Browsing Centre for Earth Sciences (CEaS) by Title
Now showing items 1-20 of 37
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Assessing the potential of stable calcium isotope ratios for paleotemperature reconstruction from studies of laboratory-precipitated inorganic carbonates and modern corals, fish otoliths and foraminifera
Determining paleo-seawater composition and temperature is critical for reconstructing Earth’s surface conditions through time and has major implications for understanding the origin and evolution of life on Earth. ... -
CO2 Ventilation, Hydrological Cycle over Southern Ocean and Clumped Isotope Thermometry in Biogenic Carbonates
(2018-02-20)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 ... -
Constraining the Lithium Seawater Mass and Isotope Budget: Diagenetic Processes Through Marine Pore Waters
Silicate weathering consumes CO2 and controls cation fluxes to the ocean, thus playing a critical role in modulating long-term seawater chemistry and climate. There are very few markers of seawater chemistry whose value ... -
Crustal evolution and tectonic processes of the Madras Block, India
The Neoarchaean (2.8–2.5 Ga) era in the earth’s history witnessed significant crustal growth related to the amalgamation and dispersion of ancient continents. The processes leading to the formation and destruction of the ... -
The Crustal Evolution of Nilgiri Block, Southern India : A Study on Archean Tectonics and Crustal Growth
(2018-08-02)The oldest dated rocks from the Acasta gneisses of the western Slave Province, Canada present an igneous age of ~4030 Ma. Following this the detrital zircons from the Jack Hills, Narryer Gneiss Terrane, Yilgarn Craton, ... -
Damping of magnetic-Coriolis waves with imposed magnetic field orthogonal to the axis of rotation
Small-scale columnar structures (<10 km radius) in Earth's outer core result from inertial waves. In highly conducting fluid, magnetic field behaviour resembles stretched elastic strings and transmits disturbances as Alfvén ... -
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
(2018-04-11)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 ... -
Evaluating Geochemical Proxies for Paleoclimate Reconstruction in Tropical Montane Peat : A Case Study from the Nilgiris, Southern India
(2018-05-14)Peat from the temperate regions has been used for paleoenvironmental reconstruction using diverse proxies for over a century now. Peat is rare and severely understudied in the tropics. The montane peat bogs of the Nilgiris, ... -
Evolutionary Aspects of Archean Kolli-Massif, Southern India : An Archive of Crustal Processes
(2018-08-13)The continental crust is the record of the history of the Earth, of the processes and events that have contributed to the planet's evolution. It is now understood that the continental crust is growing continuously since ... -
A geochemical and Ca, Sr, Nd isotopic study of the mantle: case studies of Kimberlites, Ophiolites, Abyssal Peridotites, and Layered Igneous Complexes
The Earth’s mantle constitutes 67% of its mass and despite mantle convection, it is geochemically and isotopically heterogeneous as evident from the compositions of mantle derived basaltic melts. It is a dynamic system ... -
Geochemical and isotopic study of the Lonar and Dhala impact craters and jarosites from Kutch, India as analogues to understand planetary surface processes
Impact cratering and aqueous alteration are two important processes that have modified the Earth’s surface over time and better understanding of these processes on Earth allow us to understand the surface evolution of other ... -
A geochemical and Nd-Sr-Ca isotopic study of silicate weathering, crustal recycling and petrogenesis of carbonatites
Weathering of silicate rocks releases cations and anions which are transported to the oceans by rivers where calcium carbonate precipitates from the seawater. This process results in the net consumption of atmospheric ... -
A Geochemical and Sr, Ca, Mg, Li isotopic study of the Godavari River draining the Deccan basalts
Chemical weathering of continental silicate rocks releases cations and anions which are eventually precipitated as carbonates on the ocean floor. This entire process transfers carbon from the atmosphere to the oceans leading ... -
A geochemical, Nd-Sr, and stable Ca isotopic study of siliciclastic and chemical sedimentary rocks, volcanic tuffs, and authigenic glauconites from Proterozoic sedimentary basins of India
The Archean-Proterozoic transition is marked by globally synchronous changes in tectonothermal and climatic patterns along with development of widespread epicontinental seas, with extensive shelf-sedimentation. The Indian ... -
High Resolution Reconstruction of Rainfall Using Stable Isotopes in Growth Bands of Terrestrial Gastropod
(2017-10-25)Reconstruction studies of seasonal rainfall utilizing stable isotope based proxy approach suffer from the limitations of time resolutions. Conventional methods and archives limit the achievable resolution to annual scales. ... -
High Resolution Reconstruction of Rainfall Using Stable Isotopes in Growth Bands of Terrestrial Gastropod
(2017-10-25)Reconstruction studies of seasonal rainfall utilizing stable isotope based proxy approach suffer from the limitations of time resolutions. Conventional methods and archives limit the achievable resolution to annual scales. ... -
Improved laboratory and computational models for thermal core–mantle interaction
The Earth's magnetic field is generated by thermochemical convection within its fluid outer core. The near-stationary high-latitude magnetic flux concentrations in the present day field indicate that convective ... -
Investigating the role of mantle convection in affecting surface deformation and topography in the Indian plate and the India-Eurasia collision zone
The India-Eurasia collision zone has been a subject of various studies that have tried to explain the forces behind the high elevation and large scale continental deformation in this region. However, the relative contribution ... -
An investigation into the axial dipole field and mantle-induced heterogeneity in Earth
The Earth’s axial dipole field is generated by dynamo action in the planet’s outer core. It is understood from observations that the convection in the outer core is influenced by the lateral heterogeneity in the overlying ... -
Lab Experiment Documenting Growth of Microbes in an Extreme Condition
Bacterial population during 3.2 billion years of early earth was responsible for modifying the greenhouse gas concentration in the early earth. Here we studied the primitive facultative anaerobe E.coli K12, known to contain ...