A B C D E F G H I J K L M N O P Q R S T U V W X Y Z All
Shankar, R.
- Workshop on Isotope Geochemistry and Radiochemistry in the Marine Environment May 22-30,2000
Authors
1 Department of Marine Geology and Geophysics, Mangalore University, Mangalagangotri 574 199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 56, No 3 (2000), Pagination: 340-340Abstract
No Abstract.- Behaviour and Distribution Patterns of Particulate Metals in Estuarine and Coastal Surface Waters near Mangalore, Southwest Coast of India
Authors
1 Department of Marine Geology, Mangalore University, Mangalagangotri - 574 199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 55, No 2 (2000), Pagination: 157-166Abstract
Physico-chemical properties of water (pH, dissolved oxygen, salinity and suspended matter concentrations) and geochemistry (Cu, Pb, Zn, Ni, Co, Mn, Fe, Al, Ca and loss-on-ignition) of suspended particulates have been measured for the first time in the Netravati-Gurpur estuary and the adjacent coastal environment, southwestern India. The main objective was to understand the influence of physico-chemical properties of estuarine and coastal waters on the behaviour, association and dispersal patterns of particulate metals.Suspended particulate matter (SPM) from the estuarine and coastal environments have higher Cu, Pb and Zn (by factors of 1.5-2.7) than the Netravati-Gurpur riverine SPM, indicating enrichment of these metals with increasing salinity. In contrast, Al, Fe, Mn, Co and Ni contents and the corresponding metaltal ratios are marginally lower (by factors of 1.1 - 1.5) than those for riverine SPM, suggesting not only a decrease of terrigenous influx seaward, but also removal of trace metals from the particulate phase. R-mode factor analysis of the data has shown that detrital particles (with Fe oxide coating), clays and Mn-oxide are the major factors that control particulate metal association. Factor score distribution patterns suggest that detrital particles coated with Fe oxide are deposited in the estuary and nearshore region, whereas clays and Mn-oxide seem to be transported further into the coastal sea. Copper, Pb and Zn show an anomalous behaviour and are negatively loaded on all the three major factors.
Keywords
Estuarine Geochemistry, Particulate Metal Association, Elemental Dispersal Patterns, Netravati-Gurpur Estuary, West Coast, India.- Geoscience Awareness Programmes at Mangalore University
Authors
1 Department of Marine Geology, Ocean Science and Technology Cell, Mangalore University, Mangalagangotri 574 199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 55, No 1 (2000), Pagination: 104-105Abstract
No Abstract.- Palaeomonsoon History During the Late Quaternary: Results of a Pilot Study on Sediments from the Laccadive Trough, Southeastern Arabian Sea
Authors
1 Institute of Marine Science, University of Alaska Fairbanks, Fairbanks, AK 99775, US
2 Department of Marine Geology, Mangalore University, Mangalagangotri 574 199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 53, No 4 (1999), Pagination: 401-406Abstract
Stratigraphic sections of carbonate-free sediments at 5-10 cm intervals of a 1.2 m core (CA 3800) from the Laccadive Trough (water depth: 1724m) were analyzed for organic carbon (OC), nitrogen (N), OC/N, δ13C and δ15N, using a continuous flow stabte isotope mass spectrometer. Data on CaCO3 were also used. The generally high concentrations of OC (0.9-2.16%) and CaCO3 (32.2-54.4%) presumably reflect high productivity at the core site. The predominantly marine origin of the OC is indicated by the -19.6 to -18.2 δ13C values.
Significantly higher carbonate is recorded in the Holocene than in the late Glacial, presumably reflecting increased Holocene productivity resulting from enhanced upwelling and summer monsoon during the Interglacial than Glacial. The late Glacial to Holocene increase in the mean OC/N from about 13 to 16 and δ15N by 2‰, presumably mirrors a relative increase in denitrification in the oxygen-deficient zone coinciding with enhanced Holocene productivity in the southeastern Arabian Sea. Our interpretation on the paleoproductivity is consistent with those for the western Arabian Sea proposed by earlier workers for the above time period.
Keywords
Marine Geology, Palaeomonsoon, Quaternary, Carbonate-Free Sediments, Laccadive Trough, Arabian Sea.- Saving on the Cost of Perspex Liner Used in Sediment Coring Operations
Authors
1 Department of Marine Geology, Mangalore University, Mangalagangotri 574 199, Karnataka, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 31, No 6 (1988), Pagination: 591-593Abstract
The use of polythene tube inside the expensive perspex liner in sediment-coring operations helps avoid longitudinal splitting of the perspex liner so that the latter can be repeatedly used. The merits and demerits of such a practice are discussed. After weighing the pros and cons, it is found that the use of polythene tube brings down the recurring expenditure on perspex liner practically to nil and at the same time it offers many advantages.- How old are the Old Mine Workings of Ingaldhal (Karnataka) ?
Authors
1 Department of Marine Geology, Mangalore University, Mangalagangotri 574199, Karnataka, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 33, No 1 (1989), Pagination: 64-70Abstract
Two 14C dates (2070 ± 110 years B.P. and 1820 ± 100 years B.P.) on wooden logs which were used as supports in old workings of lngaldhal copper mines are reported here. These dates are discussed in a historical/archaeological perspective.- IUGS Commission on Geoscience Education and Training
Authors
1 Mangalore University, Mangalagangotri 574199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 36, No 5 (1990), Pagination: 546-546Abstract
No Abstract.- Geocbemistry and Magnetic Susceptibility of Surficial Sediments of the New Mangalore Port
Authors
1 Department of Marine Geology, Mangalore University, Mangalagangotri 574 199 (DK), IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 38, No 4 (1991), Pagination: 412-417Abstract
A geochemical study of surficial sediments of the New Mangalore Port has shown that there is no anthropogenic input of base metals (Cu, Zn, Pb, Mn and Fe). In comparison with the adjoining inner shelf sediments, Port sediments seem to have a higher proportion of detrital particles and hence relatively less organic matter. Manganese is found predominantly as adsorbed species. Other base metals are present in the lithogenous fraction. Organo-metallic association, reported by several workers for sediments, is not found in the Port sediments. Magnetic susceptibility of the sediments (Xm = 16.6 x 10-6 emu/g) is higher than that for shelf sediments. This is because of deposition of detrital particles of magnetic minerals in the nearshore area. The susceptibility values are not high enough to suggest any particulate pollution due to the Kudremukh iron ore loading operations at the New Mangalore Port.Keywords
Geochemistry, New Mangalore Port, Base Metals, Pollution.- Sedimentological Evidence for a Palaeobeach off Mangalore, West Coast of India
Authors
1 Department of Geology and Geophysics, University of Edinburgh, West Mains Road, Edinburgh EH93JW, GB
2 Institute of Environmental Studies, Tehran University, PO Box 14155-6135, Tehran, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 40, No 3 (1992), Pagination: 241-252Abstract
Sedimentological and SEM studies have been carried out on surface and sub-surface samples of outer shelf sands off Mangalore, west coast of India. The outer shelf sediments can be described as coarse sands, moderately sorted, nearly symmetrical to positively skewed and mesokurtic. Multi·group discriminant analysis of the data shows that the sands were deposited in a beach environment during Pleistocene when the sea level was lower than at present. SEM studies reveal mechanically formed features like 'v' pits and curved grooves, which also corroborate the beach environment of deposition. The' v' pits and grooves have been smoothened due to chemical etching of the grains as the latter were in contact with sea water subsequent to the Pleistocene-Holocene transgression. Similar sand in cores obtained from east of the palaeobeach indicates its extension beneath Recent sediments. The thickness of palaeobeach sand increases landward. The cores studied have recorded tbe marsh Get black colour and abundance of vegetative matter), beach (coarse sands) and inner shelf (clayey silt) environments that prevailed at the core site as the sea transgressed. It is proposed that the outer shelf sands were not covered by Recent sediments because of the insufficient supply of sediments from the small, west-flowing rivers of Peninsular India, entrapment of sediments in estuaries, and onshore transport of sediments in the West coast region.Keywords
Palaeobeach, Mangalore, West Coast, Pleistocene-Holocene, Sedimentology.- Magnetic and Sedimentological Studies of Netravati and Gurpur River-Bed Sediments, West Coast of India
Authors
1 Department of Marine Geology, Mangalore University, Mangalagangotri-574199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 44, No 4 (1994), Pagination: 413-426Abstract
Magnetic susceptibility and sedimentological studies have been carried out on Netravati and Gurpur river-bed sediments along the west coast of India to throw light on the distribution and movement of magnetic minerals in the riverine environment. The sediments studied are coarse to fine sands, platy to leptokurtic and poorly to well sorted. Granule to medium size sands dominate in the upstream segment. whereas very fine sand and silt+clay are either absent or of negligible importance. Netravati river-bed sediments have a two-fold higher bulk susceptibility than Gurpur sediments because the Netravati drainage basin has magnetite quartzites, amphibolites and garnetiferous biotite gneisses in contrast to granitoids found in the Gurpur drainage basin. This trend of susceptibility is seen for the 13 particle size fractions studied.
Magnetic minerals are concentrated in poorly sorted, fine grained sediments of Netravati river and in leptokurtic sediments ofGurpurriver. They are particularly enriched in the size range of 0.063-0.125 mm and to a lesser extent in the >4 mm fraction. Downstream decrease in susceptibility of both bulk samples and particle size fractions reflects on the vicinity or otherwise of sampling sites to the source of magnetic minerals in the drainage basin.
On the basis of bulk susceptibility data, it is.estimated that about 87% of sediment in the Netravati main river is derived from Kumaradhari river and 13% from Netravati (upstream) tributary. However. about 78% of particles >0.35 mm in size in Netravati main river are contributed by Kumaradhari river and 22% by Netravati (upstream) tributary. The bulk susceptibility of Ourpur river sediments shows that the Venoor hole is the dominant sediment contributor (83%) to the main river when compared to Hosangadi hole (17%). In contrast, Hosangadi hole contributes ca. 63% of the fine particles (0.55-1.0 mm) to the Gurpur main channel. This discrepancy could be attributed to the higher susceptibility of coarse fraction (> 1 mm) of Gurpur (main) river when compared to its tributaries.
Magnetite is the most important mineral that accounts for nearly a half of the susceptibility. Magnetite weight percentage and susceptibility are significantly correlated (r=O.50). About 21 % of the suspectibility is explained by ilmentite and garnets. Amphiboles, pyroxenes and other weakly magnetic minerals account for ca. 27% of the susceptibility. The residual fraction, censtituting ca. 60% of sample weight, explains only 8% of the susceptibility of samples.
Keywords
Sedimentology, Magnetic Susceptibility, River Sediments, Netravati and Gurpur Rivers, Karnataka.- Late Quaternary Variations in Sedimentation Rate in the Laccadive Trough, Southeast Arabian Sea
Authors
1 Department of Marine Geology, Mangalore University, Mangalagangothri-574 199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 45, No 6 (1995), Pagination: 689-694Abstract
Radiocarbon measurements of a core from the Laccadive Trough, SE Arabian Sea have yielded ages which show that sediments from the Pleistocene, Holocene and a transition zone can be recognized by virtue of colour variation. The mean sedimentation rate decreases from 4.11 to 3.15 cm/103yr for Pleistocene and Holocene respectively, witha peak of 6.36 cmcm/103yr determined for the transitional zone. A sediment slump or turbidite emplacement resulting from higher terrigenous influx during the transition period has been inferred. This is in contrast to the bioclastic turbidite of the central continental margin-pelagic region (off Bombay-Ratnagiri sector of western India). The decrease in sedimentation rate from Pleistocene to Holocene can be most likely ascribed to entrapment of riverine sediments in estuaries and continental shelf, as a result of Holocene sea level rise.
The mean sedimentation rate in the Laccadive Trough (3.84 cm/103yr) is lower than that on the northwestern continental margin of India (4.6-9.8 cm/103yr) because of relatively low terrigenous influx from the small west-flowing rivers of Peninsular India. The Holocene sediment thickness in the Laccadive Trough is 35 cm as against 50 cm in the northeastern Arabian Sea. The onset of environmental conditions representative of Holocene is estimated at ca. 9300 yr B.P. which corroborates the date proposed for the northern Indian Ocean.
Keywords
Sedimentation, Quaternary, Laccadive Trough, Arabian Sea.- Notes
Authors
1 Dept of Marine Geology, Mangalore University, Mangalagangotri 574199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 47, No 6 (1996), Pagination: 752-752Abstract
No Abstract.- Notes
Authors
1 Dept of Marine Geology, Mangalore University, Mangalagangotri 574199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 47, No 6 (1996), Pagination: 752-752Abstract
No Abstract.- Elemental Composition and Particulate Metal Fluxes from Netravati and Gurpur Rivers to the Coastal Arabian Sea
Authors
1 Department of Marine Geology, Mangalore University, Mangalagangotri- 574 199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 43, No 3 (1994), Pagination: 255-265Abstract
Physico-chemical parameters of water (pH, dissolved oxygen, salinity and suspended Particulate concentration) and geochemistry (Cu, Pb, Zn, Ni, Co, Mn, Fe, Al, Ca and organic matter) and magnetic susceptibility of suspended particulates have been measured, incidentally for the first rime. in two west-flowing rivers - Netravati and Gurpur - of southwestern India in order to understand weathering processes, to determine gross particulate metal fluxes to the coastal Arabian Sea and to decipher anthropogenic influences, if any. Physico-chemical parameters do not show significant variations because of the heavy fresh water discharge during southwest monsoon. The composition of Netravati and Gurpur rivers SPM (suspended particulate matter) are similar and characterized by enrichment of Al, Fe, Ni and Co but strong depletion of Ca in comparison with temperate and major rivers of the world. This is an imprint of the intense chemical weathering in the study area. Copper, Pb, Zn and Mn contents in Netravati and Gurpur R. SPM are lower than world river SPM, implying that there may not be significant anthropogenic input of these metals.
The gross particulate metal fluxes from the Netravati R. are considerably higher than those in Gurpur R, because of the former's high sediment discharge. However, the fluxes are significantly lower than those of Narbada and Tapti rivers.
Magnetic susceptibility of Netravati and Gurpur SPM is nearly the same, but substantially low (by a factor of three) when compared to the silt+clay fraction of river-bed sediments, indicating that dense magnetic minerals are not transported in suspension but as bed-load.
Keywords
Geochemistry, Marine Geology, West Coast, Arabian Sea.- Magnetic Susceptibility Stuldies of Surficial Sediments from the Deep Arabian Sea
Authors
1 Department of Marine Geology, Mangalore University, Mangalagangotri 574 199, IN
2 Department of Earth Sciences, Indian Institute of Technology, Powai, Bombay 400 076,, IN
3 ELF Aquitaine Petroleum, 1000 Louisiana, Houston, Texas 77002, US
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 43, No 2 (1994), Pagination: 159-167Abstract
A wide variety of processes such as volcanic activity, submarine and continental weathering, aeolian transport and authigenesis can account for the magnetic susceptibility of the deep Arabian Sea sediments. Preliminary studies of the magnetic fraction indicate that it is predominantly composed of pseudo-single domain and viscous magnetite. It is found that magnetic susceptibility can be used to estimate the approximate iron content of marine sediments.Keywords
Magnetic Susceptibility, Marine Geology, Arabian Sea.- Magnetic-Radiometric Monitoring of Particulate Pollution from Kudremukh Iron Ore Mines, Karnataka
Authors
1 Geology and Geophysics Department, Grant Institute, The University of Edinburg, Edinburg EH9 3JW, Scotland, GB
2 Department of Marine Geology, Mangalore University, Mangalagangotri - 574 199, IN
3 Physics and Astronomy Department, JCMB, The University of Edinburgh, Edinburgh EH9 3JZ, Scotland, GB
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 48, No 3 (1996), Pagination: 349-352Abstract
Kudremukh is the largest mechanised mining project in India. In spite of the steps being taken to arrest particulate pollution, it is feared that the pollution is significant. Using magnetic and radiometric properties of catchment soils, ores and tailings, the relative proportions of naturally weathered and man-made particles in the Bhadra river-bed sediments were estimated. Upstream of the mine and the tailings dam, the river bedload is composed principally of catchment soil materials (>97%). However, downstream of the mine segment the average mine waste component is about 47%. Magnetic methods are simple, rapid, inexpensive and non-destructive and can be employed on a routine basis in the environmental monitoring program at Kudremukh and other mines.- Elemental Distributions in Surficial Sediments and Potential Offshore Mineral Resources from the Western Continental Margin of India, (1994)
Authors
1 Department of Marine Geology, Mangalore University, Mangalagangotri - 574 199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 48, No 2 (1996), Pagination: 241-242Abstract
No Abstract.- Geoscience Education
Authors
1 Department of Marine Geology, Mangalore University, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 50, No 5 (1997), Pagination: 660-661Abstract
No Abstract.- A Laboratory Study of the Flocculation of Dissolved Heavy Metals in Kali RiverDuring Estuarine Mixing, West Coast of India
Authors
1 Department of Marine Geology, Mangalore University, Mangalagangotri 574 199, IN
2 Marine Chemistry Division, Bedford Institute of Oceanography, Dartmouth, NS-B2Y 4A2, CA
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 50, No 6 (1997), Pagination: 753-758Abstract
River water-sea water mixing experiments were carried out to study the time dependence of flocculation process, the flocculation behaviour of dissolved Cu, Pb, Zn, Ni, Co, Mn, Cr and Fe in the Kali estuary. Flocculation appears to be maximum at high salinities (>25‰) and is rapid, about 7 to 60% of the dissolved metal content flocculating within half an hour of mixing. This brings out the role of sea water as a powerful flocculating agent for the dissolved load of river water.Keywords
Marine Geology, Pollution, West Coast, Kali River, Karnataka.- Factors Controlling Vertical Fluxes of Particles in the Arabian Sea
Authors
1 National Institute of Oceanography, Dona Paula, Goa - 403 004, IN
2 Department of Marine Geology, Mangalore University, Mangalagangotri - 574 199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 54, No 4 (1999), Pagination: 369-378Abstract
Particle fluxes were measured using six time-series sediment traps at three sites in the western (16°20' N; 60°30' E), central (14°31' N; 64°46' E) and eastern (15°31' N; 68°43' E) Arabian Sea. Trap deployment depths were between 900 and 3000 m and collection period was from December 1992 to February 1994.
Annual particle fluxes showed an east-west trend with minimum fluxes (22.25 gm-2) in the eastern Arabian Sea and maximum fluxes (69.81 g m-2) in the western Arabian Sea. Carbonates, contributed mainly by foraminifers and coccolithophorids, are the dominant component in all the traps. Opal fluxes were maximum in the western Arabian Sea. At all the locations, lithogenic percentages increased with depth whereas organic carbon percentages decreased. Particle flux patterns show a strong seasonality with peak fluxes during the southwest (SW) monsoon (June to September). Relatively high fluxes were also observed during the northeast (NE) monsoon (December to February).
In the western Arabian Sea, particle fluxes are dominated mainly by carbonates during the early SW monsoon but by biogenic silica during the fate SW monsoon. The increase in particle fluxes during the early SW monsoon is related to variations in the mixed layer depth which, in turn, is controlled by the strength of the Findtater Jet and the curl of the wind stress. The increase in biogenic silica fluxes during the late SW monsoon is related to the advection of nutrient-rich water from the Oman and Somali upwelling areas. In the eastern Arabian Sea, particle fluxes are high during the NE monsoon due to the effects of winter cooling.
Keywords
Oceanography, Particle Flux, Sediment Trap, Sea Surface Temperature, Arabian Sea.- Mineral Magnetic Signature of the Early Holocene Intense Monsoon Conditions Recorded in Sediments from the Southwestern Indian Continental Margin
Authors
1 Department of Marine Geology, Mangalore University, Mangalagangotri-574199, IN
2 Ocean Science and Technology Cell, Mangalore University, Mangalagangotri-574199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 71, No 5 (2008), Pagination: 670-682Abstract
We studied three sediment cores from the southwestern continental margin of India for their mineral magnetic properties like magnetic susceptibility (χIf), susceptibility of anhysteretic remanent magnetisation (χARM), isothermal remanent magnetisation (IRM), saturation isothermal remanent magnetisation (SIRM) and inter-parametric ratios (χARM/χIf and χARM/SIRM), besides particle size characteristics. We demonstrate here that magnetic susceptibility and other mineral magnetic parameters can be used to demarcate the Early Holocene intense monsoon conditions. High values of χIf, χARM IRM20mT,SIRM and χARM/χIf and χARM/SIRM in the core-bottom indicate the peak wet period -11 to 9 ka B P. The values decrease rapidly at 8 38 ka B P, in concert with a reduction in rainfall. Our interpretation is strengthened by particle size data on a limited number of samples. Silt and sand contents are higher in the pre-8.38 ka B P, high-susceptibility samples than in the post-8.38 ka B P, low-susceptibility samples. The high values of concentration-dependent parameters and χARM/χIf in the core-tops are probably due to an increase in rainfall during the past 100-400 years. We also used the mineral magnetic parameters to correlate the sedimenct cores.Keywords
Rock Magnetism, Magnetic Susceptibility, Palaeomonsoon, Palaeoclimate, Holocene, Western Continental Margin of India.- First International Earth Science Olympiad, South Korea
Authors
1 Department of Marine Geology, Mangalore University, Mangalagangotri 574 199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 70, No 6 (2007), Pagination: 1095-1096Abstract
No Abstract.- Seoul Conference on International Earth Science Olympiad
Authors
1 Department of Marine Geology, Mangalore University, Mangalagangotri - 574 199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 65, No 3 (2005), Pagination: 379-379Abstract
No Abstract.- Report on the 32nd International Geological Congress, Florence, Italy
Authors
1 Geology Department, University of Delhi Delhi - 110 007, IN
2 Department of Marine Geology, Mangalore University, Mangalagangotri - 574 199, IN
3 Department of Geology, Bangalore University, Bangalore - 560 056, IN
4 P.G. Department of Geology, Khallikote Autonomous College, Berhampur - 760 001, Orissa, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 65, No 3 (2005), Pagination: 380-382Abstract
No Abstract.- Discussion Group on Earth Science Education in India
Authors
1 Department of Geology Mangalore University Mangalagangotri - 574 199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 65, No 5 (2005), Pagination: 654-654Abstract
No Abstract.- Website for School Teachers
Authors
1 Department of Marine Geology Mangalore University, Mangalagangotri - 574 199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 63, No 5 (2004), Pagination: 568-568Abstract
No Abstract.- International Workshop on Indian Monsoon and Climate Variability during Holocene
Authors
1 Department of Marine Geology, Mangalore University, Mangalagangotri 574 199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 64, No 1 (2004), Pagination: 105-107Abstract
No Abstract.- Marketing Earth Science Education in The Netherlands
Authors
1 Department of Marine Geology, Mangalore University, Mangalagangotri - 574 199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 61, No 2 (2003), Pagination: 239-239Abstract
No Abstract.- Prof P. G. Cooray (1921-2003)
Authors
1 Department of Marine Geology, Mangalore University, Mangalagangotri - 574 199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 62, No 3 (2003), Pagination: 389-390Abstract
No Abstract.- Geochemistry of Shelf Sediments off Mulki on the Southwestern Coast of India and their Palaeoenvironmental Significance
Authors
1 Institute of Environmental Studies, Tehran University, P.O. Box 14155-6135, Tehran, IR
2 Department of Marine Geology, Mangalore University, Mangalagangotri - 574 199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 58, No 1 (2001), Pagination: 37-44Abstract
A sediment core collected from the shelf (50 m water depth) off the Mulki-Pavanje river mouth has been studied for down-core variations of base metals, magnetic susceptibility (xm) and partitioning of metals in various accumulative phases of sediment, to understand the impact of late Quaternary sea level fluctuations on shelf sedimentation processes.The 192 cm-long core may be demarcated into two zones: the lower (140 to 192 cm) dark green to greenish black clayey silt with abundant plant debris; and the upper (0 to 140 cm) light green to dark green silty sand. Sediments of the lower zone are characterised by higher Cu, Zn, Pb, Co, Mn, Fe, Al, xm and organic matter contents and higher metal/Al ratios, but lower Ca, and Pb/Al and Mn/Al ratios when compared to the upper zone indicating textural control on the geochemistry of sediments. Although Mn is high in the lower zone, the low Mn/Al ratios suggest that a part of Mn has been remobilised under anoxic-sulphidic conditions. Higher Pb/Al ratios in the upper zone may not imply mobilisation of Pb, but may be suggestive of anthropogenic input of this element from the use of leaded petrol in modern times.
Geochemical and textural variations of these sediments suggest changes in the depositional environments: Sediments of the lower zone were deposited in a marshy environment when the core site was close to the shore during the late Pleistocene low stand of sea level. The late Quaternary sea level rise led to a shift in the depositional environment - from marsh to a still stand beach environment- when silty sands were deposited. Although the core site has been in the shelf since the beginning of Holocene, there has not been much sedimentation not only because of the negligible quantity of sediment supplied by the small west-flowing rivers but also due to the rapid rise in sea level during early Holocene. The reconstructed depositional history of the core is in consonance with the recently proposed sea level curve for the western continental margin of India.
Keywords
Geochemistry, Late Quaternary, Sea level Fluctuations, western Continental Shelf, Mulki, Karnataka.- National Workshop on Teacher Education in Environlmental Magnetism
Authors
1 Ocean science and Technology Cell, Mangalore University, Mangalagangotri-574 199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 58, No 1 (2001), Pagination: 81-82Abstract
No Abstract.- Indian Monsoon and Climate Variability during the Holocene: An Introduction
Authors
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 68, No Spl Iss 3 (2006), Pagination: 343-352Abstract
No Abstract.- A Multi-Decadal Rock Magnetic Record of Monsoonal Variations during the Past 3,700 Years from a Tropical Indian Tank
Authors
1 Department of Marine Geology, Mangalore University, Mangalagangotri 574 199, IN
2 Birbal Sahni Institute of Paleobotany, 53 University Road, Lucknow 226 007, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 68, No Spl Iss 3 (2006), Pagination: 447-459Abstract
We have explored the potentia1 of using magnetic susceptibility( χif) as a proxy for past rainfall variations in a tropical region, and also the potentia1 of tank-bed sediments from Southern India as a paleoarchive The 3,700-year rock magnetic record from Thimmannanayakanakere (14°12 N, 76°24 E), a smaH tank near Chitradurga town, Karnataka, exhibits considerable fluctudtions in χif Discountlng the possibilitestres of magnetite from biogenic and anthropogenic sources and of dissolutio of magnetic minerals, the χif signal must be related principally to rainfall in the tank-catchment There is a good correlation of χif with instrumental rainfall data (r = 0 65 for Peninsular India, r = 0 45 for Chitradurga Stationa)n d histoncally recorded rainfall events Presuming that χif variations are produced mainly by rainfall variations and that there was no signtficant human impact in the catchment and no slumping or bioturbatio of sediments we have reconstructed the paleorainfall profile for thc last 3,700 years for Chitradurga region The profile is chronologically constrained by two I4c dates Several events of drought and high rainfall, and onset of aridity are corretatable with similar events documented in speleothems from chfferent parts of india, a tree-ring from western India and lake sediments from Rajasthan We have thus shown that χif 1s a proxy for rainfall in tropical regions and that tank-bed sediments from tropical lndia are an important archive of paleorainfall/paleoclimate data.Keywords
Tank-bed sediments, Southern India, Magnetic susceptibilty Rainfall reconstruction, Paleoclimate, Southwest monsoon, Late Holocene, Little Ice Age.- A Report on the 3rd International Earth Science Olympiad
Authors
1 Geological Society of India, Bangalore - 560 019, IN
2 Department of Earth Science, Goa University, Goa, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 74, No 5 (2009), Pagination: 660-660Abstract
No Abstract.- Marine Geology - A Scenario Around Indian Coasts
Authors
1 Department of Marine Geology, Mangalore University, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 73, No 4 (2009), Pagination: 587-588Abstract
No Abstract.- Entrance Test, Training Camp and the Indian National Earth Science Olympiad, January and May, 2010
Authors
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 76, No 2 (2010), Pagination: 199-200Abstract
No Abstract.- Comparison of Carbon, Nititogen and Phosphorous Fluxes in Mexican Coastal Lagoons. Loicz Reports and Studies
Authors
1 Ocean Science and Technology Cell, Mangalore University, Mangalagangotri - 574 199, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 52, No 6 (1998), Pagination: 742-743Abstract
No Abstract.- International Earth Science Olympiad - 2011: A Report
Authors
1 Earth Science Olympiad, IN