001156   Khanna P P;Siva Siddaiah N (NO, Wadia Institute of Himalayan Geology, Dehra Dun-248 001, Email: khannapp@wigh.res.in) : Determination of palladium and platinum in refractory samples with inductively coupled plasma-mass spectrometry (ICP-MS) using improved NiS fire assay. Himalayan Geol 2010, 31(1), 23-7.

A rapid and effective method with ICP-MS is developed for the determination of PGE in refractory standard reference samples (CHR-Pt+ and PTC-1) following improved nickel sulfide (NiS) fire assay preconcentration. Flux composition, flux to sample ratio, mass of nickel collector, and fusion conditions were established for successful fusion of chromitite and sulfide-rich samples. NiS beads were dissolved in aqua-regia and the solutions with no further preconcentration/separation were analyzed for palladium and platinum against synthetic standard solutions. The results obtained for the reference materials (CHR-Pt+, PTC-1 and WITS-1) are in agreement with the reported/certified values. About 90% recovery of these elements was obtained by technical improvements including sample fusion under reducing conditions. The procedure is relatively simple and can be applied to the analysis of refractory samples such as chromite and sulfide ores.

3 illus, 3 tables, 32 ref

001155   Johny C J;Sarkar S K;Punyaseshudu D (NO, National Physical Laboratory, ) : Tropopause characteristics over Indian region. Bhartiya Vaigyanik Evam Audyogik Anusandhan Patrika 2010, 18(2), 158-61.

Tropical atmosphere hold key to much of variability in global climate change. But many processes occurring in the tropical upper troposphere lower stratosphere (UTLS) region is not clearly understood. Accurate knowledge of mechanism acting in tropopause region is required for weather forecasting beyond 5 days. The temperature and water vapour characteristics in the vicinity of tropopause measured using radio occultation technique over Indian subcontinent is presented here. Tropopause temperature and height shows large variation over Indian region. Extremely cold tropopause temperature is observed over many parts of India. Water vapour in UTLS region exhibits seasonal variation.

2 illus, 1 table, 8 ref

001154   Godghate A G;Jadhav S D;Sawant R S;Salokhe A T (Chemistry Dep, Dr. Ghali College, Gadhinglaj-416 502) : Physico-chemical characteristics of borewell water samples from Uttur, Maharashtra state. Bioinfolet 2011, 8(4), 448-9.

Out of 19 bore well samples, 17 samples were within the permissible limits and safe for drinking purpose.

1 table, 5 ref

001153   Dubey P;Ravikant V;Chakrapani G J (NO, Indian Institute of Technology, Earth Sciences Dep, Email: gjcurfes@iitr.ernet.in) : Strontium isotopic compositions in selected hot spring waters in the northwestern Himalaya. Himalayan Geol 2010, 31(1), 19-22.

The present study deals mainly in presentation of data on dissolved Sr and ⁸⁷Sr/⁸⁶Sr ratios of selected hot spring and river waters in the Parbati and Beas valleys of Himachal Pradesh. The hot spring waters are characterized by highly radiogenic strontium and are more enriched in total dissolved strontium concentration as compared to the river waters. The results of this study imply that the numerous hot springs in the Himalayan region may play a significant role on the Himalayan river geochemistry.

4 illus, 2 tables, 23 ref

001152   Dobhal D P;Mehta M (Wadia Institute of Himalayan Geology, , Dehra Dun-248 001, Email: dpdobhal@wihg.res.in ) : Surface morphology, elevation changes and terminus retreat of Dokriani glacier, Garhwal Himalaya: implication for climate change. Himalayan Geol 2010, 31(1), 71-8.

The study deals with morphology, surface lowering and terminus retreat of Dokriani glacier from 1962 to 2007. Previously, the glacier boundary was recorded in Survey of India toposheet, which provides preliminary information of the glacier. Reoccupying the longitudinal profiles along centerline of glacier drawn from Survey of India maps of 1962 and 1995, and field survey in 2007, with adding surface mass balance data available for the period enabled to determine the changes in surface elevation along the centerline of the glacier. A comparison of longitudinal profiles indicates overall surface changes, substantial thinning at lower elevation and reduction of the glacier area. Surface elevation changes can be the result of reduction in accumulation and enhancement of surface melting. Average reduction of glacial ice thickness by 2.5 m^a-1 of water equivalent is significant, since the glacier has average ice thickness of 65m estimated by Ground Penetrating Radar (GPR) profiling in 1995. The terminus retreat measurements were made by fixed date observation at the end of ablation period of each year. The results shows terminus (Snout) retreat from 1991 to 2007 at an average rate of 15.6 m/yr. It was also observed that the retreating rate of terminus has decreased to 16.6 m/yr (2001-2007) from 17-18 m/yr recorded during 1991-2000.

6 illus, 2 tables, 22 ref

001151   Afzal N M;Mohiuddin M;Gyananath G;Balaji Rao B;Mehnaz M (Zoology Dep, School of Life Sciences, Nanded, Maharashtra) : Water quality assessment of Godavari river at Nanded, Maharashtra. Bioinfolet 2011, 8(4), 446-7.

Water samples were collected from Godawari river and analysed for temperature, pH, D. O., colour, turbidity and E. C. The findings revealed that water temperature, pH and D. O. were high, colour was slight muddy with higher values of turbidity and E. C.

1 table, 15 ref

000140   Warrier C U;Hameed A S;Velayudhan K T;Manjula P;Vasu K (NO, Centre for Water Resources Development and Management, Kunnamangalam P.O., Kozhikode-673 571, Email: warrieruk@rediffmail.com) : Estimation of sedimentation rate in Chilika lake, Orissa using environmental <. J appl Geochem 2009, 11(1), 102-10.

The rate and pattern of sedimentation in Chilika lake, the largest brackish water lagoon in India were studied using ²¹⁰Pb systernatics in undisturbed sediment cores. The results indicate that the sedimentation rates in three zones in the lake are 0.76 cm, 0.80 cm and 0.28 cm per year showing spatial variation. The non-uniform sedimentation rate at Chilika lake indicates that the lake has different deposition zones, with comparatively higher sedimentation rate at Northern and Central - 42 - sectors and a very slow rate at the Southern sector.

4 illus, 2 tables, 12 ref

000139   Walia C S;Singh S P;Dhankar R P;Ram J;Kamble K H;Katiyar D K (National Bureau of Soil Survey and Land Use Planning, IARI Campus, New Delhi-110 012, Email: cswalia_ps@yahoo.com) : Watershed characterization and soil resource mapping for land use planning of Moolbari watershed, Shimla District, Himachal Pradesh in Lesser Himalayas. Curr Sci 2010, 98(2), 176-82.

Precise characterization and inventorization of soil resource of Moolbari watershed was undertaken using satellite imagery and Survey of India toposheets to generate several layers of maps such as watershed boundary, drainage, soils, land use and land cover, physiography, slope and soil erosion using Geographic Information System technique. The watershed has been broadly divided into six physiographic units. Drainage pattern is dominantly rectangular and trellis and drainage density is 18 per sq. km. About 45% of the total area is under forests. The cultivated land is estimated to be 20% of the total area and the rest is mostly under grazing and scrub land. Soil-physiography relationship was established during detailed soil resource mapping. The texture of soils is dominantly loam/silt loam to clay loam with varying proportions of gravel. The soils are rich in organic matter. They are slightly to strongly acidic in reaction. The distribution of soils in the watershed is related to physiography, land use/land cover, slope and aspect.

8 illus, 2 tables, 11 ref

000138   Tiwari A N;Tambe J A;Satya Kumar Y;Nawale V P (NO, Central Ground Water Board, Central Region, Nagpur, Email: smartjivesh1@rediffmail.com) : Changing ratio of geochemical constituents of ground water with increasing conductivity in basaltic area of Maharashtra. J appl Geochem 2009, 11(1), 84-91.

It is found that with increasing electrical conductivity, the ratios of alkaline earths to alkali metals and that of weak acids to strong acids change. Basaltic waters are of basically Ca/Mg-HCO₃ type. With increasing EC, this Ca/Mg-HCO₃ type of water changes to different types like, Ca/Mg-Cl, Ca/Mg-SO₄, NaHCO₃, NaCl or Na₂SO₄ type. This may be due to heavy mineralization and surface pollution as another strong acid nitrate (NO3) is also found in high concentrations.

6 illus, 2 tables, 5 ref

000137   Srivastava P K;Manhas R S (Geology Dep, Jammu Univ, Jammu-180 006, Email: srivastav_pk@rediffmail.com) : Veitsch type magnesite deposits of NW Himalaya: geochemical comparative studies. J appl Geochem 2009, 11(1), 31-42.

Geochemical characteristics of magnesite from the Himalayan magnesite deposits is summarized. The major oxide composition of the magnesite from Chamba area shows lower MgO and higher CaO, A1₂O₃ and SiO₂ contents than those from Pan thai and Kumaun areas. The Sr content of the magnesite is comparatively high, ranging from 22 to 42 ppm and is attributed to the presence of dolomite relicts. The total REE contents from Panthal and Chamba areas have a limited range (2.88 to 14.38 ppm). Based on the major, trace and REE contents of the magnesite, it is suggested - 41 - that these deposits hosted within the Lesser Himalaya carbonate sequences are formed by diagenetic replacement of precursor dolomite while the Chamba magnesite is formed by hydrothermal replacement processes.

6 illus, 1 table, 33 ref

000136   Sinha U N (NO, , <35> 2, MAA, 6th Cross, Bagalagunte, Nagasandra Post, Bangalore-560 073, Email: sinhaun47@gmail.com) : On the predictive behaviour of the Indian monsoon in June 2009. Curr Sci 2010, 98(2), 134-5.

^ssc6 illus, 2 ref

000135   Singhal D C;Israil M;Sharma V K;Kumar B (Hydrology Dep, Indian Institute of Technology, Roorkee-247 667, Email: dcshyfhy@iitr.ernet.in) : Evaluation of groundwater resource and estimation of its potential in Pathri Rao watershed, district Haridwar(Uttarakhand). Curr Sci 2010, 98(2), 162-70.

The study attempts to delineate aquifers in the piedmont zone of Himalayan foothill region in Pathri Rao watershed, district Haridwar, Uttarakhand, India by using integrated hydrogeologic and geophysical techniques. The geophysical techniques included vertical resistivity soundings, two-dimensional resistivity image profiling and electromagnetic surveys. Nuclear isotope studies have been carried out to estimate groundwater recharge and its relative age. An assessment of groundwater availability and stage of groundwater development has also been made from the available and generated field data. On the basis of the study, it was found that the rate of recharge into the aquifers is of the order of 19% and the stage of groundwater development in the watershed is 164% indicating critical over-exploitation of groundwater. Based on the findings, possibilities of artificial recharge of groundwater have been looked into in the study area for augmentation of groundwater resources by proposing a few check dams at the suitable sites in the upstream areas of the watershed.

6 illus, 7 tables, 20 ref

000134   Pande H C;Raina A;Sharma P;Mittal A K (Geochemistry Div, KDMIPE, ONGC, Dehradun, Email: pandeharish@hotmail.com ) : Geochemistry of coal bed gases of barmer-sanchor, western Rajasthan, India. J appl Geochem 2009, 11(1), 20-30.

The objective of this study is to unravel the molecular composition and history of the coal gases of Barmer-Sanchor coalfield by means of isotope geochemistry. Methane prospect of huge reserves of Tertiary lignite from depth interval 1700 to 1600 meters of Barmer-Akli Formation in Barmer-Sanchor block has been envisaged. - 40 - Studies on the chemical and stable isotopic compositions of the desorbed gas samples from the coal seams of well BS reveal that the gases desorbed from the cores of coal seams have more than 60% methane in most cases. The hydrocarbon gases have 2-6% of higher (C +) components. Other gases with 0.78 to 6.83% of nitrogen and very high amount of CO (23-39%) are also present. The gases have been genetically characterized by stable carbon isotopic values of methane that vary from -57.2 to -69.3 per mil. The isotopic values are indicative of biogenic/diagenetic gases generated during coalification process. The study contributes to an understanding of the formation and origin of coal gas reservoirs in general and provides some information to estimate the future gas production characteristics in the Barmer and Sanchor coalfield in Western Rajasthan.

9 illus, 1 table, 7 ref

000133   Narasimha K N P;Kobayashi S;Shoji T;Sasaki M; Sethumadhav M S (Studies in Geology Dep, Mysore Univ, Manasagangotri, Mysore-570 006, Email: prakashnarasimha@yahoo.com) : XRD, EPMA and FTIR studies on garnet from Bettadabidu, Sargur area, Karnataka, India. J appl Geochem 2009, 11(1), 1-11.

One among the conspicuous occurrences of garnet mineralization in Sargur area of western Dharwar craton is located at Bettadabidu, near Mysore (Karnataka state). Garnets are confined to pelitic (garnet-biotite) schist enclaves in <62>3000Ma old gneissic complex and the host rock belongs to 3400-3000Ma old Sargur Group supracrustal rocks. Detailed mineralogical and geochemical studies of garnet and biotite of the pelitic schist using microscopy, X-ray diffraction, FTIR, SEM and electron microprobe are presented. P-T estimates (T~650 °C and P~5-8kbar) indicate to ihe formation of garnet during upper amphibolite facies metamorphism with the involvement of peak CO₂-rich fluids coinciding with the <126> 2500 Ma incipient charnockite formation event.

8 illus, 22 ref

000132   Menon R;Senthil Kumar P;Reddy G K; Seshunarayana T (National Geophysical Research Institute, Council of Scientific and Industrial Research, Uppal Road, Hyderabad-500 606, Email: rajeev896@yahoo.com) : Anomalous soil-gas helium escapes from the 1982 Gundipet micro-earthquake zone near Hyderabad, India. Curr Sci 2010, 98(9), 1187-9.

3 illus, 10 ref

000131   Kunwar P;Kachhwaha T S;Anil Kumar;Agrawal A K;Singh A N;Mendiratta N (NO, Remote Sensing Applications Centre, Lucknow-226 007, Email: kunwarpl@gmail.com) : Use of high-resolution IKONOS data and GIS technique for transformation of landuse/landcover for - 39 - sustainable development. Curr Sci 2010, 98(2), 204-12.

Sustainable development has assumed utmost importance in view of the increasing demands on the finite natural resources due to increasing population and need to protect fragile environment. Remote sensing and GIS techniques have capability to assess the available natural resources and its use, and provide information for transformation of alternative landuse, if the resource is not optimally utilized in the development process. In the present study, current landuse/ landcover has been studied and for optimal utilization of the available resources, alternate landuse has been suggested using remote sensing and GIS techniques in Phakot sub-watershed for sustainable development. For this purpose multi-temporal IKONOS satellite data have been used. About 889.49 ha area out of 1466 ha of the entire sub-watershed has been suggested for alternative landuse which is 60.7% of the total geographical area of the watershed. The transformed landuse has been recommended in various prescriptions such as double cropping/intensive agriculture, agrohorticulture, agroforestry, horticulture, afforestation/forest plantations, gap filling/forest protection and land mitigation by integrating available various natural resources in the study area.

2 illus, 2 tables, 19 ref

000130   Kuity D P;Swarnkar V (Studies in Geology and Water Resource Management School, Pt. Ravishankar Shukla Univ, Raipur, Chhattisgarh) : Estimation of P and T conditions for the crystallization of the Dongargarh granite, Dongargarh, Rajnandgaon district, Chhattisgarh. J appl Geochem 2009, 11(1), 12-21.

Central India has witnessed a long period of tectonic activity along with the acid plutonism. The granitoids of Central India are supposed to be coeval to the Bundelkhand Craton (BC) and Dharwar Craton (DC). The granitoid rocks occurring at Dongargarh area, Rajnandgaon district, Chhattisgarh, have a wide variation in the texture and mineral composition and have irregularly distributed enclaves of rhyolites and metabasics. On the basis of concentration of Rb-Sr and geothermal gradient, it is estimated that the granites of the Dongargarh area have been crystallized at a depth of 25 to 30 km in the temperature range of 500°C to 570 °C.

8 illus, 3 tables, 22 ref

000129   Khan M M A;Umar R (Geology Dep, Aligarh Muslim Univ, Aligarh-202 002, Email: rashidumar@rediffmail.com) : Significance of silica analysis in groundwater in parts of Central Ganga Plain, Uttar Pradesh, India. Curr Sci 2010, 98(9), 1237-40.

A study on variation in silica values in groundwater from a small part of the Central Ganga Plain has yielded valuable information on relative roles of geo-genic and anthropogenic solute acquisition processes and depth to the deep aquifer system in the area. It is recommended that silica analysis should be a mandatory component of all systematic hydrogeochemical studies.

3 illus, 1 table, 13 ref

000128   Kariyanna H (NO, , Chinmayee, Opp. to Govt. well, Upparahalli Extension, Tumkur-572 102) : Trace and rare earth element geochemistry of Mandovi-Zuari estuarine sediments-Goa. J appl Geochem 2009, 11(1), 111-16.

Iron ore mining forms the backbone of industrial development in Goa and nearly 60 percent of exports is from Goa. The rain water carries the washed out material from the mine dumps to the nearby agricultural lands and causes siltation problems in Mandovi-Zuari estuaries forming lateral mud bars. Briefly discusses the trace and rare earth Element chemistry and environmental impact on these two estuaries.

1 table, 1 illus, 3 ref

000127   Jain M K;Mishra S K;Shah R B (Hydrology Dep, Indian Institute of Technology, Roorkee-247 667, Email: jain.mkj@gmail.com) : Estimation of sediment yield and areas vulnerable to soil erosion and deposition in a Himalayan watershed using GIS. Curr Sci 2010, 98(2), 213-21.

Erosion is a natural geomorphic process occurring continually over the earth's surface and it largely depends on topography, vegetation, soil and climatic variables and, therefore, exhibits pronounced spatial variability due to catchment heterogeneity and climatic variation. This problem can be circumvented by dis-cretizing the catchment into approximately homogeneous sub-areas using Geographic Information System (GIS). In this study, the remote sensing and GIS techniques (through ERDAS Imagine 8.6 and ArcGIS 9.1 software) were used for derivation of spatial information, catchment discretization, data processing, etc. for the Himalayan Chaukhutia Watershed (India). Various thematic layers for different factors of Universal Soil Loss Equation (USLE) were generated and overlaid to compute spatially distributed gross soil erosion maps for the watershed using 18-year rainfall data. The - 38 - concept of transport limited accumulation was formulated and used in ArcGIS for generating the transport capacity maps. Using these maps, the gross soil erosion was routed to the catchment outlet using hydro-logical drainage paths for the derivation of transport capacity limited sediment outflow maps. These maps depict the amount of sediment rate from a particular grid in spatial domain and the pixel value of the outlet grid indicates the sediment yield at the outlet of the watershed. Upon testing, the proposed method simulated the annual sediment yield with less than ñ40% error.

10 illus, 3 table, 38 ref

000126   Gurugnanam B;Suvedha M;Vasudevan S;Murugaih M;Karthikeyan C (Earth Sciences Dep, Annamalai Univ, Tamil Nadu, Email: gurugis@yahoo.co.in) : Groundwater quality investigation in Veeranam catchment area, Tamil Nadu, India. J appl Geochem 2009, 11(1), 76-83.

A study on geochemical characterization of groundwater and its suitability for drinking and irrigation purposes was carried out in Veeranam catchment area of Tamil Nadu state. Fifty two groundwater samples were collected from dug wells and bore wells during pre and post monsoon seasons of 2006. The samples were analyzed for various water quality parameters such as pH, electric conductivity, total dissolved solids, calcium, magnesium, sodium, potassium, bicarbonate, carbonate, sulphate and chloride. Calcium, magnesium and chloride are the dominant ions in the groundwater chemistry. The chemical composition of groundwater is controlled by rock water interaction with sandstone, clay and older alluvium deposits. The chemical quality was evaluated for drinking use following the guidelines of WHO. Groundwater is potable except in some isolated pockets. It is inferred from Piper trilinear diagram that the groundwater quality is characterized by alkaline earth exceeding alkalies. As per USSL classification of water quality, mostly it falls under C₃S₁ or C₂S₁ category.

3 illus, 4 tables, 12 ref

000125   Gosain A K;Rao S;Singh P;Arora A (Civil Engineering Dep, Indian Institute of Technology, Delhi-110 016, Email: gosain@civil.iitd.ac.in) : Integration of Bio-Geo spatial database for selected watersheds in Himalayan region. Curr Sci 2010, 98(2), 183-91.

An integrated database has been designed to cater to the data collected by different - 37 - agencies on various aspects of biological and geophysical data, as part of the coordinated programme on 'Bio-Geo database and ecological modeling for Himalayas' initiated by NRDMS division of the Department of Science and Technology. The spatial database conforms to the NSDI standards. In order to facilitate the unified database system, an attempt has been made to design a geodatabase for Bio-Geo data using the state-of-art design techniques. The model is specified in an industry-standard modelling notation called the Unified Modeling Language and conforms to the same. The web interface is developed to evolve a system of information sharing, access and use of the Bio-Geo data collected for different watersheds. GIS-based query system developed has user-defined query and custom report facilities. The present article reports the detailed design and integration of Bio-Geo database. Need assessment carried out has also been discussed.

8 illus, 1 table, 2 ref

000124   Ghosh S K;Singh S S;Ray Y;Sinha S (Sedimentology Group, Wadia Institute of Himalayan Geology, Dehra Dun-248 001, Email: skghosh@wihg.res.in) : Soft-sedimentary deformational structures: seismites or penecontemporaneous, a study from the palaeoproterozoic lesser Himalayan succession, India. Curr Sci 2010, 98(2), 247-53.

Palaeoproterozoic sedimentary succession of the Lesser Himalaya contains soft-sedimentary deforma-tional structures (SSDS) caused during fluidization and liquefaction induced by seismic activity. Morphologically, the SSDS are represented by convolute bedding/lamination, ball-and-pillow, pseudonodules, and deformed cross-stratification and flame structures. After examining all other factors, it is inferred that the SSDS are the result of shocks, which can only be explained satisfactorily as triggered by earthquakes.

2 illus, 40 ref

000123   Gangal K;Vahia M N;Adhikari R (NO, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai-400 005, Email: rjoy@imsc.res.in) : Spatio-temporal analysis of the Indus urbanization. Curr Sci 2010, 98(6), 846-52.

The greater Indus valley was home to Neolithic cultures starting from 7000 BCE. They formed the antecedents of the urban Harappan civilization, whose rise and decline are dated to 2600 BCE and 1900 BCE respectively. At its peak, the Harappan civilization covered an area of more than a million square kilometres, making it the largest urbanized civilization of the Bronze Age. In this communication, we integrate GIS information on topography and hydrology with radiocarbon and archaeological dates of 1874 sites, to analyse the spatio-temporal growth and decline of the Indus urbanization. Analysis reveals several large-scale patterns in the growth and decline of urbanism. In the growth phase, urbanism appears to nucleate in three distinct geographical locations, situated in Baluchistan, Gujarat and the Ghaggar-Hakra valley. In the mature phase when urbanism is fully developed, the area distribution of sites follows a Zip-fian power law, a feature common to modern urban agglomerations. In the decline phase, the pace of de-urbanization is nonuniform with a strong geographical variation. The decline starts in the Ghaggar-Hakra region, followed by a large-scale collapse in the lower Indus plain, leaving, however, a resilient zone in Gujarat which has a delayed decline. The patterns discerned through our analysis will find use within a Bayesian framework to test hypotheses for the growth and decline of the Harappan civilization.

5 illus, 1 table, 12 ref

000122   Dewashish Kumar;Ananda Rao V;Nagaiah E; Krishnam Raju P;Mallesh D;Ahmeduddin M;Ahmed S (NO, National Geophysical Research Institute (CSIR), Hyderabad-500 606, Email: dew_Kumar@yahoo.co.uk) : Integrated geophysical study to decipher potential groundwater and zeolite-bearing zones in Deccan traps. Curr Sci 2010, 98(6), 803-14.

Geo-scientific integrated study using surface 1-D Vertical Electrical Sounding (VES), 2-D Electrical Resistivity Imaging (ERI), geological drilling and litholog preparation and finally sub-surface resistivity logging was carried out in the Deccan Basalt, hard rock region both for zeolites and groundwater in and around Aurangabad region, Maharashtra, India. In Deccan Trap the presence of zeolites along with weathered/fractured basalt is the direct indication of availability of water. The present study delineates different zones and the ERI results show the signature of high resistivity anomaly, indicating the cavity effect or cavity created due to zeolite. 2-D resistivity sections indicate zeolite-bearing zone with specific range of resistivity between 40-50 Ohm-m and 90-105 Ohm-m. Based on the resistivity anomaly and combined results, three borewells were drilled up to a maximum depth of 91.5 m. Resistivity logging was performed at three borewells and on quantitative interpretation the characteristic resistivity obtained for fresh basalt in association with zeolite has a resistivity range between 90 and 105 Ohm-m whereas the weathered zeolitic basaltic layer lies between 40 and 50 Ohm-m as - 36 - compared to 500 and 600 Ohm-m which corresponds to fresh basalt without presence of the zeolite. It is interesting to note that the change in resistivity values and kinks in resistivity logs reflected different formations. The resistivity logging aids as a supplementary tool to understand better the geological set up of the Deccan Basalt.

20 illus, 1 table, 27 ref

000121   Dave S R;Gupta K H;Tipre D R (Microbiology Dep, School of Sciences, Gujarat Univ, Ahmedabad-380 009, Email: shaileshrdave@yahoo.co.in) : Diversity of arsenite-resistant cocci isolated from Hutti Gold Mine and bioreactor sample. Curr Sci 2010, 98(9), 1229-33.

Arsenite, cobalt, chromium, copper, nickel, molybdenum, selenate and selenite-resistant cocci were isolated from Hutti Gold Mine reactor and processed water samples having extreme physico-chemical characteristics of pH 1.2-8.20, conductivity 3.2-58 mS and arsenic 11.0-1443.0 mg/l. Cultural, morphological, biochemical characters and antibiotic sensitivity of all the four cocci were studied. On the basis of biochemical and Biologr test, one isolate was identified as Staphylococcus aureus, and two of these were identified as Citricoccus sp. SRHGAs38 and Staphylococcus sp. SRDAs32 using 16S rRNA gene sequence. These isolates could be used for metal removal.

3 illus, 1 table, 21 ref

000120   Basu A (Geological Sciences Dep, Indiana Univ, 1001 E 10th Street, Bloomington, IN 47405, U.S.A., Email: basu@Indiana.edu) : Working hypothesis on the mesoproterozoic ages in India and its impact on some global concepts. J appl Geochem 2009, 11(1), 43-57.

New U-Pb age data of magmatic zircons from synsedimentary volcanic tuff and detrital zircons from known stratigraphic horizons buttressed by paleomagnetic pole positions and new Pb-Pb ages of carbonate rocks from the Vindhyan and Chhattisgarh Supergroups in peninsular India bracket the - 35 - opening and closing of these and equivalent basins (Indravati, PG. Valley, Kurnool, Kaladgi, Bhima, etc.) between <126>1750 Ma and -950 Ma, as opposed to the <126>1100 Ma to <126>518 Ma as is currently believed. The age data thus (a) require a revision of Purana stratigraphy, (b) make Purana sediments irrelevant to Snowball Earth, (c) indicate that the Indian shield rifted and formed basins much prior to the assembly of Rodinia, (d) indicate that the peninsular India remained a high ground during the existence of Rodinia, and (e) indicate that fossilized metazoans and small shelly fossils reported from these basins must be at least 1000 Ma old. A provisional time-frame for Purana stratigraphy is proposed. The new age data and records of igneous activity suggest that mostly Mesoproterozoic rifting and numerous igneous events thinned the Indian lithosphere sufficiently and eventually let the Reunion, Marion, and Kerguelen plumes rapidly thin the Indian plate to about 80-100 km.

2 illus, 94 ref

000119   Ballukraya P N;Kalimuthu R (Applied Geology Dep, Madras Univ, Chennai-600 025, Email: ballukraya@hotmail.com) : Quantitative hydrogeological and geomorphological analyses for groundwater potential assessment in hard rock terrains. Curr Sci 2010, 98(2), 253-9.

Hydrogeological and geomorphological parameters have been quantitatively correlated with groundwater availability. Weathered rock thickness has the highest control on availability of groundwater followed by lineament density whereas drainage density is seen to have minimum influence. A poor correlation is noticed between borewell depth and yield. The amplitude of seasonal variations in groundwater levels is noted to be higher in the low lying plains compared to the hilly regions. The groundwater potential zonation map, prepared using data merging techniques and assigning weightages based on the quantitative analyses of parameters on a GIS platform shows that more than 45% of borewells falling in the area under the category of excellent water availability are high-yielding.

6 illus, 5 tables, 10 ref

000118   Anandakumar S;Subramani T;Elango L (Civil Engineering Dep, Kongu Engineering College, Erode-638 052, Email: anandkeccivil@yahoo.co.in) : Major ion groundwater chemistry of lower Bhavani river basin, Tamil Nadu, India. J appl Geochem 2009, 11(1), 92-101.

An attempt has been made in this study to evaluate the major ion groundwater chemistry of Lower Bhavani River Basin, Tamil Nadu, India, which is a major source for drinking and irrigation in this region. Basic thematic maps pertaining to groundwater quality such as topography, drainage, soil, geology and geomorphology were prepared. Groundwater samples collected during July 2006 from 43 open wells spread over the basin were analysed for various physical and chemical parameters such as electrical conductivity (EC), pH, total dissolved solids (TDS), Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl^-, HCO₃^-, CO₃^2-, SO₄^2-, NO₃^- and F^-. Groundwater in the area is mainly alkaline and hard in nature. Hydrogen ion concentration (pH) ranges from 7.26 to 8.65 with an average value of 8.02. TDS varies between 100 and 1650 mg/l with an average value of 648 mg/1, with only one well in the southeastern part of the basin exceeding the permissible limit (TDS <62> 1500 mg/l) for drinking. Calcium ion concentration is high in many locations with an average of 262 mg/l during July 2006. Chloride is the second major anion next to bicarbonate and exceeds the permissible limit of 600 mg/l for drinking at three locations. Nitrate and sulphate concentrations are well within the allowable limits for drinking. Isopleth and choropleth (zonation) maps were prepared for all the physical and chemical parameters from the analytical data to model the spatial variation in groundwater quality.

6 illus, 8 tables, 14 ref

024775   Vijan A R;Rathore S S;Vig K C;Bansal M;Singh M P;Prabhu B N (Geochemistry Division, KDM Institute of Petroleum Exploration, Oil and Natural Gas Corporatio, Dehra Dun-248 195) : K-Ar and Rb-Sr ages of cretaceous glauconites from Jaisalmer basin, Rajasthan. J Geol Soc India 2000, 56(1), 15-25.

Importance of dating glauconites is that they are formed under low sedimentation rates connected with marine transgression and are commonly associated with unconformities and other stratigraphic breaks. Presents the first quantitative age estimation of glauconite samples separated from subsurface cores of Goru and Pariwar Formations of Jaisalmer basin, Rajasthan, India. SEM studies, X-ray diffraction patterns and high K₂O content (6.8 to 7.4%) of these samples indicate that they are highly evolved and are ideal for isotopic dating. The Rb-Sr age of 108±5 Ma and average K-Ar age of 103±3 Ma obtained for the glauconites from the Goru Formation are indistinguishable within error and agree with their biostratigraphic age. Glauconites from the upper most part of the Pariwar Formation give an average K-Ar age of 106±3 Ma (early Albian), which is slightly lower than their biostratigraphic age.

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024774   Thangarajan M;Masie M;Rana T;Uhl V;Gabaake G G;Bakaya T B (NO, National Geophysical Research Institute, Hyderabad-500 007) : Simulation of arid multi-layer aquifer system to evolve optimal management schemes : a case study in Shashe river valley, Okavango Delta, Botswana. J Geol Soc India 2000, 55(6), 623-48.

Multi-leaky aquifer system in Shashe river valley (Okavango delta), Botswana was simulated to study the aquifer response and thereby evolve optimal pumping schemes. The river valley falls in an arid region and has three aquifers separated by two aquitards. The upper alluvial aquifer below the narrow riverbed is being exploited to augment drinking water supply to the nearby wildlife tourist center, Maun. The bottom aquifer is saline. Continuous increase of abstraction from the upper unconfined and middle semi-confined aquifers has been causing progressive decline of water levels in these aquifers, as well as migration of saline water to the middle aquifer. In order to quantify the upward flow from the saline unit, a multi-layer model was constructed and calibrated for both steady state and transient condition. The calibration was reasonably good even with the given limited water level history for the middle (semi-confined) aquifer system. The calibration has shown that vertical conductivity (K¹) of the confining layers has a considerable influence on the hydrodynamics of multi-aquifer system. As a natural corollary, groundwater movement to the middle (semi-confined) aquifer is found to be dependent on the vertical downward leakage from the upper phreatic aquifer and upward leakage from the lowermost saline unit. As the river-derived recharge to the phreatic aquifer has been negligible due to no-flow condition existing in the riverbed for nearly a decade

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024773   Sudan C S;Sharma U K;Sahni A K;Shah S K (Department of Geology, University of Jammu, Jammu-180 006) : Trace fossils from the pin section of Spiti valley, Himachal Pradesh and their stratigraphic significance. J Geol Soc India 2000, 55(6), 649-54.

Early Cambrian trace fossils Planolites, Skolithos, Psammichnites, Neonereites, Didymaulichnus, Monomorphichnus, Dimorphichnus, Diplichnites, Rusophycus and Cruziana are described from the Kunzum La Formation (Haimanta Group) of the Pin section in Spiti valley. These trace fossils occur well below the body fossil zone reflecting their abundance at two stratigraphic levels. The Precambrian-Cambrian boundary could be well below the earliest trace fossil horizon. The abundance of trace fossils at these two levels is a universal phenomenon in the Himalaya and indicates two acme zones with proliferation of vermiform organisms in the lower zone and arthropod forms in the upper zone.

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024772   Subrahmanyam A V;Sushil Kumar;Singh D;Kak S N (Atomic Minerals Division, , 1-10-153/156, Begumpet, Hyderabad-500 016) : Discovery of pyroclastics and dyke in the Mahadek formation of Meghalaya Plateau. Curr Sci 2000, 78(10), 1189-90.

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024771   Sinha Ray K C;Srivastava A K (India Meteorological Department, Shivajinagar, Pune-411 005, ) : Is there any change in extreme events like heavy rainfall. Curr Sci 2000, 79(2), 155-8.

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024770   Sinha R;Chatterjee A (Engineering Geology Group, Department of Civil Engineering, Indian Institute of Technology, Kanpur) : Mineralogy of lacustrine sediments in the Schirmacher range area, eastern Antarctica. J Geol Soc India 2000, 56(1), 39-45.

A mineralogical study of the lacustrine sediment cores from lakes and varve deposits of the lake shore in the Schirmacher Range of East Antarctica is presented. Field observations and laboratory analysis indicate quartz and feldspar as principal allogenic phases derived from local crystallin rocks surrounding the lake basin. Illite, chlorite and minor amount of mixed-layered minerals in the lacustrine sediments are interpreted to be products of weathering in the lake catchment. In general, the clay mineralogy of sediment cores and varve sediments in indicative of low-hydrolyzing depositional environment under high latitudes and subtle weathering.

024769   Sharma S R;Parthasarathy G;Ravindran T R; Arora A K;Kumar B (NO, National Geophysical Research Institute, Hyderabad-500 007) : Laser raman spectroscopic studies on graphites from Dharwar craton: a possible metamorphic grade indicator for the host rocks. J Geol Soc India 2000, 55(4), 413-20.

The results of Laser-Raman Spectroscopic studies on graphite samples from the Archaean metasedimentary rocks of Dharwar craton to correlate the structural parameters of graphite with the metamorphic grade of the host rocks. The studies show that the first order Raman peak (O) of the graphite samples appears in the wave number range from 1581 to 1585 cm^-1; the second order Raman peak (S) appears in the wave number range from 2699 to 2721 cm^-1; and the disorder Raman (D) peak appears in the wave number range from 1349 to 1356 cm^-1. It is suggested that the intensity ratios of the Raman peaks (D/O)a are the inverse function of in-plane crystallite size of the graphite. The observed values of intensity ratio (D/O)h varies from 0.095 to 0.591, (D/D+O)a varies from 0.18 to 0.46 and (S/O)h varies from 0.21 to 0.32. This range of values indicates that the graphite samples are well crystallized. A correlation of (D/O) area ratios along with the in-plane crystallite size La (50 to 193 A°) and the metamorphic grade shows that the metamorphic grade of the host rocks of the studied samples lies in the range between upper chlorite zone and lower sillimanite zone. The estmated peak metamorphic temperatures of the host rocks are in the range of 575 to 625°C and they are in excellent agreement with temperatures obtained by the Powder X-ray diffraction studies and conventional geothermometry studies.

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024768   Sethna S F;Kothare P;Sethna B S (Department of Geology, St Xavier's College, Mumbai-400 001) : Monzodolerite dyke in the deccan traps of Saurashtra. J Geol Soc India 2000, 55(4), 431-7.

The monzodolerite dyke with a width of 25 to 30 meters, extends nearly east-west for almost 30 kms. The dyke intrudes horizontal lava flows of the Deccan Volcanic Province. Major, trace and rare earth element analyses for three samples of the monzodolerite have been given. SEM-EDXA analyses for feldspars and pyroxenes have also been given. On the basis of field evidence (in the form of unassimilated blebs of more basic magma surrounded by the monzodolerite), mineralogical variation and whole rock geochemistry, the rock is presumed to have formed by the mixing of basic and intermediate magmas rather than by a process of pure differentiation. The intermediate magma is presumed to have formed by differentiation of basaltic magma at some depth.

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024767   Roy A K;Saha A;Singh R P;Sinha R m (Atomic Minerals Directorate for Exploration and Research, , New Delhi) : Application of soil radon and trace element geochemistry for uranium exploration at Kuchanapalle, Guntur district, Andhra Pradesh. J Geol Soc India 2000, 56(1), 89-96.

A radiactive fault breccia zine trending N30°E is exposed intermittently within the Ipuru granite dome, near Kuchanapalle village in the NE margin of Cuddapah basin. A major part of the fault zone is under soil cover. Within this fault zone, a dark coloured ferruginous and uraniferous fault breccia is exposed over as area of 150m x 2.5m. In order to trace the continuity of the concealed fault zone, the uraniferous breccia zone was tested by closed circuit soil-gas radon (CCT) measurement, solid state nuclear track detection (SSNTD) survey, and trace element analysis of augur-hole soil samples. Radon levels in 164 auger holes vary from 9 to 863 per 50 sec. The alpha track density on cellulose nitrate films used in SSNTD surveys varies from 27 to 820 per sq. mm. The iso-alpha track density map has confirmed the anomalous patterns obtained by the soil-radon survey. Trace element data of soil samples have been processed using R-mode factor analysis of correlation matrix. These data along with radon and SSNTD surveys have thus been found to be very effective in delineating the extension of the radioactive breccia zone under soil cover, up to 1200 m towards north.

024766   Reddy P R;Chandrakala K;Sridhar A R (NO, National Geophysical Research Institute, Uppal Road, Hyderabad-500 007) : Crustal velocity structure of the Dharwar craton, India. J Geol Soc India 2000, 55(4), 381-6.

Re-examination of analog seismic data acquired across Western Dharwar Craton (WDC) and Eastern Dharwar Craton (EDC) (western and middle parts of Kavali-Udipi DSS profile) indicate significant velocity variations in WDC and EDC. The synthesis of velocity details with the available geological signatures suggests that the two segments of the Dharwar Craton have varying structure and evolution.

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024765   Rathna K;Vijaya Kumar K;Ratnakar J (School of Earth Sciences, Swami Ramanand Teerth Marathwada University, Vishnupuri, Nanded-431 606) : Petrology of the dykes of Ravipadu, Prakasam Province, Andhra Pradesh, India. J Geol Soc India 2000, 55(4), 399-412.

The deloritic and basaltic dykes of Ravipadu in the Prakasam Province traverse and extend beyond the gabbro pluton. The dolerites exhibit ophitic - subophitic, intergranular and equigranular textures. The basaltic dykes include lamprophyres (camptonites) and porphyritic basaltic dykes which display porphyritic/glomeroporphyritic and panidiomorphic textures. The chief rock forming minerals in these dykes are olivine, clinopyroxene and plagioclase with subordinate orthopyroxene, amphibole and biotite. The accessory minerals include opaques and green spinel. The dolerites and basaltic dykes show contrasting major element compositions, especially with respect to alkalies and alkali/silica ratios, normative mineralogy and rare earth element concentrations and patterns. The dolerites, which contain modal and normative hypersthene, are tholeiitic and show iron enrichment as the differentiation proceeds. They show LREE enriched and HREE depleted patterns with positive Eu anomalies. Basaltic dykes in which modal and normative hypersthene is conspicuously absent are calc-alkaline to alkaline and are LREE enriched without any perceptible Eu anomalies. Petrogenetic modelling suggests that the dolerites are probably replenished liquids which are geochemically similar to the parental magmas of the host gabbros, whereas the basaltic dykes are genetically unrelated to the dolerite dykes and to the host gabbros.

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024764   Rao R L N;Sethuram S;Subhash Ram;Rao B N;Tiku K L (Atomic Minerals Directorate for Exploration and Research, Department o, , Hyderabad-500 016) : Geophysical signatures of a fracture controlled U-mineralisation: a case study from mulapalle area, Cuddapah district, Andhra Pradesh. J Geol Soc India 2000, 55(4), 421-9.

Geophysical methods have been extensively used for delineation of structural features such as fractures and shear zones which often control and host economic mineralisation. Numerous fractures hosting uranium mineralisation and confined to younger intrusives and leucogranites occur within basement gneissic complex on the southwestern margin of the Mesoproterozoic Cuddapah basin. The geophysical signatures of one such mineralised fracture zone near Mulapalle are discussed. Mineralised fractures are mostly confined to a zone of cataclastic rocks characterised by widely varying magnetic character with respect to the surroundings. A stron redox barrier associated with the mineralisation is revealed by self-potential data. The mineralised zone is also indicated by a higher order resistivity attributable to the enrichment of silica in the fracture zone.

024763   Rao K N;Gadgil S;Rao P R S;Savithri K (Centre for Atmospheric and Oceanic Sciences, Indian Institue of Science, Bangalore-560 012) : Tailoring strategies to rainfall variability - the choice of the sowing window. Curr Sci 2000, 78(10), 1216-30.

The optimum sowing window for rainfed groundnut in the Anantapur region has been determined using the crop model PNUTGRO which has been validated for the region. The year-to-year variation of the rainfall patterns has a large impact on the model yield and its variation with sowing date. The results do not change much if the daily data for other meteorological variables such as temperature and radiation are replaced by the average daily values over the ten years for which these data are available. The variation in the model yield with sowing date for eighty-eight years for which daily rainfall data are available has shown that the broad sowing window of 22 June-17 August presently used by the farmers is indeed the one that minimizes the risk of failure. Within this broad window, sowing after mid-July enhances the yields considerably. The farmers in this region use the first sowing opportunity in the broad window. Using the heuristic model to analyse the sowing opportunities, it has been shown that postponing sowing until after mid-July does not involve much risk. It is also shown that incidence of locally triggered pests/diseases decreases when sowing is postponed to later than mid-July.

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024762   Ramasamy S;Madhavaraju J;Armstrsong Altrin Sam J (Sedimentology Lab, Department of Geology, School of Earth and Atmosphe, University of Madras, Guindy Campus, Chennai-600 025) : Dropstones in Talchir sediments of Palar Basin, Tamil Nadu - implications on depositional conditions and paleoclimate. J Geol Soc India 2000, 56(1), 47-52.

Recent field study of Gondwana sediments in the Palar basin near Chennai brings to light the occurrence of assorted size of boulders of extraneous source in argillaceous siltstones. These boulders are regarded as glacial in origin. It is interpreted that icebergs carried such boulders into a pro-glacial lake. Melting of the icebergs resulted in dropping of boulders into the depositional environment. Discusses the depositional environment and paleoclimate that prevailed during the deposition of these exotic boulders.

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024761   Raha P K;Parulkar S N;Ghosh S C;Some S;Kundu U S;Manoj Kumar;Saha G;Misra I K (NO, Coal Wing, Geological Survey of India, Calcutta) : "Possible microfossils" from the Archaean banded iron formation (Bailadila group), Madhya Pradesh, India. J Geol Soc India 2000, 55(6), 663-73.

SEM studies have recorded presence of filamentous and unicellular spheroidal structures which are regarded as "possible microfossils", from the stromatolitic Archaean (ca. 3.0. Ga old) banded iron formation (BIF), Bailadila Group. Spheroidal bodies have diameters that range from 0.5 to 6.9 microns. The frequency of forms with smaller diameters is greater than those with the diameter above 3.0 μm. The filamentous structures range from less than 100 nanometers to 1.2 μm in diameter. Syngenetic nature of these microfossils has been established. Though a large number of these microfossils could be identified in the SEM, they could not be observed in petrographic thin sections under optical microscope most probably because of their association with, and being clouded by, opaque haematite.

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024760   Raghav K S (NO, Geological Survey of India, 15-16, Jhalana dungri, Jaipur) : Discovery of foraminifera from Bilara group, Jodhpur district, Rajasthan. J Geol Soc India 2000, 55(4), 395-7.

Tertiary foraminifera belonging to Discorbis and Quinqueloculina are discovered by the author from the limestones of Bilara Group of Marwar Supergroup. These rocks are hitherto regarded as unfossiliferous and Neoproterozoic-Eocambrian in age. The present find of foraminifera suggests that the formations are not older than lower Eocene, throwing new light on the age of the Marwar Supergroup from the study area.

024759   Periakali P;Eswaramoorthi S;Subramanian S; Jaisankar P (Climate Change Research Unit, Department of Applied Geology, University of Madras, Guindy Campus, Chennai-600 025) : Geochemistry of pichavaram mangrove sediments, southeast coast of India. J Geol Soc India 2000, 55(4), 387-94.

Fourteen sediment samples collected from Pichavaram mangrove were analysed for grain size, organic carbon, sedimentary sulphur, calcium carbonate, Fe, Mn, Al, Cu and Mg. Factor analysis was carried out to infer the mechanisms controlling the behaviour of metals. Four factors accounted for around 75% variance. Fe, Mn and Hg are associated with organic carbon and fine fraction content of the sediments and loaded onto factor 1 which accounted for 33.6% variance. This is due to the complexation of Fe, Mn and Hg with organic matter and the adsorption of these organo-metallic compounds onto the finer sediments due to their high surface/volume ratio and presence of surface charge. Factor 2 accounted for 18.6% variance and is loaded with CaCO3, finer fraction, Al and Cu, implying contribution of Al and Cu from detrial clay minerals. The association of CaCO3 with this factor is not clearly understood. Factor 3 is loaded with organic carbon and coarse fraction of the sediments and it accounted for 13.3% variance. The association of organic carbon with coarse fraction of the sediments could be either due to the Ca²⁺ and Mg²⁺ions induced adsorption of organic matter onto mineral grains, or due to the presence of coarse vegetal debris. The fourth factor accounted for 9.8% variance and is loaded with sedimentary sulphur, no metal is associated with this factor.

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024758   Nagaraju A;Prasad K S S (Department of Geology, Sri Venkateswara University, Tirupati-517 502) : Biogeochemical patterns associated with mica pegmatite of Nellore mica belt, Andhra Pradesh. J Geol Soc India 2000, 55(6), 655-61.

Accumulation of elements in different organs of three plant species, viz., Azadirachta indica, Ficus racemosa, Ficus hyspida and their associated surface soils occurring in the Nellore mica pegmatite belt were studied. Large amounts of Sr, Ba and B were noticed in the vegetation of the Nellore mica belt. Among these plant species, Azadirachta indica (neem) has accumulated large amounts (2230 ppm) of Sr. Selectivity is the key factor for the uptake and accumulation of elements by plants. Species to species variation in the accumulation and tolerance was observed in the plants growing around mica mines. In their surrounding soils, large concentrations of Al, Fe, and La were noticed.

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024757   Mohapatra P C;Behera G (NO, Central Rice Research Institute, Cuttak-753 006) : Distribution of aquifer recharge flux at the nodes of finite elements using landuse map of IRS-1C. J Geol Soc India 2000, 55(6), 613-22.

Deals with the rise in water table levels due to acquifer recharge by surface water bodies and irrigated crops. FCC image of IRS-IC was used to develop landuse polygons. Recharge norms of Groundwater Estimation Committee were followed to determine recharge from these polygons. Steady state flow was simulated by application of finite element method. Area-based recharge fluxes were considered as point sources, concentrated at their area-centres. Fluxes in an element due to polygon-segments were determined separately and then distributed at the element-nodes by applying the principle of shape function. An area of 45 sq. km in the environs of Central Rice Research Institute, Cuttack was selected for study. Contour maps of aquifer recharge and rise in water table levels have been developed for the area. Results from the study indicates that the groundwater rises by an average of 1.7 m due to surface recharge. Based on the water requirements of the crops in the study area, it is estimated that the aquifer recharge can support paddy irrigation up to a maximum of 223.6% of the total area in Rabi season without depleting the aquifer storage.

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024756   Mohanty S;Mohanty A K;Nayak P K (Department of Applied Geology, Indian School of Mines, , Dhanbad-826 004) : Structure of manganese-bearing metasedimentary rocks of the Sausar group around Kandri mines, Nagpur district, Maharashtra. J Geol Soc India 2000, 56(1), 79-87.

Detailed mapping of the Sausar Group around Kandri Mines, Nagpur district, Maharashtra, shows that the rocks of the area have been involved in folding of three generations. The metasedimentary bands in the Kandri Mines and the surrounding area show an arcuate outcrop that closes northwest. The bedding and schistosity strike ~ E-W in the northern part and NW-SE to NE-SW in the southern part of the mine. This variation defines a synformal fold of second (F₂) generation (syncline near Kandri Mines), with WNW-ESE axial trace. The axial trace of the regional F₂ fold of the Kandri area coincides with that of the Ramtek area when extrapolated over the soil cover. The terminations of the manganese-ore bands of the Kandri Mines and Mansar Mines are the result of original sedimentary facies change.

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024755   Mohan P M;Victor Rajamanickam G (Department of Industries and Earth Sciences, Tamil University, Thanjavur-613 005) : Buried placer mineral deposits along the east coast between Chennai and Pondicherry. J Geol Soc India 2000, 56(1), 1-13.

Along the east coast of India between Chennai and Pondicherry, 163 sediment samples were collected from different sub-environments of the beach representing low water mark (LWM), foreshore (FS), berm crest (BM), backshore (BS), dune (DU), and beach ridge or strandline (SL), upto 1 m depth, at fifteen stations, spaced at a distance of approximately 10 km interval. The heavy mineral content in the bulk sediment samples ranges from 0.55 to 22.95%. This concentration may be due to the winnowing by wave action and selective sorting processes. Erosion exposes one of the stations in the beach ridge, up to 4 m depth from the surface and shows a higher concentration of heavy minerals. This information, along with analytical results of the stations from the surface upto one metre depth, indicating heavy mineral concentration of 8%, suggests the possibility of buried placer deposits at about 2 to 4 m depth along the beach ridge. Based on this prognostication, a random station was selected i.e. near Mahabalipuram and manual boreholes were drilled. These boreholes have confirmed the existence of buried placer deposits having concentration of 8 to 88% of heavy minerals around 1.5 to 4 m depth of beach ridge. R mode and Q mode factor analyses indicate the possible environmental parameters prevailing at the time of deposition as well as under the present conditions in the stations.

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