Browsing by Author "Panda, Aurovinda"

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    First Law of Thermodynamics Applied to Understanding the Energy Budget of Magmatic Dyke Systems
    (2023) Patel, Rahul; Browning, John; Sarma, D. Srinivasa; Panda, Aurovinda
    The forces and nature of volcanic activity are, in essence, the result of thermodynamic processes related to a magmatic source which contains energy. A magma chamber’s stored energy is in part reflected through the formation of dykes, magmatically driven fractures, which propagate through the Earth’s crust, using the magma energy. The laws of thermodynamics are universal, if it were possible to fully quantify the energy budget of a dyke, using thermodynamic relations, it may be further possible to forecast the timing and location of a volcanic eruption. In this study, we provide the theoretical foundation to determine the various forms of energy i.e., kinetic energy (K.E), potential energy (P.E), elastic potential energy (G), magma buoyancy energy (Eb), mechanical energy (Em) and heat energy (Q), for several wellcharacterized dyke swarms. The cumulative magnitude of all forms of energy from nine provinces of the Singhbhum craton, India is estimated close to 1.53× 1010GPa, for NandurbarDhule swarms, India 2.99× 1010GPa, for Miyakejima volcano, Japan 8.25× 108GPa, for Tatara- San Pedro-Pellado volcanic complex, Chile 7.53× 107GPa. The cumulation of all forms of energy were estimated between 7.53× 107 GPa up to 1.53× 1010 GPa for the different dyke swarms. The near power law or linear relation between total energy vs mass and total energy vs volume indicate a rapid or proportional increase in energy magnitude with respect to mass and volume. The extremely low kinetic energy of magma flow is attributed to the no-slip condition and size variability of a dyke. The estimated dyke energies and their simple scaling relation with respect to mass and volume is the first step toward understanding the behaviours of the volcanic and magmatic processes and there could be many avenues for future work on this problem.
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    Mechanical fragmentation and thermal erosion of dyke adjacent host rocks induced by fluid-dynamic shear stress and latent heat release in response to turbulent magma flow
    (2022) Patel, Rahul; Browning, John; Sarma, D. Srinivasa; Panda, Aurovinda
    We present a quantitative account of the thermodynamical and fluid-mechanical aspects of granitic host rock erosion related to dyke emplacement by considering the latent heat released from the dyke, subsequent thermal damage, and erosion processes. When these processes are coupled with the fluid-dynamic shear forces induced by magma turbulence, they provide the main driving force for mechanical fragmentation and xenolith entrainment. To make these inferences, we have estimated the Reynolds Number related to magma flow in a series of well-exposed dykes in Eastern India. We define the thresholds of turbulent to laminar flow based on Reynolds Numbers, where values over 2000 indicate that the magma had flowed turbulently. In these cases, both thermal erosion and fluid-dynamic shear stresses would have combined to fragment the adjacent host rock. Equations for the conservation of mass are derived and presented in order to quantify the complex interactions between magma and cold host rock. We further propose a novel linear integro-differential equation to determine xenolith size resulting from internal collisions and secondary fragmentation. Our model and results will be helpful in interpreting magma flow characteristics, magmatic evolution, and host rock entrainment processes in exposed outcrops of magmatic intrusions.