Conference Papers
Distribution of Benthic Ostracoda in Surface and Subsurface Backwater Sediments of Ernakulam, Kerala, Southwest Coast of India: Microenvironmental Implications
SKU:
C-63297
Fourteen surface and two core sediment samples were collected from the backwaters of Cochin, Kerala, southwest coast of India, in order to study the systematics and distribution of Recent Ostracoda. The ostracod taxa were separated from the sediments applying standard micropaleontological techniques. A total of 20 Ostracod species belonging to 17 genera and 8 families were identified. Sediment parameters such as CaCO3, organic matter and sand-silt-clay ratio were estimated for the surface as well as core samples in order to determine the relationship between substrate and Ostracoda populations, and to evaluate the favoured substrate of dominant species populations. The down core distribution of sediment parameters and ostracod assemblages is presented. Based on this data we determine that ostracods favour silty-sandy substrate environments. The rate of sedimentation was determined based on the ratio between the carapace and open valves of Ostracoda. The benthic ostracod fauna recorded is characteristic of a tropical, brackish to epi-neritic environment and few warm, shallow marine species occur in the backwaters of Cochin, may be due to the tidal influence.
Distribution of Recent Benthic Ostracoda off Rameswaram, Palk Strait, Tamil Nadu, South East Coast of India
SKU:
C-63296
An investigation to record spatial and seasonal distribution of recent benthic ostracoda was carried out along two transects (East and Northeast) off Rameswaram island of Tamil Nadu coast, India. Thirty sediment and bottom water samples were collected during January 2011 and April 2011 and analysed for various physico-chemical and sediment characteristics using standard procedures. The top 4 cm sediment was preserved in 10% formaldehyde and later in the laboratory the live and total population of Ostracoda was determined using the rose Bengal stain technique. Faunal frequencies for benthic ostracods were computed and correlated with physico-chemical and sediment characteristics. The correlation reveals that ostracod frequency has a positive correlation with sandy substrate and negative correlation with clay substrate and OM%. Faunal frequencies increased by 3 times during summer (April 2011) although values of physico-chemical and sediment characteristics do not show considerable variation from January 2011. The east transect is proximal to the coral reef and characterized by sandy substrate in both seasons, supports high populations and therefore is more congenial for ostracod proliferation. Finally, environmental variables have been correlated with those measured three decades ago to understand the causes for variations.
Drinking Water in Odisha: Resource, Status and Future Strategies
SKU:
C-164717
The state of Odisha is spread over an area of 155707 square kilometres on the eastern coast of India which is 4.74 percent of the land area of the country. It has coastline of 480 kilometres along the Bay of Bengal. The state receives a long term average annual rainfall of 1452 mm compared with the national average of 300 - 650 mm. There are 8 major river basins covering the entire state. Drinking water supply in the urban areas of the state is mostly from surface water and in rural areas it is mostly from ground water. The status of the surface and ground water resources of the state has been discussed as per the data available from the department of water resource (DOWR) and the Central Ground Water Board (CGWB). The available data indicate to a very severe water stress situation in the year 2051. The ground water resource of the state is discussed in the light of the available data. As on 2013 the net ground water availability is 16.69 BCM, the annual draft 5.02 BCM. The stage of development is 30 percent. The drinking water supply in the urban and rural areas of the state is discussed. The domestic demand, and industrial demand of surface water in the year 2051 appears to exceed the dependable flow in all the major river basins of the state. Various strategies to conserve and augment the water resources for an optimum management keeping in mind the effects of climate change are enumerated. The important aspects of the Odisha Water Policy (2007) find mention in the paper.
Early Paleocene Planktic Foraminifers and Stratigraphy, Jaisalmer Basin, Rajasthan
SKU:
C-63307
Early Paleocene planktic foraminifera (Zones P1c to P4) from well sections (Sanu, Sam, Tanot, Ram-1, GTF-1) are reported from the Jaisalmer Basin. The Subzone P1c is characterized by the hemipelagic early Danian species Globoconusa daubjergensis, Eoglobigerina edita, Praemurica pseudoinconstans, P. inconstans, Parasubbotina pseudobulloides, Subbotina triloculinoides and Globanomalina compressa. Zone P2 is identified by the total range of Praemurica uncinata and Eoglobigerina spiralis and Zone P3 by the occurrence of Igorina pusilla in association of Morozovella angulata and M. conicotruncata. Larger benthic foraminiferal species, such as Assilina dandotica, are abundant in the interval identified as Zone P4 characterized by Globanomalina pseudomenardii, Morozovella velascoensis, Igorina albeari, I. tadjikistanensis, Subbotina velascoensis, S. triangularis, Acarinina soldadoensis, and Parasubbotina varianta. This indicates a lower P4 stratigraphic range for Assilina dandotica, which was assumed to appear in Zone P5 (= Standard benthic foraminiferal Zone 5). The Paleocene-Eocene boundary was identified based on Acarinina africana and A. sibaiyaensis marking the Zones P5 to E1 interval.
Effect of Temperature and Salinity on Stable Isotopic Composition of Shallow Water Benthic Foraminifera: A Laboratory Culture Study
SKU:
C-63288
Quantitative estimation of past climatic parameters from stable isotopic composition of foraminifera relies on estimating the precise relationship between stable isotopic composition of the species analyzed and the physico-chemical factors of the seawater. This relationship can be established either on species collected from surface sediments or in plankton tows. Another method to establish such relationships is by subjecting the foraminiferal species to known physico-chemical parameters in the laboratory. In the present work, shallow water benthic foraminiferal species, Rosalina sp. and Pararotalia nipponica were subjected to different combinations of seawater temperature (25?C to 35?C) and salinity (25 psu to 37 psu) in the laboratory to assess their stable oxygen isotopic composition and its applicability in determining seawater temperature and salinity. The stable isotopic ratio of the species shows no consistent relationship with salinity. The relationship between ?18O foraminifera and seawater temperature is more consistent for P. nipponica than for Rosalina sp. Salinity appears to have less control on ?18O foraminifera as compared to the seawater temperature, within the studied salinity and temperature range. The study shows that the changes in ?18O of P. nipponica can be used effectively to infer past seawater temperature changes.
Eocene Depositional Sequence and Cycles in Kutch
SKU:
C-105409
Two depositional sequences are recognized in the Eocene succession of Kutch. The Sequence-I in the lower part is of Ypressian age and 6 Myr duration. A hiatus of about 7 Myr is estimated between the Deccan trap and Sequence-I and a hiatus of equal magnitude exists between sequences I and II. The Sequence-II is of Bartonian (and possibly extending to late Lutetian) age and a major part of it formed during a small interval of planktic foraminiferal zone E12 (0.5 Myr). A hiatus of ~7 Myr is estimated between the two sequences. Five depositional cycles of low amplitude, low frequency and confined to inner shelf are inferred in Sequence-I. In contrast, eight depositional cycles are recognized in Sequence-II and cycles in the lower part are of high amplitude, reaching to middle shelf. The average cyclicity is of > 1 Myr duration in Sequence-I and < 0.1 Myr duration in Sequence-II.
Estimating Water Resource in Wokha, Nagaland Using Geo-Informatics
SKU:
C-165858
Nagaland, a north eastern state of India has been suffering from water crisis since decades. Water scarcity has become chronic and perennial in many districts like Wokha. We have estimated the surface water resource and ground water potential zones in Wokha with the integrated use of Landsat OLI, LISS IV and Sentinel-1A SAR data. Thematic maps of LULC, slope, drainage density and fractional impervious surface are prepared. Published thematic maps of lithology, major faults and soil type are used.Our analysis shows that considering existing surface water resource and the population density of Wokha, the water crisis is more of economic nature than physical. Forested wetland and hydrologic wetlands are identified as potential new resource. Hydrologic wetlands are perennial water resources. These wetlands can act as an alternative water source. Further, our study shows that around 58% of the district have good ground water potential and they are well distributed throughout the terrain.
Evaluating Variability of Aerosol Concentration in Coal Mining Areas: A Case Study from Patratu Coal Mining Region, Jharkhand
SKU:
C-95904
The monitoring of aerosol concentration becomes a high environmental priority in mining and adjoining areas and it is one of the key parameters to assess the atmospheric pollution. Human activities, coal mine fire, overburden dumping, transportation and other mining operations or coal based industries are responsible for increasing pollution in mining regions. In the present study aerosol optical thickness (AOT) was determined using handheld MICROTOPS II sunphotometer at five different wavelengths (340, 500, 870, 936 and 1020 nm), along with temperature and precipitable water vapour (PWV) which are estimated from the measurements of solar intensity at 936nm and 1020nm during peak winter period. The pattern of measured aerosol concentration along with water vapour and temperature were spatially analyzed in GIS environment with reference to land use/land cover map of the region. The study revealed that the study area (381 sq. km) was dominated by wasteland (98.64 sq. km, 25.89%) and forest cover 136.50 sq. km (35.82%) as mapped during the year 2009. The area under coal mining is 16.87 sq. km (4.42%), built-up land is 33.88 sq. km (8.89%) and cropped area is about 62.29 sq. km (16.35%). The spatial distribution of AOT in the wavelength region 340-1020nm exhibits that the AOT values are higher for smaller wavelengths and lower for larger wavelengths indicating the dominance of fine particles in the atmosphere compared to larger sized particles. In this study, the AOT wavelength 340nm is therefore taken for further analysis due to its higher variation in the area as well as its harmful effect on human health. It was observed that AOT concentration was higher in the industrial area in the vicinity of thermal power plant, Sponge iron factory, mining area and coal based small industries located within the urban area, whereas lower in the forest and low population density areas within the agricultural lands.
Evidences of Partial Melting of Sulphides from Ajjanahalli Gold Deposit, Dharwar Supergroup, Karnataka
SKU:
C-165465
The Ajjanahalli gold deposit is a remobilized stratabound as well as stratiform type deposit where gold concentration is found within sulphidic BIF along several epigenetic quartz and quartz-carbonate veins. The sulphide minerals associated with the deposit are dominantly pyrite, pyrrhotite, arsenopyrite, sphalerite, chalcopyrite, Bi-sulphide, PGE minerals along with native phases of gold, bismuth and gold alloys such as auricupride, electrum and allopalladium. Almost all the sulphides occurring in the area have undergone deformation. There are two generations of sulphides, the primary sulphides along with sulfosalts occur as relicts and skeletal crystals, corresponding to the peak metamorphic assemblage of the area. The 2nd generation sulphides are observed as idioblastic crystals and porphyries around which the silicate and ductile sulphides have swirled. The remobilization and concentration of sulphides and gold in the Ajjanahalli gold deposit has been assisted by hydrothermal fluids as well as melting. Various studies have constrained the temperature of metamorphism at Ajjanahalli between 450 to 550?C. Studies have shown that pyrite and arsenopyrite can react to form pyrrhotite + melt at temperatures as low as 251?C. In the current study, an attempt has been made to study the evidences of sulphide melting from field, petrographic and ore microscopic studies as well as mineral chemistry. The recognition of features in sulphides which show indications of melting at the time of peak metamorphism provides a possible explanation for the erratic pattern of distribution of gold in the deposit.
Exploration for Gold near Ajjanahalli, Chitradurga Greenstone Belt, Karnataka
SKU:
C-165468
Ajjanahalli Gold Field is a well-known BIF-hosted gold-bearing area of Karnataka. The gold prospects are hosted by the volcano-sedimentary sequence of Chitradurga Greenstone Belt in Western Dharwar Craton. The major lithologies are metabasalts, Banded Iron Formation (BIF) and argillite-greywacke of Hiriyur Formation of Chitradurga Group. Three phases of deformation have been noticed in the area. The bands are folded and repeated several times exhibiting both antiformal and synformal closures with fold axes plunging towards north. Multiple generations of quartz veins traverse all lithounits. Potentiality of gold mineralization in Ajjanahalli area has already been proved by earlier investigations in the Ajjanahalli Main Block and Western Block. Hutti Gold Mining Limited (HGML) had exploited the Ajjanahalli Main block and Western block during 1995- 2002 and recovered 963.4 kg of gold from 0.60 Mt of ore. Geological Survey of India (GSI), through systematic exploration under UNFC-G4, G3 and G2 stages is continuously augmenting the gold resource in Ajjanahalli Gold prospects. The work reframed the adjacent area of Ajjanahalli Main Block into several exploration blocks such as Ajjanahalli-A, B, C, D, E, F, G and H, Gungurpenta and Gungurpenta South. Gold Resource has been established by G3 stage of exploration in Ajjanahalli-A, B and G blocks by GSI. G3 stage of exploration is completed in block-F but no potential mineralization is established. G2 stage of exploration was carried out in blocks-C, D and E by GSI and Resource has been established. Mineral Exploration Corporation Limited (MECL) has completed G2 stage exploration in block-A. G4 stage of exploration was carried out in Gungurpenta, Gungurpenta South and Ajjanahalli-H Blocks. The total Resource in Ajjanahalli prospects is 7.34 Mt with 1.43 g/t average grade and 2.76m average width.
Exploration for PGE Mineralization in the Western Dharwar Craton
SKU:
C-63389
Selected mafic-ultramafic complexes (MUCs), about the only targets of PGE mineralization in the western Dharwar craton (WDC) (Long 73?46'-73?38', Lat 12?38'-16.0'), have been assessed for PGE potential on the basis of SEM-EDS PGM data and precise partial (for Pt + Pd)/complete PGE analysis of whole rock samples collected from chromite and/or sulphide bearing zones of the complexes. The complexes examined constitute Nuggihalli, Holenarasipur and Rangapura belts of older (Sargur) Mesoarchean supracrustal group and Kankavali-Wazda, Usgao, Devaranarasipura, Shankraghatta and Channagiri of the younger (2.9-2-5 Ga) Dharwar supracrustal group. Besides, the Ajjanahalli gold-bearing sulphidic BIF, graphitic phyllites/schists and quartz veins, which are reported to be abnormally high in Pd have also been tested. Our exploration results do not suggest existence of PGE mineralization (of commercial value) associated with either any of the older group of MUCs or the sulphidic units of Ajjanahalli mentioned. The complexes like those constituting the Hanumalapur block of the Channagiri MUC with differentiated layered characteristics, chromite zone, association of anorthosite patches and V-Ti magnetite seams, and massive metaultramafite of Shankaraghatta enclosing Ni Sulphide zone bear evidence of PGE mineralization of commercial importance. Usgao complex too perhaps has the potential, but its location in a protected bioreserve has prevented further investigation and verification. On the whole, in the WDC, the younger MUCs with chromite and/or Ni(-Cu) sulphide association are favorable targets for PGE mineralization of (commercial) importance. Apart from concerted efforts to search for newer deposits of commercial value, there is a pressing need to accelerate assessment of the suitability of the already discovered deposits for commercial exploitation.
Exploration Strategies for Ni-Cu-PGE and Chromite in the Ultramafic-Mafic and Related Rocks of Karnataka, India
SKU:
C-63390
Magmatic ore deposits (MOD) as exemplified by the Ni-Cu-PGE sulphides, chromites and V-Ti magnetites and manifested in diverse groups of ultramafic-mafic rock suites range in ages from early Achaean to Phanerozoic. As part of the year long training programme for exploration strategies in MOD at the Nuggihalli schist belt (lectures, orientation survey and mapping) we had compiled and evaluated the geological milieu of ultramafic-mafic rock association of the world with special reference to the older (Sargur) and younger (Dharwar) schist belts in the western Dharwar craton in Karnataka. Based on such scrutiny, the following strategies and suggestions have been made.
Freshwater Sources of Kerala ? Hydrometeorological Scenarios, Environmental Threats and Management Strategies
SKU:
C-165441
Kerala, the southwestern coastal state of India receives an annual average rainfall of about 3000 mm. However, providing uninterrupted freshwater supply to the community round the year is a major challenge to the water managers in the state because of several factors including high population density, increased human interventions in the river catchments, environmental effects due to climate change, etc. It has now become more and more evident that the nature and contributions of rainfall, especially its pattern, have been changing drastically over the years, aggravating the incidences of floods and landslides in the wet season and water scarcity in the summer months. Although such incidences were minimal in the pre-liberalization period (1956-1990), their recurrence and impacts are getting aggravated in the post-liberalization period - a period that witnessed severe environmental degradation due to rapid urbanization and economic development in the region. As per the records of the gauging stations, the number of no-flow/low flow days are found to be increasing even in the lowland reaches of the major rivers in the state. The adverse impact of unabated groundwater ion/pumping is on the rise in many parts of the state, as the activity is being carried out without due regard to the safe yield and natural recharge capability of the aquifer systems. The rapidly changing water scenario of the state in the pre-and post-liberalization periods needs a thorough investigation, especially in regard to the structure and functions of its near surface terrestrial environment called the Critical Zone. The Critical Zone, the zone extending from tree top to the aquifer bottom, of the state is under immense stress due to many of the aforesaid reasons. The stress in the Critical Zone will have a direct effect on the quality, quantity and availability of the freshwater resources in the surface and subsurface reservoirs, which needs to be addressed adequately for laying down strategies for the conservation and management of the freshwater sources.
Geochemical Study of the Ultramafic-Mafic Plutonic and Volcanic Suites of the Nuggihalli Schist Belt, Western Dharwar Craton
SKU:
C-63393
Petrology, mineral chemistry and whole-rock geochemistry of the intrusive, layered (>3.1Ga) as well as the extrusive volcanic suites of the Nuggihalli Schist Belt (NSB) are presented in this paper. The dunite-metaperiodotite, serpentinite and syngenetic-stratiform chromite association forms the lower part of the Tagadur ultramafic-mafic complex. The upper part of the intrusion is represented by meta-gabbro-meta-anorthosites with vanadiferous titano-magnetite bodies. The extrusive ultramafic rocks are represented by pillowed, spinifex textured peridotites and high-Mg basalts of komatiitic affinity. Petrological studies of the ultramafic rocks reveal primary cumulus textures exhibited by olivine and chromite and secondary alterations, low-grade metamorphism and deformation. The chromitites hosts a variety, of unusual accessory silicate phases such as corundum, diaspore, rutile, zircon, monazite and baryte in addition to olivine, serpentine and amphibole (anthophyllite), chlorite (clinochlore). Native phases such as gold, silver, copper, iron and tin and other Fe-Ni-Cr-Cu alloys are found associated with cumulus chromite grains in the massive chromitites. Trace and REE geochemistry of these ultramafic-mafic suite reveal significant LREE enrichment and depletion, negative Ce and Eu anomalies and flat to enriched HREE pattern suggestive of their derivation from parental komatiitic magmas by high degree of partial melting of a metasomatized depleted mantle source in a subduction zone environment. Trace element and PGE geochemistry of the chromitites indicate that they are PGE poor chromitites but enriched in Au and other base metal alloys, formed under changing oxidizing and reducing conditions resultant of alteration of the primary sulphides by desulphidation processes during the Mesoarchaean. The associated ultramafic (peridotitic) and mafic (basaltic) komatiites devoid of chromite and PGE represent primitive melts, most probably derived from high degrees of partial melting of a common depleted mantle source.