Determining the original source of the stones of Stonehenge

Bevins, R.E., Pirrie, D., Ixer, R.A., O’Brien, H., Parker Pearson, M., Power, M.R. & Shail, R.K. 2020. Constraining the provenance of the Stonehenge ‘Altar Stone’: Evidence from automated mineralogy and U-Pb zircon age dating.  Journal of Archaeological Science, 120.

The iconic Neolithic structure of Stonehenge is dominated by the large, locally derived sarsen stones which comprise the Outer Sarsen Circle and the Inner Sarsen Trilithon Circle. Lithologically they are a hard form of sandstone called silcrete. Less obvious are the smaller ‘bluestones’ which form the Outer Bluestone Circle and Inner Bluestone Horseshoe. Collaborative research including the National Museums Wales, Institute of Archaeology UCL and the University of Brighton, has been using automated mineralogy to help determine the original origin of the stones. Whilst the Sarsens are now known to be locally sourced, many of the Bluestones come from the Mynydd Preseli area in west Wales some 200 km west of Stonehenge, but much is still to be learnt in detail. Our work has also shown that the so-called “Altar Stone” could not have been sourced from the location described in archaeological literature and the search is now on for its real source.

Volcano-sedimentary processes exert fundamental controls on geothermal reservoir properties

Graettinger, A.H., McGarvie, D.W., Skilling, I.P., Hoskuldsson, A.H. & Strand, K.  2019. Ice-confined construction of a large basaltic volcano – Austurfjöll massif, Askja, Iceland. Bulletin of Volcanology, 81(9).

Many geothermal reservoirs are developed in successions of basaltic rocks, where variations in the volcano-sedimentary processes result in a wide range of rock types and overall stratigraphic architectures.  This stratigraphic architecture is one of a range of different scale parameters which will affect the overall porosity-permeability and geothermal reservoir characteristics.  Superimposed on the field-based scale, there is the pore scale distribution of secondary minerals which may be precipitated within the primary pore spaces affecting the reservoir performance.  We are combining our field-based observations through to the micron scale to gain a better understanding of both geothermal reservoir performance and CO2 sequestration projects.

New resources of cobalt are critical for the transition to a low carbon future

Pirrie, D. & Shail, R.K. 2018. Mud and metal; the impact of historical mining on the estuaries of SW England, UK.  Geology Today, 34, 215-223.

Several key society challenges require us to look again for new ore deposits. With the transition from fossil fuels to a low carbon future, there will be an increased demand for geological resources needed in the materials of the future. In particular there is a projected future increased demand for cobalt and lithium.  At the same time, there is a societal need to ensure that scarce mineral resources are produced as efficiently and importantly as ethically and environmentally carefully as possible.   Increasingly there is a need to ensure that we understand where minerals are produced from given the global significance of illegal and artisanal mining, and perhaps a need to source raw materials more locally.  Current research projects in this area include exploration for Co and Au mineral deposits; understanding the environmental impact of mining and assessing the scale of global illegal mining and examining ways to mitigate mining crime.

Characterising soils through automated mineralogy

Pirrie, D., Crean, D.E., Pidduck, A.J., Nicholls, T.M. & Shail, R.K. 2019. Automated mineralogical analysis of soils as an indicator of local bedrock lithology: a tool for rapid forensic geolocation.  Geological Society, London, Special Publication, 492.  

Understanding soils is critical in many areas of applied science. Soils are critical for food production and are vulnerable to climate change.  They are the sources for sediments in the geological record. In archaeology they provide context and in forensic science can be important trace materials.  Yet despite their significance, there is little research on the mineralogy of soils.  We are using automated scanning electron microscopy to characterise soil mineralogy, and then applying these data to applied questions in forensic geoscience, geoarchaeology, mineral exploration and environmental science.

Dr Marios N. Miliorizos is a structural geologist with interests in the Variscan.

Duncan Pirrie is Professor of Geology at USW. Prior to joining USW he was Associate Professor of Geology at the University of Exeter, before setting up a commercial consultancy company.  

He has published over 115 scientific papers and books.  Research on applications of forensic geology has included linking soil characteristics with crime scenes and using soils to identify geographical locations.  

He is co-author of a book, "The Guide to Forensic Geology" to be published by the Geological Society of London.  New work, funded through the International union of Geological Sciences is investigating the detection and mitigation of mining crime.

Professor Pirrie is a Fellow of Advance HE (FHEA).

Dr Ian Skilling is a British-born volcanologist with about 25 years of research and teaching experience at universities in the United States, South Africa and UK. He pioneered the use of lithofacies analysis of clastic rocks generated by volcano-ice interaction to interpret depositional environments and edifice evolution, and has continued to focus on the interpretation of a wide range of volcaniclastic rocks.

Dr Skilling was a volcanologist with the British Antarctic Survey (Cambridge, UK), and has undertaken geologic consultancy projects for several mining companies in South Africa, Botswana and Tanzania, and collaborated on geothermal exploration programs in Kenya (UNDP). He has a particular passion for field studies, and have led 25+ field trips (often with undergraduate and postgraduate students) in many parts of the world, including Iceland, Kenya, Antarctica, UK, Canada, California, Hawaii, Botswana, Tanzania and South Africa. His most recent areas of research focus is Iceland and Oregon.  

Dr Skilling is a Fellow of Advance HE (FHEA).

In this Masters by Research project Dafydd is using advanced automated mineralogy to characterise drill cuttings from a deep geothermal well and carbon dioxide sequestration test site, to constrain the controls on geothermal reservoir porosity and permeability.

Read Dafydd's story.

Nick’s KESS2 funded project in conjunction with Terradat Ltd and SatSense is using a combination of InSAR satellite data and ground-based geophysical methods to develop new continuous monitoring methods for movements on leaky dams and landslide-prone areas such as coal mine waste tips in Wales. 

Hallin is working on stratabound mineralisation in the Dalradian of Scotland.  In particular he is focusing on a previously reported Cu / Ni sulphide ore deposit and re-evaluating the potential for cobalt mineralisation.

Rebecca’s PhD research is examining the interaction of basaltic magmas with carbonate sediments and rocks.  Her primary field area is the Precambrian of N Wales but is also studying recent samples from Popocatépetl volcano in Mexico in collaboration with Professor Valentin Troll (University Uppsala).  Highlights include understanding the complex textural and mineralogical changes which occur as a result of magma mixing with wet carbonate sediments and rocks.

This KESS 2 funded PhD research project is working alongside Alba Minerals Ltd and Gold Mines of Wales Ltd on gold exploration in the Dolgellau gold belt of North Wales.  Field data collection is being integrated with detailed logging of new exploration core to evaluate the overall controls on mineralisation.

Asad’s project involves a detailed petrological and geochemical study of granitic rocks from the northwestern border of Pakistan and Nangarhar province of Afghanistan. The project is providing an overview of the petrogenesis and regional tectonic correlation of these bodies with other granitoid rocks in the Himalayas and other parts of the northern Gondwana margin.

Soil is widely used as an important class of trace evidence in forensic geoscience investigations.  However, the forensic significance of urban particulates is less well known.  In this Masters by Research project Mathijs is evaluating the potential.

Read Mathijs' story here.

Title: The distribution of minerals and geological structure along the coastline of the Vale of Glamorgan: structural kinematics and geometry.

Supervisors:  Dr Sorcha Diskin; Dr Marios Miliorizos and Dr Duncan Pirrie