Developing Terrestrial Laser Scanning of Threatened Coastal Archaeology with Special Reference to Intertidal Structures
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UNIVERSITY OF SOUTHAMPTON FACULTY OF SOCIAL AND HUMAN SCIENCES Department of Geography and Environment Developing Terrestrial Laser Scanning of Threatened Coastal Archaeology with Special Reference to Intertidal Structures by Michael Alister Lobb Thesis for the degree of Doctor of Philosophy August 2016 UNIVERSITY OF SOUTHAMPTON FACULTY OF SOCIAL AND HUMAN SCIENCES Geography and Environment Thesis for the degree of Doctor of Philosophy DEVELOPING TERRESTRIAL LASER SCANNING OF THREATENED COASTAL ARCHAEOLOGY WITH SPECIAL REFERENCE TO INTERTIDAL STRUCTURES Michael Alister Lobb The aim of this thesis is to develop a means of using terrestrial laser scanning to rapidly record coastal and intertidal archaeology within its immediate environs and to use that context to understand its construction and function. Key to this is the underlying concept that structures built to exploit and utilise the resources of the intertidal zone are fully dependant on the dynamics of their immediate landscape. Terrestrial laser scanning provides a level of data not previously gathered in the recording of intertidal sites, allowing a highly detailed recording of complex three dimensional structures to a high level of accuracy, and, through integration with other forms of metric survey, the placement of this information within a wider topographic landscape. The challenges of the intertidal zone hamper traditional archaeological recording techniques, and very often the complexity of structures, subtleties of topography, and distance from the shore can mean that planning of sites ignores the context of the wider landscape. This thesis provides a methodological approach to dealing with these issues, but also looks at how the data generated can go further into answering questions about the interaction of human technology with the dynamics of the landscape. Case studies at a number of sites throughout England and France are presented and used to examine various aspects of the technology and its application to coastal and intertidal archaeology. Table of Contents Table of Contents ......................................................................................................... i List of Tables v List of Figures vii List of Accompanying Materials ............................................................................. xvii DECLARATION OF AUTHORSHIP .................................................................. xviii Acknowledgements .................................................................................................. xix Definitions and Abbreviations ............................................................................... xxiii Introduction ..................................................................................... 1 1.1 Threatened Coastal Archaeology Sites ........................................................................... 1 1.2 The Archaeology of Intertidal Structures ...................................................................... 1 1.3 Surveying and Recording Intertidal Archaeology ......................................................... 3 1.4 The Development and Use of Terrestrial Laser Scanning .......................................... 4 1.5 Scope and Aims of this Research ................................................................................... 5 1.6 Chapter Layout .................................................................................................................. 6 The Archaeology of Intertidal Structures ........................................ 9 2.1 What is Intertidal Archaeology? ...................................................................................... 9 2.2 Intertidal Archaeology and Relative Sea Level ........................................................... 13 2.2.1 Processes of Sea Level Change ..................................................................... 13 2.2.2 Relative Sea Level and the Tidal Frame ....................................................... 13 2.2.3 Implications for Archaeological Sites ........................................................... 15 2.2.4 Intertidal Archaeology Sites as Markers for Relative Sea Level ............... 16 2.3 Policy and Protection of Coastal Archaeology Sites .................................................. 16 2.4 Threats to Intertidal Archaeology ................................................................................. 16 2.5 Landscape Approaches to Intertidal Archaeology ..................................................... 17 2.6 Intertidal Structures – A Past Industrial Landscape .................................................. 19 2.6.1 Fallback industries? Seasonality, Choice and Interdependence of Intertidal Structures .......................................................................................................... 20 2.6.2 Salterns and Salt Production .......................................................................... 21 2.6.3 Waterfront Archaeology ................................................................................ 26 2.6.4 Tide Mills .......................................................................................................... 28 2.6.5 Oyster fishing .................................................................................................. 32 2.7 Intertidal Fishing Structures .......................................................................................... 33 i 2.7.1 Importance and Use of Fish.......................................................................... 34 2.8 A History of Intertidal Fishing Structures in the British Isles .................................. 35 2.8.1 Mesolithic ......................................................................................................... 35 2.8.2 Neolithic ........................................................................................................... 38 2.8.3 Bronze Age ...................................................................................................... 40 2.8.4 Iron Age ........................................................................................................... 41 2.8.5 Roman period .................................................................................................. 41 2.8.6 Early Medieval ................................................................................................. 42 2.8.7 Medieval ........................................................................................................... 43 2.8.8 Post-medieval .................................................................................................. 46 2.9 Fishing Landscapes – The Significance and Place of Intertidal Sites ...................... 47 2.10 Understanding Structures .............................................................................................. 49 2.10.1 Intertidal Structures and theory .................................................................... 49 2.10.2 Difficulties of identification and classification ........................................... 50 2.10.3 Dating of structures ........................................................................................ 56 2.10.4 Lifespan ............................................................................................................ 57 2.10.5 Ethnographic comparisons ........................................................................... 58 2.10.6 Fishweirs and geomorphological processes ................................................ 58 Terrestrial Laser Scanning and Intertidal Archaeology ................. 61 3.1 The Development of Terrestrial Laser Scanning ....................................................... 61 3.2 The Place of Terrestrial Laser Scanning in Metric Survey ........................................ 62 3.2.1 Airborne Laser Scanning ............................................................................... 64 3.2.2 Bathymetric Airborne Laser Scanning ......................................................... 69 3.2.3 Global Navigation Satellite Systems ............................................................. 70 3.2.4 Terrestrial Laser Scanning ............................................................................. 72 3.2.5 Mobile survey technologies ........................................................................... 73 3.3 The Nature of Terrestrial Laser Scanning Data ......................................................... 74 3.4 The Limitations of Terrestrial Laser Scanning ........................................................... 77 3.5 The Application of Terrestrial Laser Scanning to Cultural Heritage and Archaeology 79 3.5.1 Terrestrial Laser Scanning in Archaeology .................................................. 80 3.6 A Proposed Methodology for Recording Intertidal Archaeology Sites using Terrestrial Laser Scanning.............................................................................................. 82 ii 3.6.1 Best Practice and Site Methodology ............................................................. 83 3.6.2 Technical Setup ............................................................................................... 83 3.6.3 Data Collection Choices ................................................................................ 84 3.6.4 Logistical Deployment ................................................................................... 85 3.6.5 Post-Fieldwork Processing ...........................................................................