024754   Maurya D M;Rachna Raj;Chamyal L S (Department of Geology, M S University of Baroda, Vadodara-390 002) : History of tectonic evolution of Gujarat alluvial plains, western India during quaternary: a review. J Geol Soc India 2000, 55(4), 343-66.

The lineaments recognised in the Gujarat alluvial plains correspond to major structural and basement fault trends. The geomorphic and drainage anomallies in the plains are in conformity with the subsurface structural features. The variable thickness of the Quaternary sediment cover suggests sedimentation in fault-bounded sub-basins within a larger basin. The exposed sediment column of 40-50 m dates back to <126>125 ka. The Quaternary evolutionary history of the Gujarat alluvial plains has been divided into three stages marked by distinct tectonic changes. Four phases of tectonic activity during the Quaternary have played a significant role in the evolution of these plains. The first two are associated with the deposition of a large volume of sediments. The last two comprise tectonic uplifts which have shaped the present landscape of Gujarat alluvial plains. Extensive ravines, valley fill terraces, asymmetric drainage, deeply incised fluvial valleys and entrenched meanders are manifestations of tectonic uplift during the Holocene. The seismic record of the last few hundred years suggests continued tectonic instability of the area in and around Gujarat alluvial plains.

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024753   Mahendra Kumar K;Roy M;Behra G;Parihar P S; Singh J (Atomic Minerals Directorate for Exploration and Research, , Shillong-793 011) : Rare metal and rare earth mineralisation hosted in pegmatitic injections within magnetite-bearing granitoid at Jaurahi, Sonbhadra district, U.P. J Geol Soc India 2000, 55(4), 439-42.

Pegmatitic injections within magnetite-bearing granitoid host rare metal and rare earth mineralisation at Jaurahi, Sonbhadra district, Uttar Pradesh. The ore minerals identified are columbite, eschynite, samarskite, fergusonite, monazite, thorite, uranothorite and zircon in association with magnetite, ilmenite and rutile. Samples of minerlised pegmatite have analysed 0.65 to 4.42% Nb and 0.55 to 4.85% Y.

024752   Jeganathan C;Chauniyal D D (Geoinformation Division, Indian Institute of Remote Sensing, Dehradun-248 001) : Evidential weighted approach for landslide hazard zonation from geo-environmental characterization : a case study of Kelani area. Curr Sci 2000, 79(2), 238-43.

Interaction between various components of the geocomplex on the solid crust of the earth has always been of keen interest. Attempted to understand and characterize the geo-environmental parameters over the Kelani area in Bino basin, located in the fringe of Garhwal and Kumaun Himalaya. Twelve geo-environmental parameters are considered for the landslide hazard zonation. Inclusion of such diverse parameters into the model possibly would have the bias of the observer. Using remote sensing data and Geographical Information System (GIS), have attempted an evidential weighted approach, to delineate the spatial distribution of the landslide hazard zones, which is site-specific and bias free.

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024751   Hari Prasad B;Okudaaira T;Hayasaka Y;Yoshida M;Sivi R S (Department of Geosciences, Osaka City University, Osaka-558 8585, Japan) : Petrology and geochemistry of amphibolites from the Nellore-Khammam schist belt, SE India. J Geol Soc India 2000, 56(1), 67-78.

Amphibolites from the Nellore-Khammam schist belt, Khammam district, Andhra Pradesh were metamorphosed at 700±50°C, 1.1±0.1 GPa. Bulk-rock chemical characteristics for relatively immobile element ratios (e.g. Zr-Y-Ti) of the amphibolites suggest two different tectonic settings: oceanic island arc and continental margin island arc affinities. Coexistence of rocks for two different tectonic settings in the schist belt can be explained by accretion at trench as protoliths of the high-pressure metamorphic amphibolites. Because the Nellore-Khammam schist belt is located between two terrains, such as Dharwar Craton and Eastern Ghats Granulite Terrain, their mode of occurrence implicitly suggests that formation of the Nellore-Khammam shist belt may have formed at least in two steps: (1) accretion of the rocks originatng from different tectonic settings at trench and (2) subsequent high-pressure metamorphism and exhumation of the rocks caused by collision tectonics.

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024750   Deshmukhe G;Ramamoorthy K;Sen Gupta R (NO, Gujarat Ecological Society, 5 Golden Apartment, Subhanpura, Vadodara-390 023) : On the coral reefs of the Gulf of Kachchh. Curr Sci 2000, 79(2), 160-2.

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024749   Chitrao A M;Asthana M (Krishna Godavari Project, Geology Section, ONGC, , Rajahmudry-533 103) : Cretaceous valley fill sandstone of Nandigama Area, Krishna-Godavari Basin, Andhra Pradesh. J Geol Soc India 2000, 56(1), 27-38.

Cretaceous hydrocarbon reserviors have been recently found in West Godavari sub-basin of the Krishna-Godavari basin. Nandigaama area in the sub-basin has encountered gas-bearing sandstone reservoir and to exaplore the possibility of hydrocarbon potentialof the Nandigama area. Study has shown that the gas-bearing sandstone straddles the unconformity on top of HGS unit of Raghavapuram Shale and represents the estuarine valley fill sandstone deposited in Lowstand System Tract (LST). The sandstone reservoirs developed in LST constitute the primary exploratory targets for hydrocarbons in Nandigama aarea, whereas the sandstone reservoirs deposited in Transgressive System Tract (TST) may come up as an additional exploratory target.

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024748   Chaudhury S K;Gore J M;Sinha Ray K C (India Meteorological Department, , Shivajinagar, Pune-411 005) : Impact of heat waves over India. Curr Sci 2000, 79(2), 153-5.

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024747   Boruah P K;Dutta S K (Applied Gaeology Department, Dibrugarh University, Dibrugarh-786 004) : Framework mineralogy and texture of the upper palaeocene sandstones from Laitrengew-Cherrapunji area of east Khasi hills, Meghalaya. J Geol Soc India 2000, 56(1), 53-65.

Laitrengew-Cherrapunji area of East Khasi Hills, Meghalaya exposes a complete Palaeochene sequence of sedimentary rocks. The coal-bearing sandstone around Laitrengew-Cherrapunji area is regarded as Lakadong Sandstone Member of the Sylhet Formation. The Lakadong sandstones are quartz dominated, fine to medium grained, well to very welly to very well sorted, and have not been subjected to significant alteration. The intensive solution effect lowers the packing index values for the underlying Therria Formation around Laitrengew. The quartz arenite type of Therria and Lakadong sandstones is indicative of intense paleoweathering processes under humid climate and low relief. The sediments were derived from the exposed shield areas of plutonic roks and low to medium grade metasedimentary rocks. The structural, textural as well as compositional attributes of the Therria and Lakadong sandstones indicate that sediments were deposited in a slowly subsiding, stable depositional area in which the sediments were subjected to higher hydraulic energy winnowing processes. During the period, the paleioclimate was humid and tropical. The intermittent subaerial exposure of the depositional surface and development of shallow swampy lagoons in the coastal environment was supported by the palyontological evidences such as trace fossils and pollengrains of Arecaceae family.

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024746   Biswal T K;Jena S K;Datta S;Das R;Khan K (Department of Earth Sciences, Indian Institute of Technology, Powai, Mumbai-400 076) : Deformation of terrane boundary shear zone (Lakhna shear zone) between eastern ghats mobile belt and bastar craton in Balangir and Kalahandi districts, Orissa. J Geol Soc India 2000, 55(4), 367-80.

The terrane boundary between Eastern Ghats Mobile Belt and the Bastar Craton in Balangir and Kalahandi Districts of Orissa is distinctly marked by nearly two kilometer wide southeasterly dipping ductile shear zone, designated as the Lakhna shear zone. The shear zone has largely developed in the craton, but for a narrow width within the Eastern Ghats. It is dominated by quartzofeldspathic mylonites characterised by S-C fabric, asymmetric winged porphyroclasts, quartz ribbons and intragranular faults. These structures have been effectively utilized in deducing the sense of shear and evaluating the amount of strain. The results show thrusting of the Eastern Ghats over the Bastar Craton. The minimum amount of throw along the thrust has been estimated to be around 2.5 to 4.7 km assumping a dominant simple shear deformation.

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023658   Verma N;Pathak V;Yadav D C;Pathak P (Department of Chemistry, Narain P.G. College, Shikohabad-205 135) : Quality of ground waters of some villages at Shikohabad, district Firozabad (India). Asian J Chem 2000, 12(2), 458-62.

Describes the results of a survey of the physico-chemical characteristics of groundwaters of eight villages at Shikohabad, District Firozabad, U.P. over a period of one year. It can be concluded from this study that the pollutants in water of hand pumps are comparatively higher than the dugwells. Concentrations of chlorides, fluorides are within the limits as prescribed by EHO. On the other hand, nitrate-nitrogen, alkalinity and hardness are much higher. Entry of pollutants to the ground water is quite complex and several processes affect its movement.

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023657   Singh G (NO, Geological Survey of India, Chandigarh) : Quaternary geology and geomorphology of Bathinda and Sangrur districts, Punjab. Gondwana Geol Mag 1999, 14(1), 57-68.

Bathinda and Sangrur districts of the southern Punjab adjoining parts of sandy terrains of Haryana and Rajasthan, are covered with thick Quaternary sediments of alluvial and aeolian origin. The investigation in Punjab has a major constraint as a very negligible part of quaternary sequence is exposed and its base is not exposed any where. On the basis of regional disposition and available drilling data from CGWB and other sources, thickness of the Quaternary sediments in this area has been estimated to be about 350m. Seven major phases of fluvial action designated as F1 to F7 with intervening six arid phases A1 to A6 have been identified. These sediments were deposited in shallow basins in low energy condition comprising water, lacustrine and dry aeolian phases. The palaeoclimate flucturated from semi arid to tropical where rainy seasons were intervened by long dry spells.

023656   Sekar B;Bera S K (NO, Birbal Sahni Institute of Palaeobotany, University Road, Lucknow-226 007) : Reconstruction of past climatic changes around Berijam lake, Paini Hills for the last 17.7 kyr BP based on chemical analysis and <. Gondwana Geol Mag 1999, 14(1), 51-5.

The climatic changes around Berijam lake, Paini Hills, Tamil Nadu, have been inferred on the basis of elementals content variations in a 2.9 m deep clay and mud sediment profile covering a time span of 17.7 kyr BP in the past. Radiocabon measurements have been carried out on two samples of the above sediment profile namely at 1.0 m (11.1 kyr BP (BS-1225) and at 2.5m (16.2 kyr BP (BS-858). Thirteen zones have been identified for the interpretation of chemical data in terms of climatic changes. The results show that climate was generally warm and humid during 16.9 to 16.2 kyr BP, 15.6 to 14.5 kyr BP, 13.5 to 12.8 kyr BP, 11.8 to 11.1 kyr BP, 8.9 to 5.5 kyr BP and 4.4 to 3.3 kyr BP; and cool and humid during intervening periods. The interpretations on the basis of chemical data is based in broad in aggreement with the palaeoenvironment interpretation of polien data of the above sediment profile.

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023655   Ramesh N R;Rajagopalan G (Geological Survey of India, , Bangalore-560 078) : Late quaternary sediments of north-eastern India. Gondwana Geol Mag 1999, 14(1), 13-35.

Quaternary sediments of north-eastern India constitute nearly one-third of the entire spread of the continental quaternaries of the India sub-continent. A synthesis is made here of the available data, generated through systematic mapping programmes of GSI, NER, during the last two decades; extensive surveys, section measurements and sampling by one of us (NRR), as also archaeological evidences, radiometric dating and palynology. Except for some sporadic references, a well connected account is lacking on the Late Quaternary deposits of this neotectonically active region. The data revealed that the surficial deposits are formed under various depositional environments namely, fluvial- occupying the Brahmapurta valley, intermontane valleys of Tripura, piedmont deposits flanking the Arunachal Siwaliks, narrow valleys of Bomdila and Jayarampur; the glacial and glacio-fluvial-lacustrine deposits in Ziro Valley, Arunachal Pradesh and lacustrine deposits of Loktak Lake, Manipur and Yazali Valley, Arunachal Pradesh.

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023654   Mathew G;Karanth R V;Joshi M S (Department of Geology, M.S. University of Baroda, Vadodara-390 002) : Surface structures on prism faces of natural beryl crystals. Indian Miner 1998, 32(2), 61-4.

Observations on about 150 prism faces of natural beryl crystals from Badmal province, Orissa are reported. These faces were examined under a optical microscope. Striations, and growth hillocks (rectangular, rhombus-shaped, elliptical and hexagonal), spiral growth are illustrated. Natural etch pits are reported. Alignment of each pits along slip lines is explained. Guest microcrystals and intergrowth patterns are described. From these observations it is indicated that the crystals have grown by two-dimensional nucleation and spiral growth mechanism. This is the first systematic study of surface structures on prism faces of natural Indian beryl crystals.

023653   Mallik T K;Bhattacharjee D (NO, , Marine Wing, East Coast Operation-I, GSI, 9 and 10/1, Raja S.C. Mullick Road, Calcutta-700 032) : Evidence of quaternary sealevel changes along selected areas of the eastern and western coast of India. Gondwana Geol Mag 1999, 14(1), 1-12.

The Quaternary period is characterised by several glacial and interglacial episodes resulting in marine regression and transgression. The signatures of the rise and fall of sea level can be encountered in several sectors of the coastal tract and offshore areas, the evidences of which can be interpreted from lithological, geomorphological bathymetric, satellite imagery records, seismic records or from palaeontological studies. The occurrence of relict sand patches, oolite beds in the offshore indicate sealvele fluctuations. Holocene sealevel manifestation and related marine processes can be traced from various geomorphic features which are well marked by prominent beach ridges of Andhra Coast and dune ridges of Maharashtra Coast. Cliffs, raised platforms and terraces in this region indicate relative higher sealevel. Bathymetric studies off Lakshadweep coral reef indicate prominent terraces at different depths related to glacio-eustatic oscillations. Satellite imagery records of western Coast of Kerala indicate different beach ridge orientation and activity of rivers showing widening and formation of deltas at a place presently situated away from the coast that indicate shore line changes due to sealevel fluctuation.

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023652   Kumar S N;Prasannakumar V;Nair P K R (Dept. of Geology, University College, Trivandrum-695 034) : Molybdenite-fluorite association in Kalpatta granite, south India. Indian Miner 1998, 32(2), 1-6.

Kalpatta granite is a late Proterozoic post-kinematic multi-phase intrusive in the Precambrian crystalline rocks of North Kerala. Three generations of pegmatite traverse the granite. Molybdenite-fluorite-sulphide association is reported from the youngest pegmatite phase. Recognition of similar granites will help in the exploration for molybdenum in several granite plutons reported from the Precambrian terrains of South India.

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023651   Kale M G;Soman G R (Department of Gaeology, University of Pune, Pune-411 007) : Petrography of calcertes from quaternary sediments of Central Narmada Valley around Jabalpur, Madhya Pradesh. Gondwana Geol Mag 1999, 14(1), 69-83.

In the Central Narmada Valley around Jabalpur the Quaternary sediments belonging to Narsinghpur Formation (Middle to Late Pleistocene) and Devakachar Formation (Late Pleistocene) are exposed. The Narsinghpur Formation is represented mainly by red coloured siltstones representing floodplain deposits formed under oxidising conditions. The Devakachar formation is represented by cyclic fining upward sequences of laterally accreted conglomerates-sandstones representing channel lag and point bar deposits and siltstones with thin intercalations of fine dandy layers representing floodplain deposits and crevasse-splay deposits formed in meandering stream. In the sediments belonging to Devakachar formation, profuse development of isolated calcium carbonate concretions in the coarser clastics, passing upward into more continuous bedded buckled calcrete layers, and occasional development of rhizoliths horizon consisting of irregular tube-like bodies of calcium carbonate are noticed. Thin section study shows the development of equant calcite rhombs coarsening towards pore centre, evenly distributed dense crystalline mosaic of clear blocky calcite and development of isopachous layers of bladed blocky calcite crystals around framework grains indicative of meteoric phreatic diagenesis.

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023650   Jowhar T N (NO, Wadia Institute of Himalayan Geology, 33 General Mahadeo Singh Road Dehra Dun-248 001) : Refinement of the alkali feldspar - muscovite geothermometer and its application to the Badrinath crystalline complex, Himalaya, India. Indian Miner 1998, 32(2), 7-20.

A discussion on the derivation of Thompson (1974) alkali feldspar - muscovite geothermometer is presented and refinement of this geothermometer is made employing available thermodynamic data. An application of this geothermometer was carried out on three rock units of the Badrinath Crystaline Complex, viz., feldspar gneiss, Badrinath granite and associated pegmatites. The published geological and radiometric data indicates that the country rock (feldspar gneiss), a Precambrian unit was intruded by the Badrinath granite around 20 Ma ago. Temperature estimates, however, are in the neighbourhood of 500°C for the country rock as well as the intrusive. These temperature values are significantly lower than the melt-crystal equilibration for a muscovite granite. It implies that there was a post-granie emplacement thermal event during which temperature got stablized to a lower value causing equilibration of K-Na exchange between muscovite and alkali feldspar.

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023649   Joseph Solomon A;Nagendra R (Department of Earth Sciences, IIT, Bombay) : Sedimentological studies of Maniyara fort formation, Babia, north west Kutch. Indian Miner 0000, 32(2), 21-6.

Oligocende limestones of Babia in north western Kutch have been investigated for their petrographic character and depositional environment. Petrologically, the limestones of Maniyara Fort Formation are referred to Forminiferal Wackstone, Sandy Foraminiferal Wackstone, Nummuitic Packstone and Dolomite. Different types of porosity like inter-particle, intraparticle, vuggy and moldic are observed in these rock types. Recrystallization of micrite to sparry calcite is the most common diagenetic change in them. The clacisic content in these limestones are largely silty and clayey in nature. The environment of deposition was shallow marine with low to moderate energy condition.

023648   Francis Anto K (Ground Water Department, Civil Station, , Calicut-673 020) : Fluid inclusion studies granulites from Kambam valley, Tamil Nadu, South India, in relation to their metamorphic evolution. Indian Miner 1998, 32(2), 27-42.

Kambam Valley represents a deep crustal break in the NE part of the Southern Granulite Terrain (Madurai and Trivandrum blocks), South India. The valley extends for more than 150 km with a general NNE-NE trend and cuts across the eastern Kodaikanal ranges. The dominant rock types are chamockite and mafic granulites interbanded with metapelite and calc-silicate lithologies. Numerous granites, syenites and a carbonatite body intrude the above lithologies. The dominant fluid species in the above metamorphic lithologies is CO₂. Calc-silicate lithologies have, in addition aqueous-saline inclusions. Highest density of 1.106 gcm^-3, is recorded from primary CO₂ inclusions in orthopyroxene bearing quartz veins, seen amidst charnockite. The above density is the highest so far reported from the SGT and is concordant with peak pressures of <62> 9 kbar deduced from mafic granulite assemblage, using mineral barometry. The peak density and pressure are akin to those recorded from the northern slopes of Nilgiris. Slightly lower densities of 1.054-1.058 gcm^-3 are given by CO₂ inclusions in garnet, and quartz inclusions in garnet from chamockites. Secondary trails in calc-silicate lithologies are dominated by CO2 inclusions which is consistent with late garnet forming decarbonation reactions and resulting internal CO₂ buffering. Consonant late stage increase in XCO₂ is evident from the incomplete replacement of wollastonite by calcite-quartz mosaic. A late near isobaric cooling path, subsequent to decompressional uplift, is infered from the above observations.

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023647   Deota B;Desai N (Department of Geology, M.S. University of Baroda, Baroda-390 002) : Quaternary landscape of south Gujarat : an implication for modern landuse. Gondwana Geol Mag 1999, 14(1), 37-49.

Quaternary landscape of south Gujarat is characterised by three major geomorphic units, viz. coastal zone, alluvial plains and trappean highlands. Each of these are made up of unique combination of slope, elevation, soil and water resource, that affects the landuse pattern. These parameters have been utilized for evaluating capability rating of quaternary landscape of south Gujarat for landuses, like residential, industrial, agricultural and forest. The results indicate that Coastal zone should be kept open for its scenic beauty. However, it could be used for tourism and partly for wetland fisheries. Alluvial plains should mainly be utilised for agricultural purpose. Parts of trappean highlands should be used for residential and industrial development, while moderately and highly dissected terrain should by utilised for forest development. Escarpments should be kept open for its scenic beauty.

023646   Chakraborty P B (Regional Research Station, Coastal Saline Zone, BCKV, Kakdwip-743 347) : Water resource of sundarban delta - problems and potentialities. Envir Ecol 2000, 18(1), 171-6.

Water is the most vulnerable resource for the survival of mankind. Sundarban delta suffers from several agro-climatic limitations in utilizing its bountiful surface and subsurface water resources. Rainfall is, therefore, the only available and utilizable water resource that needs efficient planning and management. Rainfall yields a good amount of run-off which can be re-cycled through harvesting in well designed and maintained ponds and other structures for sustainable production. Cultivation of aquacrops in these structures and also in low land situations is most viable practice. Effective utilization of rain water depends on choice of crops and cropping system. Further, moisture retained in profile of the harvested paddy field can be exploited for successful crop production adopting conservation farming system. Hence, effective planning and efficient management of these resources can change the socio-economic scenario of Sundarban through increasing per unit production.

023644   Antony J P;Philip R;Praveenkumar V R (Department of Geology, University of Kerala, Kariavattom Thiruvananthapuram, Kerala-629 581) : Geology and preliminary fluid inclusion studies of Bababudan schist belt, Karnataka craton, India. Indian Miner 1998, 32(2), 43-54.

Compiled stratigraphy is proposed for Kalasapura and Sakrtepatna areas (late Arachaean Bababudan Schist Belt:BSB) by integrating geologic setting and available age data. The limited radiometric analyses for U and T (also U/Th ratio) from Karthikere-Kalasapura based conglomerates may help in future uranium exploration targets. At Kalasapura, lower Bababudan sequence (metavolcanics and quartzites) overlies basement rocks whereas upper Bababudan Sequence (metavolcanics intercalated with chlorite shists and quartzites) is well preserved at Sakrepatna. The primary igneous and sedimentary features are conspicuously noted in these two areas. The grade of metamorphism increases from core (greenschist facies at Sakrepatna) to periphery of BSB (amphibolite facies at Kalasapura). A preliminary attempt has also been made to estimate the pressure of entrapment of the quartz pod within the chlorite schist from Sakrepatna area using fluid inclusion data. The samples of study contain low to moderate CO₂ density fluids (0.80 to 0.85 g/cc). The metamorphic fluids in the study area indicate probable mixtures of carbonic and aqueous brine. 2.5 to 3 Kb pressue has obtained from CO₂ barometry, assuming a temperature range of 400-500°C for the greenschist facies rocks for the Sakrepatna area.

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022515   Singh R K (NO, ICAR Research Complex for NEH Region, Sikkim Centre, Tadong-737 102) : Weather variations in the mid hills of Sikkim - a case study of Tadong area. J Hill Res 1999, 12(2), 151-3.

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022514   Roy A K (Department of Geology, Asutosh College, Calcutta-26) : Chemistry of arsenic and arsenic minerals relevant to contamination of groundwater and soil from subterranean source. Everymans Sci 1999, 34(1), 15-21.

Arsenic contamination of water is a growing threat to the public health and development programme of West Bengal, Tripura and Bangladesh. This article throws light on the possible nature of the source material together with chemical and biochemical processes involved in the contamination.

021373   Swain P K;Sahu N K;Karim M A;Mohanty S N (NO, Geological Survey of India, Nayapalli, Bhubaneswar-751 012) : Preliminary search for gold mineralisation in Naukot volcanics, Keonjhar district, Orissa. Indian Miner 1999, 53(1-2), 97-102.

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021372   Sujatha S D;Sathyanarayan S;Satish P N;Nandan Kumar J V (Department of Studies in Geology, University of Mysore, Mysore-570 006) : Heavy metal toxicity and its impact on lentic water resources, Mysore. Karnataka. J appl Hydrol 1999, 12(2-3), 46-52.

Mysore, one of the tourist centres of India, is surrounded by major and minor lakes. The major lakes, like kukkarrahalli and karanji near Mysore are contaminated with sewage water and municipal sludge. This has resulted in the time bound accumulation of anthropogenic heavy metals : Cu, Cd, Co, Ni, Cr, V, Mn, Zn, Fe and Sr in the late water. An attempt has been made to study the concentrations of heavy metals in the water and sediments of these lakes to assess the Environmental Impact of human activities around these lakes. The study has shown higher concentrations of heavy metals in the suspended load and sediments beyond the permissible levels, and have already posed severe toxicity hazards to the biomass.

021371   Sinha R;Navada S V;Chatterjee A;Saravana Kumar;Mitra A;Nair A R (Department of Civil Engineering, Indian Institute of Technology, Kanpur-208 016) : Hydrogen and oxygen isotopic analysis of antarctic lake waters. Curr Sci 2000, 78(8), 992-5.

New data on the stable oxygen and hydrogen isotopic composition of freshwater lakes of Schirmacher oasis, east Antarctica are presented. Spatial variation of tritium, deuterium and oxygen-18 isotopes in lake waters has been interpreted in terms of their environmental significance. Low levels of tritium indicate no significant input from station activities. Variation in δ¹⁸ O and δ²H values is attributed to difference in relative contribution from glacial cover and fresh snow precipitation.

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021370   Sikdar P K (Centre for Study of Man and Environment, , Ck-II, Sector II, Salt Lake City, Calcutta-700 091) : Development dynamics and management of groundwater in and around Calcutta, India. Indian J Geol 1999, 71(3), 173-86.

The twin city of Calcutta and Howrah lies on the two sides of the Hugli river. The area is underlain by a succession of fluvio-deltaic sediments of Quaternary age consisting of clay, silt, fine to coarse sand and occasional gravel. Groundwater occurs under confined condition within the sandy horizon which is sandwiched between two clay horizons. A comparative study of the piezometric surface of 1956, 1985 and 1994 indicates a change in the groundwater flow pattern. In 1950's the groundwater flow was from north to south in conformity with the regional slope of the land. In 1985 the flow pattern shows a centripetal one with the formation of a prominent groundwater trough in the southcentral part of Calcutta. The groundwater is being overexploited to the tune of 73.5 million litres per day from Calcutta and Bidhannagar which might lead to increase cost of pumping, land subsidence, depreciation of groundwater quality and permanent contamination of the aquifers. Therefore, to cope up with these adverse situation a groundwater management plan has been formulated based on the basis of the present utilisation pattern of groundwater, future demand, status of the piezometric surface, long term change in the piezometric surface and quality of groundwater. The management plan envisages three distinct zones of development, viz,., Zone 1-Where no tubewells to be developed, withdrawal to be regulated by reducing tubewell operation time; Zone 2-status quo to be maintained in respect of tubewell development and Zone 3-further development of a limited number of additional tubewells.

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021369   Sharma K K; (Department of Applied Geology, University of Madras, Guindy Campus, Chennai-600 025) : Detection of water pollution using electro-chemical potentials. Indian J Geol 1999, 71(3)3, 169-72.

Surface geoelectrical methods are now-a-days increasingly applied in solving a range of hydrogeological problems involving both quantity and quality issues, particularly in the problem of detecting and monitoring groundwater contamination. Electrical geophysics has proven to be helpful in mapping contaminants and in optimizing the location of monitoring wells. The sources of SP and factors affecting them are very well known and hence, an attempt has been made to revive the use of SP methods for solving pollution related problems. Discusses a case study from an area having pollution from tannery effluents, bringing out the efficiacy of SP in identifying the zones of pollution. It is concluded that the SP is found to be useful in this case and three point average method is best suited for smoothing the field data from this area.

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021368   Saxena A S;Prasad R N (Geophysics Division, Geological Survey of India, Lucknow-226 024) : Geophysical surveys for basemetal mineralisation in Anyar block, Sirmur district, Himachal Pradesh. Indian Miner 1999, 53(1-2), 59-66.

Gephysical investigation in Anyar block, on the right bank of river Tons, under Sirmur District, H.P., revealed indications of lead and zinc mineralisation, in two separate ore bodies at shallower depth. The above block is also closs-by and to the north of proven Amtiyargad basemetal discovery, Dehradoon, U.P. These ore bodies, one in north-western and other in south-eastern part of the area, are embedded in dolomitic limestone of Deoban group of Precambrian age. The basic discovery, in reference to economic minerals (Pb & Zn), was effected by time-domain induced polarisation (IP) and self-potential (SP surveys, which proved to be of considerable value in guiding the drilling programme and then to predict the amount of ore to be expected in each body. Since the area is also reported to be sphalerite bearing, the SP response is not recorded at some places. The weak IP response in the intervening area suggested the mineralisation of disseminated nature at depth.

021367   Sankaran A V (NO, , 10, P and T Colony, I Cross, II Block, R T Nagar, Bangalore-560 032) : Some recent investigations about dynamics of mantle upwelling. Curr Sci 2000, 78(8), 948-52.

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021366   Roy N K;Mondal P C (Central Chemical Laboratory, Geological Survey of India, 27, Jawaharlal Nehru Road, Calcutta-700 016) : Analysis of platinum and palladium in geological samples ny graphite furnace atomic absorption spectrometry. Indian Miner 1999, 53(1-2), 67-70.

Platinum and palladium in geological samples have been determined by Graphite Furnace Atomic Absorption Spectrometry (GFAAS). Both lead fire assay (Pb-FA) and acid decomposition (aqua regia/HF/HCIO4) followed by Te-coprecipitation have been employed to preconcentrate the precious metals in geological samples. A comparative study between two preconcentration techniques has been done. In the Pb-FA method, 50g sample is taken for the preconcentration of precious metals whereas 5g sample is the maximum limit for acid digestion method. Detection limit of 0.5 and 1 ppb for Pd and Pt respectively in case of Pb-FA and 5 and 10 ppb for Pd and Pt respectively in case of acid digestion method are obtained. The methods have been applied to an in-house standard and an international standard sample (SARM-7) and the results are found to tally to that of recommended values. The accuracy and precision studies have been done using the in-house standard sample. A few geological samples of varied composition have been analysed by applying the methods and the results are compared. It is found that both the methods gave more or less identical results.

021365   Roy Choudhury K (Mineral Physics Division, Geological Survey of India, 15 Kyd Street, Calcutta-700 016) : Occurrence of mercurian sphalerite in north Sindesar Ridge, Udaipur district, Rajasthan. Indian Miner 1999, 53(1-2), 91-6.

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021364   Philip G;Ravindran K V;Thakur V C (Wadia Institute of Himalayan Geology, , 33 Mahadeo Singh ROad, Dehradun-248 001) : Mapping ophiolites: a study in the Indus suture zone of north-western-Himalaya, using IRS-1C/1D data. Curr Sci 2000, 78(8), 1014-9.

Ophiolites, which have been tectonically emplaced along continental margins and island arcs, are significant to the understanding of mountain belt evolution. At the same time mapping of ophiolites in the hostile and inaccessibale mountainous terrains of Hilmalaya has always posed a great challenge to geologists. The emphasis is on the mapping of the geological features especially the lithological inferences in the Nidar Ophiolotc Complex of the Indus Suture Zone of the Ladakh and Karakoram range of NW Himalaya using high resolution IRS-1C/1D satellite data and refinement of the existing geological maps. While the published geological maps show sequential distribution and occurrence of a number of litho-units, the satellite images have helped not only in delineating the lithological boundaries more precisely but also in demarcation of a number of subunits within the already mapped litho-units. The outcrops of the dissimilar lithological units are better delinated on satellite data-based map and hence can be used to refine the existing map of the terrain.

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021363   Paul J C;Sahu A P;Sharma S D (Department of Soil and Water Conservation Engineering, College of Agricultural Engineering & Technology, OUAT, Bhubaneswar-751 003) : Water balance and incidence of drought at Bhubaneswar. J appl Hydrol 1999, 12(2-3), 9-14.

Climatological water balance studies have been made for Bhubaneswar taking 35 years (1962-1996) of climatic data. Bhubaneswar has a water need of 1619mm, with a rainfall of 1479.5mm, actual evapotranspiration of 1195.5mm, water surplus of 284mm and a water deficit of 423.5mm. Taking the various components of water balance, aridity index and moisture index have been computed to study the incidence of drought. Bhubaneswar has experienced only 2 disastrous, 3 severe, 8 large and 4 moderate drought years.

021362   Nandi A;Bhattacharya A;Dutta A (NO, Geological Survey of India, Palaeontology Division, E R Calcutta-700 016) : Triassic plant megafossils from the Kamthi formation, Talchir coalfied, Orissa. Indian Miner 1999, 53(1-2), 107-10.

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021361   Mohanty J K;Sahoo R K (NO, Regional Research Laboratory, Bhubaneswar-751 013) : Chrome-garnet (uvarovite) and chrome-chlorite (Kammererite) from Boula-Nausahi igneous complex. Indian J Earth Sci 1998, 25(1-4), 13-16.

Alteration of ultramafic rocks at Boula-Nausahi igneous complex has resulted in development of secondary minerals such as serpentine, talc, tremolite, magnesite, uvarovite and kammererite. Except uvarovite and kammererite, all other minerals are fairly common and abundant. Mineralogical, XRD and chemical characters of these two rare secondary minerals have been dealt with and their formation have been ascribed to serpentinization and hydrothermal alteration of ultramafic rocks.

021360   Misra S;Sarkar S S (Geological Studies Unit, Indian Statistical Institute, Calcutta-700 035) : Petrogenesis of closepet granite, south India : a reappraisal. Indian J Earth Sci 1998, 25(1-4), 68-93.

Closepet Granite is an I-type granite (emplaced syn- to late kinematically with the second phase of deformation of Dharwar Orogeany). The major, trace and isotopic compositions of its different phases viz. Mafic, Grey and Pink show that the pluton consists of a mantle component (quartz monzonite) and a crustal component (Peninsular Gneiss). The three phases can be discriminated by their REE chemistry viz. CeN/YbN ratios, Eu anomalies and LREE/HREE ratios, and also by their biotite compositions. Close association of these phases in space and time together with their overlapping chemistries (increasing Larsen Index and CeN/YbN ratios, progressive evolution of Eu anomalies; decreasing Mg no. and increasing mol. Al(Al+Si) ratios of biotites) suggest that they were related by a progressive fractionation process. The clinopyroxene- quartz monzonite, the earliest member of the pluton, is likely to have been generated by 60 (wt)% fractionation (FC) of a basaltic parent at ≥ 40 Km depth. This phase itself was subjected to 30 to 40 wt% fractionation to achieve its compositional spread. The Mafic (<126> Porphyritic) phase can be approximated by 43 - 62 wt% fractionation (FC) of quartz monzonite at depth below plagioclase stability field (<126> 10Kbar). The Grey and Pink phases were generated by progressive fractionation of quartz monzonite with increasing crustal assimilation.

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021359   Madhusudan I C;Maiti S K;De M K;Singh A;Das P C (NO, Geological Survey of India, Eastern Region, Geophysics Division, 4, Chowringhee Lane, Calcutta-700 016) : Geophysical studies of Tamar gold prospect, Babaikundi-Birgaon sector, District Ranchi, Bihar. Indian Miner 1999, 53(1-2), 37-44.

Preliminary search for gold in metasedimentaries and associated volcaniclastic intercalations in Proterozoic fold belt of the Singhbhum Group and Chhotanagpur Gneisses, lying between Sonapet valley in the south and Tamar-Porapahar shear zone in the north, has revealed gold concentrations in primary lithogeochemical samples. Outcrop of the silicified pyritiferous ferruginous quartzite, exposed as small discontinuous bodies in extensively soil-covered area of the Babaikundi-Birgaon sector, has also been examined and found to be the host-rock for gold mineralisation. To trace the host-rock under cover geophysical surveys have been conducted. To identify the role of geophysics in defining exploration strategy for gold in the Proterozoic fold belt of eastern India. Gravity, Magnetic, Resistivity and Induced-Polarisation surveys were employed and observations were taken over an approximate area of 2.5 sq.km. The surveys have identified the geophysical expressions of the lithological domain containing gold and of the formations hosting mineralisations and have brought out a conceptual strategy for locating potential gold bearing horizons under cover. A combined magnetic (V.F.) and gravity signature across the domain indicates a significant sheared/fractured contact. The magnetic map has been found very useful for structural mapping in connection with gold prospecting in an area, having scanty outcrops.

021358   Krishnakumar G (India Meteorological Department, , Pune) : Vertical moisture flux and intensity of monsoon. J appl Hydrol 1999, 12(2-3), 1-8.

Distribution and characteristics for monsoon rainfall in India are important for the country's economic development. The vertical moisture flux and the intensity of monsoon play an important role in defining the monsoon characteristics. Study of the moisture analysis for a continuous five-year period of 1991-1995, taking into account six-month periods of May to October An attempt is made, in this study, to compute water vapour for different stations. The data of eleven radiosonde stations representing the West Coast, the land and the East Coast is made use of. The flux values are as low as 0.06 units in case of Jodhpur in 1991 and as high as 7.05 units in case of Guwahati. The studies confirm as considered by various authors the fact that the Zonal and meridional transport of water content from the west to eastward is significant for intense monsoon periods.

021357   Kalsotra M R (NO, , ) : Study on the cyclic bauxite episodes in plateau region of central India. Indian Miner 1999, 53(1-2), 1-24.

The lateritic bauxite duricrusts on source rocks viz. Vindhyans, contemporary clastics and Deccan basalt form extensive caps on residual plateaux of Satpura and Vindhyan Ranges, in central India. They are restricted to four principal levels of 350m, 600m, 840m and 1000m, representing relicts of cyclic old land surfaces that were eroded following successive uplifts, triggered off by northward movement of India over inhomogeneities in asthenosphere, and 45-50 Ma grand Indo-Asian continental collision. Measured from the present local base level of erosion to the plateau tops, the net amount of downward denudation varies from 400 m (on clastics) to 650 m (on basalt). The duricrusts on the clastics are late Mesozoic-pre-Lametas, whilst Trappean bauxite crust is dated Eocene. Hereafter, no significant development of bauxite seems to have taken place in the Indian sub-continent. The bauxite crusts of all the weathering cycles are differentiated into three distinct vertical and lateral facies, attributed to the then palaeodrainage conditions. The basal lithomarge clay facies, corresponding to the water-logged zone of meteoric solutions, is overlain by the laterite facies, which passes laterally in the direction of better drainage of palaeo-channels, into bauxite facies. The wide tensional joints, developed during tectonic uplifts, in the hard bauxite facies, facilitated formation of residual boulders through exfoliation and spheroidal weathering with interspaces filled.

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021356   Jain C K;Bhatia K K S;Sharma M K (NO, National Institute of Hydrology, Roorkee-247 667) : Statistical analysis of ground water quality data of Doon valley, Dehradun. J appl Hydrol 1999, 12(2-3), 27-33.

Ground water samples representing the shallow ground water of Doon valley, Dehradun have been analysed for various water quality constituents during premonsoon and post-monsoon seasons and correlation coefficients among different parameters determined. An attempt has been made to develop regression equations to predict the concentration of water quality constituents having significant correlation coefficients with electrical conductivity. The usefulness of these equations in predicting the ground water quality is discussed. A good agreement is found between the observed and computed values.

021355   Islam M S (Department of Geography, University of Chittagong, Chittagong 4331, Bangladesh) : Implication of relative sea-level movements in vertical land displacement and coastal dynamics : examples form the Bengal basin. Indian J Earth Sci 1998, 25(1-4), 42-57.

Bengal delta is one the largest deltaic landmass of its kind and occupies most of Bangladesh. It is floored with sediments carried by the mightly Ganges-Brahmaputra-Meghna river-system from the upstream highlands. Evidence of land subsidence from various parts of the delta and of uplift of the Pleistocene landmasses - the Barind and Madhupur Tracts, have been reported by many authors. Some have attempted to quantify the rates of vertical land displacements. However, due to lack of any geological datum level, such calculations are alwasy debatable. The reconstructed paleotidal level, preferably the MHWST, could serve as an alternative reference datum and may be used to measure vertical displacement of any land level from where samples are taken for radiocarbon dating. The application of this methodology, for the first time in Bangladesh, has shown the evidences of spatio-temporal variation of crustal movements and delta progradations during the Holocene period. On the southwestern sector, the coast lines have migrated in a southeast direction, but in the eastern sector it has apparently remained stable. Hence to separate delta building processes, following the Ganges and the Brahmaputra-Meghna river-systems, were definitely simultaneous in operation in the Bengal Basin. The unification of these rivers is a recent phenomenon, possibly less than a thousand years BP. Since then, sedimentation with higher rates is taking place in a fluvially controlled high energy deltaic system.

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021354   Hussain S M;Mohan S P;Manivannan V (Department of Geology, University of Madras, A C College Campus, Madras-600 025) : Recent cytherellids, bairdids and cytherids (ostracoda) from the Gulf of Mannar, off Tuticorin, southeast coast of India. Indian J Earth Sci 1998, 25(1-4), 17-28.

Systematic study the Recent Ostracoda based on 48 bottom sediment samples collected from the innershelf of Gulf of Mannar, off Tuticorin, Tamil Nadu has been presented. 3 species belonging to the family Cytherellidae, 5 to Bairdiidae and 5 to Cytheridae are described. Among these, Cytherella dictyon, Anchistrocheles sp. cf. A. mcquadei and Neomonoceratina porocostata are recorded for the first time from the Indian waters. Two new species, Triebelina tuticorensis and Hemicytheridea khoslai are established. One species, Cytherelloidea praecipua Bold, which is revised and placed under the genus Keijcyoidea, is also recorded for the first time from the east coast of India.

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021353   Hegde S B;Hegde S G;Puranik S C (Department of Studies in Geology, Karnatak University, Dharwad-580 003) : Low- and high-intensity magnetic separation studies of ferruginous manganese ores of Gadag schist belt, Karnataka. Indian Miner 1999, 53(1-2), 103-6.

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021352   Hanumanthu R C;Babaiah P B (Department of Geology, S V University, Tirupati-517 502) : On the dolerite dykes of narasampalli area in Ramagiri schist belt anantapur district, Andhra Pradesh, India. Indian J Geol 1999, (NULL), 187-91.

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021351   Ghosh S (Geological Survey of India, Central Petrological Laboratory, Calcutta-700 016) : Samelia iron meteorite-an example of uneven distribution of shock-pressure domains. Indian Miner 1999, 53(1-2), 45-58.

Samelia is a Medium Octahedrite with a large variety of macrostructures and microstructures, both primary and secondary. Most significant feature of Samelia iron is the presence of shock-transformed epsilon structures of kamacite equivalent to those experimentally produced under shock pressure varying from 200 kb to 1000 kb and these structures are unevenly distributed in different pressure domains. At places, the residual temperature due to high shock pressure (more than 750kb) resulted in shock - induced recrystallisation of kamacite. Dominant shock-induced pressure that acted of Samelia belongs to 400-600 kb which was followed by 200-400 kb and 600-800kb in decreasing order. Samelia was not subjected to any shear or stress-induced deformation but it was subjected to thermal annealing at least in three stages. It was annealed during the formation of plessite, during shock-induced recrystallisation and finally in the atmospheric reheating. The annealing temperature was around 750°C both in the atmosphere and outside the atmosphere. The primary cooling of the Samelia iron took place between <62>750°C and 300°C with a very slow rate of cooling - nearly 3°C/10⁶ years.

021350   Ghosh D N (Department of Applied Geology, Indian School of Mines, Dhanbad-826 004) : Variation in biocharacters of two species in Kallirhynchia (Buckman) from callovian beds of Kutch, India. Indian J Earth Sci 1998, 25(1-4), 1-12.

Kitchin (1900), described and figured 14 rhynchonellid species from the Jurassic Fromations of Kutch; Rhynchonella fornix Kitchin and Rhynchonella subplicatella Kitchin were two among them. Later Buckman (1917) while working on brachiopods of the Namayu beds Northern Shan States, Burma, included these two species under his newly defined genus Kallirhynchia, in the original definitions of these two species Kitchin (op. cit.) commented (p. 615) that while in R. fornix the shell is always broader than long, in R. subplicatella the shell is as broad as long. The present collection includes one sample each of these two species from the Middle Callovian Upper-middle Macrocephalus beds of Kutch, India. Morphologically the two species show close similarity to each other. Biometric studies on the variation in biocharacters of these two samples also indicate that the differences in unit characters between the two populations are statistically insignificant. Bivariate statistics of biocharacter distributions (LXW, LXT & WXT) in the two samples also indicate that the growth rates of the biocharacters in the two populations should be considered statistically identical. These observations emphatically negate Kitchin's (op.cit) contention that the two species differ between themselves in respect of relative proportions of shell dimensions. On the basis of these observations it has been concluded that the two species should be lumped together under one specific name and according to page.

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021349   Ghosh B;Ray J;Mukhopadhyay S (Department of Geology, University of Calcutta, 35, Ballygunge Circular Road, Calcutta-700 019) : Mineral chemistry of ultramafic-mafic intrusive bodies of mangalapuram-timminayakkampatti areas of the southern granulite terrain, salem district, Tamilnadu. Indian J Geol 1999, 71(3), 193-204.

The chemistry of the constituent mineral phases of the ultramafic-mafic intrusives in the Mangalapuram-Timminayakkampatti complex (M-T complex) and the high grade granulitic envelope occuring in the Southern Granulite Terrain of the Indian Shield has been presented. P-T condition of equlibration of the intrusives represents an igneous cooling path from 1051°C to 743°C (under water enriched condition) at ca. 7 kb based on different relevant thermobarometric methods. Significance of this deduced P-T condition of equlibration for the intrusives has been critically viewed.

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