Recursos de colección

ETD at Indian Institute of Science (3.241 recursos)

Repository of Theses and Dissertations of Indian Institute of Science, Bangalore, India. The repository has been developed to capture, disseminate and preserve research theses of Indian Institute of Science.

Centre for Earth Sciences(ceas)

Mostrando recursos 1 - 7 de 7

  1. Establishment of an Experimental System in India to Measure the Mixing Ratio and Stable Isotopic Composition of Air CO2 & Observations from Urban and Marine Environments

    Guha, Tania
    The thesis presents observations on the CO2 mixing ratio and the carbon isotopic ratio (13C/12C i.e. δ13) of atmospheric CO2 from the Indian region, for the period 2008 - 2011. An experimental system was established at the Centre for Earth Sciences, Indian Institute of Science, Bangalore. The experimental protocol involves collection of air samples, extraction of CO2 from the air samples collected, and finally the measurement of the CO2 mixing ratio and isotopic ratios of the extracted CO2 using pressure gauge readings and the dual inlet peripheral of the isotope ratio mass spectrometer, IRMS MAT 253. The isotopic ratios measured...

  2. CO2 Ventilation, Hydrological Cycle over Southern Ocean and Clumped Isotope Thermometry in Biogenic Carbonates

    Prasanna, K
    The thesis presents observations on the CO2 concentration and carbon isotopes in air CO2 (δ13C) to constrain the inter-annual variability of carbon inventory over the Southern Ocean between the years 2011-2013. Based on the observation, the region of CO2 venting was identified over the Southern Ocean. Further, isotopic characterization allowed inferring about the possible sources of CO2 degassing and contribution from the dissolved inorganic carbon (DIC) that exsolved to generate CO2. It is concluded that the origin CO2 is mainly from the degassing of CO2 available from the dissociation of DIC or organic degradation. Live Foraminiferal samples of Globigerina bulloides from...

  3. Tectonic Evolution of Central Madurai Block, Southern India and Potential Heat Source for High-Temperature Metamorphism

    Rashid, Janwari Shazia AB
    The Madurai Block is the largest granulite block in Southern Granulite Terrain which lies between Palghat-Cauvary shear zone in the North and Achankovil shear zone in the South. This terrain underwent extreme crustal metamorphism under ultrahigh-temperature metamorphic conditions which provides vital information about the tectonic process of the lower crust. Ultrahigh temperature metamorphism was defined by Harley (1998b) as a subclass of granulite facies metamorphism of crustal rocks in which peak temperature exceeds 900°C at moderate pressures (7-13 kbar) in the deep crust. However, considering the lacunae about the present understanding of ultrahigh temperature metamorphism, the study attempts to identify...

  4. Study of the Seasonal Water Cycle over the Indian Subcontinent and the Southern Ocean using Stable Isotopes in Rainwater and Water Vapor

    Rahul, P
    Stable isotope ratios in rainwater and water vapor act as a tracers of the hydrological cycle. The data on stable isotopic composition in rainwater and water vapor are limited due to the lack of observational studies across the Indian subcontinent and over the ocean. These present day observations are important database to deduce the paleo-climatic condition from geological archives. In majority of the cases, isotopic records are translated into physical factors with the present background knowledge where relationships with physical variables are well established. In case of tropical region, the primary controlling factor identified behind the stable isotopic variations is...

  5. Seismic Site Response Evaluation Using Ambient Vibrations And Earthquakes : Applications in Active And Vulnerable Regions with Emphasis on the 2001 Bhuj (India) Earthquake

    Natarajan, Thulasiraman
    Local site conditions are known to influence ground motion during earthquake events and increase the severity of damage. Data from earthquakes are useful to study the response but they are available only from active regions. Ubiquitous ambient vibrations on the other hand offer a more practical approach to quantify site responses. This thesis explores the use of various methods for obtaining site responses. The primary area of study is the Kachchh rift basin, NW India, a Mesozoic rift that features significant lateral variations in surface geology and has experienced ground responses during 1819 and 2001 earthquakes. The Mw 7.6, 2001...

  6. Seismic Site Response Evaluation Using Ambient Vibrations And Earthquakes : Applications in Active And Vulnerable Regions with Emphasis on the 2001 Bhuj (India) Earthquake

    Natarajan, Thulasiraman
    Local site conditions are known to influence ground motion during earthquake events and increase the severity of damage. Data from earthquakes are useful to study the response but they are available only from active regions. Ubiquitous ambient vibrations on the other hand offer a more practical approach to quantify site responses. This thesis explores the use of various methods for obtaining site responses. The primary area of study is the Kachchh rift basin, NW India, a Mesozoic rift that features significant lateral variations in surface geology and has experienced ground responses during 1819 and 2001 earthquakes. The Mw 7.6, 2001...

  7. Mesoproterozoic Suturing Of Archean Crustal Blocks In Western Peninsular India : New Insights On India-Madagascar Correlations

    Ishwar Kumar, C
    The structural lineament mapping of southern India along withgeological, geochronological datasets help in redefining the Precambrian crustal blocks.The newly proposed Kumta and Mercara suture zones welding Archean crustal blocks in western peninsular India offer critical insights into the crustal evolution of Gondwana. The Kumta suturemainly consists of schistose rocks including quartz-phengite, garnet-biotite, chlorite, fuchsite and marble, whereas the Mercara suture contains mylonitic quartzo-feldspathic gneiss, garnet-kyanite-sillimanite gneiss, calc-silicate granulite and metagabbro. Metamorphic pressure-temperature estimations (Kumta suture: 11-18 kbar at 790-550oC; Mercara suture: 13 kbar at 825oC) suggest that, the sediments have undergone subduction to greater depths. The K-Ar age of biotite,...

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