Unravelling the Dynamical Mechanisms Underpinning Intra-Plate Volcanism Within and Around Earth's Continents
type: CreativeWork
description: This thesis investigates the dynamical mechanisms at the root of Earth's intra-plate volcanism from a computational fluid dynamics perspective. It analyses different convective processes that enable and sustain decompression melting in the uppermost asthenosphere and, subsequently, proposes novel pathways to understanding the distribution, intensity and temporal evolution of volcanism observed within and around Earth's continents. Volcanism within and around Earth's continents displays diverse characteristics and is hard to reconcile with the plate tectonic framework. Where volcanic provinces exhibit a geometrical pattern known as a linear age progression, in which volcanoes grow older in the direction of plate motion, mantle plumes are the preferred driving mechanism for the initiation of mantle melting. Elsewhere, shallower convective instabilities, bound to significant changes in lithospheric thickness, have been gaining popularity in explaining the onset of decompression melting at depth. However, not all volcanic provinces within and around Earth's continents bear such unique geometrical and structural features. In such contexts, the applicability of mantle plumes and edge-driven convective instabilities remains unclear. In this work, I present a systematic series of 2-D and 3-D numerical models that involve sharp transitions in lithospheric thickness within and around continental lithosphere to study the development of shallow convective instabilities and their relation to magmatism. Some simulations incorporate plate motion and an upper-mantle plume to reproduce a range of possible interactions, as documented in the observational record. Model results demonstrate that more intense edge-driven circulations develop in regions where lithospheric geometry allows flow coalescence and where asthenospheric shear, relative to lithospheric motion, promotes ascending flow. However, the activation of decompression melting through edge-driven flows depends substantially …
abstract: This thesis investigates the dynamical mechanisms at the root of Earth's intra-plate volcanism from a computational fluid dynamics perspective. It analyses different convective processes that enable and sustain decompression melting in the uppermost asthenosphere and, subsequently, proposes novel pathways to understanding the distribution, intensity and temporal evolution of volcanism observed within and around Earth's continents. Volcanism within and around Earth's continents displays diverse characteristics and is hard to reconcile with the plate tectonic framework. Where volcanic provinces exhibit a geometrical pattern known as a linear age progression, in which volcanoes grow older in the direction of plate motion, mantle plumes are the preferred driving mechanism for the initiation of mantle melting. Elsewhere, shallower convective instabilities, bound to significant changes in lithospheric thickness, have been gaining popularity in explaining the onset of decompression melting at depth. However, not all volcanic provinces within and around Earth's continents bear such unique geometrical and structural features. In such contexts, the applicability of mantle plumes and edge-driven convective instabilities remains unclear. In this work, I present a systematic series of 2-D and 3-D numerical models that involve sharp transitions in lithospheric thickness within and around continental lithosphere to study the development of shallow convective instabilities and their relation to magmatism. Some simulations incorporate plate motion and an upper-mantle plume to reproduce a range of possible interactions, as documented in the observational record. Model results demonstrate that more intense edge-driven circulations develop in regions where lithospheric geometry allows flow coalescence and where asthenospheric shear, relative to lithospheric motion, promotes ascending flow. However, the activation of decompression melting through edge-driven flows depends substantially …
author: Duvernay, Thomas
language: en_AU
date published: 2023
date modified: 2026-07-24T01:07:45Z
provider: Australian Catholic University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Australian Catholic University

PropertyValue
property ID: Handle
value: http://hdl.handle.net/1885/274179