Browsing Centre for Earth Sciences (CEaS) by Title
Now showing items 21-40 of 43
-
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 ... -
An investigation of the role of buoyancy in magnetic polarity transitions in rapidly rotating dynamos
The dynamo operating within the Earth’s outer core generates a predominantly north-south dipolar magnetic field. Occasionally, the magnetic dipole axis flips its orientation and retains its approximate alignment with the ... -
The keeper of Chronicles - Investigating calcium carbonate archives using clumped thermometry
Calcium carbonates (CaCO3) are the most abundant mineral archive for reconstructing past climate owing to their tendency to register the environmental condition during their formation. From biogenically mediated carbonates ... -
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 ... -
Late Cenozoic climate reconstruction from the Northern Indian Ocean using foraminiferal clumped isotope thermometry and stable isotope technique
The Late Cenozoic era (23.03 million years ago to the present) offers a critical time window to examine the role of greenhouse gases, notably CO2 (ranging between 910 ppm and 180 ppm), in the operation of Earth's system ... -
Mesoproterozoic Suturing Of Archean Crustal Blocks In Western Peninsular India : New Insights On India-Madagascar Correlations
(2017-08-21)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 ... -
MHD Waves Driven by Small-scale Motion and Implications for the Earth's Core
(2018-05-22)Rotating convection in the Earth's core produces columnar vortices of radius ~10 km or less near the inner core boundary. Small-scale motions in the core can travel as Alfvén waves in the face of Ohmic diffusion, provided ... -
Modulation of Metal Fluxes and their Isotope Ratios in the Ganga (Hooghly) Estuary
This thesis aims at constraining the impact of estuarine processes on the net riverine fluxes of select metals and their isotopic composition to seawater. I studied the Ganga (Hooghly) River estuary, a monsoon-dominated ... -
On the spatio-temporal distribution of stable isotope ratios in the hydrological cycle over India and the Southern Ocean
The isotopic composition of water vapor and precipitation at continental and oceanic sites depends on factors such as: the geographical location of the sampling site, meteorological conditions at the moisture source ... -
Precambrian ocean, life, and syn to post-collisional records in the Himalayas (Kumaun)
The Ph.D. thesis focuses on the central sector of the Himalayas, i.e., Kumaun. Here, an attempt has been made to understand the poorly understood genesis of magnesium carbonates (sparry magnesite) of the Precambrian ... -
Quantification of Air-Sea CO2 exchange from the Southern Ocean during last deglaciation
Glacial and interglacial cycles are natural, rhythmic patterns of global climate. These cycles are primarily driven by variations in solar forcing, commonly known as Milankovitch cycles. The solar forcing includes eccentricity ... -
Reconstruction of temperature for Cenozoic and Proterozoic Ocean water using clumped isotope thermometry
Clumped isotope thermometry is a novel tool which is used for the determination of formation temperature for carbonates of diverse origin and understanding different marine and terrestrial processes. The primary interest ... -
Seasonal Isotopic Variability and Major Ion Chemistry of the Cauvery River Basin, Peninsular India
Surface water and groundwater interactions are inherently complex because they occur across a range of spatial and temporal scales. This thesis envisages to improve our understanding of surface water and groundwater in ... -
Seismic Site Response Evaluation Using Ambient Vibrations And Earthquakes : Applications in Active And Vulnerable Regions with Emphasis on the 2001 Bhuj (India) Earthquake
(2017-09-26)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. ... -
Seismotectonics Of The Andaman-Nicobar Plate Boundary And Evaluation Of 2004 Deformational And Depositional Features Towards Assessing Past Tsunamigenic Earthquakes
(2016-07-11)Tsunami hazards were greatly underestimated along the coasts of countries bordering the northeastern Indian Ocean until the occurrence of the 26 December 2004, Mw 9.2 earthquake and its ensuing tsunami. Sourced off the ... -
Stable isotope and biogeochemical study of arsenic contamination in shallow groundwater at seasonal time intervals from West Bengal (Nadia district)
Seasonal monitoring of groundwater is essential to ascertain safe water for the population and ecosystem for drinking, irrigation, domestic purposes and to keep track of groundwater quality with natural (climate change ... -
Stable isotope geochemistry of carbonatites: New insights into the petrogenesis and evolution
Carbonatites are carbonate-rich magmatic rocks that are commonly thought of having a mantle origin and are thus, of great interest to geologist for understanding the chemical evolution of the upper mantle. This thesis ... -
Stable Isotopic Composition of Rice Grain Organic Matter as an Archive of Monsoonal Climate
(2018-08-30)Rice grows in saturated soil water condition and its requirement for water is highest amongst other cereal crops. In India, the southwest monsoon wind regime brings rainfall that provides a favourable environment for rice ... -
A stable Strontium isotopic (δ88/86Sr) study of seawater from the Bay of Bengal, coastal groundwater from the Bengal Basin, and the Ganges, Brahmaputra, Mahanadi, and Godavari rivers in India
Strontium (Sr) is an alkaline earth element that has four naturally occurring stable isotopes, 84Sr, 86Sr, 87Sr and 88Sr. During measurements of the radiogenic Sr isotope ratio (87Sr/86Sr), which is a widely used tracer ... -
Study of the Seasonal Water Cycle over the Indian Subcontinent and the Southern Ocean using Stable Isotopes in Rainwater and Water Vapor
(2017-11-28)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 ...