Thesis

Once my thesis is accepted, pdf versions of the chapters will be available here. In the meantime, here is a brief chapter summary and links to the relevant animations.

Chapter 1 - Introduction

Background information on orogenesis (mountain building), sandbox analogue modelling and computational finite element modelling as justification to my approach of using as discrete element model.

Chapter 2 - Discrete Element Modelling

Discussion of the fundaments behind a discrete element model and some specific information about the way I chose to write mine. Part of this chapter is already available in the DEM fundamentals page.

Chapter 3 - Material Properties

The properties of the DEM material were investigated using a slump angle of repose test and by growing singly vergent critical wedges. Global friction was found to be a function of internal friction, basal friction, packing geometry and particle shape. The effect of these can be seen in the
Chapter 3 - Singly vergent wedge animations.

Chapter 4 - Doubly Vergent Wedge Boundary Conditions

To generalise the model to simulate doubly vergent wedges (ones where the velocity discontinuity is at some point along the base rather than at a boundary), two different lower boundary conditions were tried. The results of the different boundary conditions can be viewed in the
Chapter 4 - Doubly vergent wedge animations.

Chapter 5 - Natural Variability in Non-erosive Wedges

In order to describe when a wedge does something out of the ordinary, the Normal Variability of the system must be characterised. This series of four runs with the same parameterisation but a different seed of random packing allows the Normal behaviour of the system to be characterised. This behaviour is compared with the evolution of the Pyrenees.
Chapter 5 - Doubly vergent wedge animations.

Chapter 6 - Influence of Erosion on Wedges

A simple erosion law is applied where all material above some threshold elevation is removed. A time averaged flux steady state is achieved. The depth of material at the surface and time for material to reach the surface from some constant depth are investigated as proxies for metamorphic grade and thermochronometric age distributions. In this way I test the exhumational steady state assumtion.
Chapter 6 - Doubly vergent wedge animations.