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Acta Geologica sinica(English Edition) 2011年第1期85卷 107-115页

作者： Perumala v.s.RAJU elapavalooru v.s.s.k.babu Roland k.W.MERkLE National Geophysical Research Institute Hyderabad India(Council of Scientific and Industrial Research) Department of Geology University of Pretoria PretoriaSouth Africa

The occurrence of rhythmic layering of chromite and host serpentinites in the deformed layered igneous complexes has been noticed in the Nuggihalli schist belt （NsB） in the western Dharwar craton, karnataka, south India. For this study, the chromitite rock samples were collected from Jambur, Tagadur, Bhakatarhalli, Ranganbetta and Byrapur in the NsB. Petrography and ore microscopic studies on chromite show intense cataclasis and alteration to ferritchromite. The ferritchromite compositions are characterized by higher Cr number （Cr/[Cr＋AI]）（0.68-0.98） and lower Mg number （Mg/[Mg＋Fe]）（0.33-0.82） ratios in ferritchromite compared to that of parent chromite. The formation process for the ferritchromite is thought to be related to the exchange of Mg, AI, Cr, and Fe between the chromite, surrounding silicates （serpentines, chlorites）, and fluid during serpentinization.

关键词： chromite ferritchromite Nuggihalli schist belt Dharwar Craton India

Fluid-driven Hydrovolcanic Activity along Fracture Zones and near seamounts:Evidence from Deep-sea Fe-rich spherules,Central Indian Ocean Basin

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Acta Geologica sinica(English Edition) 2021年第5期95卷 1591-1603页

作者： Ankeeta AMONkAR sridhar D.IYER elapavalooru v.s.s.k.babu Natarajan sHAILAJHA Areef sARDAR s.MANJU CsIR-National Institute of Oceanography Dona PaulaGoa 403004India Marine science School of EarthOcean and Atmospheric SciencesGoa UniversityGoa 403206India Formerly with CsIR-National Institute of Oceanography Dona PaulaGoa 403004India CsIR-National Geophysical Research Institute HyderabadTelangana 500007India Department of Earth science Pondicherry UniversityPondicherry 605014India

An insight on occurrence of Fe-rich spherules from the Central Indian Ocean Basin(CIOB)provides an understanding of their distribution at a water depth of>5,000 *** the present study,Fe-rich spherules are identified to occur in two different sediment types(i.e.,siliceous and pelagic)and tectonic settings(*** seamounts and fracture zones).These are single spheres or aggregates,of different sizes(63 to 390μm)and show textural variability(smooth/quenched,brickwork,corkscrew,interlocking and dendritic).A comparative study based on physical morphology and chemical composition suggests a common mechanism of *** association of spherules with fracture zones(FZ)and seamounts signifies that morpho-tectonic features play an important role in fluid-driven *** on the evidence and geologic conditions existing in the basin,we conclude that molten fuel-coolant interaction(MFCI)coupled with submarine hydrothermal exhalations could be an ideal mechanism for the formation of spherules and *** accretion of the spherules on the surface sediments could be a result of recent volcanic phenomena,while those occurring at different depths(280-355,and 460-475 cm-bsf)within the sediment core indicate two different *** study provides a global implication in understanding fluid-driven magmatism in a deep-sea intraplate environment.

关键词： Fe-rich spherules deep-sea sediments hydrovolcanic activity CIOB

Occurrence and Emplacement of Chromite Ores in sindhudurg District,Maharashtra,India

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Acta Geologica sinica(English Edition) 2010年第3期84卷 515-527页

作者： sridhar D.IYER elapavalooru v.s.s.k.babu Premchand G.MIsLANkAR Anup R.GUJAR Navso v.AMBRE victor J.LOvEsON National Institute of Oceanography Council of Scientific and Industrial ResearchDona PaulaGoa 403004India National Geophysical Research Institute Council of Scientific and Industrial ResearchHyderabad 500007India Central Institute of Mining and Fuel Research Council of Scientific and Industrial ResearchDhanbad 828108India

In the present study,we present the occurrence and emplacement of chromite ore deposits from two abandoned mines（kankavali[Janoli]and Wagda） in the sindhudurg district of Maharashtra,*** ores,that occurred as lenses and are associated with metamorphic and ultrabasic rocks,consist of octahedral grains of chromite,while clinochlore is present between the interstices of these *** kankavali（Janoli） and Wagda ores revealed a dominance of Cr_2O_3 followed by FeO and variable proportions of A1_2O_3,MgO,and siO_*** former deposits have a slightly higher Cr_2O_3（average 52 wt%） and FeO（～18 wt%） than those from Wagda（Cr_2O_3～50 wt%,FeO～25 wt%）.The similar Cr~# values（0.73 for kankavali[Janoli],0.74 for Wagda） correspond to those reported for typical podiform-type chromite *** suggest that the ores were emplaced as phacoliths in folded outcrops with a steep easterly dip and a northwest-southeast *** postulate the continuation of the fold structure from Janoli to Wagda（～4.5 km apart） and the probable （sporadic） occurrence of chromite along this *** possibility of the contribution of chromite grains from these areas to the coastal placer deposits cannot be ruled out.

关键词： chromite podiform formation placer sindhudurg India

Application of Response surface Methodolody to Prediction of Dilution in Plasma Transferred Arc Hardfacing of stainless steel on Carbon steel

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Journal of Iron and steel Research International 2009年第1期16卷 44-53页

作者： v Balasubramanian A k Lakshminarayanan R varahamoorthy s babu Centre for Materials Joining and Research (CEMAJOR) Department of Manufacturing EngineeringAnnamalai UniversityAnnamalai Nagar 608002Tamil NaduIndia

The application of response surface methodology was highlighted to predict and optimize the percentage of dilution of iron-based hardfaced surface produced by the PTA （plasma tratisferred arc welding） process. The experiments were conducted based on five-factor five-level central composite rotatable design with full replication technique and a mathematical model was developed using response surface methodology. Furthermore, the response surface methodology was also used to optimize the process parameters that yielded the lowest percentage of dilution.

关键词： plasma transferred arc hardfacing dilution response surface methodology

Grain to outcrop-scale frozen moments of dynamic magma mixing in the syenite magma chamber,Yelagiri Alkaline Complex,south India

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Geoscience Frontiers 2014年第6期5卷 801-820页

作者： M.L.Renjith s.N.Charan D.v.subbarao E.v.s.s.k.babu v.B.Rajashekhar Marine and Coastal survey Division Geological Survey of IndiaCochin 682037India Geochemistry Division CSIR-National Geophysical Research InstituteHyderabad 500007India New Zealand Petroleum and Minerals Wellington 6037New Zealand

Magma mixing process is unusual in the petrogenesis of felsic rocks associated with alkaline complex worldwide. Here we present a rare example of magma mixing in syenite from the Yelagiri Alkaline Complex, south India. Yelagiri syenite is a reversely zoned massif with shoshonitic (Na2O t k2O?5e 10 wt.%, Na2O/k2O ? 0.5e2, TiO2s character. systematic modal variation of plagioclase (An11e16 Ab82e88), k-feldspar (Or27e95 Ab5e61), diopside (En34e40Fs11e18Wo46e49), biotite, and Ca-amphibole (edenite) build up three syenite facies within it and imply the role of in-situ fractional crystallization (FC). Evidences such as (1) disequilibrium micro-textures in feldspars, (2) microgranular mafic enclaves (MME) and (3) synplutonic dykes signify mixing of shoshonitic mafic magma (MgO ? 4e 5 wt.%, siO2 ? 54e59 wt.%, k2O/Na2O ? 0.4e0.9) with syenite. Molecular-scale mixing of mafic magma resulted disequilibrium growth of feldspars in syenite. Physical entity of mafic magma preserved as MME due to high thermal-rheological contrast with syenite magma show various hybridization through chemical exchange, mechanical dilution enhanced by chaotic advection and phenocryst migration. In synplutonic dykes, disaggregation and mixing of mafic magma was confined within the conduit of injec-tion. Major-oxides mass balance test quantified that approximately 0.6 portions of mafic magma had interacted with most evolved syenite magma and generated most hybridized MME and dyke samples. It is unique that all the rock types (syenite, MME and synplutonic dykes) share similar shoshonitic and met-aluminous character;mineral chemistry, REE content, coherent geochemical variation in Harker diagram suggest that mixing of magma between similar composition. Outcrop-scale features of crystal accumu-lation and flow fabrics also significant along with MME and synplutonic dykes in syenite suggesting that Yelagiri syenite magma chamber had evolved through multiple physical processes like

关键词： Magma mixing Disequilibrium textures Petrology synplutonic dykes Geodynamics

Optimizing pulsed current gas tungsten arc welding parameters of AA6061 aluminium alloy using Hooke and Jeeves algorithm

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中国有色金属学会会刊：英文版 2008年第5期18卷 1028-1036页

作者： s.babu T.sENTHIL kUMAR v.BALAsUBRAMANIAN Centre for Materials Joining Research (CEMAJOR) Department of Manufacturing EngineeringAnnamalai UniversityAnnamalai Nagar-608 002Tamil NaduIndia Department of Automobile Technology Bharathidasan Institute of TechnologyAnna UniversityTiruchirappalli-620 016Tamil NaduIndia

Though the preferred welding process to weld aluminium alloy is frequently constant current gas tungsten arc welding (CCGTAW),it resulted in grain coarsening at the fusion zone and heat affected zone(HAZ).Hence,pulsed current gas tungsten arc welding(PCGTAW) was performed,to yield finer fusion zone grains,which leads to higher strength of AA6061 (Al-Mg-si) aluminium alloy *** order to determine the most influential control factors which will yield minimum fusion zone grain size and maximum tensile strength of the joints,the traditional Hooke and Jeeves pattern search method was *** experiments were carried out based on central composite design with 31 runs and an algorithm was developed to optimize the fusion zone grain size and the tensile strength of pulsed current gas tungsten arc welded AA6061 aluminium alloy *** results indicate that the peak current (Ip) and base current (IB) are the most significant parameters,to decide the fusion zone grain size and the tensile strength of the AA6061 aluminum alloy joints.

关键词：脉冲电流钨电极惰性气体保护焊铝合金颗粒尺寸

Elastic and Optoelectronic Properties of kCdF3:ab initio Calculations through LDA/GGA/TB-mBJ within FP-LAPW Method

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Chinese Physics Letters 2015年第1期32卷 108-112页

作者： k. Ephraim babu N. Murali k. vijaya babu B. kishore babu v. veeraiah Modelling and simulation in Materials science Laboratory Department of Physics Andhra University Visakhapatnam 530003 Andhra Pradesh India Department of Engineering Chemistry A UCE(A) Andhra University Visakhapatnam 530003 Andhra Pradesh India

Ab initio calculations are performed on the electronic, structural, elastic and optical properties of the cubic per- ovskite kCdF3. Tile kohn sham equations are solved by applying the full potential linearized augmented plane wave （FP-LAPW） method. The exchange correlation effects are included through the local density approximation （LDA ）, generalized gradient approximation （GGA） and modified Becke-Johnson （mBJ） exchange potential The calculated lattice constant is in good agreement with the experimental result. The elastic properties such as elastic constants, anisotropy factor, shear modulus, Young＇s modulus and Poisson＇s ratio are calculated. kCdF3 is ductile and elastically anisotropic. The calculations of the electronic band structure, density of states （DOs） and charge density show that this compound has an indirect energy band gap （M-F） with a mixed ionic and covalent bonding. The contribution of the different bands is analyzed from the total and partial density of states curves. Optical response of the dielectric functions, optical reflectivity, absorption coefficient, real part of optical conductivity, refractive index, extinction coefficient and electron energy loss, are presented for the energy range of O-40ev. The compound kCdF3 can be used for high-frequency optical and optoelectronic devices.

关键词： GGA Cd Elastic and Optoelectronic Properties of kCdF3:ab initio Calculations through LDA/GGA/TB-mBJ within FP-LAPW Method LDA FP

Petrogenesis of carbonatitic lamproitic dykes from sidhi gneissic complex,Central India

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Geoscience Frontiers 2018年第2期9卷 531-547页

作者： M.satyanarayanan D.v.subba Rao M.L.Renjith s.P.singh E.v.s.s.k.babu M.M.korakoppa CsIR-National Geophysical Research Institute Hyderabad 500007India Geological survey of India Hyderabad 500068India Department of Geology Bundelkhand UniversityJhansi 284128India NCEGR Geological Survey of IndiaBengaluru 560070India

Petrographic, mineral chemical and whole-rock geochemical characteristics of two newly discovered lamproitic dykes(Dyke 1 and Dyke 2) from the sidhi Gneissic Complex(sGC), Central India are presented here. Both these dykes have almost similar sequence of mineral-textural patterns indicative of:(1) an early cumulate forming event in a deeper magma chamber where megacrystic/large size phenocrysts of phlogopites have crystallized along with subordinate amount of olivine and clinopyroxene;(2) crystallization at shallow crustal levels promoted fine-grained phlogopite, k-feldspar, calcite and Fe-Ti oxides in the groundmass;(3) dyke emplacement related quench texture(plumose k-feldspar, acicular phlogopites) and finally(4) post emplacement autometasomatism by hydrothermal fluids which percolated as micro-veins and altered the mafic phases. Phlogopite phenocrysts often display resorption textures together with growth zoning indicating that during their crystallization equilibrium at the crystal-melt interface fluctuated multiple times probably due to incremental addition or chaotic dynamic self mixing of the lamproitic magma. Carbonate aggregates as late stage melt segregation are common in both these dykes, however their micro-xenolithic forms suggest that assimilation with a plutonic carbonatite body also played a key role in enhancing the carbonatitic nature of these dykes. Geochemically both dykes are ultrapotassic(k_2 O/Na_2 O: 3.0-9.4) with low CaO, Al_2 O_3 and Na_2 O content and high siO_2(53.3-55.6 wt.%)and k_2 O/Al_2 O_3 ratio(0.51-0.89) characterizing them as high-silica lamproites. Inspite of these similarities, many other features indicate that both these dykes have evolved independently from two distinct magmas. In dyke 1, phlogopite composition has evolved towards the minette trend(Al-enrichment) from a differentiated parental magma having low MgO, Ni and Cr content; whereas in dyke 2, phlogopite composition shows an evolutionary affinity towards the lamproit

关键词： Lamproite Phlogopite Carbonate aggregates Metasomatized mantle sidhi Gneissic Complex Central India

Fluoride contamination in groundwater:A global review of the status,processes,challenges,and remedial measures

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Geoscience Frontiers 2024年第2期15卷 1-29页

作者： E.shaji k.v.sarath M.santosh P.k.krishnaprasad B.k.Arya Manisha s.babu Department of Geology University of KeralaKariavattom CampusThiruvananthapuramKerala 695581India school of Earth sciences and Resources China University of Geosciences(Beijing)29 Xueyuan RoadBeijing 100083China Department of Earth science University of AdelaideAdelaideSA 5005Australia Department of Geology Central University of KeralaTejaswini HillsPeriyeKasaragodKerala 671316India

Groundwater pollution by fluoride is one of the prime concerns of the world population due to its toxicity,which results in adverse health *** this paper,we review the current scenario of the fluoride contamination of groundwater in various countries across the globe and its impact on human *** the last decade,several newly affected regions have been reported all over the world,with more than 100 countries affected by fluoride contamination in groundwater(concentration exceeding the acceptable limit of 1.5 mg/L defined by the World Health Organization).Fluoride poisoning is mainly due to the unsupervised ingestion of products for dental and oral hygiene and over-fluoridated drinking *** is estimated that more than 200 million people from different countries are affected by fluoriderelated groundwater issues and health *** highest among these are from the countries in Africa(38),Asia(28),and Europe(24),followed by countries like south America(5),North America(3),and Australia(2).The source of fluoride in drinking water is primarily geogenic,together with forage,grasses and grains,tea,and anthropogenic *** countries affected were correlated with climatic zones and geological factors to gain insights into geospatial *** analyses show that most of the fluoride pollution-prone zones are located in high-grade metamorphic terranes with granitoid or alkaline intrusions,geothermal hot springs,and volcanic regions with arid or semi-arid climatic *** study also finds that children across the globe are more vulnerable than adults to fluoride *** review finds that,although there are efficient fluoride removal techniques,including filters with next-generation nanomaterials,to date,there has not been a single technique developed that can claim to be a practically robust solution for fluoride removal from drinking ***,we suggest developing next-generation filters that can retain essential miner

关键词： Fluoride Groundwater Water contamination WHO standards Climate zones Remediation sustainable Development Goals

A new cache of Eoarchaean detrital zircons from the singhbhum craton,eastern India and constraints on early Earth geodynamics

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Geoscience Frontiers 2019年第4期10卷 1359-1370页

作者： Bulusu sreenivas sukanta Dey Y.J. Bhaskar Rao T. vijaya kumar E.v.s.s.k. babu Ian s. Williams CsIR-National Geophysical Research Institute Hyderabad 500007India Department of Earth sciences Indian Institute of Science Education and ResearchKolkata 741246India Research school of Earth sciences The Australian National UniversityCanberra 2601Australia

The dominant geodynamic processes that underpin the formation and evolution of Earth’s early crust remain enigmatic calling for new information from less studied ancient cratonic ***,we present U-Pb ages and Hf isotopic compositions of detrital zircon grains from^2.9 Ga old quartzites and magmatic zircon from a 3.505 Ga old dacite from the Iron Ore Group of the singhbhum craton,eastern *** detrital zircon grains range in age between 3.95 Ga and 2.91 *** with the recently reported Hadean,Eoarchean xenocrystic(up to 4.24 Ga)and modem detritus zircon grains from the singhbhum craton,our results suggest that the Eoarchean detrital zircons represent crust generated by recycling of Hadean felsic crust formed at^4.3-4.2 Ga and^3.95 *** observe a prominent shift in Hf isotope compositions at^3.6-3.5 Ga towards super-chondritic values,which signify an increased role for depleted mantle and the relevance of plate *** Paleo-,Mesoarchean zircon Hf isotopic record in the craton indicates crust generation involving the role of both depleted and enriched mantle *** infer a short-lived suprasubduction setting around^3.6-3.5 Ga followed by mantle plume activity during the Paleo-,Mesoarchean crust formation in the singhbhum *** singhbhum craton provides an additional repository for Earth’s oldest materials.

关键词： U-Pb zircon ages Hf isotopes singhbhum craton Hadean Eoarchean Geodynamics