, 57(1), 13-30.

The northerly-trending faults have caused not only pronounced deflection of rivers and streams and development in some places of loops and hairpin geometry of drainage, but also present-day stream ponding. The modification of Holocene landforms including the deep incisions across ridges in the undulating terrain, the descent of old winding rivers as waterfalls and cascades through deep gorges across fault-delimited ridges, the occurrence of planar scraps and triangular facets devoid of gullies or with a few straight furrows, the repeated blockage of streams as they cross or follow the NNW-SSE trending faults, and the higher-than-normal seismicity indicates geologically recent and continuing tectonic movements in the fault-riven Sahyadri and coastal domains. In the western margin of the Dharwar Craton, the Central Sahyadri mountain emerged from the erosion surface, that lay a little above the sea-level, as a consequence of pronounced vertical movements accompanying northward strike-slip displacement along the NNW-SSE faults. The northerly push of the fault-delimited blocks caused breaking up at their edges on the ESE-WNW oriented reverse faults and shear zones, giving rise to peculiar rightside-overstepping arrangement of the high mountain ranges and en echelon configuration of the more than 700 m high Western Ghat escarpment...

15 illus, 51 ref

009879   Tomar A S;Ranade D H (AICRP on Dryland Agriculture, College of Agriculture, J.N.K.V.V, Indore-452 001) : Pan coefficient determination for evapotranspiration at Indore, Madhya Pradesh. Indian J Soil Conserv 2001, 29(2), 173-5.

Site-specific value of pan coefficient for different seasons has been worked out to compute reference evapotranspiration (ETM0) instead of using the generalized value of pan coefficient based on the meterorological classification. Futher the Penman method modified by Doorenbos and Pruitt (1977) is used to calculate the value of pan coefficient for different climatic (summer, monsoon and winter) and cropping (zaid, kharif and rabi) seasons, By considering these values for calculating ET0 optimum irrigation water has been worked for different crops in and around semi-arid Indore region of Madhya Pradesh.

5 ref

009878   Suner F;Esenli F;Uz B;Esenli V;Hayder Gultekin A (Mining Faculty, Department of Zoology, Istanbul Technical University, 80626, Maslak, Istanbul) : Significance of REE study of origin of sparry magnesite in Orhaneli region, Turkey. J Geol Soc India 2001, 58(3), 231-7.

Pattern of REE distribution in various type of magnesite ore occurring within the Late Cretaceous ultramafics in Orhaneli Region (Western Anatolia) were studied to interpret their genetic significance. The samples were classified into three different groups viz. massive, lentiform and pignolite or stockwork. Individual groups exhibit distinctly different REE distribution patterns with variable Eu, Ce and Yb anomalies. Three types of REE distribution patterns are recognizable with the following characteristics : high LREE/HREE ratios without having Ce and Eu anomalies, similar LREE and HREE abundance with uncertain positive and negative Eu and Ce anomalies, and low REE abundance with markedly positive Eu, negative Ce and slightly negative Yb anomalies. It is postulated that the redox conditions in the primary mineral formation system was subjected to change and as a result, subsequent mobilization followed by recrystallization took place in the formation of primary magnesite minerals. Although a low temperature environment is indicated for magnesite formation, it is possible that REE-poor solutions derived from the fluid-rock interaction had caused mobilization and later recrystallization of magnesite ore.

5 illus, 2 tables, 14 ref

009877   Sinha D K;Raju K A;Veera Bhaskar D ;Asha K (Atomic Minerals Directorate for Exploration and Research, , Jaipur-302 018) : Sulphur isotopic characteristics of pyrite and galena from the Singhora group, Chattisgarh supergroup, India : genetic implications. J Geol Soc India 2001, 57(2), 171-7.

Rocks of Singhora group, Chattisgarh supergroup, deposited a protobasin, contain pyrite and galena near Juba and Banjhapalli villages of Raipur district, Madhya Pradesh. Veins of fluorite, quartz and quartzo-feldspathic material reported along the eastern and western margins of the protobasin contain galena and pyrite in the sedimentary rocks. Pyrites are developed diagenetically, epigenetically and by remobilization in Rehatikhol Formation of Singhora Group, while only epigenetic pyrite occurs in the basement. High positive δ³⁴S values (+31.58% δ³⁴S for 5 samples) for diagenetic pyrite indicate reaction between iron-bearing minerals and H2S and/or HS^-1 generated by reduction of seawater sulphate. High δ³⁴S values (+23.35%) for galena is due to reaction between diagenetic pyrite and base metal bearing fluids at elevated temperatures. The galena-pyrite pair developed epigenetically shows 135°C temperature for their formation at near equilibrium conditions. Galena grains collected from quartzo-feldspathic/quartz veins from the eastern margin of Singhora protobasin near Chiwarkuta village yielded δ³⁴S value of +11.1%, while pyrite from quartz veins of Birsinghpali-Kapudih tract of western margin has given δ³⁴S value of +3.3%..

3 illus, 3 tables, 18 ref

009876   Singh R P;Sahoo A K;Bhoi S;Girish Kumar M; Bhuiyan C (Department of Civil Engineering, Indian Institute of Technology, Kanpur-208 016) : Ground deformation of the Gujarat earthquake of 26 January 2001. J Geol Soc India 2001, 58(3), 209-14.

Gujarat earthquake of 26 January 2001 brought out changes on the land features and ocean parameters. Describes the changes observed on the land surface in the field and also from the satellite data. The results of resistivity soundings in the epicentral region reveal a low resistivity layer especially in the liquefaction sites. These sites are found to be the cause of sinking of the houses, whereas elsewhere the damage pattern was totally different.

6 illus, 9 ref

009875   Sikka A K;Singh D V;Samra J S (Research Centre, Central Soil and Water Conservation Research and Training Institute, Udhagamandalam-643 004) : Characteristic features, zonation and problems of western ghats for natural resource management. Indian J Soil Conserv 2001, 29(2), 107-17.

Hilly ecosystems of Western Ghats are fragile, but endowed with potentially rich natural resources. Presents physical and climatic features of Western Ghats, their zonation into different hydro-ecological regions, problems and also suggests the need of infrastructures and research linkages required to strengthen area based research and technology development activities as regard to Soil and Water conservation and Watershed Management in the Western Ghats. The entire stretch Western Ghats is classified into five Hydro-ecological Regions and ten hydro-ecological zones based on altitude, rainfall, soils, land use and vegetation. It is suggested to extend strengthen the research activities at three more locations, one each covering Low altitude Low and Medium Rainfall area (rain shadow area), Coastal Lower Ghats with High Rainfall and Mixed Vegetation and Coastal Lower Ghats with High Rainfall and Dense Vegetation, respectively.

2 illus, 3 tables, 12 ref

009874   Sikdar P K;Sarkar S S;Palchoudhury S (NO, Indian Inst Social Welf & Business Management, Dept Environm Manageme, Calcutta-700 073) : Geochemical evolution of groundwater in the Quaternary aquifer of Calcutta and Howrah, India. J Asian Earth Sci 2001, 19(5), 579-94.

During the last five decades, there is a distinct lowering of piezometric head in Calcutta and Howrah. The groundwater flow pattern changed from an open system, which was from north to south in the mid-1950s to a closed one in the mid-1980s with the formation of a groundwater trough. This closed flow system persisted in the 1990s with the increase in the area of the trough. Detailed geochemical investigation of groundwater samples (N = 57) along with statistical analyses (viz. correlation, principal component and mixing analyses) on these chemical data reveal : that the groundwater samples can be categorised into eight hydrochemical facies, which may be assigned to the three broad types - `fresh", `blended' and `brackish" water; a pronounced and well-defined trend of variation of chemistry of the groundwater; Modified connate water, and/or interaction with the aquifer matrix was possibly responsible for the evolution of the `brackish" water Mixing of `fresh" water and `brackish" water; (in ca 48:52 proportion) is presently taking place due to heavy groundwater withdrawl and such mixing will cause deterioration in quality, from `fresh" water to the `blended" variety (mean TDS = 724 mg/L.

29 ref

009873   Schill E;Appel E;Zeh O;Singh V K;Gautam P (ETH Zurich, Inst Geophys, , Honggerberg HPP 0 14, CH-8093 Zurich, Switzerland) : Coupling of late-orogenic tectonics and secondary pyrrhotite remanences: towards a separation of different rotation processes and quantification of rotational underthrusting in the Western Himalaya (northern India). Tectonophysics 2001, 337(1-2), 1-21.

Total amount of crustal shortening within the Indian plate includes straight forward and rotational shortening. The complex tectonic history of the western Himalaya impedes a direct observation of rotational shortening between India and its northern margin. A combination of palaeomagnetic results and tectonic structurres along a similar to 300 km NW-SE section, from NW-Zanskar (33.9 degress N, 76.5 degress E) to Malari (30.0 degress N, 79.6 Degrees E ) in northern India, enable a separation of rotations on different scales, correction of the observed rotations, and quantification of uniform rotational shortening. New palaeomagnetic results from metacarbonates of the Tethyan Himalaya in Sarchu, Losar, and Spiti and earlier studies from NW-Zanskar and Malari reveal a characteristic remanent magnetisation carried by pyrrhotite (unblocking spectrum: 250-330 degrees C). Negative fold tests (99% level) indicated remanence acquisition after the main folding of the Himalaya. The formation of pyrrhotite during thermal events (T<62> 200 degrees C) suggests a remanence acquisition related to exhumation and cooling. Temperatures of about 200-300 degrees C indicate a thermochemical remanence acquistition with an Eohimalayan age, dated in two areas by K-40/Ar-39 techniques on illites. The resulting rotation angles in respect to stable India show an `anomalous' counterclockwise rotation in NW-Zanskar and a trend of decreasing clockwise rotations to the SE.

44 ref

009872   Sarvothaman H (Geological Survey of India, , Bandlaguda, Hyderabad-500 068) : Archaean high-Mg granitoids of mantle origin in the eastern Dharwar craton of Andhra Pradesh. J Geol Soc India 2001, 58(3), 261-8.

Few xenoliths of high-Mg granitoids occur in the Archaean granodiorite and granite of Eastern Dharwar craton. They are composed of quartz, plagioclase, K-feldspar, clinopyroxene, biotite, ore and occasionally orthopyroxene. They show wide variation in silica content from 61.4 to 73 wt.%. The Mg-numbers in the units which contain 61.4 to 63.5 wt.% silica vary from 0.44 to 0.57; in the Total Alkalis-Silica diagram, these units plot in the fields of andesite, dacite and trachy-dacite, and in the QAP diagram they show quartz-monzodiorite composition. In the units which contain <62>65 wt.% silica, the Mg-numbers range from 0.43 to 0.51 and, in the normative Ab-An-Or diagram, they show granodiorite and tonalite compositions. These high-Mg granitoids show enrichment of Ba and Cr, and their chondrite normalised REE patterns display moderate slopes indicating LREE enrichment and HREE depletion. Quartz-monzodiorite reveals sanukitoidal geochemistry and it is likely to have been derived from a source which is LREE-rich and having high Mg-number such as the products of mantle peridotite. Fractional crystallisation of sanukitoid would have generated high-Mg granodiorite and tonalite.

6 illus, 2 tables, 17 ref

009871   Sam J A A;Ramasamy S;Makhnach A (Sedimentology Laboratory, Department of Geology, University of Madras, Chennai-600 025) : Stable isotope geochemistry and evidence for meteoric diagenesis in Kundankulam formation, Tamil Nadu. J Geol Soc India 2001, 57(1), 39-48.

Results obtained from stable isotope study of Neogene carbonates of Kundankulam, Tamil Nadu show negative values for δ¹³C, which range from -2.6% to -9.7% PDB. The δ¹⁸O values range from -4.5% to -11.4% PDB. The depleted nature of the δ¹⁸O and δ¹³C values suggests the strong effect of meteoric diagenesis in the Kundankulam carbonates. Standard bivariate plots of δ¹⁸O versus δ¹³C for carbonate materials/rocks helped to identify their depositional and diagenetic environments. Petrographic study points out large-scale emplacement of ferroan sparry calcite cement into vugs and other leached cavities.

009870   Roy Y H;Subrahmanyam C;Rastogi A;Deka B (Natl Geophys Res Inst, , Hyderabad-500007) : Anomalous seismic reflections related to gas/gas hydrate occurrences along the western continental margin of India. Geomar Lett 2001, 21(1), 1-8.

Gas hydrates along continental margins are commonly inferred from the presence of bottom simulating reflectors (BSRs) on reflection seismic records. Shale and mud diapirs are often observed in the proximity of BSR-inferred gas hydrates. Analysis of data from documented gas-hydrate occurrences suggests that the areas where mud volcanoes exist on the seafloor are promising locations for sediments with high gas-hydrate concentration. Along the western continental margin of India (WCMI), identified several anomalous reflections on single-channel, analogue seismic records in the proximity of BSRs, from which the presence of gas-charged sediments and gas seepages was inferred. These features characterize both the shelf-slope region of the WCMI and the adjoining deep-sea areas. The seismic records also reveal mud/shale diapiric activity and pockmarks near the gas hydrates.

32 ref

009869   Raza M;Casshyap S M;Khan A (Department of Geology, Aligarh Muslim University, Aligarh-202 002) : Accretionary lapilli from the basal Vindhyan volcanic sequence, south of Chittaurgarh, Rajasthan and their implication. J Geol Soc India 2001, 57(1), 77-82.

Well-preserved accretionary lapilli of different types are reported from the basal volcanic sequence (Khairmalia basalts) of Lower Vindhyan occurring to the south of Chittaurgarh. Four types of lapilli are identified on the basis of the nature of their core, surrounding rim zone and physical appereance. The first two types comprise cores of volcanic glass and welded tuff surrounded by rims similar to the coated accretionary lapilli or type-B of Reimer. The third type is a typical armoured lapilli, and the fourth type is a core type lapilli or type - A of Reimer. The internal structure and characteristics of the lapilli suggest their formation from ash-charged volcanic cloud produced by repeated volcanic explosions. Their excellent preservation, lack of fragmentation, presence of large size vesicles and absence of sedimentary structures in the matrix suggest little post-depositional transport. The initial explosive volcanic events and resultant basic flows and volcaniclastics, succeeded by deposition of interlayered fine clastics and conglomeratic coarse cross-bedded sandstone in the adjoining down warped (? half graben) basin(s) has heralded the onset of Vindhyan sedimentation in a fluctuating shore zone environment in southeastern Rajasthan.

4 illus, 21 ref

009868   Ravishankar;Pal T;Mukherjee P K;Shome S; Sengupta S (Geological Survey of India, , Kolkata-700 016) : Association of microbes with arsenic-bearing siderite concretions from shallow aquifer sediments of Bengal delta and its implication. J Geol Soc India 2001, 58(3), 269-71.

^ssc1 illus, 8 ref

009867   Ravi Shankar;Pandey P (Geological Survey of India, , Jawaharlal Nehru Road, Kolkata-700 016) : Geoseismological studies of Kutch (Bhuj earthquake of 26 January 2001. J Geol Soc India 2001, 58(3), 203-8.

Extensive geoseismological studies of the 26 January 2001 Kutch earthquake have been carried out by Geological Survey of India in an area of 1.2 million sq km. The isoseismal map of the earthquake has been prepared adopting MSK-64 Intensity Scale. Separate studies have been conducted for evaluating the effect of the earthquake on engineered structures, geothermal manifestation and groundwater. A 13-Station MEQ array, in operation for the last two and a half months in the Kutch region, has precisely delineated the aftershock activity. Collation and analysis of data obtained from different sources have enabled understanding of source mechanism of the seismic event.

3 illus, 1 table, 11 ref

009866   Rao V K;Prasad S N (NO, , ) : Fluid genesis through serpentinites and the origin of subsurface electrical conductors in Northwest India and adjoining regions. Earth Planet Sci Lett 2001, 190(1-2), 79-91.

Large-scale conductivity anomalies have been detected and subsequently modelled/inverted based on the data of geomagnetic deep sounding in Northwest India by various researchers. By analytical dissection of several other geophysical parameters, in conjunction with the constrained modelling of electrical parameters of the conductors, the origin of three Northwest Indian conductors have been resolved. A unique relationship has been found and the same advocated amongst the high values of Poisson's ratio and the electrical parameters of conductors. These high values of Poisson's ratio conform to the presence of serpentinites in the region at appropriate depths. Under the present geotectonic setting, the upward migration of serpentine from mantle to subcrustal level and its consequent dehydration leading to fluid genesis seems to be the appropriate cause for the conductivity anomalies in the Northwest Indian region, including Lesser Himalaya. However, the exact mechanism for upward migration (a fact established elsewhere) may, at present, remain tentative. Some indirect inferences have been drawn through a hypothesized model (cartoon) to shed light on the possble mode of fluid transport resulting in conductivity anomalies of the region.

009865   Ramkumar M (NO, Delta Studies Institute, Andhra University, Visakhapatnam-530 003) : Sedimentary environments of the modern Godavari delta: characterisation and statistical discrimination towards computer assisted enviornment recognition scheme. J Geol Soc India 2001, 57(1), 49-63.

Documentation of the textural and geochemical criteria of individual sub-environments of the modern Godavari delta shows that in view of prevalent shared nature of transportation, deposition and preservation processes, the textural and geochemical characteristics are not distinct enough to have these sub-environments separated by visual methods on the basis of measurements of constituent variables. Multivariate discriminant function analyses of these data show that the sub-enviornments of the modern deltaic system could be separated practically to the tune of 80.26% accuracy. The percentage of distinctness depends on the sensitivity of each parameter to different sub-environments and also the ability to separate between sample variations. These results have enabled the construction of a scheme for recognition of environments of unknown samples.

2 illus, 13 tables, 48 ref

009864   Ramakrishna V V S;Acharya R N;Reddy A V R; Garg A N (Department of Chemistry, University of Roorkee, Roorkee-247 667, Uttar Pradesh, India) : Use of gold as monostandard for the determination of elemental concentrations in environmental SRMs and Ganga river sediments by the k(o) method. Appl Radiance Isotopes 2001, 55(4), 595-602.

Instrumental neutron activation analysis (INAA) using the k(O) method by employing gold as monostandard has been used for the determination of 18 elements (As, Ba, Br, Cl, Cr, Co, Cs, Dy, Fe, Hf, Ga, In, La, Mn, Na, Rb, Sc and Th) in standard reference materials (SRMs) of environmental origin and four sediment samples collected from the Ganga river in northern parts of India. Data obtained for SRMs agree within 5-10% with the certified values for most elements. Merits and demerits of the K(O) method are discussed. An attempt has been made to identify the sources of heavy metal pollutants in the sediment samples and study the mobility pattern for toxic heavy metals originating from the tanneries along with the river flow.

32 ref