Characterising pre-vegetation paralic sedimentary systems and developing improved architectural reservoir models A thesis submitted to the University of Manchester for the degree of Doctor of Philosophy in the Faculty of Science and Engineering 2019 Ginny-Marie Bradley University of Manchester Faculty of Science and Engineering School of Earth and Environmental Sciences Basin Studies and Petroleum Geoscience/Engineering Funded by NERC CDT in Oil and Gas Table of Contents List of figures ..................................................................................................................... 5 List of tables ...................................................................................................................... 8 List of abbreviations .......................................................................................................... 9 Abstract ........................................................................................................................... 10 Declaration ...................................................................................................................... 12 Copyright statement ....................................................................................................... 13 Acknowledgements......................................................................................................... 14 Status of papers .............................................................................................................. 15 Chapter 1: Introduction .................................................................................................. 17 1.1 Aims of the thesis .................................................................................................. 18 1.2 Rationale................................................................................................................ 18 1.3 The Tumblagooda Sandstone................................................................................ 21 1.4 The advancement to pre-vegetation paralic studies ............................................ 21 1.5 Key aims of the project ......................................................................................... 22 1.6 Thesis structure ..................................................................................................... 22 1.7 Architectural Definition ......................................................................................... 24 Chapter 2: Previous Work ............................................................................................... 26 2.0 Introduction to braided fluvial systems. ............................................................... 27 2.1 Pre-vegetation fluvial systems .............................................................................. 29 2.2 Pre-vegetation tidal systems ................................................................................. 33 2.3 Impact of vegetation ............................................................................................. 34 2.4 Fluvio-paralic stratigraphy..................................................................................... 37 2.5 The Tumblagooda Sandstone................................................................................ 40 2.5.1 Geological history ........................................................................................... 40 2.5.2 Tumblagooda Sandstone ................................................................................ 41 2.5.3 Previous interpretations ................................................................................. 45 2.5.4 Fauna .............................................................................................................. 50 Chapter 3: Dataset and methodology............................................................................. 53 3.0 Introduction........................................................................................................... 54 3.1 Fieldwork ............................................................................................................... 54 3.1.1 Logging ............................................................................................................ 54 3.1.2 Sampling ......................................................................................................... 56 3.1.3 Photogrammetry............................................................................................. 59 3.2 Data processing and analysis ................................................................................ 62 3.2.1 Facies Analysis ................................................................................................ 62 3.2.2 Petrography .................................................................................................... 62 3.2.3 Digital outcrop modelling ............................................................................... 65 3.2.4 Annotating models and obtaining channel size statistics .............................. 66 3.2.5 Stochastic modelling ....................................................................................... 67 3.3 Limitations ............................................................................................................. 69 Chapter 4: The applicability of modern tidal analogues to pre-land plant paralic depositional models........................................................................................................ 72 Abstract ....................................................................................................................... 74 4.1 Introduction........................................................................................................... 75 4.2 Geological setting .................................................................................................. 77 2 4.3 Previous work ........................................................................................................ 79 4.3.1 A mixed marine to non-marine interpretation ............................................... 79 4.3.2 Non-marine interpretation ............................................................................. 80 4.4 Methodology ......................................................................................................... 81 4.5 Lithofacies descriptions ......................................................................................... 82 4.6 Facies associations................................................................................................. 98 4.6.1 Facies Association 1 ........................................................................................ 98 4.6.2 Facies Association 2 ........................................................................................ 99 4.7 Depositional system ............................................................................................ 101 4.7.1 Fluvial braidplain ........................................................................................... 101 4.7.2 Tidal dominance ............................................................................................ 102 4.7.3 Intertidal sandflat.......................................................................................... 103 4.7.4 Intertidal sand-bar to shallow subtidal ......................................................... 105 4.7.5 Stacking patterns .......................................................................................... 105 4.8 Discussion ............................................................................................................ 106 4.8.1 Interpretation of the depositional system.................................................... 106 4.8.2 Significance of Heimdallia assemblages ....................................................... 107 4.8.3 Early Palaeozoic depositional controls in a pre-plant world ........................ 108 4.8.4 Application of modern analogues................................................................. 116 4.9 Conclusions .......................................................................................................... 117 Chapter 5: Reassessing the sedimentology and architecture of pre-vegetation fluvial successions using large digital outcrop models. ........................................................... 120 Abstract ..................................................................................................................... 122 5.1 Introduction ......................................................................................................... 123 5.2 Background .......................................................................................................... 124 5.3 Geological Setting ................................................................................................ 128 5.4 Methods............................................................................................................... 129 5.5 Results ................................................................................................................. 132 5.5.1 Lithofacies ..................................................................................................... 132 5.5.2 Facies associations (FA)................................................................................. 146 5.5.3 Architectural elements ................................................................................. 151 5.5.4 Sequence