A Preliminary Biogeochemical Study over the Uraniferous Quartz-Pebble—Conglomerate Zone near Kalasapura, Chickmagalur District, Karnataka, Southern India

Quartz-pebble-conglomerate(QPC) bearing unconformable zone at the base of Bababudan Group of rocks inDharwar Craton in southern India is well known for its stratigraphicsignificance and uraniferous nature. Over this QPC zone, soil cover is verythin which is almost devoid of vegetation. A cursory biogeochemical study hereindicated poor (170 to 520 ppb) uranium content in the scantily occurring herbsand shrub species as well as in the soil substratum (1.8 - 3.1 ppm). The valuesin plant species are much below the background values. Almost barren nature ofsoil surface and stunted growth of herb and shrub species suggested thatgeobotanical rather than biogeochemical study is more serviceable as a clue forthe hidden QPC-type horizons, which quite often bear signatures of uraniummineralization

Biogeochemistry over the sulfidic/auriferous zone near Ajjanahalli in the central part of Chitradurga schist belt, Dharwar craton.

The sulfidic/auriferous ridge near Ajjanahalli in Chitradurga schist belt is chiefly constituted by BIF and flanked on either side by a closely knit assembly of phyllitic schists and carbonaceous shales. The mineralization is confined to the shear zone and the ore minerals are disseminated in the fracture filling quartz/carbonate veins of epigenetic nature.Pyrite, chalcopyrite, arsenopyrite and pyrrhotite are the chief sulfide minerals within which gold is hosted. The mineralized ridge is covered by fairly thick natural vegetation including herbs, shrubs and tree species. About half meter to meter thick well drained, coarse textured silty to gravelly soil form a crust over this mineralized ridge. The area is a semi-arid tract with moderate annual rainfall of ~500mm. In the present study, this auriferous zone has been chosen for geobotanical and biogeochemical study to appraise the morphological characteristics of plant species and the metal dispersion pattern in them in relation to metal content in the ground. Soil geochemistry suggests a poor to moderate accumulation of Cu (139-627 ppm), most in the range of 250-600 ppm. Many other metals show normal dispersion.Arsenic is in high concentration ranging from 695-5470 ppm. Similarly, Se also shows anomalous content (1304-2136ppm).Plants show inhomogeneous accumulation of metals. Cu is in poor concentration, probably owing to its poor contentin soil. Slightly alkaline nature of soil could have also hindered its dissolution and the consequent mobility. Arsenic is significantly accumulated in a Fern species (Pteris vittata) which is confined only to the mine-sections in mineralized ridge. Interestingly, a clear higher uptake pattern of Au by this Fern is also noticed, whereas other species do not show such comparable patterns of As and Au. Gold in soil also shows moderate concentration (40-320 ppb). Thus, Fern species hint at the possibility of considering it as a local indicator for gold in sulfidic zones. But, detailed sampling of this species is necessary before ascertaining its value as an index plant. Other metals like Co, Zn and Mn, though present in variable concentrations in plants, they do not reflect much significance. Se, though toxic to plants at higher concentrations, was found to be enriched in plants, aptly reflecting the sulfidic nature of the substratu

Biogeochemistry over the sulfidic​/auriferous zone near Ajjanahalli, Chitradurga Schist belt, Dharwar craton, souther India

The sulfidic​/auriferous ridge near Ajjanahalli in Chitradurga schist belt is chiefly constituted by BIF and flanked on either side by a closely knit assembly of phyllitic schists and carbonaceous shales. The mineralization is confined to the shear zone and the ore minerals are disseminated in the fracture filling quartz​/carbonate veins of epigenetic nature. Pyrite, chalcopyrite, arsenopyrite and pyrrhotite are the chief sulfide minerals within which gold is hosted. The mineralized ridge is covered by fairly thick natural vegetation including herbs, shrubs and tree species. About half meter to meter thick well drained, coarse textured silty to gravelly soil form a crust over this mineralized ridge. The area is a semi-​arid tract with moderate annual rainfall of ∼500mm. In the present study, this auriferous zone has been chosen for geobotanical and biogeochem. study to appraise the morphol. characteristics of plant species and the metal dispersion pattern in them in relation to metal content in the ground. Soil geochem. suggests a poor to moderate accumulation of Cu (139-​627 ppm)​, most in the range of 250-​600 ppm. Many other metals show normal dispersion. Arsenic is in high concn. ranging from 695-​5470 ppm. Similarly, Se also shows anomalous content (1304-​2136 ppm)​. Plants show inhomogeneous accumulation of metals. Cu is in poor concn., probably owing to its poor content in soil. Slightly alk. nature of soil could have also hindered its dissoln. and the consequent mobility. Arsenic is significantly accumulated in a Fern species (Pteris vittata) which is confined only to the mine-​sections in mineralized ridge. Interestingly, a clear higher uptake pattern of Au by this Fern is also noticed, whereas other species do not show such comparable patterns of As and Au. Gold in soil also shows moderate concn. (40-​320 ppb)​. Thus, Fern species hint at the possibility of considering it as a local indicator for gold in sulfidic zones. But, detailed sampling of this species is necessary before ascertaining its value as an index plant. Other metals like Co, Zn and Mn, though present in variable concns. in plants, they do not reflect much significance. Se, though toxic to plants at higher concns., was found to be enriched in plants, aptly reflecting the sulfidic nature of the substratum

Petrology and geochemitstry of late Archaean granitoids in the northern part of EDC, Southern India: implications for transitional geodynamic setting

The results of field, petrographic and geochemical work of the granitoids of Hutti-Gurgunta area in the northern part of Eastern Dharwar Craton (EDC) is presented in this paper. This crustal section comprises polyphase banded to foliated TTG gneisses, middle amphibolite facies Gurgunta schist belt and upper greenschist facies Hutti schist belt and abundant granite plutons. The focus of the present study is mainly on basement TTG gneisses and a granite pluton (∼ 240 sq km areal extent), to discuss crustal accretion processes including changing petrogenetic mechanism and geodynamic setting. The TTGs contain quartz, plagioclase, lesser K-feldspar and hornblende with minor biotite while the granite contain quartz, plagioclase, K-feldspar and hornblende. Late stage alteration (chloritisation, sericitisation and epidotisation) is wide spread in the entire area. A huge synplutonic mafic body which is dioritic to meladioritic in composition injects the granite and displays all stages of progressive mixing and hybridization. The studied TTGs and granite show distinct major and trace element patterns. The TTGs are characterized by higher SiO2, high Al2O3, and Na2O, low TiO2, Mg#, CaO, K2O and LILE, and HFS elements compared to granite. TTGs define strong trondhjemite trend whilst granite shows calc-alkaline trend. However, both TTGs and granite show characteristics of Phanerozoic high-silica adakites. The granite also shows characteristics of transitional TTGs in its high LILE, and progressive increase in K2O with differentiation. Both TTGs and granite define linear to sub-linear trends on variation diagrams. The TTGs show moderate total REE contents with fractionated REE patterns (La/YbN =17.73–61.73) and slight positive or without any significant Eu anomaly implying little amount of amphibole or plagioclase in residual liquid. On the other hand, the granite displays poor to moderate fractionation of REE patterns (La/YbN = 9.06–67.21) without any significant Eu anomaly. The TTGs have been interpreted to be produced by low-K basaltic slab melting at shallow depth, whereas the granite pluton has been formed by slab melting at depth and these melts interacted with peridotite mantle wedge. Such changing petrogenetic mechanisms and geodynamic conditions explain increase in the contents of MgO, CaO, Ni and Cr from 2700 Ma to 2500 Ma granitoids in the EDC

Biogeochemical study over the copper mineralized areas of Kalyadi, Karnataka.

Ultramafics intercalated with metasedimentaries in Kalyadi area host copper mineralization and the overburden of this mineralized zone has been studied from the point of geobotany and biogeochemistry. In the mineralized zone, the soil cover is very thin (1-1.5 ft), and supports sparse and stunted vegetation. Shrubs dominate the herbs and trees. Dodonaea viscosa, Cassia auriculata,Maytenus emerginata, Pavetta indica, Erythro xylon, Tecoma stans, Aerva lanata, Hyptis suaveolens, Atylosia albicans,Stachyterphyta indica, Chromolaena odarata are the plant species which have been studied and sampled. Morphologically, nosignificant changes could be made out from the species growing in the mineralized area. Depending upon the distribution and homogeneity of the plant species sampling has been carried out following a grid pattern. The elements analyzed for plant species and soil included Cu, Cr, Zn, Ni, Co, Mn and Mg. Trace element study of soil and floral species indicates moderate but inhomogenous dispersion of Cu from the bed rock source. Only a few samples of Leguminosae, Dodonaea viscosas, Erthyron xylon, Leucas ciliata and Pavetta indica showed slightly higher values. Thus, these species are considered as better up-takers of copper. Restricted Cr,Ni and Co in almost all the analyzed plants could be due to their lesser mobility. The overall biogeochemical observation has helped to recognize Leucas ciliata, Cassia auriculata and Erthyron xylon as species slightly favourable for Cu up-take and could serve as local indicators. Statchyterphyta indica is recognized as a good up-taker of Zn

Biogeochemical Study of Copper Mineralized Zone near Kalyadi, Karnataka

Ultramafics intercalated with metasedimentaries in Kalyadi area host copper mineralization and the overburden of this mineralized zone has been studied from the point of geobotany and biogeochemistry. In the mineralized zone, the soil cover is very thin (1–1.5 ft), and supports sparse and stunted vegetation. Shrubs dominate the herbs and trees. Dodonaea viscosa, Cassia auriculata, Maytenus emerginata, Pavetta indica, Erythro xylon, Tecoma stans, Aerva lanata, Hyptis suaveolens, Atylosia albicans, Stachyterphyta indica, Chromolaena odarata are the plant species which have been studied and sampled. Morphologically, no significant changes could be made out from the species growing in the mineralized area. Depending upon the distribution and homogeneity of the plant species sampling has been carried out following a grid pattern. The elements analyzed for plant species and soil included Cu, Cr, Zn, Ni, Co, Mn and Mg. Trace element study of soil and floral species indicates moderate but inhomogenous dispersion of Cu from the bed rock source. Only a few samples of Leguminosae, Dodonaea viscosas, Erthyron xylon, Leucas ciliata and Pavetta indica showed slightly higher values. Thus, these species are considered as better up-takers of copper. Restricted Cr, Ni and Co in almost all the analyzed plants could be due to their lesser mobility. The overall biogeochemical observation has helped to recognize Leucas ciliata, Cassia auriculata and Erthyron xylon as species slightly favourable for Cu up-take and could serve as local indicators. Statchyterphyta indica is recognized as a good up-taker of Zn

Trends of observation on wells, Remedial measures and feasibility studies of Hoskote taluk, Bangalore rural district, Karnataka, India

Hosakote is a Taluk in Bangalore Rural District. It’s headquartered at Hosakote town, 25 km away from Bangalore City.Currently, Hosakote depends on ground water (bore wells) as the main source of water supply. Due to depletion of rainfall year by year,overexploitation a n d less recharges, the yield from the borewells are diminishing considerably. In summer season, the water table goes much below thus creating scarcity of water. Hence, the ground water source is not dependable and there is an inevitable need to develop a project for alternate source of water supply. And as such this p a p e r presents the water problems in the Taluk, the reasons for the problems and remedies to correct the problems. The scope of this paper includes: i. Profiling of Hosakote Taluk and understanding their water requirements and demands. ii. Identifying environmental and social impacts of the suggested remedies and to suggest mitigation measures to overcome these impacts. A preliminary feasibility report entitled, Integrated Water Supply project for Hoskote Town (2012), prepared by Infrastructure Development Department (IDD), Government of Karnataka, presents the water supply system and scenario of the Taluk. The primary objective of the project is to explore feasibility to cater to existing & future water demand of Hosakote City by providing treated water from Doddakere Lake while supplementing the source of incoming water to the lake with water from Bellandur Lake after tertiary treatment. Bellandur Lake receives water primarily from Koramangala- Challaghatta Sewage Treatment Plant (STP) which treats the sewerage to tertiary level. A report entitled Ground Water Information Booklet, Bangalore Rural District; prepared by Central Ground Water Board, Ministry of Water Resources, Government of India, reports that most of Karnataka State’s ground water is in critical condition. It addresses the need to stop exploration of ground water and presents ways to improve the water resources of the Taluk

Quality Indices of Fluoride Concentration in Groundwater of Malkhaid Sub-basin, Gulbarga District, Karnataka

: Groundwater is the major source of drinking water in the study area., High fluoride content above permissible limit (>1.5 mg/l) are recorded at many places in groundwater samples of study area resulting in health hazards, causing dental and skeletal fluorosis. The major litho-units of study area are limestone, shales and Deccan traps. Integrated quality indices, multi-criteria decision making and sensitivity function analyses are used to analyze the groundwater samples using mathematical modelling. The geochemistry of groundwater relating major ionic constituents with fluoride using statistical analysis are carried out to understand the source and mechanism of enrichment of fluoride in groundwater. Based on multi-criteria decision making approach, the majority of the samples fall under the category of decreased quality region. Results of sensitivity function analyses indicate, waters belong to less recommended range. Saturation indices of fluoride minerals are interpreted using Chadha’s diagram. The geochemical analysis indicates the alkalis, viz., Ca2+ and Mg2+ indicated negative correlation with fluoride. This could be due to the oversaturation of carbonate minerals as inferred from saturation indices. Positive correlation between Fwith that of Na+ ions and pH is observed, which may be due to the rock dissolution processes. From the above studies it is interpreted that the mineral dissolution through rock water interaction is the major controlling process of fluoride enrichment in groundwater. Water treatment and de-fluorination at village levels are to be considered for using groundwater for drinking purpose

Nitrate levels in Hoskote taluk, Bangalore rural district, Karnataka,

Hoskote Taluk is one of the eight Taluks of Bangalore Rural District in Karnataka with a current approximate population of 3, 03, 428; the total water demand comes out at around 49.5 MLD @ 135 LPCD, (WHO Standard).Water and health are inter-twined in many ways and it is important to address the increasing need for adequate and safe water to protect both the people and the planet. Water is one of the earth’s most precious and threatened resources and health is each one of our most precious resource. Hence we need to protect and enhance them both. In the recent years, groundwater in the study area forms the mainstay of drinking water supply for meeting the community needs. But the threat of groundwater contamination is looming large over the study area. Contamination of groundwater source could occur due to pollution from industrial, agricultural and community living. Also, geology of the region has an important bearing on certain dissolved constituents in the groundwater supply, in particular like fluorides. In view of this, it is of paramount importance to look for and to evaluate the Nitrate levels in the drinking water of the area and assess their status of potability in the light of the criteria laid by Bureau of Indian Standards (B.I.S). Nitrate disease caused by excess intake of Nitrate. Results show that there is a definite contamination of ground water in the study area with respect to Nitrate and a clear correlation between the ill health faced by the public and ground water contamination is notice

Physical volcanology and geochemistry of Paleoarchean komatiite lava flows from the western Dharwar craton, southern India: Implications. for Archean mantle evolution and continental growth.

Palaeoarchaean (3.38–3.35 Ga) komatiites from the Jayachamaraja Pura (J.C. Pura) and Banasandra greenstone belts of the western Dharwar craton, southern India were erupted as submarine lava flows. These high-temperature (1450–1550°C), low-viscosity lavas produced thick, massive, polygonal jointed sheet flows with sporadic flow top breccias. Thick olivine cumulate zones within differentiated komatiites suggest channel/conduit facies. Compound, undifferentiated flow fields developed marginal-lobate thin flows with several spinifex-textured lobes. Individual lobes experienced two distinct vesiculation episodes and grew by inflation. Occasionally komatiite flows form pillows and quench fragmented hyaloclastites. J.C. Pura komatiite lavas represent massive coherent facies with minor channel facies, whilst the Bansandra komatiites correspond to compound flow fields interspersed with pillow facies. The komatiites are metamorphosed to greenschist facies and consist of serpentine-talc ± carbonate, actinolite–tremolite with remnants of primary olivine, chromite, and pyroxene. The majority of the studied samples are komatiites (22.46–42.41 wt.% MgO) whilst a few are komatiitic basalts (12.94–16.18 wt.% MgO) extending into basaltic (7.71 – 10.80 wt.% MgO) composition. The studied komatiites are Al-depleted Barberton type whilst komatiite basalts belong to the Al-undepleted Munro type. Trace element data suggest variable fractionation of garnet, olivine, pyroxene, and chromite. Incompatible element ratios (Nb/Th, Nb/U, Zr/Y Nb/Y) show that the komatiites were derived from heterogeneous sources ranging from depleted to primitive mantle. CaO/Al2O3 and (Gd/Yb)N ratios show that the Al-depleted komatiite magmas were generated at great depth (350–400 km) by 40–50% partial melting of deep mantle with or without garnet (majorite?) in residue whilst komatiite basalts and basalts were generated at shallow depth in an ascending plume. The widespread Palaeoarchaean deep depleted mantle-derived komatiite volcanism and sub-contemporaneous TTG accretion implies a major earlier episode of mantle differentiation and crustal growth during ca. 3.6–3.8 Ga