007194   Rashmi;Das S;Maheshwari R (Geology and Geophysics Dep, IIT Kharagpur, Kharagpur-721 302, Email: rashmi_singh06@yahoo.co.in) : New method of estimation of initial orientation and shape of deformed pebbles using TURBO C++ and its apllication to Bisrampur conglomerate, Singhbhum district, Jharkhand. Himalayan Geol 2007, 28(1), 99-126.

Method for determining the initial preferred orientation of the deformed pebbles using numerical technique has been developed. Although R_f /φ analysis is a more reliable method available for the estimation of strain and calculation of initial axial ratios and orientation, its practical application involves tedious and time-consuming procedures. More importantly the method is limited to pebbles/clasts showing an initial non-random orientation. This new method of initial pebble orientation determination should prove useful in Precambrian terrains, especially where sedimentary structures are scarce. The program should be useful to geoscientists working on object-oriented programs. Besides achieving sufficient accuracy, the program is easy to run on personal computers. The program has been written in Turbo C++ and compiled in C++ compiler in a personal computer. The procedure of strain estimation by matching R_f vs φ plots with standard e-curves following Lisle (1985) have been used as the basis for developing the computer program to obtain finite strain ratio and orientation of initially preferred orientated clasts. For computation of initial orientation and shape of the clasts the concepts of Dunnet & Siddans (1971) and Ramsay & Huber (1983) have been used. The orientation data are not dependent on any preconceived reference direction such as cleavage or bedding. The method does assume, in its undeforming procedure that the angular vector means of the initial distribution was parallel to bedding / surface of deposition.

10 illus, 3 tables, 41 ref

007193   Rashmi;Das S (Geology and Geophysics Dep, IIT Kharagpur, Kharagpur-721 302) : Proterozoic sedimentation in Singhbhum Basin - a look through Bisrampur-Ghatsila-Galudih Corridor. Himalayan Geol 2007, 28(1), 133-60.

The deformed folded sequence of metaclastic units possesses records of depositional history along the eastern cratonic margin of an unstable foreland that formed during the early phase of the Singhbhum Orogeny. A continuity of sedimentation and stratigraphic history enables to identify proximal and distal parts of a submarine fan system that originated from the south and opened up towards the north. Proximal, medial and distal associates of the submarine fan system are well preserved along the projected Bisrampur-Ghatsila-Galudih corridor and also elsewhere. The proximal sequence preserved in and around Bisrarnpur is a product of submarine fluidized non-cohesive granular-debris flow, triggered by instability of the basin flank. Local basement topography largely controlled the energy distribution in the clast-fluid system through fluid-sediment decoupling. The overall sedimentation pattern is suggestive of a genetic linkage between debris flow and turbidity current both simultaneously operating within a submarine feeder channel. The medial and distal components of the submarine fan system are excellently preserved in the Ghatsila-Galudih region as sandstone-shale turbidites deposited in small overlapping submarine fan system. During basin filling, instability of the basin flank and basin floor, involving both vertical subsidence and horizontal stretching of the basin strongly influenced the sedimentary character through various scales of turbidity current activities, intra-basinal contemporaneous flows. This was followed by an ultimate stagnation and onset of post depositional processes.

29 illus, 3 tables, 68 ref

007192   Raina A K;Negi S S (NO, Forest Research Institute, Dehra Dun-248 006, Email: rainaak@icfre.org) : Soil mineral relationship with different forest types in Mussoorie Forest Division of Uttaranchal, India. Himalayan Geol 2007, 28(1), 79-86.

The importance of soil minerals in forestry is of great significance, especially in evaluating the soil fertility for higher production. The study was carried out at Dhanaulti and adjoining blocks of Jaunpur range, Mussoorie forest division (Uttaranchal) to correlate soil mineral relationship with different forest types. Geologically, the rocks of the study area are of Pre-cambrian to early Paleozoic age and are covered with recent and sub recent deposits. Study area includes Typic Hapludoll, Typic Argiudoll, Ruptic-Alfic Eutrochrept and Typic Dystrochrept and soils are classified as Mollisols and Inceptisols respectively. It has been observed that Cedrus deodara forests occur in the soils of Mollisols developed on limestone, dolomite, quartzite and shale whereas Pinus roxburghii and Quercus leucotrichophora occurr on Inceptisols, developed on phyllite, slate, sandstone, slate etc. The results of the study revealed that the impact of geology on vegetation is evident in some sites. Investigations show that relief and geology of the area govern soil types, whereas effect of altitude and climate on geology gives rise to natural vegetation. Climate and aspect on a particular site has given rise to the various pedogenic processes active at the site. Based on the study it was inferred that geology, floristic composition and soil is in perfect harmony with each other.

3 illus, 4 tables, 21 ref

007191   Narayanan V;Anirudhan S;Grottoli A G (Geology Dep, Kerala Univ, Kariavattom, Thiruvananthapuram-695 581, Email: sap5354@rediffmail.com) : Oxygen and carbon isotope analysis of the miocene limestone of Kerala and its implications to palaeoclimate and its depositional setting. Curr Sci 2007, 93(8), 1155-9.

Lower Miocene to Mio-Pliocene sedimentary basin of Kerala consists of Quilon carbonate sequence (Lower-Middle Miocene), which is confined between two clastic units (Ambalapuzha and Mayyanad formations). The carbonate sequence is not extensive but restricted between Alappuzha in the north and Edava (Thiruvananthapuram district) in the south. Stable isotopic analysis on Quilon limestone for δ¹⁸O points to a warmer Miocene climate, with an average value of 34.25 degree C. This value is slightly higher than the previously estimated temperature during the Miocene. The down core decrease of δ¹³C values of the limestone can be correlated with the transgressive phase during which carbonate get deposited in the Tertiary sequences of Kerala, as proposed by previous workers. Bivariate plots for δ¹⁸O and δ¹³C reveal that the limestone forms in the field of warm-water skeletons.

2 illus, 2 tables, 26 ref

007190   Nanjundiah R S;Krishnamurti T N (Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore-560 012, Email: ravi@caos.iisc.ernet.in) : Intraseasonal oscillation of tropical convergence zones: theory and prediction. Curr Sci 2007, 93(2), 173-81.

Intraseasonal oscillation of Tropical Convergence Zones (TCZ) over the Indo-Pacific region has been studied. Both meridional and zonal propagating modes with timescales of about 40 days are prominent over the Indian and West Pacific regions. The mechanisms governing both these modes are reviewed. It is found that ocean-atmospheric interaction plays an important role in modulating these modes. The role of oceans is further highlighted in a series of seasonal forecasts using a coupled ocean-atmosphere model. It is found that forecasts of intraseasonal oscillations show significant improvement upon assimilation of sub-surface ocean data from the ARGO (a global programme to observe sub-surface profiles in the oceans) array of floats.

9 illus, 52 ref

007189   Naithani A K;Bhatt A K;Sundriyal Y P (Geology Dep, H.N.B. Garhwal University, Srinagar (Garhwal)-246 174) : Landslide hazard mapping: a case study for the Hydropower Project in a part of Garhwal Himalaya, Uttaranchal, India. Himalayan Geol 2007, 28(1), 63-73.

Landslide hazard zonation mapping of Loharinag-Pala area, where a hydropower scheme of 600 MW is proposed on Bhagirathi River was carried out. The study area lies in the southern mountain front of the Main Central Thrust (MCT), which receives majority of the southwest summer monsoon. In the study statistical analysis of various geo-environmental factors such as the lithology, slope, structure, relative relief, landuse and hydro-geological conditions were used. For preparing the landslide hazard zonation map a quantitative approach called landslide hazard evaluation factors (LHEF) rating has been used. Remote sensing data were also used for data base creation. The study indicates that structures, steeper angle of hill slopes and rainfall plays major role in triggering landslides in this part of the Himalaya. The study further suggests that in the geotechnical investigation of hydropower, landslide hazard evaluation factor (LHEF) rating scheme can provide rapid hazard assessment for river valley projects in a mountainous terrain.

8 illus, 2 tables, 25 ref

007188   Midya S K;Sarkar H (Physics Dep, Serampore College, Serampore, Hooghly-712 201, Email: drskm06@yahoo.co.in) : Variation of stratospheric ozone with relative humidity and sharp depletion of absolute humidity associated with Nor'wester over Kolkata. Indian J Phys 2007, 81(2), 217-24.

Presents the variation of stratospheric ozone concentration with relative humidity over Kolkata. Analysis confirms that there is close correlation between them. The relative humidity in general, increases during commencement of severe thunderstorm. As drop in temperature occurs during thunderstorms, absolute humidity decreases during the onset of thunderstorm. The sharp depletion of absolute humidity at the time of starting of Nor'wester over Kolkata has been studied. Possible explanations of such type of variation of humidity are presented. One possible method of forecasting of severe thunderstorm is also offered.

3 illus, 1 table, 13 ref

007187   Mahajan A K;Sporry R J;Champati Ray P K; Ranjan R;Slob S;Van W C (NO, Wadia Institute of Himalayan Geology, 33, GMS Road, Dehradun-248 001, Email: mahajan@wihg.res.in) : Methodology for site-response studies using multi-channel analysis of surface wave technique in Dehradun city. Curr Sci 2007, 92(7), 945-55.

Two-dimensional shear wave velocity investigation using the multi-channel analysis of surface waves helps identify lateral and vertical variations of shear wave velocity at shallow depth. This information is required for predicting the ground motion response to earthquakes in areas underlain by thick soil cover. At one such area in Dehradun, at the foothills of the Himalaya, shear wave velocities of the near-surface soil were determined for 50 locations covering almost all representative units with respect to variation in local geology and geomorphology. Based on the average shear wave velocities of the upper 30 m of the soil, sites located in the south-southwestern and central part of the city are predominantly classified as class `D' (180-360 m/s) except a few locations like Clement Town (site no. 43) and Majra (site no. 48), which can be classified as class `E' due to very low shear wave velocity, in accordance with the NEHRP 1997 provision. The northern part of Dehradun city shows high velocities, ranging from 300 m/s at the surface to more than 700 m/s at depth of 30 m. These sites located in the northern and eastern parts of the city with average shear wave velocity (Vs) values more than 360 m/s have been classified as class `C' site (360-760 m/s). The characteristic period estimated for each site of the soil column varies from 1.5 to 3.12 Hz. Based on the shear wave velocity, input motion, static and dynamic properties of different soil layers, site-response spectrum and amplification functions have been derived. The response spectrum suggests spectral acceleration value for two-storey structures of 3 to 8 times higher than the peak ground acceleration at the bed rock level, i.e. 0.05 g. The analysis also suggests peak amplification at 3-4, 2-2.5 and 1-1.5 Hz in the northern, central and south-southwestern parts of the city respectively.

12 illus, 37 ref

007186   Kumaravel V;Sangode S J;Rohtash Kumar;Siva Siddaiah N (NO, Wadia Institute of Himalayan Geology, 33, General Mahadeo Singh Road, Dehra Dun-248 001) : Pedogenic variations in the Plio-Pleistocene Siwalik paleosols from the Subathu Sub-basin, NW Himalaya, India. Himalayan Geol 2007, 28(1), 47-61.

The Plio-Pleistocene Siwalik paleosols from three stratigraphic sections (Haripur, Ghaggar, and Moginand) in the Subathu sub-basin of the Himalayan Foreland Basin, NW Himalaya are studied for their field characteristics and lateral variability. Paleosols in the Haripur section are developed over flood plains of relatively distal alluvial fan setup as compared to Ghaggar and Moginand. The Haripur paleosols display pedocomplexes comprising multi storied compound and composite profiles that are rare in the Ghaggar and Moginand sections. The Haripur paleosols are characterized by Bt (argillic) and Bk (calcic) horizons with rare Bs (spodic) horizons. Whereas, the Ghaggar and Moginand paleosols are characterized mainly by aridisols with petrocalcic horizons and alfisols with Bt and Bk horizons. The nature of mottles and calcretes is entirely different for Haripur paleosols than the Ghaggar and Moginand indicating relatively well drained and arid conditions for the latter. The difference in the nature of the paleosols amongst the Haripur, Ghaggar and Moginand sections can be attributed to their proximal to distal depositional setup over alluvial fan sedimentation. Hence, the climatic signature from these paleosols needs to be inferred carefully taking into account their field characters.

7 illus, 2 tables, 49 ref

007185   Jin S;Park P H;Park J U (Space Geodesy Research Group, Korea Astronomy and Space Science Institute, 61-1 Hwaam-dong, Yuseong-gu, Daejeon 305-348, South Korea) : Why is the South Korean peninsula largely aseismic? Geodetic evidences. Curr Sci 0000, 93(2), 250-3.

Northeast Asia, including Korea, North China, Philippines and Japan, is one of the most seismically active regions in the world, with some of the most catastrophic earthquakes in human history. However, the South Korean peninsula has remained largely aseismic with respect to the surrounding highly-seismic areas. Presents geodetic evidence in support of the largely aseismic nature of South Korea by analysing the crustal strain and energy density rates derived from recent dense geodetic observations. The dilation rates show that Northeast Asia is under high WNW-ENE oriented compressional strain regime, but the rates are lower in South Korea. In addition, the scalar strain rates and strain energy density rates further imply that the South Korean peninsula is a stable block with low rates. High rates are mainly inferred in North China, southwest Japan and the western boundary of the Philippine Sea plate, consistent with high seismicity in these areas. Furthermore, we speculate that the low seismicity in South Korea may continue in the future.

5 illus, 17 ref

007184   Humane S K;Nagle A K;Shahare P D;Kundal P P (P.G.Dep of Geology, Rashtrasant Tukadoji Maharaj Nagpur University, Law College Square, Nagpur-440 001, Email: sumedhahin@yahoo.com) : Late cretaceous intertrappean carbonates of Rajahmundry area, Andhra Pradesh: effect of Deccan volcanism. Himalayan Geol 2007, 28(1), 127-32.

The Intertrappean (Late Cretaceous ) carbonate rocks are exposed in Kondagudam quarry near Pangadi, Duddukuru -Chunnapraya quarry and Duddukuru-Talumala quarry near Duddukuru and Manibhaugaru quarry and Babagaru quarry near Gauripattanam area of Rajahmundry, which belong to the Deccan Trap Subprovince. The lower upper horizons of the Intertrappean carbonates show varity of petrological and structural transformations due to the injection and drenching of Deccan volcanic fluids. The carbonates occurring adjacent to the Deccan Traps are very hard, highly brecciated and show deformations, alterations and structural disturbances because of Deccan volcanism. The Babagaru quarry near Gauripattanam area exhibits more vigorous effects on lower carbonate horizon. The strong intrusion of fluids into the already precipitated limestone has resulted in the development of breccia including fragments of basalt and quartz. This also suggests that during the deposition of lower Inter-trappean carbonate horizon, Deccan volcanism was not completely seized but instead it was intermittently erupting for some time until further more precipitation of carbonates. The soaking of fluids by lower carbonate horizon resulted into the development of cracks, which were filled at places by secondary calcite. The Kondagudem quarry shows evidence of hydrothermal activity by the presence of asbestos vein with fibers perpendicular to lower and upper creamy- white limestone horizon. This limestone shows preferred orientation of calcite crystals in the direction of precipitation of asbestos fibers modifying its earlier form into new elongated laths like calcite crystals. Calcite, monocrystalline quartz, plagioclase feldspar, olivine alongwith altered ground mass etc. are the important minerals of the lower Intertrappean carbonate horizon. The petrographical and diagenetic studies suggest that intermittent Deccan volcanism during marine transgression affected the biotic constituents of the lower Intertrappean carbonate horizon for some time and formed cracks or fenestrae in them as a result of desiccation and soaking. The second major eruption has also affected the upper Intertrappean limestone beds. The presence of dasycladacean algae associated with shallow water forms of foraminifers in the Intertrappean carbonates indicate that they were deposited in very shallow marine waters.

6 illus, 15 ref

007183   Gadgil S;Rajeevan M;Francis P A (Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore-560 012, Email: sulo@caos.iisc.ernet.in) : Monsoon variability: links to major oscillation over the equatorial Pacific and Indian oceans. Curr Sci 2007, 93(2), 182-94.

Nature of the two critical modes for monsoon variability, viz. EI Nino Southern Oscillation and equatorial Indian Ocean Oscillation is considered and their links to the monsoon elucidated. Suggests possible reasons for the rather poor skill of simulation of the interannual variation of the Indian summer monsoon rainfall by atmospheric general circulation models, run with the observed sea surface temperature as boundary condition. Discusses implications of what we have learned for the monsoon of 2006, and possible use of information on the two important modes for prediction of the rainfall in all or part of the summer monsoon season. Concludes with the view of what the focus of research and development should be for achieving a substantial improvement in the skill of simulation and prediction of the Indian summer monsoon rainfall in the near future.

16 illus, 66 ref

007182   Chakravarthi V;Singh S B;Ashok Babu G; Veeraiah B;Stephen J (DRS Group, National Geophysical Research Institute, Hyderabad-500 007, Email: vcvarthi@rediffmail.com) : Delhi-Hardwar ridge and surrounding basement structure - some inferences from deep resistivity sounding measurements. Curr Sci 2007, 93(2), 224-30.

Hitherto unknown lateral extension of the concealed Delhi-Hardwar Ridge (DHR) towards the east in the Palwal sub-basin of India is inferred from deep resistivity sounding measurements. The resistivity of the ridge is found to be more than 3000 Ohm.m, which is distinct in contrast to the sediment and basement resistivity. The depth of the ridge is estimated to be of the order of 600-800 m below ground level. Analysis of resistivity data across the ridge clearly shows that the basement dips towards the ridge and several depressions within the basement are not uncommon. Further, a significant lateral variation in resistivity of Neogene sediments in and around the DHR indicates postdepositional tectonic activity within the sub-basin. Basement depths estimated compare well with the interpreted depths from aeromagnetic data.

8 illus, 1 table, 25 ref

007181   Chakrabarti G;Shome D (NO, Durgapur Government College, Burdwan University, Durgapur-713 214) : Reworked diamictite accumulation as debris flow in aqueous medium - an example from late Palaeoproterozoic basal Gulcheru Formation, Cuddaph Basin, India. Himalayan Geol 2007, 28(1), 87-98.

In the Gugudu-Dadithota-Pamapalle region of the Cuddapah basin, the upper Palaeproterozoic Gulcheru Formation is represented by a stratified metasedimentary rock sequence overlying the Archaean gneiss with a profound unconformity. The Gulcheru Formation in this part of the basin comprises a basal multi-layered diamictic conglomerate (Facies association A), cross-bedded siliciclastic (Facies association B) and rhythmic alternations of fine-grained siliciclastic with silty and calcareous shale (Facies association C) showing branched synaeresis crack structure. A distinct decrease in angularity and size of coarse clastics with increase in sorting through time is recorded in the multilayered diamictites. This gradual change in sphericity and sorting implies reworking of a ground moraine deposit (discharging into a gently-sloping shelf region) in a high energy set-up during marine transgression. Presence of wave-ripples, herringbone cross-stratification in the overlying siliciclastic supports the existence of high energy shallow-marine environment during sediment accumulation. The dominant colour change of the overlying shale from greenish-grey at the base to reddish-brown towards top evidences a gradual warming of the environment, vis-a-vis, shallowing of the basin. Follow-up increase in sea-level resulting in the accumulation of stromatolitic dolomite of the overlying Vempalle Formation not only documents a gradual change in palaeoclimatic set-up from cold to tropical warm but also a marine transgression toward the terminal Palaeoproterozoic time.

16 illus, 2 tables, 31 ref

007180   Bhattacharyya A;Eckstein D;Shah S K;Chaudhary V (Birbal Sahni Institute of Palaeobotany, Road Univ, 53, Lucknow-226 007, Email: amalava@yahoo.com) : Analyses of climatic changes around Perambikulum, south India, based on early wood mean vessel area of teak. Curr Sci 2007, 93(8), 1159-64.

Study shows that rainfall during October and November (northeast monsoon) of the previous year and April of the current year is the most important climatic variable in developing the EW vessel of an annual ring. Based on this tree ring parameter, the northeast monsoon of this region has been reconstructed, which extends from AD 1743 to 1986.

8 illus, 2 tables, 38 ref

007179   Bhat G S;Narasimha R (Centre for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore-560 012, Email: bhat@caos.ernet.in) : Indian summer monsoon experiments. Curr Sci 2007, 93(2), 153-64.

Eight major field experiments have been carried out so far addressing the Indian summer monsoon. While these experiments were international and the impetus was external till 1980, India's own monsoon programmes evolved since then. Objectives and outcomes from some of these experiments are described. It is shown that monsoon experiments have contributed in several ways. Each experiment enhanced the infrastructure facilities in the country, brought together scientists from different organizations to a common platform and also injected new people in this field. A large amount of data have been generated and their analysis has led to better understanding of the summer monsoon and discovery of new phenomena.

10 illus, 68 ref

006046   Tomar H;Narain U (Physics Dep, Meerut College, Meerut, Uttar Pradesh) : Geomagnetic variations: tyes (seasonal annual, diurnal daily) and causes (DST index, esternal effect). Asian J envir Sci 2007, 2(1-2), 66-72.

After examine the daily and seasonal variablity of long time series of magnetometer data from Dst index it was observed that a local min of horizontal magnetic component was near 18 local time (LT) and weakest activity was near 06 LT. Each station gives the approximately the same result. Each station has different base line in such a way that average level of activity was about 10nT which was and reduced to 3nT by introducing a new "base method" for the elimination of secular variation. The addition of 2 new southern hemispheric stations to old Dst index anew index called Dst 6 was formed, in which the hemispheric differences between annual variations (larger activity during local winter and autumn solstice) were removed which were previously shown in Dst index. Three external drivers were also taken in accounts which were previously shown in Dst index. Three external drivers were also taken in accounts which are as follows: the heliographic latitude, the equinoctial effect, and the Russell-Mc-Pherron effect. By using new Dst index it was clear that three effect account for only 50% of daily and seasonal variability of index remaining 50% is still not clear but it was suggested that station distribution may play a role.

5 illus, 1 table, 19 ref

006045   Tomar H;Narain U (Physics Dep, Meerut College, Meerut, Uttar Pradesh) : Diurnal and semidiurnal variation of geomagenetic field. Asian J envir Sci 2007, 2(1-2), 40-6.

Diurnal and Semidiurnal variations of the geomagnetic field are investigated at 18 obervatories using long series of hourly values. The seasonal variations of amplitude of the 12 hour and 24 hour lines are obtained for the H and Z components using 28 day sliding window. Fourier analysis is used either all days within the window or only the five quietest days. At midlatitudes a strong lack of symmetry about the summer solstice is observed for both lines and both components. This effect is enhanced when selecting quiet days. When averaged over the entire series, the sign of this seasonal asymmetry is the same at 9 out of 10 midlatitude observatories for both lines and for given component; it is opposite for the H and Z components. Such a coherent seasonal asymmetry is not found at low and high latitudes. At high late todes a strong annual variation is found inside the polar caps, while a strong semiannual variation is found in the auroral zones. When selecting quiet days, these two effects are weaker, and the seasonal asymmetry becomes comparable to that at midlatitudes. At all latitudes the year-to-year variations of the seasonal asymmetry are uncorrelated with solar activity. It is suggested that lower thermospheric winds may have a similar seasonal asymmetry between spring and autumn equinoxes. Such an asymmetry in present in the published literature. Possible causes for this wind asymmetry are reviewed.

5 illus, ref

006044   Shankar U;Sain K (NO, National Geophysical Research Institute, Hyderabad-500 007, Email: umashankar_ngri@yahoo.com) : Specific character of the bottom simulating reflector near mud diapirs: Western margin of India. Curr Sci 2007, 93(7), 997-1002.

Multi-channel seismic recording was carried out along the western continental margin of India in the early nineties for the exploration of hydrocarbons. Analysis of seismic data demonstrated a characteristic reflector, which usually coincides with  the predicted base of methane hydrates stability field and mimics the sea-floor, known as the bottom simulating reflection (BSR) on marine seismic reflection data. Existence of reflections which mimic the seafloor, reverse polarity, seismic blank zone, strong diffraction patterns around the mud diapirs, weak amplitude blocks and pock-marks suggests that gas hydrates are present in deep-water regions. Five characteristic seismic facies associated with bottom simulating reflectors and mud diapirs were identified. In this study, we present the results of seismic surveys which indicate the existence of natural gas hydrates in the western margin of India. These results will be applied to select areas for coring (or drilling) and detailed exploration such as 2D seismic survey with long offset or 3D seismic survey in the future.

8 illus, 2 tables, 40 ref

006043   Sarkar P K (Geology Dep, Fergusson College, Pune-411 004, Email: pksarkar123@yahoo.com) : Rare, circular, pipe-shaped structure in the deccan trap lava flows in the Girna river section near Malegaon, Nashik district, Maharashtra, India. Curr Sci 2007, 93(7), 915-16.

6 illus, 3 ref

006042   Mohan G;Surve G;Tiwari P K (Earth Sciences Dep, Indian Institute of Technology Bombay, Powai, Mumbai-400 076, Email: gmohan@iitb.ac.in) : Seismic evidences of faulting beneath the panvel flexure. Curr Sci 2007, 93(7), 991-6.

Study brings out the exitence of an active fault system beneath the Panvel flexure, possibly linked to west-coast tectonics.

4 illus, 4 tables, 22 ref

006041   Mitra S;Bidyananda M (Geological Sciences Dep, Jadavpur Univ, Kolkata-700 032, Email: bmaibam@yahoo.com) : Cation partitioning of garnets from sittampundi granulite: their petrogenetic implications. Curr Sci 2007, 93(7), 1003-9.

Garnets from high P-T granulite fields of Sittampundi (South India) were investigated by ⁵⁷Fe Mossbauer spectroscopy and electron microprobe analysis. The room-temperature three-band spectra which have been split into two doublets, revealed Fe²⁺ ions to be exclusively located at the dodecahedral site (isomer shift = 1.303-1.389 mm/s; quadrupole splitting (QS) = 3.423-3.822 mm/s) and Fe³⁺ ions at tetrahedral site (isomer shift = 0.006-0.163 mm/s; QS = 0.520-0.663 mm/s). The octahedral site was completely free from both these ions. Fe³⁺/ΣFe varying between 0.073 and 0.150, and the presence of octahedral Si indicate that the studied garnet formation lies in high P-T field. The high values of QS for tetrahedral Fe³⁺ suggest that the occupied site is regular with little distortion. The fairly broad linewidth, 0.455-0.596 mm/s of Fe³⁺ doublet may arise from a substitution of some tetrahedral Si by the (OH)^-1 group. The strong partition and ordering of Fe²⁺ and Fe³⁺ in dodecahedral and tetrahedral sites, leaving the octahedral site totally free from iron suggest slow cooling and recrystallization of garnet at high temperature.

1 illus, 6 tables, 33 ref

006040   Kumar S;Pandey S K (Centre of Advanced Study in Geology, Lucknow Univ, Lucknow-226 007, Email: surendra100@hotmail.com ) : Microbial mat-induced sedimentary structures in the neoproterozoic Bundi hill sandstone, Indargarh area, Rajasthan. Curr Sci 2007, 93(7), 1009-12.

Communication records the development of wrinkle structures and desiccation cracks in the fine-grained Bundi Hill Sandstone belonging to the Neoproterozoic Bhander Group of the Vindhyan Supergroup. The presence of wrinkle structures in the sandstone suggests the role of microbial mats in binding sandy sediments and providing cohesion to the upper surface, which could produce the wrinkle structures and on drying could also produce the mat-related cracks.

3 illus, 1 table, 19 ref

006039   Girkar M M;Satam S B;Todkari S S;Yadav S R (Ornamental Fishry Development Dep, , Manne Product Export Development, A.R.O., Mumbai, Maharashtra) : Observation on physiochemical parameters at Bhatye shore off Ratnagiri, India. Asian J envir Sci 2007, 2(1-2), 57-9.

Samples of seawater were collected fortnightly during the period November 2001 to November 2002, to study the hydrochemistry of seawater of Bhatye shore. Physicochemical parameters i.e. salinity, temperature, pH and dissolved oxygen (D.O.) were recorded. Salinity ranged between 18 to 35 ppt, temperature 25 to 30°C, pH between 6.6 to 7.7 and dissolved oxygen was ranged between 4.9 to 5.7 mg/l. Generally maximum salinity and temperature was recorded in May, minimum salinity was recorded in July, the minimum and maximum pH was recorded on July and April respectively, while maximum and minimum dissolved oxygen was recorded in January and July respectively.

1 table, 9 ref

006038   Gaur A S;Vora K H (NO, National Institute of Oceanography, Dona Paula, Goa-403 004, Email: asgaur@nio.org ) : Ancient technology of jetties and anchoring points along the West coast of India. Curr Sci 2007, 93(7), 987-91.

Indian coast, with a long history of maritime activities, has been dotted with several ancient ports. The evidence for this exists in port-related structures on the shore and in relics lying in the sea adjacent. Marine archaeological explorations have revealed the existence of jetties at Dwarka, Rupen Bandar and Porbandar, and offshore anchoring points at Bet Dwarka, Miyani, Visawada and Somnath on the Gujarat coast. The preferred anchoring points fall in a water depth of 5-7 m. This communication also discusses the effect of tide when using jetties and loading points along various parts of the west coast India.

9 illus, 18 ref

006037   Bhattacharyya A;Sharma J;Shah S K;Chaudhary V (Birbal Sahni Institute of Palaeobotany, Road Univ, 53, Lucknow-226 007, Email: amalava@yahoo.com) : Climatic changes during the last 1800 yrs BP from paradise lake, sela pass, Arunachal Pradesh, northeast Himalaya. Curr Sci 2007, 93(7), 983-7.

Exploratory pollen and carbon isotopic study carried out from a 1 m deep sediment profile at the Paradise Lake (4176 m amsl) near Sela Pass has revealed vegetation vis-a-vis climatic changes during Late Holocene. Around 1800 yrs BP (around AD 240), conifer-broad-leaved forest used to grow in the vicinity of the study site under warm and moist climate, similar to the prevailing present-day conditions which turned out to be comparatively more warmer 1100 yrs BP (around AD 985) corresponding to the Medieval Warm Period. The glaciers seem to have receded and tree line might have been closer to the site. Around 550 yrs BP (around AD 1400) decrease in Tsuga, Juniperus and Quercus suggests a trend towards comparatively cooler and less moist climate corresponding to the Little Ice Age. This is followed by an amelioration of climate more or less equivalent to the present day. Carbon isotopic analyses in sediments at different intervals reveal fluctuation of C-3 taxa dominantly throughout under variable moist climatic regime.

2 illus, 27 ref

005185   Vyas D;Raghavendran K;Balram;Mallika V;Prasad J;Satyanarayana K (Regional Laboratory, , Cauvety Basin, Oil & Natural Gas Corporation Ltd. (ONGC), Chennai, Email: vyas_d@ongc.co.in) : Geochemical surface prospecting studies - a case history to predict nature of subsurface hydrocarbons for exploration. J appl Geochem 2006, 8(2A), 288-98.

The paper deals with the adsorbed gas studies pertaining to Kottur - Mettupalayam areaof Cauvery basin and Bhimavaram - Penumadam area of Krishna Godavari Basin, to predict the occurrence / nature of subsurface hydrocarbons. For geochemical surface prospecting studies reveal that the Kottur Mettupalayam area of Cauvery Basin is oil prone in nature, while Bhimavaram-Penumadam area is gas prone. Matching / superimposing producing deep well gas data of the same area over adsorbed gas data further supports the above inference on the nature of subsurface hydrocarbons. A correlation between subsurface and surface data is also established. The study is useful in predicting nature of subsurface hydrocarbons, if any, undergoing geochemical prospecting in virgin areas even prior to drillng. Secondly, hydrocarbon apical and halo anomalous zones, observed in these areas, most probably represent subsurface accumulations suggesting more potential areas for exploration. These types of studies may help in predicting the nature of subsurface hydrocarbons in virgin areas.

10 illus, 2 tables, 7 ref

005184   Vidyadharan K T;Palaniappan K (NO, , Southern Region, Geological Survey of India, Hyderabad) : Mafic-ultramafic and related rocks of Southern Indian shield-potential target areas for PGE mineralisation. J appl Geochem 2006, 8(2A), 475-500.

Mafic-ultramafic rocks in the southern-part of India are associated with the gnessic complexes, granulites and schist belts of Tamil Nadu, Karnataka, Goa, Andhra Pradesh and Kerala. Though detailed works have been carried out in known occurrences of Tamil Nadu, many ultramafic/ultrabasic bodies have been identified recently and they are yet to be explored. Since the orthomagmatic type of association forms the most optimal exploration target for Ni-PGE, those belonging to the larger layered intrusions with chromite association, form better targets. Intrusive mafic-ultramafic bodies as layered and differentiated complexes are recorded in southern India in granulite, greenstone belts, greenstone-granulite transition zones and within the gneissic complex. Extrusive, pillowed, spinifex textured and nodular ultramafics with characteristic komatiitic affinity are recorded mainly from the western Dharwar craton within the Sargur milieu whereas the intrusive variants occur both in the Dharwar and Sargur schist belts. Unlike classical layered complexes of Stillwater and Bushweld, no co-genetic granophyre association representing magma contamination zones are recorded from the layered complexes of southern India. Unlike the Baula- Naushai complex of Orissa, magma mixing zones also are not yet recorded from any ultramafic bodies. The komatiites are known for their nickel association and its relevance vis-a-vis the 'thermal erosion model' has to be understood as no major PGE or nickel are recorded from the ultramafic complexes of southern India, though several smaller or bigger ultramafic extrusive bodies are recorded from the western greenstone belt of Karnataka. The details of several mafic-ultramafic bodies, mode of occurrence, their brief geological milieu, sulphide-chromite association and the status of work done, chromite, PGE analysis recorded are dealt in this paper, so that interesting preliminary exploration programmes can be taken up for identifying potential target areas and for R&D work.

5 illus, 71 ref

005183   Venkateswar Rao V (NO, , Deputy Director General, Geological Survey of India, Bangalore-560 034) : Ferrous and nonferrous minerals - Indian scenario. J appl Geochem 2006, 8(2A), 423-9.

Ferrous and nonferrous mineraals are store house of the metals that play essential inseparable role in our daily life. Without these minerals no country can industrially develop, the latter measured by the quantum of mineral consumption. Though adequate reserves of some of the ores of iron, manganese, aluminum etc. were discovered by the efforts of the Geological Survey of India, the country is yet to attain self sufficiency in tungsten, chromium and lead. Minerals are wasting assets, are not evenly distributed all over the world and searching for a mineral deposit is like searching a needle in a haystack. These mineral deposits are distributed over various metallogenetic provinces and epochs. Fortunately, in India, also we have such favourable scenario. Some world class deposits of copper (Malanjhkhand), lead-zinc (Rampura-Agucha) and bauxite (East coast) were so far discovered in India. The Archaean-Proterozoic rocks in India contain important deposits of iron, manganese, copper, lead-zinc, aluminum, placer deposits of tin etc. Some of the major metallogenetic provinces are located in the states of Andhra Pradesh. Chattisgarh. Goa. Jharkhand. Haryana. Karnataka. Madhya Pradesh. Orissa. Rajasthan and Tamilnadu. Though favourable geological milieu exists in India, the discoveries so far form a fraction of the potential that exists. Geological Survey of India, after covering the entire country by systematic geological mapping has embarked on nationwide geochemical mapping. The geochemical mapping is likely to lead to the discovery of many new mineral deposits as seen to be a proven tool in China for discovery of new mineral deposits.

8 ref

005182   Subrahmanyam B (NO, , 1-2-99/3, Street No. 2, Habshiguda, Hyderabad-500 007) : Conceptual model for kimberlite exploration in Andhra Pradesh. J appl Geochem 2006, 8(2A), 522-6.

Failure of conventional strategy of 'known to unknown' in locating kimberlites in Wajrakarur area, Andhra Pradesh necessitated to suggest alternative strategy of 'unknown to known' which involves visualisation of 'conceptual model' from the study of different station intervals of gravity data with emphasis on the structural elements that control the emplacement of kimberlites viz. 'mantle upwarp' crustal faults, junctions of trends/lineaments and granite bodies (batholith ). The granite bodies at the margin of active volcano - sedimentaries offer 'stable platform' while the junctions of structural trends within them suggest potential target areas. Further, detailed electrical investigations in these potential target areas outline the 'areas of interest' which assume added significance when supported by geological and geochemical data. The discovery of kimberlites made since 1985 in Andhra Pradesh have amply demonstrated the correctness of the model. Based on this model, three new areas are suggested.

4 illus, 15 ref

005181   Singh R V;Verma M B;Maithani P B (Atomic Minerals Directorate for Exploration and Research, Atomic Energ, , Begumpet, Hyderabad-500 016, Email: ranvijaisingh@rediffmail.com) : Resources of potable water in fluoride infected Nalgonda district-a case study in and around Damarcherla: geo-environmental approach. J appl Geochem 2006, 8(2A), 604-17.

Groundwater with high content of fluoride (<126>3 ppm) occurs in the calcium deficient granite and gneisses in Nalgonda district of Andhra Pradesh. The area is mainly covered by peninsular gneisses, granite, schist, basic dykes and quartz reef of Archean crystallines/Lower Proterozoic (94% of the total 14,170 Sq.Km). Southeastern part of Nalgonda exposes intercalated sequence of quartzite/shale/siltstone/limestone of Kurnool Group, which lies unconformably over the basement in and around Damarcherla, selected for study of water quality. Depth of water table varies from 1.5m to 95m below the ground level. Water samples (n=38), spread over an area of 45 Sq km, have been analyzed for pH, TDS, CO₃^--, HCO₃^-, Cl^-, F^-, PO₄^--, SO₄^--, Na⁺, K⁺, Ca⁺⁺, Mg⁺⁺, Fe⁺⁺, Cu⁺⁺, Zn⁺⁺, Sr⁺⁺, Ba⁺⁺, and Si⁺⁴. A few samples analyzed anomalous content of Fe and Sr (up to 555 and 832 ppb respectively). Total dissolved salts (TDS), Ca⁺⁺, Mg⁺⁺, Na⁺, Cl^-, SO^--₄ are within permissible limit of the ground water for drinking purposes and weight ratio of TDS versus Na/(Na+Ca) falls in the central part of the curve indicate similar quantity of salt content of major rivers. Water is alkaline in nature, Na⁺ HCO₃^- type and its pH varies from 7.3 - 8.9, whereas three samples exceeded the permissible limit (7 - 8.5). Fluoride content is within permissible limit (range <60>1 to 1.5 ppm, n=37) except one water sample which shows marginal higher content of 1.7 ppm. Total hardness of the water varies 99-425 with an average hardness of 245 matches well with the Indian Standards. Thus, the area covered by the rocks of Kurnool Group is identified as suitable for potable water resources.

4 illus, 3 tables, 24 ref

005180   Singh D K;Tiwari R R;Dangwal D N;Singh R P; Mahata P K;Soni Rajiv;Jyoti;Sharma K K;Singh R R (Geochemistry Div, KDM Institute of Petroleum Exploration, ONGC, Dehradun-248 195, Email: dksrajput@yahoo.co.in) : Adsorbed gas survey in kutch-Saurashtra offshore basin. J appl Geochem 2006, 8(2A), 277-87.

Adsorbed gas concentration above threshold value is a positive indication that hydrocarbons have been generated within the basin. Hydrocarbons from subsurface pools seep and get adsorbed on surface soils leaving identifiable signatures is, an established phenomenon. Present surface geochemical survey is a maiden attempt in the Kutch Saurashtra Offshore Basin, which is the main thrust area for future exploration activities. Pseudo highs, namely Taluses, are seen in the study area and their Holding capacity has to be ascertained to establish whether they are the possible source of petroleum. One hundred and eighty one soil samples were collected and analysed over gas chromatograph for light hydrocarbons. Hydrocarbons up to butanes were observed in majority of samples indicating thermogenic origin and petroliferous nature of adsorbed gases. These hydrocarbons are co-genetic and have not been influenced by secondary alteration effects during their upward migration from source and subsequent adsorption on the soil particles. Two prospects have been identified where the anomalies are seen lying over central part of the study area between two structural highs in Prospect X and over upper part of anticline in Prospect Y. On the basis of above study the blocks covered in the study, appear to be promising for further exploration.

7 illus, 3 tables, 15 ref

005179   Siddiquie S N;Reddy K K;Mukherjee A;Sravan Kumar C;Khan P H;Wadhwa R (NO, , National Mineral Development Corporation Ltd., Khanij Bhawan, Masab Tank, Hyderabad-500 028) : Diamond reconnaissance surveys and prospecting works in Ahdhra Pradesh involving remote sensing, helimag survey, stream sediment sampling technique coupled with geological geochemical and geophysical studies/surveys. J appl Geochem 2006, 8(2A), 501-9.

Embodies the work done recently in pursuit of diamond exploration in Andhra Pradesh. The multidisciplinary approach for kimberlite exploration and evaluation involves Remote Sensing studies (using IRS-1D.PAN+LISS-III merged data), low flight(60m AGL) and low spacing(200m) Helimag survey, stream sediment sampling for the recovery of kimberlitic affinity minerals like pyrope garnet, Cr- diopside. picro-ilmenite and Cr-spinel etc. These were coupled with geological, geochemical and geophysical (mostly ground magnetic and multi electrode resistivity-MER) studies. High resolution mapping using DGPS was conducted for kimberlite evaluation followed by Large Diameter Drilling and pitting for collection of bulk samples. These samples were then used to conduct micro-diamond recovery tests to establish the diamond potential of the kimberlite.

6 illus, 1 ref

005178   Sharma R;Godara V K;Vashishta V K;Rawat B; Dewakar (Geochemistry Div, KDM Institute of Petroleum Exploration, ONGC Ltd., Dehradun-248 195, Email: sharma_r@ongc.co.in) : Chemostratigraphic studies in bhuban formation of Agartala dome structure of Assam and Assam arakan basin of India. J appl Geochem 2006, 8(2A), 320-31.

Technique of chemostratigraphy has been applied for subzonation of stratigraphic levels in Surma formation in Agartala Dome structure of Tripura area of Assam and Assam Arakan Basin of India. Data for 12 major and trace elements were obtained in 107 samples taken from cutting/core samples of wells AD-α and AD-β in Agartala Dome structure of Western Tripura of Assam- Arakan basin. Results of analysis of outcropping type section samples, analysed in parallel study, have revealed that samples of Bokabil and Middle Bhuban have higher concentration of Cu, Ni. Co, Zn, Fe, Li and K than Upper Bhuban samples. The samples of Lower Bhuban have the lowest concentration of these elements. Based on elemental enrichments, depletions and development of persistent trends recognized from the geochemical profiles, the intervals in the studied wells are divided into geochemically distinct intervals termed as chemostratigraphic units'. These units correspond closely with the principal lithostratigraphic divisions of the Bokabil/Bhuban formations in wells AD-α and AD-β. Some new chemostratigraphic units have also been identified.

6 illus, 1 table, 10 ref

005177   Sankaran A V (NO, , No. 10, P&T Colony, First Cross, Second Block, RT Nagar, Bangalore-560 032, Email: av.sankaran@gmail.com) : Oceans of mineral-bound water in earth's lower mantle: seismic study confirms earlier speculations. Curr Sci 2007, 92(10), 1340-2.

1 illus, 16 ref

005176   Sangurmath P (NO, , Hutti Gold Mines Co. Ltd., Hutti-584 115, Email: prabhakar_sangurmath@rediffmail.com) : Geochemical studies of the alteration zones of buddini gold deposit in the hutti-maski greenstone belt, India. J appl Geochem 2006, 8(2A), 458-70.

Buddini gold deposit is located in the southern pan of the Precambrian Hutti-Maski greenstone belt and consists of eight auriferous lodes in sheared chlorite schist. The gold mineralization is noticed in the quartz-ankerite-sulphide veins. The lodes are surrounded by overlapping zoned alteration envelopes. Alteration is super-imposed on Iow-grade metamorphism equivalent to quartz-albite-epidote sub-facies of greenschist facies of metamorphism. The alteration envelopes are characterized by chloritisation, propylitisation, carbonatisation, sericitisation, silicification and pyritisation. 39 rock samples viz. 13 from chlorite schist, 18 from sheared chlorite schist and 8 from lodes were analysed for major and minor elements. Samples were taken across contiguous rocks i.e chlorite schist, fissile chlorite schist and ore zone, from two different locations (Mopla Shaft and Shaft No-2, Main cross-cuts) at I, II and III levels of Buddini mine. The SiO₂ distribution pattern indicates that the migration of SiO₂ has taken place towards the lodes, confined to the metabasic volcanic rocks leading to silicification. The study of quartz-ankerite veins and the chemistry of alteration zones reveal that all the components required for the mineralization in the study area were present in the host rock and were mobilized and probably migrated by diffusion into the shear zone systems. The silica rich solutions were responsible for leaching of gold and the solutions together with gold migrated towards the low pressure sites and formed veins, dialation zones and lenses. The alteration zones are contemporaneous and brittle deformation developed during regional metamorphism. The wall-rock alteration and gold mineralisation are synchronous and probably part of one progressive event. Summarises the salient aspects on the alteration zone geochemistry, the alteration history and geometry of the altration zones of Buddine gold deposit.

5 illus, 3 tables, 24 ref

005175   Sambasiva Rao V;Bhargav J S;Siva Sankar K (NO, , Central Ground Water Board, Southern Region, Hyderabad-500 029) : Chemical quality of ground water in Andhra Pradesh. J appl Geochem 2006, 8(2A), 589-603.

Survey on chemical quality of ground water in Andhra Pradesh by Central ground Water Board, in premonsoon season revealed high electrical conductivity, nitrate and fluoride in the ground water. High Electrical Conductivity (<62>5000 μS/cm) occurs in 3% of the samples from coastal region. Samples unfit for drinking with respect to nitrate have been found to be. more in Rayalseema (31%) followed by Telangana (25%) and coastal (15%) regions. Nalgonda district has the highest incidence of nitrate with 64% of the wells beyond BIS. Telangana region has highest incidence of fluoride with 11% of the samples beyond the permissible limit followed by Rayalseema (9%) and coastal region (8%). Prakasam district has the highest incidence of fluoride with 37% of the wells having fluoride beyond the maximum permissible limit. for irrigation, majority of the wells are in the categories of C3S1 (46%), C2S1 (18%) and C3S2 (12%) representing medium to high salinity and low to medium sodium content. These should be used on soils with good drainage and for good salt tolerant crops. The hydrochemical facies in the state shows that waters from a majority of wells have under gone mineralization and those waters of Ca-Mg-HCO₃, Na-HCO₃ type which are from recharge areas are low in percentage indicating scanty rain fall and insufficient natural recharge conditions.

5 illus, 5 tables, 8 ref

005174   Safi M J;Bhagwanth Rao M;Rao K S P (Chemical Engineering, College of Technology Univ, O.U., Hyderabad-500 007) : Beneficiation of phosphate ore from the Eastern mine "A" in Syria. J appl Geochem 2006, 8(2A), 536-45.

Phosphorite ore from the Kineifiss "A" Eastern mine "A" has undesirable high amounts of chloride, MgO, and CaO/P₂O₂ ratio. Hence this work aims at optimizing processes, which reduce the chlorine and MgO contents, and to reduce CaO/P₂O₅ ratio. Physical methods such as grinding, wet screening, attrition and flotation were used for this investigation. Flotation tests V were carried with respect to all parameters such as the amount of the reagents, the time of attrition before flotation, pH ranges, the total flotation time and the ratio of solid/water. Sodium Dodecyl Benzene Sulphonate (SDBS) was used as a carbonate collector in the carbonate flotation process. It was found that 1 SDBS /kg sample yields the optimum results for high grade ore flotation. For the low-grade ore the carbonate flotation process was not effective enough to get sufficiently concentrated phosphate. Therefore, as an additiohal step, the sink material was taken to silica flotation after de-watering. The optimum amount of the silica collector (PROCOL CK - 921 Amine) was found to be 8 ml in total. The beneficiated phosphate thus obtained can be used in the production of phosphoric acid.

5 illus, 4 tables, 7 ref

005173   Reddy A G S;Rao P N (NO, , Central Ground Water Board, Southern Region, 3-6-291, Hyderguda, Hyderabad) : Occurrence, behaviour and genesis of fluoride in ground water of wailpalli watershed in Nalgonda district, Andhra Pradesh, India. J appl Geochem 2006, 8(2A), 618-30.

Ground water in Wailpalli Watershed, Nalgonda district has the average fluoride content of 2.79 mg/l in pre-monsoon and 2.83mg/l in post-monsoon. Wells occurring close to E-W trending lineaments and waters from deeper aquifers have high fluoride concentration. Low fluoride content is observed from the wells falling in the watershed divide thereby showing structural control over fluoride distribution in the watershed. Fluoride concentration in ground water does not show perceptible change with time. Fluoride exhibits positive co-relation with Na and HCO₃ and negative correlation with Ca and Mg. Porphyritic granite, which is rich in fluorite mineral, forms the source of fluoride in the ground water. High fluoride content in ground water could be due to water - rock interaction during the process of percolation, high evapo-transpiration and intense weathering. Sodium bi-carbonate waters accelerate the dissolution of CaF₂ to release fluoride into the ground water.

7 illus, 2 tables, 24 ref

005172   Ray A K;Chakraborty T K;Mukhopadhyay G C (Monitoring Div (All Mineral), , Geological Survey of India, CHQ, 2nd Floor, 27, Jawaharlal Nehru Road, Kolkata-700 016) : Geochemistry of coal with special reference to high arsenic and mercury in Raigarh coal field, Chhattisgarh. J appl Geochem 2006, 8(2A), 394-6.

Higher concentration of some of the potential toxic trace elements like As and Hg in Raigarh coal may generate pollutants during mining stacking and coal combustion. Correlation of Ash vs. trace elements suggests that Cu, Pb, Cr and Ti are associated with inorganic components of the coal. No specific mode of occurrence of As has been indicated. The study may help to minimize the health impact of coal use and help to avoid future problems. However, surface as well as groundwater do not show any sign of pollution at present.

3 tables, 7 ref

005171   Ravi G S;Viswanathan G;Viswanathan S (Atomic Energy Dep, Atomic Minerals Directorate for Exploration and Research, Government of India Visakhapatnam-530 018, Email: ravigs_2112@yahoo.com ) : Wavelength-dispersive x-ray fluorescence spectrometric technique for evaluating monazite and zircon resources in onshore and offshore placers. J appl Geochem 2006, 8(2A), 527-35.

Conventional microscopic grain-counting method of estimating monazite [(Ce,La,Th)PO₄] and zircon [Zr(SiO)₄] in placer deposits is error-prone, tedious, time-consuming, a strain on the eyes and involves the use of toxic heavy liquids To overcome these problems, the paper proposes an alternative simple, accurate, precise, and rapid technique using wavelength- dispersive x-ray fluorescence spectrometry (WDXRFS). The technique is based on the valid assumption that the intensities of the characteristic secondary x-ray fluorescent radiations of CeKα and ZrKα, generated from samples of placers, truly reflect the proportions of monazite and zircon, respectively, in them. A Philips PW 1410 sequential x-ray spectrometer. PW 1140 x-ray generator, rhodium x-ray tube, LiF 220 analysing crystal, fine collimator (150 nm), scintillation counter, and air path, with short fixed counting time, were used for WDXRFS. The method proposed uses pressed powder-pellets of 41 mm diameter made from 1-g powders of samples and analytical standards. The background-corrected net counts per second (cps) of CeKα and ZrKα obtained from the standards are correlated with the monazite and zircon weight percentages, respectively, in them, and least-squares regression equations derived. The net cps of CeKα and ZrKα obtained from the samples are converted to their monazite and zircon contents, respectively, using the regression equations.

3 illus, 7 tables, 4 ref

005170   Rao C R M (NO, , Geological Survey of India, Southern Region, Bandlaguda, Hyderabad-500 068, Email: chebrolumohan@yahoo.com) : National geochemical mapping program vis-a-vis present analytical capabilities and future challenges. J appl Geochem 2006, 8(2A), 510-21.

History of the development of geochemical mapping has been closely connected with the progress of geoanalysis and instrumentation. Regional, national and international geochemical mapping programs are the inevitable outcome of the trends in the development of geochemical exploration. Elements that are determined in existing regional or national geochemical mapping projects have been highly diversified due to the limitations in the available instrumental facilities. However, the elements determined in an international geochemical mapping program should be unified in order to obtain a consistent global geochemical overview. Detection limits of trace and ultra-trace elements should be lowered below their crustal abundances in order to make the geochemical maps of the elements much more informative. Unified data quality monitoring procedures and certified reference materials should be used to render the data produced by various mapping projects globally comparable. Multi-method, multi-element analytical schemes that could achieve these requirements should be developed. Geochemical maps produced in this way would be of immense value for monitoring the earth's environment and for the appraisal of the world's mineral resources.

8 tables, 21 ref

005169   Pranaya Sangvai (NO, , Reliance Industries Limited, Mumbai) : Growing acceptance of applied geochemistry-focus on marine resources like gas hydrates and hydrocarbons. J appl Geochem 2006, 8(2A), 400-6.

Marine resources have been categorized by different people in different ways. Study of these living and non-living resources as a whole -both coastal and open-ocean, geological, geophysical, geomicrobial and geochemical parameters, processes and properties including resources of shallow and deep water areas and the interfaces between the ocean, its floor and the atmosphere is a field of high specialization and warrants a new approach. Pressure generated by both human-induced activities and natural phenomena result in impacts on coastal resources and brings about the changes in the availability of resources and their ecological functions. Let us look at one example to feel the impact of necessity. Non-living marketable resources include energy minerals like peat deposits which are estimated to be 50 million tons and yet are not economically used. Easy to find oil and gas resources are over and deep water needs exploration activities of highest standard but they are expensive. Gas hydrates need more research: Technologies right use is key driver and therefore there is growing acceptance of geochemistry in locating, exploring and exploiting these resources. The whole world which includes private companies like Reliance is embracing geochemistry as a complementary and supportive tool. Addresses marine resources like Gas hydrates and hydrocarbons and their potential and application of geochemistry in exploitation.

13 illus, ref

005168   Pophare A M;Varade A M;Kanojkar D M;Borade K G (Geology Post Graduate Dep, Rashtrasant Tukadoji Maharaj Nagpur Univ, R.B.D. Laxminarayan Campus, Law College Square, Amravati Road, Nagpur-440 001, Email: apophare@yahoo.com) : Ore genetic modelling of tungsten mineralisation at kuhi-khobana-agargaon belt, Nagpur district, Maharashtra. J appl Geochem 2006, 8(2A), 430-40.

Lower to middle Proterozoic Sakoli Fold Belt (SFB) in Central India encompasses several important litho-asseinblages, which holds variety of mineral resources of economic importance. The mineralisation includes gold, copper, lead-zinc chromite. tin and tungsten. The tungsten mineralization occurs as a 16 km linear horizon, in the western part of Sakoli Fold Belt. This mineralisation is confined in the vicinity of Kuhi, Khobna and Agargaon villages in Nagpur district. The wolframite-scheelite mineralization is conformable on a regional scale and hosted within the quartz-chlorite-mica-tourmaline schist, meta-pelites and meta-sedimentary sequences. These are flanked at places by granite-gneiss and granitoids. Fluid inclusions data (temperature, salinity and gaseous species) indicates a uniform fluid signature for wolframite mineralization in all the three areas. This suggest genesis of tungsten mineralization from identical ore bearing fluids. The salinity of these fluids gives an average value of 12 wt. %NaCl equivalent, which ranges between the salinities of low to moderate fluids. The trapping temperature of these fluids is in the range of 420°C - 460°C. The genesis of wolframite-scheelite (ñ Mo) mineralization at Kuhi-Khobna-Agargaon can be attributed to the activity of metal bearing hydrothermal fluids. These fluids might be generated due to intrusion of tungsten bearing granitoid into Sakoli meta-pelites. The CO₂ played an active role in the transport and deposition of tungsten metal into the host rocks.

5 illus, 1 table, 24 ref

005167   Pophare A M;Varade A M (Geology P.G. Dep, Nagpur Univ, R.B.D. Laxminarayan Campus, Law College Square, Amravati Road, Nagpur-440 001, Email: apophare@yahoo.com) : Adsorpton isotherm and petrographic studies of coal seams of sawang area, east Bokaro coalfield, Jharkhand, India. J appl Geochem 2006, 8(2A), 376-93.

Evaluates five coal seams of the Sawang area with repect to their maceral composition cleat attreibutes and adsorption isotherm studies along with technological properties. The analysis of methane adsorption isotherm shows that the actual gas adsorbed is 17 m³/t at 58.38 Kg/cm² pressure, in sample CG-81. This is the maximum sorption capacity of coal sample on equilibrium moisture condition. The vitrinite (Vt^mmf) maceral group composition of the investigated coal seams ranges from 62.50%- 83.14%, whereas the inertinite content (I^mmf) varies from 14.92%- 36.81%. The liptinite content (I^mmf) varies from traces to 3.08 %. Technological properties of these coal sample shows that the moisture content ranges from 1.17% to 2.98 % whereas volatile matter content is placed in the range of 24.44% to 34.13 %. The ash content ranges from 7.86% to 30.01 %. Fixed carbon content varies in narrow range from 41.50% to 55.90%. Fuel ratio (ratio of Fixed Carbon and Volatile Matter) variation shows a restricted range from 1.53% to 1.97%. All the coal samples were found to be strongly caking.

25 illus, 8 tables, 22 ref

005166   Parthasarathy G (NO, National Geophysical Research Institute, Hyderabad-500 007, Email: gpsarathy@ngri.res.in) : Zeolite zonation and amygdaloidal minerals from the killari borehole of deccan traps, Maharashtra, India. J appl Geochem 2006, 8(2A), 546-57.

Mineralogical data on the amygdaloidal minerals from the core samples of the Killari borehole are presented and the zeolite zonation in the Killari borehole are discussed. In the borehole at Killari, Deccan Trap sequence consists of eight lava flows in addition to the partially eroded flow exposed at the surface. Based on their chemical characterization the lower four flows occurring below 177m have been assigned to the Poladpur Formation and the rest of the upper flows to the Ambenali Formation, both belonging to Wai Subgroup of Deccan Basalt Group. Zeolites, calcite, chalcedony and clay minerals have been observed as amygdaloidal fillings. Visual and optical observations indicate that zeolites (chabazite, natrolite, heulandite and mordenite) are common as amygdaloidal fillings down to a depth of 255m, below which laumontite is found as an additional phase. Chalcedony is observed both in the amygdales and in the form of thin veins along cooling cracks. In the drill cores of Killari, moganite, a novel silica polymorph occurs along with chalcedony in the amygdales and cooling cracks of basaltic flows, which also contain chabazite, heulandite, natrolite and mordenite, and clay mineral ferrous saponite. The ferrous saponite has been used for environmental applications, viz., adsorption and reduction of hexavalent chromium. However, both moganite and saponite are absent in flows, which have laumontite. The studies suggest that moganite is stable at load pressures less than 500 MPa. Moganite in the bore hole samples of Killari area moganite is preserved in rocks younger than 130 Ma where the geological formation is unaffected by surface weathering.

9 illus, 2 tables, 26 ref

005165   Pahari S;Banerjee A;Mishra A;Prasad I V S V (NO, , K.D.M.I.P.E., Oil and Natural Gas Corporation Ltd. (ONGC), Dehradun-248 195) : Evaluation of petroleum source rocks of cauvery basin, India. J appl Geochem 2006, 8(2A), 234-50.

Source potential of Mesozoic and Tertiary sedimentary deposits of Cauvery Basin have been evaluated to identify the potential source rocks, assess their maturity and hydrocarbon charge potential. Potential source rocks are present in Andimadam (Lower Cretaceous age), Sattapadi (Upper Cretaceous age), Kudavasal (Upper Cretaceous age) and Karaikal (Eocene age) formations in the Cauvery Basin. Kerogen type of Protonovo, Kudavasal and Bhuvanagirt formations are mainly type-Ill whereas Karaikal. Sattapadi and Andimadam formations contain about35%, 30%, 50%Type-II organic matter (OM). respectively. The middle of Andimadam formation attained 0.75% VRo at 23, 50, 22, 10 and 20 mybp at PND location of Pondicherry area, BVG location of Ariyalur area, TKD location of Tranquebar area, VZK location of Tranquebar area and PH10 location of Palk Bay area, respectively. Middle of Sattapadi and Bhuvanagiri formations attained 0.75% VRo only in the studied Tranquebar and Ariyalur -Pondicherry wells. Kudavasal formation has not yet attained 0.75% VRo anywhere in Cauvery Basin. Calculated hydrocarbon generated (HCG, MT hydrocarbon /Sq m) values are low in Kudavasal and Bhuvanagiri (0.5 maximum) formations; moderate in Sattapadi Shale (4.0 in southern part of Nagapattinam and north of Palk bay area); and high in Andimadam Formation (32, 16, 4, 2 and 10 in Tranquebar, Ariyalur. Nagapattinam, Ramnad and Palk bay areas respectively). Best targets for future exploration are the deep basin reservoirs in Ariyalur Pondicherry sub basin for gas and conventional accumulations in major parts of Nagapattinam and Palk Bay sub basins in Andimadam formation.

16 illus, 5 tables, 10 ref

005164   Mukherjee A;Prabhakar G (NO, , National Mineral Development Corporation Ltd. (NMDC), Masab Tank, Hyderabad-500 028) : Aqueous low salinity co₂-H₂O fluids : evidences from some late archean greenstone hosted Indian gold deposits. J appl Geochem 2006, 8(2A), 471-4.

Deals with the type, nature composition and origin of ore bearing fluids in a few Late Archean Greenstone hosted Indian gold deposits viz., Hutti and Chikkasiddavanahalli. The modification of the fluids refects the type of complexes of metals that are carried in the solution. It is inferred that Au deposition is dependent on the stability of the thio sulfide complex of gold and depletion of H₂S in the Au containing ore foming solution at a given stage results in gold deposition. The fluid composition of Hutti and Chikkasiddavanahalli area is also discussed. The primary inclusions in Hutti gold mine consist of CO₂ monophase (Type -1) and biphase liquid rich inclusions (Type - III). The homogenization temperature (Th°C)on biphase aqueous rich (Type - III) inclusions of Hutti gold mine varies from 174° to 223°C. The salinity of these ranges from 7.3 to 10.1 wt% NaCl equivalent and the density of the aqueous fluid ranges from 0.89 to 1.10 g/cm³. Three types of fluid inclusions have been observed in Chikkasiddavanahalli Banded Iron Formations viz.. Type - I (CO₂ - H₂O). Type - II (H₂O. L+V) and Type - III (CO₂). The homogenization temperature (Th°C) of the Type -1 (CO₂ - H₂O) inclusions of Chikkasiddavanahalli ranges from 280°C to 350°. The Chikkasiddvanahalli fluids have low .. salinity (2 wt% NaCl equivalent). A remobilization deposition model has also been proposed for Chikkasiddavanahalli area.

1 illus, 6 ref

005163   Mokashi D D;Khadtare S V;Jadhav J H (Mahatma Phule Krishi Vidyapeeth, Zonal Agricultural Research Station, , Solapur-413 002) : Nakshtrawise rainfall variability and probability analysis for drought prone areas. Bioinfolet 2007, 4(1), 1-5.

Rainfall analysis of nine different places of scarcity zone was carried out. The rainfall data as per the availability of last 40 to 49 years was used for Nakshtrawise and Decadal analysis for Drought Prone Areas of Maharashtra. In northern part at Dhule, <62>50 mm rainfall was received in Mrugashira to Magha nakshtra with less variabilit (CV. <60>100). In cenral part, the rainfall in Mrugashira nakshtra at Kopergaon and Rahuri and Aaridra nakshtra at Kopergaon have less variability (CV <60>100) in kharif season. In northern part at Dhule, Mrugashira to Purva nakshtras have the highest probability (<62>50%) of rainfall in Mrugashira nakshtra was only at Rahuri. In southern part, the initial probability of getting <62>50% rainfall was in Mrugashira nakshtra at Mohol in kharif season.

2 tables, 7 ref

005162   Martin Deva Prasath P;Vijayakumar R;Khan T H (Chemistry Dep, TBML College, Porayar-609 307, Email: martinprasath@rediffmail.com) : Distribution of heavy metals of chaetomorpha, before and after tsunami at tharangampadi coast (South East coast of India). J appl Geochem 2006, 8(2A), 417-22.

Distribution of heavy metals (Zn, Cu, Fe, Mn, Cr, Cd, and Pb) in water, sediments and marine algae using atomic absorption spectrophotometer at Tharangampadi coast lying along the south east coast of India was studied before and after Tsunami attack. Accumulation of heavy metals was observed in the order of sediments <62> marine algae <62> water. In water, the order of heavy metals was found to be Mn<62>Fe<62>Zn<62>Cu<62>Cr<62>Cd<62>Pb; in sediments the order was Mn<62>Fe<62>Cu<62>Zn<62>Cr<62>Cd<62>Pb and in marine algae it was Fe<62>Mn<62>Zn<62>Cu<62>Cr<62>Cd<62>Pb. In water, the highest recorded value among heavy metals was Mn. It varied from 498.78 μg/l to 514.23 μg/1 and the lowest recorded value among metals was Pb and it varied from 0.002 μg/l to 0.005 μg/1 after tsunami. In sediments the highest recorded value among heavy metals was Mn and it varied from 724.9 μg/g to 820 μg/g and the lowest value among metals was Cd and it varied from 0.31 μg/g to 0.447 μg/g. In marine algae the highest recorded value among the heavy metals was Fe. It varied from 389.16 μg/gto543 μg/g and the lowest value in metals was Cd, which varied from 0.49 μg/g to 0.62 μg/g. Hence, in all the three samples studied, the metal concentrations showed significant variations after tsunami in Tharangampadi coast.

4 illus, 3 tables, 8 ref