011987   Saadon M N;Camerlengo A L (Faculty of Science and Technology Universiti College, , Terengganu (UPM), Mengabang Telipot 21030, Kuala Terengganu (Malaysia)) : On the main characteristics of the circulation of the South China sea of peninsular Malaysia eastern continental shelf. Ultra Scient phys Sci 2000, 12(3), 311-18.

Physical oceanographic and meteorological research conducted in Malaysis, especially the seas around Peninsular Malaysia, is reviewed. Variability of physical parameters in the South China Sea and the Malacca Strait are strongly related to the meteorological conditions in the region. Changed in the vertical profiles of temperature, salinity, and density are mainly due to the prevailing monsoon seasons in the area. Similarly, the wave height, current circulation and tidal level are basically influence by the monsoon seasons. The formation of a National Oceanographic Directorate (NOD) of Malaysia and its roles in research and development in oceanography are also discussed.

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011986   Richariya L K;Mishra R (NO, School of Studies in Geology, Vikram University, Ujjain-456 010) : Pumping test analysis of large diameter wells in alluvial terrain around Jabalpur, Using papadopulas-Cooper method. J Indian Wat Wks Ass 2000, 32(1), 45-8.

011985   Ramkumar M (Delta Studies Institute, Andhra University, Visakhapatnam-530 003) : Multivariate statistical analyses for deducing controls of carbonate deposition and diagenesis: a case study from South India cretaceous sequence. Indian J Geochem 1999, 14, 79-95.

Carbonate lithotopes of Kallankurichchi Formation (Lower Maestrichtian), Ariyalur Group, Tiruchirapalli district, South India have been analysed for their chemical constituents namely IR, Ca, Mg, Fe, Sr, Mn, Ba, Ti, Cr, Al, Na and K and stable isotopes oxygen and carbon. Quantitative petrographic data in terms of grains, matrix, cement, porosity types and spar types were generated by point count method. Statistical treatment of all these data through correlation and factor analysis had revealed that the deposition of these carbonates was controlled by the amount of terrigenous influx. Primary depositional fabric (that in turn was dependent on prevalent energy conditions) has exerted control over pore systems influencing later stage diagenetic alterations. Revealed that in a carbonate diagenetic system, if the bulk chemical compositions of diagenetic components are widely different, dissolution-precipitation mode of transformation favouring cementation takes plae. If not, neomorphic alteration via thin film transformation takes place when assisted by the factor surface-volume ratio of solid phases.

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011984   Ramkumar M (Delta Studies Institute, Andhra University, Visakhapatnam-530 003) : Role of chemostratigraphic technique in reservoir characterisation and global stratigraphic correlation. Indian J Geochem 1999, 14, 33-45.

Chemostratigraphic analysis, a new tool that combines sedimentology, geochemistry and stratigraphy, is now widely applied in sedimentary basin modelling. It helps understanding the sediment dispersal pattern to establish geochemically distinct, sedimentary units that are important in understanding reservoir properties and interwell, interbasinal and intrabasinal correlation of strata. As many geochemical signatures of sediments are found to be global in nature, documentation of their trends through age may serve as an alternative and reliable classificatory scheme of stratigraphy even where the conventional methods could not resolve to sub-divide further. Although widely applied world over, for the betterment of exploration strategies, application of it on Indian terrains is found to be scarce. This paper portrays a brief review on this technique and its utilities apart from some inherent limitations.

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011983   Prasad K S S;Raju A N;Nayudu P T (Department of Geology, S V University, Tirupati-517 502) : Study of beryls from Nellore mica belt, Andhra Pradesh. Bull pure appl Sci-Sect F 1998, 17(1-2), 5-9.

Multigeneration sequence of beryls, crystallizing from the outer zones to the cores of individual pegmatites, follows an increasing trend of alkali similar to the pegmatic group. The distribution, variation and relationships of Li, Cs, Na, K, Rb etc. reflects the geochemical and paragenetic characteristics of the beryls with their parent pegmatites. The high alkali and Cs content with the close association of albite and muscovite, favour a late crystallisation during albitic metasomatism.

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011982   Naik A (Department of Earth Sciences, Sambalpur University, Sambalpur-768 019) : Geochemistry and genesis of pink granites of Sambalpur area, Orissa, India. Indian J Geochem 1999, 14, 59-68.

Pink granite occurs as dykes and veins intruding medium grained and porphyritic granodiorite around Sambalpur town. Petrographically two varieties are distinguishable, one is characterised by the presence of perthitic K-feldspar where as the second variety contains normal K-feldspar. Although they differ slightly in geochemical composition, both are A-type granites. They are possibly associated with the tectonic activity that give rise to the intracratonic Chhattisgarh basin.

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011981   Mangaonkar K;Gundi G;Desai P;Gore V (Department of Chemistry, Ramnarain Ruja College, Matunga, Mumbai-400 019) : Chemico-mineralogical studies of some Indian limestone samples. Ultra Scient phys Sci 2000, 12(3), 386-91.

Limestone is one of the most important naturally occurring minerals, used in industry either in its original form or in a processed form or in a processed form for numerous types of products and applications. Therefore quality of the source limestone becomes very important. Number of limestone samples from different states in India were characterized by studying their chemical analysis, thermal behavior and mineralogical properties using optical microscopy and X-Ray diffraction method.

011980   Limaye M A;Desai S J (Department of Geology, M S University of Baroda, Vadodara-392 002) : Petrographic significance of Cordierite bearing metapelites of Danta area, Banaskantha district, north Gujarat. Bull pure appl Sci-Sect F 1998, 17(1-2), 17-20.

The Cordierite bearing metapelites belonging to Ajabgarh Group are reported from Danta area. The metapelites are exposed in association with calc granulites, calc gneisses in the vicinity of Erinpura granite of post Delhi age. The mineral assemblages seen in the metapelites are cordierite-hypersthene-almandine-sillimanite-k-felspar-biotite-quartz. The textural characteristics reveal a polymetamorphic event involving formation of biotite at the expense of cordierite, orthopyroxene, almandine and exhibits transformation from lower granulite to upper amphibolite facies of regional metamorphism.

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011979   Gole S (S P College, , Pune) : Geochemical mass balance in a small watershed in the seasonal tropical region of the Western Ghats : the case of a tributary in the source region of Koyna, India. Trans Inst Indian Geogr 1997, 19(2), 27-30.

The objective of the study is to establish the rate of weathering profile development and the rate of denudation in a small wsatershed in Western Ghats. The Sonpar watershed is drained by the major right band tributary of the Koyna river in the latter's source region. The basin covers an area about 45.59 sq.km (17.6 sq miles) and lies in the Raigad district of Maharashtra. Besides calculating the geochemical balance the paper provides an insight in the methodology applied, which involved number of steps like the assessment of the average weathering profile thickness, establishment of hydrological balance, calculation of hydrochemical analysis, assessment of silica losses during the course of weathering, calculation of denudation rate by estimating the total solutional and suspended loss. The rate of silica losses provides the rate of weathering profile development. All these calculations were carried out for the year 1989, by monitoring the river discharge and analysing chemically the samples of weathered material from the profile. The whole basin is characterized by steep slopes, some residual relatively flat, narrow stream terraces, a relatively high relative relief and is being disseted by streams and gullies. The estimated age of regolith formation and denudation seems to lie between 20,000 to 30,000 years.

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011978   Elangovan K;Balasubramanian A;Thirugnana Sambandam R;Rengarajan R;Satish P N;Janardhan A S (Department of Civil Engineering, PSG College of Technology, Coimbatore-641 004) : Geochemical modeling of crystalline aquifers of Salem district, Tamil Nadu. Indian J Geochem 1999, 14, 1-17.

Geochemical models are useful to calculate the distribution and activities of mineral species present in groundwater. The study Salem district is underlain by Archaean crystalline metamorphic complex. Normally the groundwater occurs up to a depth of 300 m below ground level. So groundwater is exploited using compressor fitted pumpsets. As the groundwater is saturated with calcium carbonate, the use of compressor air disturbs the equilibrium condition of calcium carbonate with groundwater and ultimately scale formation takes place in the delivery pipes. Generally oversaturated minerals tend to form as scales especially calcium carbonate. Groundwater from 60 locations were collected and analysed for major and minor ions. The geochemical model PHREEQE has been used to find out the disequilibrium indices of calcite along with other minerals. Calcite, aragonite, dolomite, hematite, goethite, Fe (OH)₃ and strontianite are reported as saturated minerals in groundwater of Salem district

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011977   Bukhari S K;Loan B A;Dhar B L;Fotedar B K (Post graduate Department of Geology, Jammu University, Jammu-180 001) : Physico-chemical studies of Banganga waters, Vaishnodevi hill area, Jammu Himalayas. Indian J Geochem 1999, 14, 19-32.

Twelve samples of water from Banganga Nallah of Vaishnodevi limestone were analysed for the elements Ca, Mg, K, Na, Cu, Ni, Pb, Zn, Co, Fe and Mn. Two elements Pb and Fe were observed to be present above permissible limits and hence the waters are not fit for human consumption with respect to these elements. Further 20 rock samples of Vaishnodevi Limestone were subjected to chemical analyses for major elements in order to calculate dilution factor depending upon surface run off. It was revealed the dilution factor during monsoon periods was large enough to put down the concentration of various elements to desirable levels for human consumption. Carbonate, sulphates and nitrates are present below the permissible limits. S.A.R. and S.S.P. values are too low to cause any soil hazard. Proper filtration plants and disinfection with chlorine/bromine and proper sanitation is recommended to render the waters chemically fit for large number of visitors who visit the area every year. Besides, proper forestation in the source areas with raising of embankments from Adkunwari to Katra are recommended to keep waters environmentally clean and uncontaminated.

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010873   Venkatesh B;Jain M K (NO, HRRC of National Institute of Hydrology (NIH), Hanuman Nagar, Belgaum-590 001) : Simulation of daily flows using topography-based rainfall-runoff model. J Instn Engrs-Pt CI 2000, 81(Dec), 127-32.

Physically-based distributed model, TOPMODEL has been applied to Malaprabha catchment in Karnataka. The model uses topographic index which highlights hydrologically significant area within the catchment for runoff generation. The results indicate that a large portion of stream water is generated from saturated contributing area and that the model can be used to simulate the flows in the dry catchment quite accurately. The efficiency of the model was found to be 0.9 and 0.801, respectively in the calibration and validation run. The model is able to simulate the timing and magnitude of the peak flows satisfactorily.

010872   Sidhu G S;Das T H;Singh R S;Sharma R K;Jadaun S P S;Rao B R M (NO, National Bureau of Soil Survey and Land Use Planning (ICAR), Regional, IARI Campus, New Delhi-110 012) : Soil resource inventory of watershed for land use planning - a GIS approach. Indian J Soil Conserv 2000, 28(1), 22-9.

Various layers of maps prepared by interpretation of satellite data (IRS-IB bands 2,3 and 4) and topographical maps were used for digitization and generation of data base on ARC/INFO GIS system on a macrovax and generation of data base. ARC/INFO GIS version 5.0/6.0 was used to digitise, edit, build, transform, display, analyse and plot the maps. By using the `Union' module, geomorphology, soils, land use/land cover maps were combined to generate action plan suggested for every parcel of land. The results showed a well established soil scape relationship in the area. The study revealed that major area (53.8%) of the watershed is under afforestation. The soil conservation practices followed by silvipasture are urgently required in areas which are subjected to severe and very severe erosion on steeply sloping lands. About 1/4th area of the watershed can be brought under double cropping by adopting suitable soil conservation and water harvesting technology so that irrigation can be made available in rabi lean period at critical stages of crop growth.

010871   Sharma D R;Gupta A C (Vacuum and Pressure Standards, National Physical Laboratory, , New Delhi-110 012) : Pressure metrology based on liquid column displacement. MAPAN 2000, 15(2), 43-55.

Describes the importance and techniques of pressure measurement based on liquid displacement in a column under applied hydrostatic pressure. This article outlines the inherent errors associated with the instruments working on liquid displacement technique; such as manometer and barometers, and to provide information for correcting these errors. The methods of measuring the absolute, barometric, differential and gauge pressure with the liquid manometry have been discussed. The variety of design of these instruments which are critical in obtaining precision and accuracy of pressure measurement in the standard laboratories and industries are also described. A great deal of the material presented reflects the experience and expertise of the National Physical Laboratory in the field of precision liquid manometry developed as the Primary/Transfer Standards in the range from 130 kPa to 10^-4 Pa.

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010870   Satyanarayana B;Vijaya Kumar J;Srinivas M; Narsing Rao A;Reddy K T (Geology Department, Osmania University, Hyderabad-500 007) : Petrographic studies on porphyritic metadolerites of Hyderabad and Ibrahimpatan areas, A P. Bull pure appl Sci-Sect F 1999, 18(1-2), 21-6.

The petrography of the porphyritic dolerites intersecting the grey granites has been studied. Their mineral assemblages and textural pattern indicate that they have undergone metamorphism.

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010869   Samra J S;Singh S C (NO, Central Soil and Water Conservation Research and Training Institute, 218, Kaulagarh Road, Dehradun-248 195) : Silvopasture systems for soil, water and nutrient conservation on degraded land of Shiwalik foothills (sub-tropical northern India). Indian J Soil Conserv 2000, 28(1), 35-42.

Natural resource conservation through proper land-use systems is a major environmental concern of the foothill sub-tropical region of northern India. Acacia nilotica based silvopastures were investigated for six years (1990-95) on a gravely Typic Mesic Udic Ustocrepts having 2% slope and 1108 mm annual rainfall at northern India. The experiment involved five treatments: pure stand of A. nilotica (AN), A. nilotica + Eulaliopsis binata (AFB), A. nilotica + Saccharum munja (ASM), A. nilotica + Vetivera zizanioides (AVZ), and A. nilotica + natural grasses (ANG). Eulaliopsis binata had maximum root length (3.06 km m^-3 of soil) in 0-30 cm soil layer, while the root spread was maximum (4942 cm²) in case of S. munja. The silvopasture systems of ANG, AEB, ASM, AVZ and AN recorded 18.1 12.3, 7.1, 14.5 and 32.3% runoff; 0.79, 0.51, 0.38, 0.61 and 5.25 t ha^-1 soil loss; 6.97, 4.80, 4.71, 6.01 and 17.20 kg ha^-1 N loss, and 3.43, 2.17, 1.15, 2.19 and 4.94 kg ha^-1 K loss per year, respectively. The soil organic carbon status in 0.15 cm layer improved from 0.39% to 0.52% under ASM, and 0.44% to 0.55% under AEB after five years. The ASM system was more conservation effective than other systems but suppressed tree growth. The AEB system was equally conservative but more productive and less competitive with trees, and hence recommended as an eco-friendly conservation technology for rehabilitation of degraded lands of Shiwalik foothill region.

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010868   Narsing Rao A;Reddy M N (NO, P G College of Science, Saifabad, Osmania University, Hyderabad) : Study on the occurrence of flux-grade dolomite deposits near Lakshmipuram and Govindapuram, Khammam district, A.P. Bull pure appl Sci-Sect F 1999, 18(1-2), 31-4.

Geological studies were carried out with an objective of evaluating the suitability of dolomite deposits for steel industry. About 60 samples were collected for laboratory studies to assess the qualitative and quantitative aspects of the dolomite. Detailed study of geology reveal that inexhaustible resources of flux grade dolomite are available in the Pakhal meta-sedimentaries.

010867   Nainwal H C (Department of Geology, HNB Garhwal University, Srinagar-246 174) : Impacts of road construction on environment in Garhwal Himalaya. Bull pure appl Sci-Sect F 1999, 18(1-2), 1-7.

Various ecological and environmental disturbances caused on road construction are analysed in detail and several geological aspects are also discussed to minimise these disturbances.

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010866   Mishra A;Gulati J M L;Patra A K;Samal K C; Panigrahi B;Jena S N (NO, Regional Research Station(O U A T), Chiplima-768 025) : Variability and correlation studies on weather components. Pollut Res 1999, 18(2), 183-6.

Amount of rainfall and number of rainy days registered highest coefficient of variation among the weather components studied. In eight out of twelve months, evaporation exceeded rainfall. Mean minimum temperature and mean minimum relative humidity exhibited higher coefficient of variation over mean maximum temperature and mean maximum relative humidity respectively. Different weather components were found to have certain inter-relationship amongst themselves.

010865   Luthra R K (Temperature Standards, National Physical Laboratory, , New Delhi-110 012) : Development of international temperature scales. MAPAN 2000, 15(3), 85-94.

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010864   Joshi V;Krishna A P (NO, G.B. Pant Institute of Himalayan Environment and Development, Garhwal Unit, Srinagar) : Control measures for soil erosion, landslides and debris flow in Hindu-Kush Himalayan belt of People's Republic of China. Indian J Soil Conserv 2000, 28(1), 1-6.

Mountainous tract of China falling in the Hindu-Kush Himalayan belt experiences severe soil erosion, landslides and enornmous debris flows. The causes are complex geological structures, diverse geomorphic features, intense neotectonic activities, recurring earthquake, anthropogenic activities and monsoonal effect. Due to resulting recurrent damages and deaths every year, there has been scientific and systematic mitigation efforts using Mountain Risk Engineering (MRE) concepts in China. These have gradually become very effective in control and management of erosion, landslides and debris flows. Such control measures and techniques being practised in China were observed to be effectively fulfilling the twin objectives of stabilization and reclamation of landsides and debris flow affected areas.

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010863   Gupta S V (National Physical Laboratory, , New Delhi-110 012) : Impact of new schedule VII-heading B on consumers and manufacturers of weighing instruments with dial as indicating device. MAPAN 2000, 15(3), 75-83.

010862   Goel A K;Singh J K (Dept. of Soil and Water Conservation Engineering, College of Technology, G.B.P.U. A and T, Pantnagar-263 195) : Hypsometric analysis for foothills of Shivalik. Indian J Soil Conserv 2000, 28(1), 84-5.

010861   Duggal I S;Kaushal M P;Rani N;Jindal P K (Kandi Watershed and Area Development Project, PAU, Patiala - Ki-Rao, Chandigarh) : Sediment yield simulation in Kandi area of Punjab. Indian J Soil Conserv 2000, 28(1), 16-21.

Study has been carried out for the development of runoff and sediment yield models using the historical observations of a micro-watershed in the catchment of Patiala- Ki-Rao, along the Shivalik foothills. A computer programme MSEDIMENT was developed to determine peak runoff rate by Rational method, runoff depths by Curv Number method and sediment yield by Modified Universal Soil Loss equation. The peak runoff rate, runoff depth and sediment yield models were calibrated and validated for micro-watershed II. The simulated values of peak runoff rates show close agreement with the historic values in most of the storms. The simulated runoff depths varied within 30 per cent from the historic values. The simulated sediment yields were in close agreement with historic values. The models developed were used for the prediction of peak runoff rate, runoff depth and sediment yield for micro-watershed I. The results indicate that the models are valid for the Pariala-Ki-Rao region of Kandi area of Punjab.

010860   Das P K;Borthakur J (Department of Geological Sciences, Gauhati University, Guwahati-781 014) : Study of clay minerals of the Brahmaputra river sediments around Nimatighat, Jorhat district, Assam. Bull pure appl Sci-Sect F 1999, 18(1-2), 27-30.

Clay minerals from the Brahmaputra river sediments around Nimatighat were studied by XRD method. The clay minerals are mostly of kaolinite, illite and chlorite. These clay minerals are derived from the acid igneous and metamorphic rocks weathered under humid climatic condition with high rainfall and adequate drainage system and deposited in the river bed.

010859   Chitale V (NO, , 425/14, TMV Colony, Pune-411 037) : Future of the Kosi river and the Kosi project. J Instn Engrs-Pt CI 2000, 81(Dec), 109-14.

Kosi river was notorious for shifting, flood devastation and sand deposition over a vast area in north Bihar. In order to provide an immediate relief, the Kosi project comprising gradient control by Hanumannagar barrage near Bhimnagar and river confinement by marginal embankments was implemented. At that time, it was realised that the river will continue to aggrade in the post-project period and long-term measures will have to be conceived in time. This perspective of the future of the Kosi now appears to have been lost sight of. The river observations have, however, now revealed great danger to which the developed countryside outside the embankments will be exposed in future. The necessity is, therefore, emphasised to undertake mathematical model studies to predict the time frame of the likely breaches in the embankments and their possible locations so that suitable strategy to avoid any sudden catastrophe can be evolved and put in practice in time.

008794   Sundarsingh S D;Veeraputhiran R; Balasubramanian T N (Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore-3) : Rainfall climatology - a tool for crop planning. Madras agric J 1999, 86(10-12), 620-4.

Analysis of rainfall for 47 years (1951-1997) at Coimbatore was done to find out the occurance of normal, abnormal and drought months. Monthly probability analysis was also made to compute R/PE ratio. For Coimbatore a growing period of 75 days may be planned for annual cropping from last week of September to first week of December without any greater risk.

008793   Rao V P;Rao N V (Centre of Exploration Geophysics, Department of Geophysics, Osmania University, Hyderabad-500 007) : Calibration of a portable gamma ray spectrometer for in-situ determination of uranium, thorium and potassium concentrations in rocks and soils for geological and environmental studies. Radiat Prot Envir 1999, 22(4), 182-9.

Presents the results of calibration of a portable gamma-ray spectrometer (Nal (Tl), 124 cc) for in-situ measurements of Uranium, Thorium and Potassium concentrations in rocks and soils for geological and environmental studies. The calibration coefficients, viz., sensitivities and stripping factors were determined by measuring the spectral gamma countrates on the AMD calibration pads at Nagpur. The performance of the instrument has been evaluated by computing the minimum detectable activity and errors of measurements for the three radionuclides.

008792   Raju N V;Prasad B S N;Narasimhamurthy B; Thukarama M (Department of Physics, University of Mysore, Mysore-570 006) : Winter-to-summer variations of atmospheric turbidity over Mysore (12°N, 76°E). Indian J Radio Space Phys 2000, 29(6), 333-40.

Multiwavelength radiometer (MWR) is being operated since 1988 in Mysore (12°N, 76°E). Solar radiation is collected through ten spectral channels (in the visible and near infrared) for clear sky conditions. From these measurements and using Langley technique, data base on aerosol optical depth, τPλ, for the period 1988-89 has been established. The number density and size distribution of aerosols are related to aerosol optical depth (or extinction) through the Angstrom's equation τpλ=β<108>< F255>^-α, where α is size related, β represents the amount of aerosols, and λ is the wavelength on a log-log scale. The value of α and β for the winter (December and January) and summer (March and April) months and their inter-annual variations have been examined to assess the influence of meteorological factors and atmospheric pollutants on atmospheric turbidity.

008791   Rajan D;Rizvi S R H;Bhatia V B;Gupta H V (National Centre for Medium Range Weather Forecasting, , New Delhi-110 003) : Intercomparison of satellite derived OLR and total precipitable water content over India and their impact on the analysis-forecast system. Indian J Radio Space Phys 2000, 29(6), 341-8.

The three layers of vertically integrated precipitable water content, temperature, outgoing long-wave radiation (OLR) from NOAA series of polar orbiting satellites are being routinely derived at Chennai in real time. An attempt is made in this study to compare and evaluate the impact of OLR and total precipitable water content (TPWC) data in global data assimilation and forecast system (GDAFS). Since India is surrounded by large data sparse oceanic regions, the remotely sensed data from satellites are the only source of meteorological information currently available for use in numerical weather forecasting. The OLR and TPWC values from NOAA satellite are comparable with other sources. The impact of OLR and TPWC in GDAFS are encouraging.

008790   Prasad M;Majumder A K;Rao T C (Regional Research Laboratory (C.S.I.R.), , Hoshangabad Road, Near Habibganj Naka, Bhopal-462 026) : Mineralogical and beneficiation characteristics of a lean grade siliceous rock phosphate ore from Hirapur (M.P.). Indian Min Engng J 2000, 39(9), 21-4.

Study aims for assessment of the mineralogical behaviour of the low grade (12.1% P2O5) siliceous rock phosphate ore of Hirapur using different instrumental technquies such as petrographic microscopy, XRD, IR, DTA to pave the way for adoption of the most suitable route for its beneficiation. It has revealed from mineralogical study that the ore predominantly consists of phosphate minerals as fluorapaite <126>30% and quartz (<126>45%), muscovite, hematite and clays as the major gangue minerals. The other minor diluents present in the sample were kaolinite, dolomite, rutile and tremolite. Most of the phosphate mineral appeared free from interlockings with quartz and ferrugenous minerals at particle size below 200 mesh. Froth flotation technique was employed to develop a flowsheet for beneficiation of the present siliceous ore containing 12.1%P2O5, 55.36% SiO2 and 15.45% CaO to yield a phosphate concentrate containing 34.40%P2O5, 14.20% SiO2 with a P2O5 recovery of 70.4% (weight percent yield of 25.0).

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008789   Mishra S C;Swamydas C (Indian Rare Earths Limited, , Manavalakurichi) : Beneficiation of beach sand minerals. Indian Min Engng J 2000, 39(9), 29-31.

008788   Mahapatra S;Bandopadhyay A (NO, Indian Institute of Tropical Meteorology, Pune-411 008) : Impact of digital filtering initialization on the performance of a semi-Lagrangian semi-implicit model over Indian region. Indian J Radio Space Phys 2000, 29(6), 319-22.

Non-recursive digital filtering initialization (DFI) scheme has been applied adiabatically as well as diabatically to a semi-Lagrangian semi-implicit (SLSI) limited area model to study its impact on the model performance for short-range prediction over Indian region. For comparison purpose, the input is also initialized by dynamic normal mode initialization (DNMI). It is found that both the versions (adiabatic and diabatic) of DFI could produce fairly well balanced initial state and could effectively suppress the high-frequency oscillations from the forecast fields. The filter is found to be more effective in controlling the noise in the first few hours of integration. The changes induced to the analysis by both the version of DFI are reasonably small and are comparable with the changes made by DNMI. The 24-h forecasts obtained rom the adiabatic as well as diabatic versions of DFI are comparable with those produced from DNMI and also with the forecasts obtained from uninitialized input. The main advantage of DFI is found to be its great simplicity in conception and application. Its implementation is very easy, requiring only the calculation of the filter coefficients and minor adjustments of the model code.

008787   Bhima Rao R;Ravi Prasad A (Regional Research Laboratory, (Council of Scientific & Industrial Rese, , Bhubaneswar) : Beneficiation of diamondiferrous deposits by using heavy media cyclones. Indian Min Engng J 2000, 39(9), 37-9.

Deals on the use of heavy media cyclones to recover heavies from diamondiferrous kimberlite rock, of Panna (M.P.). The results of the sink float and heavy media cyclones indicate that the percentage recovery of heavies between 0.8 to 2.2% could be achieved in the specific gravity range of 3.3 to 2.8 gm/cc. Based on these observations, the use of commercial heavy media cyclone are recommended for recovery of diamonds from the Kimberlite ore body.

008786   Bhattachary A;Sen P (MECON Limited, , Ranchi) : Selection of primary crushing system for an iron ore mine. Indian Min Engng J 2000, 39(9), 17-20.

Selection of curshing system of an iron ore mine and its location is one of the important factors controlling the economics of mining. The various alternatives are to be assessed and their effect on cost of mining at Net Present Value is to be estimated for arriving at a realistic comparison. The case of a hilly iron ore deposit has been taken and various alternatives of crusher selection evaluated before arriving at the most cost effective solution over the life of the proposed mine.

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007956   Yamuna Singh;Singh K D P (Atomic Minerals Division, , Begumpet, Hyderabad-500 016) : Discovery of radioactive proterozoic sandstones of Karkati dongri near Dongarsilati, north Bastar, Madhya Pradesh : implications for uranium mineralisation. J Indian Ass Sedimentologists 1999, 18(1), 41-9.

For the first time, a middle Proterozoic radioactive sandstone (upto 0.11 percent ThO2, and 0.014 percent U3O8) sequence near Dongarsilati, north Bastar, Madhya Pradesh is being reported. The lower part of the sequence is nearly massive, and exhibits a mixed gradation from grit to gritty arkose to gritty sandstone to ferruginous sandstone with impersistent pebbly layers; while the upper one is fairly bedded, coarse- to fine-grained and mostly ferruginised. Ferruginous (hematite and geothite), siliceous (quartz) and clayey (illite) matters constitute the matrix and cement. Lithology of sandstones suggests that entire sedimentation took place in low energy, fluviatile and oxidising conditions, predominated by debris flows; and the surrounding radioactive granites and associated charnockites provided most the detritus. After deposition, at places the sandstones underwent silicification. Based on close similarities in lithology and geological history of the studied sandstones, they have been correlated with the Gundul Formation of the Abujhmar basin. The radioactivity in sandstones is mainly due to monazite, besides zircon, rutile and iron oxides. The sandstones possess most of the features needed for hosting uranium mineralisation. It is quite likely that during the course of structural disruptions, uranium was remobilised from the fertile basement granites (known to contain <60>0.002-0.098 percent U3O8) of the area.

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007955   Yamuna Singh;Dubey D P (NO, Atomic Minerals Directorate for Exploration and Research, Begumpet, Hyderabad-500 016) : Nature of cementation and its role in the diagenetic history of Late Proterozoic Bhander Limestone of Rewa area, Central India. J Indian Ass Sedimentologists 1999, 18(1), 111-22.

Petrological studies on the Late Proterozoic Bhander Limestone of the Rewa area, Central India indicate that the limestone has sparry calcite cement. Based on the fabric characteristics of the spars, four types of sparry calcite cements are discernible : fibrous non-ferroan calcite cement, dog tooth fringe cement, drusy mosaic cement and syntaxial rim cement. Microfabric indicates that the Bhander Limestone was first chemically precipitated as lime mud, which was disintegrated by wave action, carried, and laid down as oomicrite and intramicrite. The fibrous cement, forming coating on allochemical grains, must have been syngenetic precompaction. Percolating (slightly acidic) waters dissolved the fibrous aragonite, and calcium carbonate so liberated formed the low-magnesian, non-ferroan dog tooth fringe cement into which the fibrous cement grades. Both of these cements were formed due to the effect of circulating water in the pore filling under near-surface intermittently emergent marine environment. After early diagenetic cementation and partial lithification, the Bhander Limestone has undergone a shallow submergence, where pore water chemistry favoured precipitation of ferroan calcite as drusy mosaic cement in the moldic porosity created during dissolution. Ferroan nature of micrite calcite also point out its formation in a reducing environment. Other diagenetic changes in the limestone include neomorphism, compaction and pressure solution, silicification and dolomitisation.

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007954   Verma S P (Centro de Investigacion en Energia, UNAM, Priv. Xochicalco S/N, Col. Centro, Apartado Postal 34, Temixco, Mor. 62580, Mexico) : Error propagation in equations for geochemical modeling of radiogenic isotopes in two-component mixing. Proc Indian Acad Sci-Earth Planet Sci 2000, 109(1), 79-88.

Presents error propagation equations for modeling of radiogenic isotopes during mixing of two components or end-members. These equations can be used to estimate errors on an isotopic ratio in the mixture of two components, as a function of the analytical errors or the total errors of geological field sampling and analytical errors. Two typical cases ("Small errors" and "Large errors") are illustrated for mixing of Sr isotopic. Similar examples can be formulated for the other radiogenic isotopic ratios. Actual isotopic data for sediment and basalt samples from the Cocos plate are also included to further illustrate the use of these equations. The isotopic compositions of the predicted mixtures can be used to constrain the origin of magmas in the central part of the Mexican Volcanic Belt. These examples show the need of high quality experimental data for them to be useful in geochemical modeling of magmatic processes.

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007953   Venkataramana M;Sengupta K;Bhat G S;Ameenulla S;Raju J V S (Space Physics Laboratory, Vikram Sarabhai Space Centre, Trivandrum-695 022) : Inertial-dissipation flux measurements over south Bay of Bengal during BOBMEX-Pilot experiment. Proc Indian Acad Sci-Earth Planet Sci 2000, 109(2), 239-47.

Describes measurement of air-sea parameters and estimation of sensible and latent heat fluxes by the "Inertial-Dissipation" technique over south Bay of Bengal. The data were collected on ORV Sagar Kanya during BOBMEX-Pilot cruise during the period 23rd October 1998 to 12th November 1998 over south Bay of Bengal. The fluxes are estimated using the data collected through fast response sensors namely Gill anemometer, Sonic anemometer and IR Hygrometer. The analyses carried out for two days, one relatively cloud free day on November 3rd and the other cloudy with rain on November 1st, are presented. Sea surface and air temperatures are higher on November 3rd than on November 1st. Sensible heat flux for both the days does not show any significant variation over the period of estimation, whereas latent heat flux is more for November 3rd than November 1st. An attempt is made to explain the variation of latent heat flux with a parameter called thermal stability on the vapor transfer from the water surface, which depends on wind speed and air to sea surface temperature difference.

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007952   Tricca A;Porcelli D;Wasserburg G J (Lunatic Asylum of the Charles Arms Laboratory, Division of Geological, California Institute of Technology, Pasadena, CA 91125 USA) : Factors controlling the groundwater transport of U, Th, Ra, and Rn. Proc Indian Acad Sci-Earth Planet Sci 2000, 109(1), 95-108.

A model for the groundwater transport of naturally occurring U, Th, Ra, and Rn nuclides in the ²³⁸U and ²³²Th decay series is discussed. The model developed here takes into account transport by advection and the physico-chemical processes of weathering, decay, α-recoil, and sorption at the water-rock interface. It describes the evolution along a flowline of the activities of the ²³⁸U and ²³²Th decay series nuclides in groundwater. Simple sets of relationships governing the activities of the various species in solution are derived, and these can be used both to calculate effective retardation factors and to interpret groundwater data. For the activities of each nuclide, a general solution to the transport equation has been obtained, which shows that the activities reach a constant value after a distance χ^-_i, characteristic of each nuclide. Typical values for weathering rates and recoil fractions for a sandy aquifer indicate that recoil is the dominant process for Th isotopic ratios in the water. Measured data for Ra isotope activity ratios indicate that recoil is the process generally controlling the Ra isotopic composition in water. Higher isotopic ratios can be explained by different desorption kinetics of Ra.

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007951   Torres-Alvarado I S;Verma S P;Carrasco-Nunez G (Centro de Investigacion en Energia, UNAM, Priv. Xochicalco s/n, Col. Centro, Apdo. Apdo. Postal 34, 62580, ) : Compilation of radiogenic isotope data in Mexico and their petrogenetic implications. Proc Indian Acad Sci-Earth Planet Sci 2000, 109(1), 67-78.

Seven hundred and twenty-five Sr, two hundred and forty-three Nd and one hundred and fifty-one Pb isotopic ratios from seven different Mexican magmatic provinces were compiled in an extensive geochemical database. Data were arranged according to the Mexican geological provinces, indicating for each province total number of analyses, range and mean of values and two times standard deviation (2σ). Data from seven provinces were included in the database: Mexican Volcanic Belt (MVB), Sierra Madre Occidental (SMO), Baja California (BC), Pacific Ocean (PacOc), Altiplano (AP), Sierra Madre del Sur (SMS), and Sierra Madre Oriental (SMOr). Isotopic values from upper mantle and lower crustal xenoliths, basement outcrops and sediments from the Cocos Plate were also compiled. Most samples with reported Sr and Nd isotopic data are spread within and around the "mantle array". The SMO seems to have been formed by a mixing process between mantle derived magmas and continental crust. The MVB appears to have a larger mantle component, with AFC as the dominant petrogenetic process for the evolved rocks. There is still a need for Pb isotopic data in all Mexican magmatic provinces and of Nd isotopes in BC, AP, SMS and SMOr.

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007950   Thangarajan M (NO, National Geophysical Research Institute, Hyderabad-500 007) : Approaches for modelling of hard rock aquifer system. J Geol Soc India 2000, 56(2), 123-38.

The flow problem in the fractured rocks has aloways been a challenging one. Evolving conceptual model of a fractured system requires either a gross simplification or a detailed description of the aquifer properties controlling the groundwater flow. There is only a basic conceptual understanding of flow in the vicinity of weathered and fractured hard rock aquifers. Often, simple continuum models are applied to analyse pumping test data, and the results then used to produce quantitative calculations on a regional scale. Even if the regional system can be represented using the continuum equivalent approach, it is unlikely that the results of applying continuum models at the local scale have any general validity, and the aquifer parameters so derived may be different from the aquifer parameters appropriate for describing regional flow in quantitative terms. The analysis should provide cost-benefit analysis for locating new high yield wells. To do this, it is necessary to investigate in detail the flow in the vicinity of a pumping borehole, and to apply appropriate non-continuum models. Reviews the following models viz. equivalent porous medium (EPM), dual porosity medium, discrete fracture network (DFN), stochastic continuum (SC) and channel network (CN), which are used to conceptualize fractured systems. The utility of integrated DFN and SC modelling approach to simulate fractured aquifer systems is brought out through a case study in Ireland.

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007949   Subbarao K V (Department of Earth Sciences, Indian Institute of Technology, Mumbai-400 076) : Sr isotopic evidence on the spilitic degradation of the Deccan basalt. Proc Indian Acad Sci-Earth Planet Sci 2000, 109(1), 49-55.

Similar Sr isotopic ratios (<126> 0.7055) for the tholeiite-spilite flow unit and the associated mineral phases of Bombay (Deccan Traps) provide a direct evidence for the spilitic degradation of tholeiite. In contrast, a dramatic increase in the rare earth elements (REE) from basalt to spilite is rather puzzling as rare earths are considered to be relatively immobile. The geochemistry thus suggests that the process of spilitization is due to the reaction with a complex fluid having identical Sr-isotopic composition as that of the basaltic magma-thereby masking the details of the mixing process.

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007948   Subba Rao N;Srinivasa Rao G;Venkateswara Rao S;Reddy P M;John Devadas D (Hydrogeology Laboratory, Department of Geology, Andhra University, Visakhapatnam-530 003) : Environmental control of groundwater quality in a tribal region of Andhra Pradesh, India. Indian J Geol 1999, 71(4), 299-304.

Groundwater quality in the tribal region of Visakhapatnam district, Andhra Pradesh is discussed with emphasis on calcium and fluoride ions. Concentrations of the two ions in the groundwaters of the region are significantly lower than the safe-limits prescribed for drinking purpose, causing health-hazards, such as dental caries, osteoporosis and gastrointestinal irritation. The rapid soil-erosion and the associated run-off water caused by geomorphological conditions, deforestation due to shifting cultivation and climatic factors are probably responsible for their low concentration. Fluoridation of water-supplies is an immediate measure whereas, afforestation of shifting cultivated areas and creation of awareness among tribals about ill-affects of deforestation are the permanent preventive measures against such deficiency diseases.

007947   Somani R L;Srivastava P (Department of Geology, University of Rajasthan, Jaipur) : Origin and evolution of hydrothermal fluids associated with granitoid-hosted tungsten mineralization at Degana, Rajasthan. J Geol Soc India 2000, 56(6), 661-71.

Degana tungsten deposit is found genetically and spatially related to the post-Delhi granite. Hydrothermal fluids associated with this granitic magmatism have evolved in three stages. Early greisenization stage took place in the temperature range 480°-260°C. Brecciation followed by boiling and emplacement of quartz sheets responsible for most of the wolframite mineralization occurred in the temperature range of 270°-350°C. In the last stage, addition of meteoric water took place in the temperature range of 130°-260°C. Salinity of mineralizing hydrothermal fluids ranges from 67-9 eq. wt% NaCl. Evidence of fluid boiling suggests a depth of mineralization at 600-1250 m, consistent with a range of hydrostatic pressure for about 60-300 bars.

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007946   Somani O P;Sinha R P;Banerjee D C (Atomic Minerals Directorate for Exploration and Research, Department o, , West Block-7, R.K. Puram, New Delhi-110 066) : Scandium potential of some ixiolite-bearing pegmatites and tin slag of Bastar district, Madhya Pradesh, India. Curr Sci 2000, 79(12), 1652-5.

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007945   Sinha R;Raymahashay B C (Engineering Geology Group, Department of Civil Engineering, Indian Institute of Technology, Kanpur-208 016) : Salinity model inferred from two shallow cores at Sambhar Salt Lake, Rajasthan. J Geol Soc India 2000, 56(2), 213-17.

Sambhar lake of central Rajasthan, located between Ajmer and Jaipur, is a hypersaline lake. Focuses on the mineralogy of the lacustrine sediments of this region. X-ray diffraction patterns of shallow auger hole samples show a broad pattern of flucturation in vertical profiles. It is apparent that rock weathering in the catchment area supplies a flux of clastic minerals like quartz, feldspar and mica during the wet period. This is followed by an evaporite sequence of carbonate-sulfate-chloride in dry climate. Thus, an abundance of calcite indicates the beginning of evaporation, while later stages are characterized by the dominance of thenardite and finally of halite.

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007944   Sinha R;Brahmankar D B (Engineering Geology Group, Department of Civil Engineering, Indian Institute of Technology, Kanpur-208 016) : Hydrological, morphological and sediment transport characteristics of Wainganga river, central India. J Indian Ass Sedimentologists 1999, 18(1), 1-14.

Analysis of hydrological data coupled with field investigations of the Wainganga river, a major tributary of the Godavari, in central India suggest that the river differs significantly from other Indian rivers, both peninsular as well as extra-peninsular, in terms of channel morphology, water discharge variation, and total sediment load transferred. The Wainganga river is characterized by low to moderate discharge and very small sediment load in spite of a large catchment area being drained. Structural controls on drainage pattern are evident in various parts of the basin, which influence the fluvial processes operating in the region.

007943   Sikka D R;Sanjeeva Rao P (NO, , 40 Mausam Vihar, New Delhi-110 051) : Bay of Bengal monsoon experiment (BOBMEX) - a component of the Indian Climate Research Programme. Proc Indian Acad Sci-Earth Planet Sci 2000, 109(2), 207-9.

Indian Climate Research Programme (ICRP) focuses on the study of climate variability and its impact on agriculture. To address the role of the Bay of Bengal in monsoon variability, a process study was organised during July-August 1999, deploying research ships, buoys, INSAT, coastal radar and conventional observational systems to collect information about the coupled ocean-atmosphere system over the warm waters of the Bay of Bengal. The paper gives the background of the ICRP and the organisation and implementation of the Bay of Bengal Monsoon Experiment (BOBMEX) in its field phase.

007942   Sikdar P K (Department of Environment Management, Indian Institute of Social Welfare and Business Management, Management House, College Square West, Calcutta-700 073) : Geology of the quaternary aquifers of the Twin city of Calcutta - Howrah. J Geol Soc India 2000, 56(2), 169-81.

The top clay bed of Quaternary sequence contains peaty intercalations indicating bog or marshy condition at depths of 2-5 m and 12-12.6 m. The peat layers were deposited during the period c.3990 years B.P. to c. 7030 years B.P. Grain size analysis of the sandy horizons indicates that the sands were deposited in a fluvial environment. Lithofacies analysis of the Quaternary sediments indicates that the gravelly sand horizons occurring in E - W and NNE - SSW trends in the depth range of 80-120 m are potential aquifer zones. These two trends of deposition of very coarse sediments probably indicate the route of sediment movement where high energy condition prevailed. The sandy sediments at a depth span of 24 to 81 m are yellowish to brownish coloured suggesting oxidising conditions of deposition. The sediments occurring above and below this horizon are grey to light grey in colour indicating reducing conditions of deposition. The over-extraction of groundwater from the aquifer has resulted in the change of the groundwater flow pattern from an "open" system in 1956 to a "closed" one in 1993 with the formation of a groundwater trough in the south-central part of Calcutta.

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