004351   Dutta S;Khare P;Tathe A (India Meterological Dep, , Pune-411 005, Email: dutta.drsomenath@gmail.com) : Isolated heavy rainfall over sylhet, Bangladesh and convective instability. Mausam 2015, 66(4), 675-86.

An attempt has been made to study the thermodynamic aspects associated with spells of heavy rain over a mountainous station Sylhet, located on the windward side of the Khasi-Jayantia hills with respect to southerly wind during the southwest monsoon season. For this purpose, eight cases have been selected and studied, which include, days when isolated heavy rainfall occurred over Sylhet, with preceding and succeeding days reporting comparatively less rainfall. For each of these epochs, consisting of three consecutive days, Convective available potential energy (CAPE), Convective inhibition energy (CINE), Moist static energy (MSB), a non-dimensional kinetic 'parameter ('K'), vertically weighted average value of MSE (σ) etc., have been computed to examine their daily variations. Convective precipitation model, developed by De and Dutta (2005), has been used here to compute rainfall intensity (RFI) in mm/hr, which is solely due to convection. Eight such cases have been studied. It appears from the study that in most of the cases, a rise in rainfall from the first day to second day is generally associated with a corresponding rise in the CAPE and the parameter 'K', a fall in 'σ' and in CINE. While a fall in rainfall on the third day is associated with a corresponding fall in CAPE and 'K' and a rise in CINE and 'σ'. The study also shows that the above Convective precipitation model, in general, is capable at least qualitatively, in capturing the observed fluctuation of daily rainfall in six cases, whereas the remaining two cases are not in the same conformity.

8 illus, 4 tables, 16 ref

004350   Das S;Islam M N;Das M K (India Meterological Dep, , New Delhi-110 003, Email: somesh07@yahoo.com) : Simulation of severe storms of tornadic intensity over Indo-Bangla region. Mausam 2016, 67(2), 479-92.

Many severe thunderstorms of tornadic intensity were reported in the northwestern parts of Bangladesh during 30 August to 14 September, 2008. Two among them occurred at Nilphamari and Kurigram districts on 30th August, and at Nilphamari district on 3rd September. The tornadic storms are studied based on a field survey, surface data, radar and satellite observations and model simulations. Low level moisture influx by southerly flow from the Bay of Bengal coupled with an upper level westerly jet stream causing intense instability and shear in the wind fields triggered a series of storms for two weeks. The exact time and locations of the storms are investigated by using the hourly precipitation data retrieved from a S-band radar of Bangladesh Meteorological Department. (BMD) located at Dhaka. Subsequently, the storms are simulated by using the WRP-ARW model on double nested domains at 9 and 3 km horizontal resolutions based on 6 hourly FNL analyses and boundary conditions of NCEP. Among the typical characteristics of the storms, the CAPE, Storm-Relative Environment Helicity (SREH), Bulk Richardson Number Shear (BRNSHR), dew point depression, and potential vorticity are studied. Results show that while there are differences of 2-3 hours between the observed and simulated time of the storms, the distances between observed and simulated locations of the storms are several tens of kilometers. The maximum CAPE is generally above 2400 J kg^{-1. The maximum amount of vorticity transferred by directional shear in the storm updraft (helicity) due to convective motion simulated by the model is 766 m2 sec-2, and the highest value of BRNSHR that define the region in which low-level mesocyclogenesis is more likely is 168m2 sec-2 among the 2 cases, which is generally supposed to produce rotating storms according to the prescribed range.}

8 illus, 1 table, 80 ref

004349   Das A K;Kundu P K;Bhowmik S K R;Rathee M (India Meterological Dep, , New Delhi-110 003, Email: ananda.das@imd.gov.in) : Verfication of real-time WRF-ARW forecast in IMD during monsoon 2010. Mausam 2016, 67(2), 333-56.

Performance of the mcsoscale model WRF-ARW has been evaluated for whole monsoon season of 2011. The real-time model forecasts are generated day to day in India meteorological Department for short-range weather prediction over the Indian region. Verification of rainfall forecasts has been carried out against observed rainfall analysis whereas for all other meteorological parameters verification analysis which was generated using WRFDA assimilation system. Traditional continuous scores and categorical skill scores are computed over seven different zones in India in the verification of rainfall. For other parameters (upper-air as well as surface), continuous scores are evaluated with temporal and spatial features during whole season. The forecast errors of meteorological parameters other than rainfall are analyzed to portray the model efficiency in maintaining monsoon features in large scale along with localized pattern. In the study, time series of errors throughout the season also has been maneuvered to evaluate model forecasts during diverse phases of monsoon. Categorical scores suggest the model forecasts are reliable up to moderate rainfall category for all seven zones. But, rainfall areas with rainfall above 35.5 mm per day associated with migrated weather system from Indian seas could not be predicted as the model displaces them in the forecast. The verification for a whole monsoon season has shown that the model has capability to predict orographic rainfall for the interactive areas with low level monsoon flow over Western Ghats. The model efficiency are in general brought out for a single monsoon season and errors characteristics are discussed for further improvement which could not perceived during real-time use of the model.

17 illus, 2 tables, 35 ref

004348   Das A K;Kaur S (India Meteorological Dep, , New Delhi-110 003, Email: dasakimd@gmail.com) : Performance of IMD multi-model ensemble and WRF (ARW) model for sub-basin wise rainfall forecast during monsoon 2012. Mausam 2016, 67(2), 323-32.

The Numerical Weather Prediction models, Multi-model Ensemble (MME) (27 km x 27 km) and WRF (ARW) (9 km x 9 km) operationally run by India Meteorological Department (IMD) have been utilized to estimate sub-basin wise rainfall forecast. The sub-basin wise operational Quantitative Precipitation Forecast (QPF) have been issued by 10 field offices named Flood Meteorological Offices (FMOs) of IMD located at different flood prone areas of the country. The daily sub-basin wise NWP model rainfall forecast for 122 sub basins under these 10 FMOs for the flood season 2012 have been estimated on operational basis which are used by forecasters at FMOs as a guidance for the issue of operational sub-basin QPF for flood forecasting purposes. The performance of the MME and WRF (ARW) models rainfall at the sub-basin level have been studied in detail. The performance of WRF (ARW) and MME models is compared in the heavy rainfall case over the river basins (Mahanadi etc.) falls under FMO, Bhubaneswar and it is found that WRF (ARW) model gives better result than MME. It is also found that performance of WRF (ARW) is little better than MME when compared over all the flood prone river sub basins of India. For high rainfall categories (51-100, <62>100 mm), generally tnese leads to floods, the success rate of model rainfall forecasts are less and false Eilarms are more. The NWP models are able to capture the rainfall events but there is difference in magnitudes of sub basin wise rainfall estimates.

7 illus, 7 tables, 6 ref

004347   Boodhoo K;Lollchund M R;Dilmahamod A F (Chemistry Dep, Faculty of Science, Mauritius Univ, South Africa, Email: r.lollchund@uom.ac.mu) : Trends analysis of precipitation data over the tropical South-West Indian ocean (SWIO) basin using the ensemble empirical mode decomposition (EEMD) method. Mausam 2016, 67(2), 423-30.

In this paper, we propose the use of the Ensemble Empirical Mode Decomposition (EEMD) method in the analysis of trends in climate data. As compared to existing traditional methods, EEMD is simple, fast and reliable, It works by decomposing the time-series data into intrinsic mode functions until a residual component is obtained which represents the trend in the data. The dataset considered consists of satellite precipitation estimates (SPE) obtained from the Tropical Rainfall Measuring Mission (TRMM) for the tropical South-West Indian Ocean (SWIO) basin recorded during the periods January 1998 to December 2013. The SWIO basin spans from the latitudes 5° S to 35° S and the longitudes 30° E to 70° E and comprises of part of the east coast of Africa and some small island developing slates (SIDS) such as Comoros, Madagascar, Mauritius and Reunion Island. The EEMD analysis is tarried out for summer, winter and yearly time series of the SPE data. The results from the study are presented in terms of intrinsic mode functions (IMFs) and the trends. The analysis reveals that in summer, there is a tendency to have an increase in. the amount of rainfall, whereas in winter, from 1998 to 2004 there has been an initial increase of 0.0022 mm/hr/year and from there onwards till 2013 a decrease of 0.00052 mm/hr/year was noted.

7 illus, 3 tables, 23 ref

004346   Amudha B;Subadra P A;Rani V R (India Meterological Dep, Regional Meterological Centre, Chennai-600 006, Email: amudha2308@gmail.com) : Perspective on land breeze characteristics over Chennai. Mausam 2015, 66(4), 719-28.

An indigenous High Wind Speed Recorder (HWSR) which samples the wind direction and wind speed at one minute interval was installed at Chennai (Nungambakkam) in October 2009. The data obtained from such a modern observing system with high sampling frequency has been utilised to understand the land 'breeze characteristics over the station during January to March of the period 2010-12. Regularity observed in the transition of wind direction from easterlies to westerlies heralding the commencement of land breeze in the late night and early morning hours, frequency distribution of the hours in which land breeze occurs, the normal wind direction during ssteady land breeze and other interesting features have been presented. Analysis revealed that on 94 per cent of the occasions during the study period, LB was a regular and significant feature over Chennai Nungambakkam. The time of commencement of LB was in the early morning hours between 00 and 03 hours IST on 50 per cent of the occasions while time of decay of LB was between 08 and 11 hours IST in 73 per cent of the occasions.

5 illus, 4 tables, 14 ref

004345   Amudha B;Raj Y E A;Asokan R (India Meterological Dep, Regional Meterological Centre, Chennai-600 006, Email: amudha2308@gmail.com) : Characteristics of movement of low level clouds associated with onset / wet spells of northeast monsoon of Indian sub-continent as derived from high resolution INSAT OLR data. Mausam 2016, 67(2), 357-76.

Characteristics of the northeast monsoon (NEM) have been studied utilising the outgoing long wave radiation (OLR) data derived over the north Indian Ocean and south peninsular India (SPI) from the series of Indian geostationary satellites. The contrasting feature of movement of the equatorial cloud zone from southeast to northwest direction during the onset phase of NEM has been reiterated using 1° x 1° gridded higlr resolution OLR data for the period 2000-2012. Presence of OLR values less than 180 Win^{-2 over a large part of coastal Tamil Nadu on the date of onset and the simultaneous commencement of rainfall with clouding approaching SPI from southeast is clear from the study of superposed epoch analysis of the data. Triad means of OLR also substantiate this inference. During active spells of NEM which succeed prolonged dry spells, replication of the south to north movement of clouding by the OLR contours and the plausible reasons for such a movement have been brought out. The active monsoon situation existing over Sri Lankan region during the withdrawal phase of NEM over SPI is demonstrated with the depiction of the movement of OLR contours less than 230 Wm-2 over the region.}

9 illus, 2 tables, 38 ref

004344   Amrender Kumar;Chattopadhyay C;Mishra A K; Jain A K (Agricultural Knowledge Management Unit, Indian Agricultural Research Institute, New Delhi-110 012, Email: akjha@iari.res.in) : Neural network based prediction models for evaporation. Mausam 2016, 67(2), 389-96.

From statistical perspective, artificial neural networks (ANNs) are interesting because of their potential use in prediction. In this study, ANNs based approach has been used to assess the prediction of evaporation with meteorological variables, viz., maximum temperature (MaxT), minimum temperature (MinT), ielative humidity in the morning (RHI), relative humidity in evening (RHII), bright sunshine hours (BSH) and wind speed (WS) for different locations (Una, Karnal, Pantnagar, Raipur, Anantpur, Bangalore and Pattambi) in India. ANNs models were developed using Multilayer perceptron (MLP) architecture with two-phase algorithm of Backpropagation (BP) and Conjugate gradient descent (CGD) for prediction of evaporation as output and different combination of meteorological variables as input in different locations. Weekly predictions of evaporation have been obtained for subsequent years not included in model development. The performances of the developed models with different combination of weather variables compared based on mean absolute percentage error (MAPE). The sensitivity analysis indicated that the mean temperature and mean relative humidity are more sensitive to evaporation.

1 illus, 2 tables, 21 ref

004343   Agarwal A;Arora M;Nemabishal Gurung R K (National Institute of Hydrology (NIH), Jal Vigyan Bhavan, , Roorkee Uttarakhand-247 667, Email: avinash@nih.ernet.in) : Springs of MID Western Himalayan (Uttarakhand) and their response. Mausam 2016, 67(2), 509-12.

6 illus, 15 ref

004342   Abdel-Wahab M;Essa K S M;Embaby M;Elsaid S E M (Meterology and Astromy Dep, Faculty of Science, Cairo, Email: mohamedksm56@yahoo.com) : Analytical and numerical solutions of crosswind integrated concentration by using different eddy diffusivities methods. Mausam 2015, 66(4), 785-92.

The objective of this paper is to calculate the concentration of air pollution, by solving the Atmospheric Diffusion Equation (ADE) using Laplace transform and Adomian decomposition methods. The solution depends on eddy diffusivity profile (K) and wind speed at the released point (u). We solve the ADE analytically in two dimensions using Laplace transform method and get the inversion of Laplace analytically and solving it numerically using Adomian decomposition method, then, compared our results with observed data.

3 illus, 4 tables, 16 ref

003191   De A;Roy A;Mitra M;Bhattacharya R K (Applied Mathematics Dep, Univ of Calcutta, 92, A.P.C. Road, Kolkata-700 009, Email: ajit_math@rediffmail.com) : Computation of synthetic seismogram in real earth model by Eigen function expansion. Mausam 2016, 67(3), 659-68.

The method of eigen function expansion has been used in the present study to compute synthetic or theoretical seismogram in layered elastic half-space of real earth model. Simple dislocation source model has been considered. The transverse (SH) or radial and vertical (P-SV) components of displacement field, have been computed as summed modes and compared by using both exact and numerical techniques. The methods used in the study, include exact evaluation by propagator matrix approach using Reflection-Transmission coefficients as well as numerical computations using Runge-Kutta method of order 4. The specialty of the present study is to evaluate approximate displacement field for the earth models with homogeneous and / or inhomogeneous layers. The normalization technique has been used in the study to control the overflow errors. The study has an advantage to get an idea of earth structure or source model by an inverse iterative technique.

10 illus, 30 ref

003190   Chandra R (North East Region, IWMP, Mukesh & Associates, New Delhi) : Floristic diversity in a wetland of Barkot range of Doon valley Dehradun (India). e-J appl For Ecol 2016, 4(1), 55-9.

India is exceptionally rich in biodiversity and is one of the 12 mega diversity centres of the world. Doon valley geographically lies between 770 35 East to 780 19 East longitude and 290 57 30 North latitude. A study was conducted in the year 1998-99 to record the biodiversity of the Golatappar area of Barkot Range of Doon valley. The study provided the significant assessment of the biodiversity of the area. It was found that Clerodendrom infortunatum, Cyprus globulus, Pterospermum acerifolium and Diospyros montana, Adina cordifolia were most important trees species of the area according to the importance value index. Under shrub strata Clerodendron infortunatum was the most dominant species and under herb Cyprus globulus and Euphorbia hirta. Shannon Wiener index was highest for the trees (2.97) followed by the shrubs (1.85) and lowest for the herbs (1.27). The study shows the assessment of the floristic diversity of the study area.

002248   Sujith P P;Sheba V M;Gonsalves M J B D (Aqua-Geomicrobiology Lab, CSIR-National Institute of Oceanography, Dona Paula-403 004, Email: mjudith@nio.org) : Diversity and activity of methanotrophic related bacteria in subsurface sediments of the Krishna-Godavai basin, India. Curr Sci 2016, 110(9), 1801-9.

The present study assesses the distribution, diversity and activity of aerobic methanotrophic related bacteria (MRB) dwelling in Krishna-Godavari (KG) basin, India. The counts of MRB ranged from non-detectable (ND) to 8.6 x 10^{4 CFU gram dry weight of the sediment, with maximum counts at 24.2 m below seafloor. Greater methanotrophic bacterial abundance was at the surface/subsurface sediments of the core at station MD161-8 than at the bottom sediments. Identification of these isolates by 16S rDNA sequence analysis showed their taxonomic affiliation to Alcanivorax, Me-thylophaga, Marinobacter, Joostella, Methylobacterium, Desulfovibrio species and other uncultured bacterial clones. The isolates grew under optimum pH of 8, temperature of 28°C and salinity of 35, and on different carbon sources like yeast extract, D-glucose, etha-nol and methanol. The addition of nitrogen sources like amino acids and yeast extract improved methanotrophic activity by the isolates. These results add to our understanding of MRB and their activity in modulating the emission of methane from gas hydrate-rich ecosystems like the KG basin.}

2 illus, 2 tables, 48 ref

002247   Srinivasamoorthy K;Vasanthavigar M;Gopi S; Vijayaraghavan K (Earth Sciences Dep, Pondicherry Univ, Pondicherry-605 014, Email: moorthy_ks@yahoo.com) : Isotopic and hydrochemical techniques to address river water quality: Sarabanga river, Tamilnadu, India. Indian J Geomorph 2015, 20(1), 33-44.

The Sarabanga river basin originates at Shevaroy hills in Salem district with <60> total spread of 1089 sq.km and configures river Cauvery in Namakkal district c Tamilnadu. The geology is composed of rock types representing metasedimentar rocks. The area is drought prone with meager and erratic rainfall with crystallin geological formations, the scenario of groundwater regime is gloomy. Increasin^ urbanization and industrialization has added to the problem for requirement of sufficient quantum of good quality water. A proper appraisal of chemical quality of water is necessary for interline water resources development. In view of the above, it becomes imperative to study hydrogeological and hydrogeochemical aspects of surface water bodies in Sarabanga. A total of 36 water samples were collected from surface water bodies like tanks, ponds and river for two different seasons Pr monsoon and Post monsoon and analyzed for major cations, anions and isotope (oxygen and hydrogen). The water in the study area is generally odorless an colorless in most of the places. The temporal variation of ions like Cl, F, HCO3, NO3 and Si shows increasing trend due to the effective leaching from rock matrix along with anthropogenic activities. The Hill - Piper fades demarcated weathering and ion exchange process controlling water chemistry. Ions like Na, Cl, NO3 and F exceeds the drinking limit when compared with WHO standards. The USSL plot indicates high salinity, high and very high sodium water, which can be applied for irrigation only in soils having good internal drainage. The 82H- SI SO relationship indicates, water fractionation by evaporation.

27 ref

002246   Sharma R;Ratheesh S;Basu S (Oceanic Sciences Div, Atmospheric and Oceanic Sciences Group, Space Applications Centre, Ahmedabad-380 015, Email: rashmi@sac.isro.gov.in) : Estimating biological parameters of a coupled physical-biological model of the Indian ocean using polynomial chaos. Curr Sci 2016, 110(8), 1544-9.

A statistical emulator techniqiue, namely polynomial chaos, has been used to estimate two time-dependent biological parameters of a coupled physical-biological model of the Indian Ocean. This has been achieved by minimizing a distance function representing misfit between model simulated and satellite-derived surface chlorophyll. First, the parameters have been assumed to be constant in time and optimized values have been found by minimizing a time-averaged distance function. Since no significant improvement in model simulation has been found using a fixed set of optimum parameters, minimization has been carried out daily, assuming the parameters to be time-dependent. Emulation with this set of parameters has led to a significant improvement in the simulated surface chlorophyll. Smoothing of the parameters with singular spectrum analysis has caused less noisy simulations, at the cost of increasing the model data misfit. Time-varying parameters have been found to be more suitable for the hindcast of daily averaged chlorophyll both in the Arabian Sea and the Bay of Bengal.

5 illus, 1 table, 23 ref

002245   Sati M S;Mamgain M G;Rawat G S (Geology Dep, H.N.B. Garhwal Univ, Srinagar-246 174, Email: sati.madhusudan@rediffmail.com) : Overview of the geoenvironmental studies of the badiyargad catchment, Garhwal Himalaya, Uttarakhand, India. J Mount Res 2014, 9(Dec), 83-94.

The Badiyaragad is a fifth order stream that flows from N to S up to Badiyar, taking a turn towards east up to Sayari and then again flowing towards south joining Alaknanda on the opposite of Khankra. The catchment in the middle is drained by the river and numerous tributaries join it laterally. The tributary channels have deposited large alluvial fans. The river has deposited alluvial terraces, which are very distinct towards the lower reaches and form three to four levels. The upper slopes and high altitudinal areas are covered with periglacial and glacial deposits. The terrace, fan and hill slopes have provided an ideal geoenvironment for human activities including agriculture, horticulture, dense settlements and other civil establishments.The Badiyargad catchment is various natural hazards cloudbursts, landslide and floods due to its peculiar geomorphic condition, high relief of peripheral ridges and impact of monsoon winds. The studies carried out so far indicate that the losses causes by these phenomena both in terms of life and property are mainly due to unwise human interaction with the geo-environmental of the area. The paper gives an overview of the geoenvironmental status of Badiyargad catchment and suggests the necessity of undertaking further detailed studies including resources mapping for balanced development of the area.

5 illus, 10 ref

002244   Ranith R;Senthilnathan L;Machendiranathan M; Thangaradjou T;SaravanaKumar A;Sasamal S K;Choudhury S B (Centre of Advanced Study in Marine Biology, Faculty of Marine Sciences, Annamalai Univ, Parangipettai-608 502, Email: umaradjou@gmail.com) : Integrated role of SST, PAR and CDOM in summer reef bleaching during 2010 and 2011 along the Lakshadweep islands. Curr Sci 2016, 110(9), 1832-6.

The role of sea-surface temperature (SST), photosyn-thetically active radiation (PAR) and chromophoric dissolved organic matter (CDOM) on bleaching events along the Lakshadweep archipelago was studied for the summer of 2010 and 2011. The present study revealed similar SST pattern (30.8-31.9°C) and high PAR availability (48-50 E m^{-2 day-1) during the summer weeks of 2010 and 2011. However, the CDOM content varied significantly between 0.5 and 7 during 2010 and 2011. Stress from the elevated SST and PAR levels coinciding with low CDOM content (ultra violet radiation (UVR) transparent water column) might have resulted in large-scale bleaching during 2010. Low PAR and high CDOM (UVR opaque water column) might have prevented Lakshadweep corals from large-scale bleaching during 2011. Statistical analysis also confirmed that the high bleaching event of 2010 was due to coupled stress imparted by SST, PAR, CDOM and the unusually calm state of the sea.}

4 illus, 1 table, 26 ref

002243   Priyatham Kumarm B;Vijayanand B;Pandey K K; Majumdar A;Krishna K V G;Mohanty R (NO, Atomic Minerals Directorate for Exploration and Research, Nagapur-440 001, Email: kkapadey.amd@gov.in ) : New occurrence of tapiolite from Kuberpur pegmatite, Surajpur district, Chhattisgarh, India. Curr Sci 2016, 110(9), 1620-2.

3 illus, 2 tables, 7 ref

002242   Ojha A;Daspattanayak P (Ravensha Univ, Cuttack, Odisha) : Land-use / land-cover dynamics in Chilika lake catchment. Indian J Geomorph 2015, 20(1), 9-22.

Land use and land cover is an important component in understanding the interactions of the human activities with the environment and thus it is necessary to be able to simulate changes. Empirical observation revealed a change in land use land cover classification in Chilika Catchment. The study area is situated 19°27 '49.888 "N to 20°J9 '55.159 "N latitude and85°3 '8.396" E to 85°51 '53.652 "E longitude covering 18 revenue blocks of four district (Puri, Ganjam, Khurda and Nayagarh). Chilika Catchment area is also a tourist destination for many historical places and scenic beauty are coming under the catchment area. From this catchment area 52 rivers and rivulets are coming into Chilika Lake. Some anthropogenic and natural pressures have great role for changing the Landuse / Land cover of the catchment. Population dynamic is also an important pressure for changing the Landuse / Landcover. In this paper an attempt is made to study the changes in Land use /Land cover in this Catchment over 40 years period (1975 to 2012). The study has been done through Remote sensing approach using SOI toposheet and Landsat &IRSP6 LISS III imageries of 1975 and 1995, 2012. CIS software is used to prepare the thematic maps. In the present study, a Landuse / Landcover maps of Chilika catchment for the years 1975, 1995 and 2012 is prepared by Image processing and visual interpretation technique. Ground truth observations with GPS were also performed to check the accuracy of the classification.

8 ref

002241   Nath A J;Brahma B;Pathak K;Das A K (Ecology and Environmental Science Dep, Assam Univ, Silchar-788 011, Email: arunjyotinath@gmail.com) : Why should we preserve wetlands?. Curr Sci 2016, 110(9), 1619-20.

1 illus, 1 table, 19 ref

002240   Naidu K B;Reddy K S N;Sekhar C R;Rao P G; Krishna K N M (Geology Dep, Andhra Univ, Visakhapatnam-530 003, Email: naidu0756@gmail.com) : REE geochemistry of monazites from coastal sands between Bhimunipatnam and Konada, Andhra Pradesh, East coast of India. Curr Sci 2016, 110(8), 1550-8.

The rare earth elements (REE) geochemistry of mona-zites of Bhimunipatnam-Konada coastal sand deposit was studied using EPMA method. The average LREE concentration was 53.31%, which is more than HREE (av 1.38%). ZLREE more than actinides (Th + U) indicates that provenance for monazite in the study area is garnet-bearing paragenesis rocks such as char-nockites and metapelitic rock (khondalite). The REE fractionation patterns and positive europium anomalies indicate that monazites were formed from magma/ anatectic melt with high oxygen fugacity. The U-Th-Pb geochemical dating of moniazites is 1000 Ma (average), which indicates that they are derived from pro-toliths of charnockites and metapelitic rocks such as khondalites, which are formed during meso-neo-Proterozoic ages in the Eastern Ghats Granulite Belt.

2 illus, 5 tables, 37 ref

002239   Murty A S N;Sain K;Sridhar V;Prasad A S S S R S;Raju S (No. 19-104/4, Kalyanapuri, Uppal, Hyderabad-500 039, Email: asnngri@gmail.com) : Delineation of trap and subtrappean mesozoic sediments in Saurashtra Peninsula, India. Curr Sci 2016, 110(9), 1844-51.

Mapping of sediments beneath volcanic Traps is a highly challenging task. Here we report on the analysis of wide-angle seismic data from Trap-covered Sau-rashtra peninsula to address this problem. Travel-time modelling of mainly seismic refraction and some reflection phases yields basement configuration, trap and subtrappean sediment thicknesses along the Jodia-Ansador (NW-SE) profile in Saurashtra peninsula. Travel-time skip and amplitude decay in seismic refraction data indicate the presence of low-velocity sediments beneath the Traps. The result reveals two layers with Deccan Traps (4.85-5.0 km s^{-1) followed by Mesozoic sediments above the basement (5.8-6.1 km s-1). Using the lower bound velocity (3.2 km s-1), sediment thickness varies between 800 and 1500 m. Based on upper bound velocity (4.3 km s-1), we find both the sediment thickness and basement depth increase by 600-700 m. The thickness of sediments is more in the northwest and decreases gradually in the southeast, suggesting that the northwestern part of the profile is an important zone for hydrocarbon exploration in the Saurashtra peninsula. With the lower bound velocity of Mesozoics, we find that the basement (5.8-6.1 km s) is deep (<126>2100 m) in the northwest and shallows up near Atkot to <126>1.0 km depth, and then deepens further southeast, showing the basement upwarped. The overall velocity and boundary uncertainties are of the order of ±0.15 km s-1 and ± 0.15 km respectively.}

6 illus, 2 tables, 24 ref

002238   Manjare B S;Jawadand S A (Geology Dep, RTM Nagpur Univ, Nagpur, Maharashtra) : River morphometry using remote sensing and GIS techniques in the SUB basin of Vena river, Nagpur district, Maharashtra India. Indian J Geomorph 2015, 20(1), 45-61.

Integrated approach based on advanced applications of remote sensing and geographical information systems (GIS) proves as an efficient and effective result-oriented method for studying the development and management of water resources. The present study is an attempt to critically evaluate and assess various morphometric parameters of sub watersheds of the Upper Vena river basin, Maharashtra using remote sensing and GIS. In this study, topographic maps, satellite images and geologic maps of the study area have been used to generate thematic maps of drainage, geomorphology, lineaments and elevation.. The various aspects of geomorphometric parameters such as drainage density, slope, shape of the basin, bifurcation ratio, length ratio along with geological parameters gives the precise and objective overview about the watershed. In the given study area the sub watersheds have been numbered as VW1 to VW16.

8 illus, 6 tables, 14 ref

002237   Manjare B S (Geology Dep, RTM Nagpur Univ, Nagpur (MS), Maharashtra, Email: yogesh_manjare1@rediffmail.com) : Slope analysis in some part of Wardha river sub basin of Maharashtra by using SRTM DEM: an integrated approach of GIS techniques. Indian J Geomorph 2015, 20(1), 1-8.

This study is an attempt to delineate the slope in and around Wardha andAmravati district of Maharashtra by using Digital elevation models using integrated approach of Remote Sensing and GIS techniques. DEMs are used for visual analysis of topography, landscapes and landforms other than modeling of surface processes. DEMs are increasingly used for visual and mathematical analysis of topography, landscapes and landforms, as well as modeling of surface processes. Selection of suitable source of DEM and its resolution play important role in deriving the parameters. In applications of geographic information systems (GIS), provide opportunities for modeling, analyzing and displaying geographical phenomena connected with topography and relief. Much valuable information in the form of attributes related to the surface of a real terrain can be gained by interpretation of terrain models. The slope classification and slope element have been extracted from the SRTM DEM with 90 mt. resolutions with superimposing with the SOI toposheet and various slope classes made for the slope analysis. In the slope classification nearly level to steep slope class were found and analysed.

8 ref

002236   Gnanasundar D (West central region, central ground water board, government of India) : Understanding coastal aquifer hydrodynamics essential in GIS application for demarcating artificial recharge zones. Indian J Geomorph 2015, 20(1), 23-32.

In recent times, the major concern in coastal aquifers is the deterioration in groundwater quality. As the deterioration in groundwater quality leads to several adverse effects on drinking water, agriculture, industry, revenue, health etc. there arises a need to understand in-depth the groundwater regime of the coastal aquifer system as well as its dynamics over a period by adopting several scientific approach. Apart from the existing conventional methodology and tools, Remote sensing and GIS has provided new dimension in this field. As these modern technologies offer high speed computerized data processing and analysis its application to utilize enormous quantum of spatial data finds best applicable earth resources management and more particularly groundwater aquifer related issues and solutions. However, all these modern technologies need to be based on basic understanding of the subject.

4 illus, 1 table

002235   Borgohain S;Das J;Saraf A K;Singh G;Baral S S (Earth Sciences Dep, Indian Institute of Technology Roorkee, Roorkee-247 667, Email: susantaborgohain@gmail.com) : Morphodynamic changes of Lohit river, NE India: GIS-based study. Curr Sci 2016, 110(9), 1810-16.

The Lohit River is a south bank tributary of the Brahmaputra River. Till 1987, the Lohit River used to meet the Brahmaputra at a place near Bairagi Chapari (27.77°N, 95.44°E). By 1995, the confluence point had shifted about 20 km downstream. One small channel of the Lohit River captured the Dangori River during the 1988 flood. Gradually the Lohit River started flowing along the captured channel. By 1995, it became the trunk channel of the Lohit River and Dibru Saikhowa region became an island. Banklines of Brahmaputra and Lohit rivers have undergone significant changes near their confluence point within the last few decades. By 1987, the south bank of the Brahmaputra near Rohmoria (27.55°N, 95.15°E) shifted about 1.6 km southward from its position in 1973. Interestingly, within the period 1988-90 the south bank shifted about 4.1 km south. This major shifting was the result of capturing of the Dangori River by the Lohit River. However, migration of the rivers towards the south has stopped after 1995. Analysis of SRTM DEM reveals that topographic elevation has played a major role in changing the course of the Lohit River.

9 illus, 33 ref

002234   Aravindan S (Earth Science Dep, Annamalai Univ, ) : Introduction to hyperspectral remote sensing. Indian J Geomorph 2015, 20(1), 63-75.

7 illus, 1 ref

001188   Vijaya Kumar P G;Mishra S K;Pandey A (WRD&M Dep, IIT Roorkee, Roorkee-247 667, Email: vijayakumarlekshmi@gmail.com) : Computation of dam break flood disaster risk index. J Indian Wat Resour Soc 2015, 35(2), 41-50.

This paper presents a new Dam Break Flood Disaster Risk Index (DBFDRI) for quantitative assessment of the level of risk involved due to disaster likely to be caused by a dam break flood and it can be quite useful for taking various priority based mitigating measures. The index is determined by employing the results of HEC-RAS 4.1.0 for various locations downstream of the dam considering the parameters affecting the dam break flood disaster assessed from field survey.

7 illus, 4 tables, 17 ref

001187   Varghese S;Roychaudhuri S;Mashood P A; Tripathi S K (NO, Survey of India, Marine and Coastal Survey Div, Block DK 6, Sector II, Salt Lake, Kolkata-700 091, Email: saajuvarghese@gmail.com) : Geomorphology of the offshore of Rushikulya river mouth in northern Bay of Bengal. Indian J Geosci 2015, 69(3-4), 233-40.

Seabed survey was undertaken in territorial waters off Rushikulya River, Bay of Bengal by Geological Survey of India (GSI) during ST-223 cruise of R. V. Samudra Kaustubh. The work was aimed at determining the sediment distribution pattern and coastal changes associated with sea level rise. The sediment of the inner to middle shelf region of the central part of east coast near the spit of the Rushikulya River mouth is characterized by very hard, compact dark grey clayey silt and clay with medium to coarse sand and layers of wood pieces at different levels formed in the point bar of meandering Rushikulya River channel in a tidal flat environment. Poor sorting of sediments is due to distributed system and channelized systems. These alternating layers of sand and mud are a distinctive feature of tidally influenced meandering channels. All these features coupled with ardent smell of sulphur and carbonaceous material-rich sedimentation indicate a tidal mud flat environment with tide channels and tidal sand bars in front of the Rushikulya River. The submerged paleo-spit of the Rushikulya River marks the limit of the paleogegraphy associated with Rushikulya River.

6 illus, 16 ref

001186   Unnikrishnan E;Bhat K K;Dinesh A C (Geological Survey of India, Marine and Coastal Survey Div, , Mangla Devi Road, Pandeshwar, Mangalore-575 001, Email: unnik1@yahoo.com) : Tidal ridges and associated sandwaves off Valsad, Gulf of Cambay, Gujarat. Indian J Geosci 2015, 69(3-4), 223-32.

An area of 125 km off Valsad in the Gulf of Cambay was covered by swath bathymetry to identify major and minor flow-related bedforms and their temporal changes. Surface sediment samples were also collected from various domains during the survey to correlate with morphology. Three narrow and elongated, parallel underwater ridges pass through the area. The "Eastern Ridge" coined by earlier workers, having a relief of 30 m, passes through the western part of the area. The one on the eastern part is 15 m high and the other in the middle has a height of 6 m. The underwater ridges have divided the rest of the seabed into four flat channels for the tidal currents to flow up and down. Current-generated bedforms such as ripples, mega-ripples and sandwaves are noticed along the channel beds and flanks of ridges at places. A train of nine large and discrete sandwaves along a two-km-wide patch of seabed having crest lengths more than a km across the tide direction with heights <62>5 m are present at the centre of the channel, t%the east of the middle ridge. Smaller sandwaves that are 1-2 m high having a crest length of 300-500 m are present on the western flank of the eastern ridge. The long axes of most of them are at an angle to the axis of the middle ridge and the leeward side points to the south. The current direction is not uniform throughout the bay. During inflow, the water flows mainly through the shallower channels in the eastern side and during ebbing; it flows out through the deeper channels in the west. Megaripples and ripples are also identified over some of the sandwaves and ridges. The sediment distribution pattern and morphology of the area are closely related. Channel beds are made up mainly of mud or silt. The ridges are covered by light olive-brown, very well- to well-sorted sand. The sediments present over the sandwaves are essentially light yellowish brown sandy gravel. There is no lateral shift in the position of the ridges in comparison to the older profile. The gravelly material of the sandwaves appears to be river-borne but modified by the tidal currents into large sandwaves when the bay was much shallower and the tidal currents were fast and powerful enough to transport gravelly material.

11 illus, 8 ref

001185   Uddandam P;Rai J;Prasad V;Joshi H;Nigam R (NO, Birbal Sahni Institute of Palaeobotany, 53 Univ Road, Lucknow-226 007, Email: premrajuddandam@gmail.com) : Holocene calcareous nannoplanktons from western continental shelf of Bay of Bengal. Geophytology 2015, 45(2), 195-200.

Sixty-six surface sediment samples from the northern and western Bay of Bengal were analysed for the study of calcareous nannoplanktons. The samples were also studied for the nannoplankton assemblage composition with regional differences. The sediment samples from northern Bay of Bengal showed very low abundances of Emiliania huxleyi and Gephyrocapsa oceanica indicating very low productivity of nannoplanktons. The sediment samples from the western Bay of Bengal is composed of high species diversity with the dominance of Gephyrocapsa oceanica and sub dominance of Emiliania huxleyi indicating high productivity and the river discharge effect on the assemblage. The ratio between the Gephyrocapsa oceanica and Emiliania huxleyi can be used as a proxy to decipher the monsoonal fluctuations and associated runoff fluctuations.

1 illus, 1 table, 24 ref

001184   SubbaRao N;Moeen S;Surya Rao P;Dinakar A; Nageswara Rao P V;Sunitha B;Rudra D;Srinibvasu N (Geology Dep, Andhra Univ, Visakhapatnam, Email: srnandipati@gmail.com) : Morphometric appraoch using remote sensing and GIS in watershed management. J appl Geochem 2016, 18(1), 45-56.

Geomorphology (particularly the relief and slope/gradient), geomorphic processes (fluvial) and climate (rainfall) have exerted a dominant control over the development of drainage. In the present study area, the watershed has two micro-watersheds (microwatershed-1 and micro-watershed-II) of contrasting hydrological response. The development of drainage pattern is a result of geomorphological control (bifurcation ratio, Rb, A 3). As compared to the micro-watershed-I (third-order), the micro-watershed-II (fourth-order) has higher values for the total stream numbers ("Nu) and their lengths ("Lu), basin area (a), drainage density (D), stream frequency (F), infiltration number (Di), drainage texture (Dt), relief (H), relief ratio (Rr), relative relief ratio (Rrf) and ruggedness number (Rn). Basin perimeter (p) and basin length (l) are almost the same for both the micro-watersheds, while the length of the overland flow (Lg) is lower in the micro-watershed-II. Basin shape parameters, i.e., circulatory ratio (Rc), elongation ratio (Re) and form factor (Ff) indicate that both the micro-watersheds are elongated. An evaluation of various morphometric parameters ("Nu, "Lu, a, D, F, Di and Dt) indicates that the micro-watershed-II contains more surface water resources (higher values for "Nu, "Lu and a) and the micro-watershed-I has greater potential for sub-surface water resources (lower values for D, F, Di and Dt). It is suggested that plain areas of the watershed especially those of the micro-watershed-I are ideal for augmenting the sub-surface waters, while the areas occupied by first- and second-order streams particularly those of the micro-watershed-II are potential zones for augmenting the surface water resources. Further, the surplus runoff during the rainy season can be harnessed through the construction of check dam/percolation, which helps in groundwater augmentation.

4 illus, 3 tables, 45 ref

001183   Sharma M K (National Institute of Hydrology, , Roorkee-247 667) : Assessment of ground water quality of metropolitan city Vadodara, Gujarat using water quality index. J Indian Wat Resour Soc 2015, 35(2), 28-33.

Metropolitan city of Vadodara is itf largest town in India (population wise) and the third in the state of Gujarat. The city witnessed a sudden spurt in industrial activity with the establishment of Gujarat Refinery, Indian Oil Corporation. It is the industrial nucleas of the Gujarat State. Vadodara and its surrounding areas are today humming with industrial activity. The mixture of different kind of untreated/partially treated/treated industrial waste is being discharged through a number of drains passing in and the city. Further, the surface runoff caused by rainfall and spills from loading of oil tankers also contribute to the ground water contamination. In the present investigation, assessment of the ground water quality of different drinking water sources in and around metropolitan city of Vadodara has been carried out by using water ^quality index. The water quality data of ground water ofpre- and post-monsoon seasons of the year 2008 and 2009 has been used for the calculation of water quality Index. Fifteen parameters (TDS, HCO₃, Cl, SO₄, NO₃, F, Ca, Mg, Na, K, Fe, Mn, Ni Cr arid Cd) were used to calculate the water quality index and each of the 15 parameters (TDS, HCO₃, Cl, SO₄, NO₃, F, Ca, Mg, Na, K, Fe, Mn, Ni Cr and Cd) has been assigned a weight (w_i) according to its relative importance in the overall quality of water for drinking purposes. It ivas observed that quality was not observed to improve in about 50% of the locations after monsoon season during the year 2008 but during the year 2009, the quality of ground water was observed to improve in post-monsoon season in most of the samples. The groundwater ofLimda, Harni, Nandesari and Makarpura was found to be 'unsuitable for drinking purposes'.

3 tables, 11 ref

001182   Shareef N M;Mohan K G;Rao S;Vidya S; Jayaprakash C;Dinesh A C (Geological Survey of India, Marine and Coastal Survey Div, Block DK 6, Sector II, Salt Lake, Kolkata-700 091, Email: shareef_n123@rediffmail.com) : Granulometric studies and sediment characteristics of beach sediments between Yermal and Mukka, Dakshina Kannada district, Karnataka. Indian J Geosci 2015, 69(3-4), 309-22.

Granulometric, geochemical and grain morphological studies were carried out to understand the nature and characteristics of sediments between Yermal and Mukka. The study revealed the role of transporting media in shaping the grain morphology and in sediment sorting. The study also revealed the contribution of provenance to the composition of sediments. Heavy mineral concentration in the sediments is relatively negligible and the predominant mineral present is quartz. The chemical analysis of the sediments shows that silica content varies from 84.70% to 93.40% with an average of 89.90%. The samples collected from the stabilized dunes in the backshore areas have relatively higher amount of silica than the samples collected from berms. Higher concentration of silica near to the debouchment area of Mulki-Pavanje rivers and along the coastal stretch south of it is suggestive of its role as one of the major sources of silica sand deposited along the beaches. The relative enrichment of SiO₂ in the southern side is possibly indicative of a southerly drift of sediments due to littoral currents.

5 illus, 3 tables, 9 ref

001181   Schuiling R D (Faculty of Geoscience, Utrecht Univ, The Netherlands, Email: R.D. Schuiling@geo.uu.nl) : The earth: first in geoengineering. J appl Geochem 2016, 18(1), 1-2.

The Earth is saved from the fate of Venus by a process that has efficiently removed CO₂ from the atmosphere since its origin. The first step of this process is the weathering of silicates, which results in the formation of bicarbonate solutions. After these have been transported to the oceans, they are sustainably stored as carbonate rocks (limestones and dolomites), which contain around a million times more CO₂ than the atmosphere, the oceans and biomass combined. Later on this process was complemented by the formation and storage of organic carbon (as coal, oil, gas and carbon particles in sediments). On Venus none of these processes has operated, because Venus lacks liquid water, which is an essential requirement for weathering and for life. As a consequence all the CO₂ emitted by the volcanoes on Venus has stayed in the atmosphere, which now has a pressure of 75 bars CO₂ and a surface temperature of 465 degrees centigrade (Fraser, 2008), which makes that planet obviously unfit for life.

5 ref

001180   Saxena R K (NO, Birbal Sahni Institute of Palaeobotany, 53 Univ Road, Lucknow-226 007, Email: rksaxena2207@yahoo.com ) : Indian tertiary palynology: its growth and development. Geophytology 2015, 45(2), 107-20.

The Tertiary palynology made its beginning in India in 1941. An attempt has been made here to summarize the information generated so far on the Tertiary paiynology in various Indian sedimentary basins and to analyze its growth since its beginning. The first two decades (1941-1960) witnessed publication of only 14 papers, mainly devoted to description of palynofossils from Indian Tertiary sediments. The first attempt to utilize palynofossils in biostratigraphy of Early Tertiary sediments of north-east India was made in 1962. This paved the way for many more such studies in other areas in future. The analysis has been made of decade-wise publications and also decade-wise trend of growth in number of publications. It is noted that among the institutions, the Birbal Sahni Institute of Palaeobotany, Lucknow has been the major contributor followed by Oil and Natural Gas Corporation and others (including Osmania University, Wadia Institute of Himalayan Geology, Geological Survey of India and various other universities and institutions). Contributions made by these institutions were also analyzed. An effort has been made to analyze publications, subject-wise, e.g. palynostratigraphy, depositional environment, palaeoecology/ palaeogeography morphology/nomenclature, review/general papers, etc. Altogether, 517 papers have so far been published. Of these, maximum are from Assam-Meghalaya followed by Gujarat, Himachal Pradesh, Tamil Nadu, Kerala, Rajasthan, etc. Age-wise, maximum papers are published on Palaeocene-Eocene, followed by Miocene, Oligocene and Pliocene. Agood number of papers do not provide precise geologic age and are categorized as Palaeogene, Neogene and Tertiary. Interestingly, maximum papers on Tertiary palynology are published in The Palaeobotanist, followed by Geophytology, Current Science, Journal of the Palaeontological Society of India, etc. In spite of a large number of papers published so far on Indian Tertiary palynology, there are gaps to be filled. An effort has been made to identify such gaps and suggestions have been given for future studies.

17 illus, 144 ref

001179   Satyanarayana G V;Nandi B K;Rao P R;Pathan M S (Geological Survey of India, Marine and Coastal Survey Div, NH - 5, Marripalem, Visakhapatnam-530 018, Email: gvsatty@rediffmail.com) : Fluctuation of curie isothern depth around Barren island, Andaman sea. Indian J Geosci 2015, 69(3-4), 287-92.

Magnetic data have been used as a tool to extract information about the crustal structure below the Barren Island emphasizing the thermal history of the crust. From the known thermal history of this area including volcanic eruption in the recent past, perturbations in the geo-isotherms below this island are evident. Naturally, fluctuation of the geo-isotherms below this eruptive volcano will change the position of Curie isotherm depth. Magnetic survey has been repeated in the recent past at an interval of about one year along two north-south and two east-west traverses close to Barren Island in the Andaman Sea for monitoring volcanic activity since 1991. Thermal disturbances caused by accumulation of magma in the magma chamber of Barren volcano and its flow through feeder dyke are responsible for volcanic events and fluctuation of magnetic susceptibility of magnetic crust surrounding the major submerged part of this island. These eruptions/ volcanic activities change the thermal state of the magnetic crust which in turn chang<& the Curie isotherm depth - the depth below which magnetic rock loses its susceptibility due to temperature more than Curie point. The fluctuation of magnetic anomalies around the island observed during repeat survey has been translated into change in the Curie isotherm depth. It is found that the explosion of Barren volcano is related to Curie isotherm depth. When Barren volcano is dormant/ inactive the Curie isotherms attain a maximum depth. As accumulation of magma in the magma chamber continues, the Curie isotherm depth starts moving up till next explosion takes place.

3 illus, 7 ref

001178   Roychaudhuri S;Sengupta D;Biswas N R;Dutta S; Mashood P A (Geological Survey of India, , Central Head Quarters, PSS-P&M-2, 27, Jawaharlal Nehru Road, Kolkata-700 016, Email: subha191@gmail.com) : Heavy mineral potential in the inner shelf off Paluru, Odisha. Indian J Geosci 2015, 69(3-4), 177-92.

The seabed within the territorial waters off Odisha coast has been systematically studied for an assessment of placer mineral resources. The placer mineral assemblage comprises ilmenite, sillimanite, garnet, monazite, zircon, rutile - ilmenite being the most dominant. In the southern sector (Gopalpur-Chatrapur) these minerals generally occur in fine to medium sand on surface as well as in subsurface (proved down to 4 m below sea floor) sediments. The average heavy mineral (HM) incidence is 7.17 wt.% in surface sediments while the subsurface HM incidence drops from 5.73 wt.% to 4.31 wt.% from 1 m b.s.f to 4 m b.s.f. While in the northern sector (north of Chilka Lake) the placer minerals are located in finer sediments having silt input with HM occurrence in surface sediments as 3.90 wt % (average); the subsurface sediments host 3.30 wt.% (average) HM down to 4 m b. s. f. The most promising area, which could be of future economic interest except Gopalpur, lies in the offshore of Paluru Hill, immediate north of Rushikulya River Mouth.

11 illus, 1 table, 8 ref

001177   Prasadm J;Bhattacharya D K (Geology Dep, Ranchi Univ, Ranchi, Email: dkbprofru78@gmail.com) : New insights into chemistry of high MgO ultramafic cumulates (komatiites) and associated platinum group elements in parts of Chotanagpur gneissic terrain, Eastern India. J appl Geochem 2016, 18(1), 35-44.

Occurrence of high MgO containing ultramafic cumulates (Komatiites) are recorded near Semra village within metaultramafites and dolomitic marbles in close spatial association with amphibolites of tholeiitic composition in the NW fringe of Chotanagpur Gneissic Terrain (CGT). The two megascopically distinguishable varieties of komatiites are observed. The commonly occurring one is a cumulate and the other occasionally recorded one is a spinifex textured komatiite. These rocks contain olivine (at places altered to serpentine), pyroxenes, chromite, magnetite, spinel as their mineral component. Ore petrography study reveals the presence of pyrrhotite, pentlandite, chalcopyrite, pyrite, galena and sphalerite as sulphides and chromite, magnetite and chromespinel as oxides phases. The sulphide minerals host appreciable concentration of Platinum Group Elements (PGE). Major, trace and rare earth geochemistry suggest their Al depleted nature similar to the Barberton type komatiites. High Ti together with variable Al₂O₃/TiO₂ and (Gd/Yb)n <62>1 suggest garnet fractionation during partial melting and formation along the margin of a rising plume. Chemistry and concentration of PGE in the rock suggest a fertile magma and hence detail exploration for precious elements is suggested.

6 illus, 4 tables, 45 ref

001176   Odedede O;Ugbe F C (Geology Dep, Delta State Univ, Abraka, Delta State, Nigeria, Email: odededeo@yahoo.com) : Geochemistry of the gneissic rocks of the basement complex around KPATA, North Central Nigeria. J appl Geochem 2016, 18(1), 15-21.

The basement rocks around Kpata area of North Central Nigeria consist of gneiss and migmatite-gneiss intruded by the Pan-African granitoids. Foliation in the gneisses defined by parallel mineral banding and indicates evidence of deformation and migmatitic processes. Geochemical analysis shows that major oxides SiO₂ (68.42-71.88 wt %) Al₂O₃ (14-18 wt %) Fe₂O₃ (2.40-5.90 wt %) and K₂O ranges from 1.07-2.01 wt %. Linear plots of major oxides against SiO₂ exhibit both positive and negative linear trends. Petrogenetic plots of Na₂O+K₂O versus SiO₂ suggest an igneous origin.

16 illus, 17 ref

001175   Nandi B K;Rao P R (Geological Survey of India, Marine and Coastal Survey Div, , Block DK 6, Sector II, Salt Lake, Kolkata-700 091, Email: bkngeo@gmail.com) : Geophysical analysis of sediment deposited since late quaternary period in parts of Ganga prodelta area off Sagar Island, Bay of Bengal, India. Indian J Geosci 2015, 69(3-4), 253-60.

Shallow seismic reflection, magnetic, free-air satellite gravity and bathymetric surveys of the continental shelf, about 100 km off Sagar Island have been conducted to find out the seafloor configuration, variation of sediment thickness (belonging to Late Quaternary period) and subsidence/upliftment history of the sedimentary basin in parts of Ganga prodelta. Bathymetry shows a smooth seafloor gradually dipping in the southeast within water depths of 31-100 m. The pattern of seismic signature and its amplitude variation has brought to light two or three different sedimentary facies, identified by different sub-seabed reflectors, within the limit of penetration of seismic energy. Variable rate of sedimentation in this tidal zone between Ganga-Brahmaputra system of rivers has been found to be a reality from seismic data besides identifying an omnipresent marker reflector (at a depth of 108-123 m from the sea level) that may be contemporary to the last glacial maxima (LGM). Analyses of magnetic and free-air gravity data indicate the depth of the magnetic basement below the total sediment column and probable upliftment of the basin floor associated with intrusion of high-density lithospheric/ asthenospheric material resulting in crustal thinning, either before or contemporaneous with the initial stage of sedimentation.

8 illus, 9 ref

001174   Manglik A;Mandal P (NO, CSIR-National Geophysical Research Institute, Uppal Road, Hyderabad-500 007, Email: ajay@ngri.res.in) : Singhbhum craton. Curr Sci 2016, 110(7), 1144-5.

8 ref

001173   Mandaokar B D (Birbal Sahni Institute of Palaeobotany, 53 Univ Road, Lucknow-226 007, Email: bdmandokar@yahoo.com ) : Palynostratigraphy and palaeoecological interpretation of Early Miocene sediments of Amarpur, Tripura, India. Geophytology 2015, 45(2), 153-60.

A rich and diversified palynofloral assemblage, comprising 97 genera and 124 species, has been recorded from the Middle Bhuban Formation of Amarpur, Tripura. The palynoassemblage is represented by dinoflagellate cysts (11 genera, 10 species), fungal remains (14 genera, 14 species), pteridophytic spores (16 genera, 32 species), gymnospermous pollen (4 genera, 9 species), angiospermous pollen (37 genera, 44 species) and reworked Permian and Cretaceous palynofossils (15 genera, 15 species). On the basis of frequency and distribution of palynofossils, three cenozones have been recognized. These are (in ascending order): Pteridacidites vermiverrucatus Cenozone, Malvaceammpollis bakonyensis Cenozone andAtbertipollenites crassireticulatus Cenozone. The assemblage clearly indicates a tropical to subtropical, warm humid climate with high rainfall and sedimentation in a delta distributary channel with marine influence. The terrestrial elements of upland as well as lowland flora tend to merge with fresh water constituents. Dominant pollen genera of the assemblage (Spinizonocolpites, Monocolpopollenites and Malvaceammpollis) suggest brackish water mangrove swamp along the coastal line. Stratigraphically significant taxa, viz. Clavaperiporites jacobii, Proteacidites triangulus, Spinizonocolpites echinatus, Pteridacidites vermiverrucatus, Retitrescolpites typicus, Malvacearumpollis bakonyensis and Albertipollenites crassireticulatus, suggest an Early Miocene (Aquitanian-Burdigalian) age.

3 illus, 2 tables, 6 ref

001172   Kar Y C;Satyanarayana G V;Nandi B K;Pathan M S (Geological Survey of India, Marine and Coastal Survey Div, Mangla Devi Road, Pandeshwar, Mangalore-575 001, Email: bkngeo@gmail.com) : Depositional environment and structural features inferred from geophysical surveys of Pentakota, Andhra Pradesh coast, Bay of Bengal. Indian J Geosci 2015, 69(3-4), 273-86.

High-resolution single-channel shallow seismic, magnetic and bathymetric surveys off Pentakota, Andhra Pradesh coast, Bay of Bengal reveal morphology of the continental shelf and structural breaks underneath thick sedimentary column. The deposition and disposition of sediment sequences within the sediment column have been identified from the acoustic impedance contrast. Sequence analysis reveals one transgressive and two high-stand system track defining maximum flooding surface. Changes in the gradient of the continental shelf have been evidenced in four occasions from bathymetry and seismic data. A surface fault parallel to the coastline at 100 m water depth has been observed and its relation with the movement of the basement blocks has been studied. Analysis of magnetic data suggests that the magnetic basement is piecewise continuous, running parallel to the coast, devoid of any major intrusive and covered by blanket of sediment having thickness of 1 to 5 km. 2D modelling of magnetic anomaly profile along with free-air satellite gravity data using GM-SYS module of Geosoft software reveals thinning of crust near to the coast at around 25 m water depth.

8 illus, 13 ref

001171   Kar Y C;Banerjee D;Pathan M S;Meetei L I (Geological Survey of India, Marine and Coastal Survey Div, , Mangla Devi Road, Pandeshwar, Mangalore-575 001, Email: yckar320@gmail.com ) : Seabed morphology and sub-seabed structure inferred from geophysical survey within territorial water off north Andhra Pradesh coast, Bay of Bengal. Indian J Geosci 2015, 69(3-4), 261-72.

Geophysical investigation comprising shallow seismic, magnetic and bathymetric surveys was taken up to study the subsurface features of the continental shelf off north Andhra Pradesh coast, within territorial waters off Kalingapatnam and Bhimunipatnam, during cruise ST-215 in April 2011. The general bathymetry of this area is a smooth, gently sloping seafloor. The shallow seismic reflection survey delineates three sub-bottom reflectors sub-parallel to the seafloor and two reflectors having an angular relation to the overlying strata showing on-lap features. An unconsolidated sediment layer is deposited over the topmost major reflector producing lensoid depositional lobes. Two sets of depositional sequences with widely differing depositional styles could be identified from shallow seismic records of the area. The first sequence set comprising two lower para-sequences shows oblique clinoforms that truncate at the overlying strata forming top-lap structures. The other sequence deposited over the previous one consists of two para-sequences with a dominant depositional pattern of seaward down-stepping sigmoidal clinoforms. They reveal progradational and aggradational components of shelf sediments with continuous displacement of off-lap breaks towards sea due to glacio-eustatic sea level changes. The total field magnetic anomaly map shows alternate high and low magnetic, signatures varying from -619 to 539 nT. The near-coast magnetic response is predominantly of short wavelength due to high-grade khondalite-charnockite basement at shallow depths underlying the sedimentary strata with relict carbonates coupled with the effects of red sand dunes near Bhimunipatnam containing heavy mineral placer concentration. The low magnetic domains are the downthrown graben structures formed by the subsided basement which is subsequently filled up by sediments giving an alternate ridge-depression terrain morphology. High-gradient contours demarcating two sets of lineaments separate the ridge and basinal units in the magnetic anomaly map.

8 illus, 6 ref

001170   Kalaivanan K;Gurugnanam B;Suresh M;Arunkumar M (NO, , Central for Applied Geology, Gandhigram Rural Instiute - Deemed Univ, Email: kalai.geo87@gmail.com) : Drainage morphometric analysis of Kadavanar river basin using GIS techniques, Dindigul, district, Tamil Nadu, India. J appl Geochem 2016, 18(1), 69-75.

Geographical Information System (GIS) technique is an effective tool to determine the morphometric characteristics. The study was carried out to analyze the morphometric characteristics of Kadavanar River basin using geo-processing techniques. This technique is found relevant for the extraction of river basin and its drainage networks. The extracted drainage network was categorized according to Strahler's classification, and it reveals that the terrain exhibits dendritic to the sub-dendritic drainage pattern. The Kadavanar drainage basin is sprawled over an area of 2254.65 km2. The study area was designated as seventh-order basin and lower order streams mostly dominate the basin with the drainage density value varies between1. 37 and 1.92. The elongation ratio of the basin is 0.82 indicating that the study area is elongated with very low relief and steep slopes. The drainage texture of the basin is 7.02 and 14.26 falls under fine drainage texture. Hence, from the study, it can be concluded that remote sensing data coupled with geo-processing techniques prove to be a competent tool in a morphometric analysis, and the data can be used for basin management and other hydrological studies in thefuture.

3 illus, 3 tables, 25 ref

001169   Hukam Singh (Birbal Sahni Institute of Palaeobotany, 53 Univ Road, Lucknow-226 007, Email: hukams@gmail.com) : Palynofloral investigation of Akli formation (Palaeocene) of Giral Lignite Mine, Barmer district, Rajasthan, India. Geophytology 2015, 45(2), 209-14.

Palynological analysis of lignite and associated sediments, including fragmentary amberpieces, from a sediment profile recently exposed at northern part of Giral Lignite Mine yielded palynoassemblage of pollen, spores and fungal remains. The dominant elements are angiospermous pollen belonging to the families Arecaceae, Annonaceae, Onagraceae Ctenolophonaceae and Bombacaceae, followed by pteridophytic spores having close affinity with Dicksoniaceae, Schizaeaceae, Pteridaceae, Matoniaceae and Lycopodiaceae. Based on palynofossils, it can be inferred that the area supported dense tropical evergreen to semi-evergreen low land forest. Pteridophytic spores show sub-aquatic to swampy conditions and fungal remains indicate prevalence of warm-humid climate. Presence of a good amount of Arecaceae pollen and a few dinoflagellate cysts also suggests that site was close to coast.

2 illus, 2 tables, 15 ref

001168   Hegde S V (Geological Survey of India, Marine and Coastal Survey Div, Mangla Devi Road, Pandeshwar, Mangalore-575 001, Email: shrikantmardi@yahoo.co.in) : Offshore sand resource estimation using 3D rasters. Indian J Geosci 2015, 69(3-4), 331-8.

Resource estimation is an integral part of any mineral investigation. Different methods and software packages are available for resource estimation. Most of them compute resources using vectors or two-dimensional rasters and therefore, variations in the third dimension (depth) are not properly accounted for. All three dimensions, viz. X, Y and Z, of an ore body can be better represented by a 3D raster model which has to be created by interpolation of data collected from field. GRASS G1S, which is a leading open-source geographic information system, is well equipped with modules to create and manipulate 3D rasters. This paper deals with 3D interpolation of offshore sand investigation data and estimation of volume.

5 illus, 4 tables, 14 ref

001167   Gupta P;Sharma A;Joshi N (Environmental Sciences Dep, Kanya Gurukul Mahavidyalaya, Gurukula Kangri Vishwavidyalaya, Haridwar) : Groundwater quality assessment for irrigation suitability in salinity affected coastal river basin of Gujarat. J Indian Wat Resour Soc 2015, 35(2), 20-7.

The groundwater system along the coast of Saurashtra is affected by high salinity. In the Minsar river basin, the groundwater salinity varies from very high near the sea coast to medium and low salinity values in the upland areas. Chemical analyses of voter samples in the region show that calcium and magnesium are the dominant cations present in groundwater next to sodium. Similarly, bicarbonate anlon is also present in considerable amounts next to chloride. To assess the suitability of groundwater for irrigation purposes, a total of 71 groundwater samples, collected from zones at varying distances from the sea coast, were analyzed for computing water quality indicators v/r., salinity, sodium absorption ratio (SAR), percent sodium (%Na), residual sodium carbonate (RSC), magnesium hazard (MH), permeability index (PI) and boron concentrations. US Salini/rLaboratory based classification was also carried out. Results reveal that quality of groundwater for irrigation is more suitable at distatices gnerally beyond 12 km from the sea coast. Proper-soil management and selection of crops with good salt tolerance are recommended in the rkgion.

3 illus, 3 tables, 18 ref

001166   Ganai J A;Rashid S A;Masroor Alam M (Geology Dep, Aligarh Muslim Univ, Aligarh, Email: jganai.ganai9@gmail.com) : Petrography and geochemical studies of upper paleozoic sandstones from the Tethys Himalaya, Spiti valley, Himachal Pradesh. J appl Geochem 2016, 18(1), 3-14.

Sandstones from the shale-sandstone association of Permo-Carboniferous sequence of the Kanawar Group of Spiti region are takenup for detailed petrographic and geochemical investigation. Compositionally, they are quartz-arenite, sub-litharenite and subarkose. Their chemical index of alteration (CIA) values range from 53 to 78 i.e., indicating low to intense chemical weathering. The point counts shows the presence of quartz as a dominant framework mineral with varying amounts of rock fragments (mainly chert, phyllite, gneissic components) and feldspars andindicate cratonic interior and recycled orogenon the Qt (quartz)-F (feldspar)-L (lithic fragments) triangular diagram, suggesting their derivation mostly from stable cratons. The integrated petrographic and geochemical studies suggest that sandstones from the Tethys Himalaya, Spiti region, are derived probably from a felsic (granitic) dominant source occurring to the south of the basin.

8 illus, 2 tables, 44 ref