What is Hadrian's Wall made of, where did this material come from and how has it been reused in other buildings in the communities that emerged in the centuries after the Roman Empire? By studying the fabric of Hadrian's Wall using a geological approach combined with archaeological methods, is it possible to refine our answers to these questions? This study describes how the relationship between the geology of the Wall's landscape and its fabric may be used to further understand the Wall and presents a significant set of new geological and archaeological data on the Wall's stones from across the length of the Wall. This data set has been collected in two complementary ways. First as a citizen-science project, where volunteers from local communities were trained to visually characterise sandstones and resulting in data collecting on large numbers of the Wall's stones along the length of the Wall. Secondly, analytical research was used to gather in scientific data for a selected sets of rocks and stones. Geochemical data was captured using an X-ray fluorescence spectrometer, and petrographic observations made using a petrographic microscope and thin sections.The combined methods provide a framework for geological analysis of the Wall supported by robust data. It builds on earlier work on Roman quarrying and stone preparation highlighting not only stone sources, but the criteria for choosing stone, stone preparation methods, and the implied routes to the Wall. At the heart of this study lies the ability to uniquely identify different sandstone types. Geological methods used to achieve this are explored, as are the ways in which the sandstones form. This highlights both the possibilities and limits of this approach. AUTHORS: Rob Collins is Researc h Associate in the Department of Archaeology at Newcastle University. His principal research interests are in frontier studies and the collapse of complex societies, making use of archaeological remains of built structures and small finds to provide a social interpretation of the material record. Ian Kille is Community Geologist for WallCAP at Newcastle University. He also runs Northumbrian Earth, set up in 2006 to create community and visitor events to explore the geology of the north-east. He completed his PhD at Imperial College studying magmatic processes within the Mull volcanic complex. Kathleen O'Donnell is Post-Excavation Archaeologist at CFA Archaeology. She completed her PhD on the Quarries of Hadrian's Wall in 2021 and was a Research Associate with WallCAP. Her main research interests are landscape archaeology and geoarchaeology.
