PhD in Geographical and Earth Sciences - The Rocks of the Future: How do Anthropogenic Rocks Form?

The Anthropocene is a proposed geological epoch encompassing significant human impact on the Earth (e.g. Waters et al. 2016). In a geological and geomorphological context, humans are agents in sculpting the landscape and creating artificial ground (e.g. Price et al. 2011). Examples of artificial ground deposited by humans on the Earth’s surface range from excavated natural rock, such as spoil from deep mining, to anthropogenically-created materials such as steelmaking process wastes (e.g. Price et al. 2011; Riley et al. 2020). In Great Britain, ~40 km3 of artificial ground (equivalent to six times Ben Nevis) has been deposited over the past 200 years (Price et al. 2011). Given that worldwide annual anthropogenic shift of sediment is estimated to be ~57000 Mt, greatly exceeding that of transport by rivers to the oceans (22000 Mt) (Price et al. 2011), lithification of artificial ground will play a major role in creating the rocks of the future. 

Artificial ground poses a variety of challenges. Many types of artificial ground are unsuitable for building foundations on due to their physical properties while the unconsolidated nature of artificial ground can lead to devastating mass movement (e.g. failure of colliery spoil tips (Siddle et al. 1996)). Artificial ground will often contain toxic chemicals (e.g. metals, (Hobson et al. 2017)), or lead to secondary pollution of surrounding watercourses (e.g. acid mine drainage from colliery spoil (e.g. Simate and Ndlovu 2014)). However, artificial ground can present opportunities too. ‘Brownfield’ land – underlain by artificial ground – is frequently reused for construction and development (e.g. Hammond et al. 2021). Due to its varied chemical and physical properties, artificial ground can enhance biodiversity within an area (Macgregor et al. 2022). Artificial ground with certain chemical properties can also potentially be used as CO2 sinks (Washbourne et al. 2015; Riley et al. 2020). Given these challenges and opportunities, it is important to understand the evolution of the physical and chemical properties of artificial ground. Understanding this is also timely given ever-expanding volumes of artificial ground and political focus on repurposing land underlain by artificial ground for development. One such potential physical and chemical change is lithification.

Project Aim and Research Questions

The broad aim of this project is to investigate the processes involved by which unconsolidated artificial ground becomes rock. This aim will be addressed by investigating case studies where artificial ground has already become lithified – current analogues to future anthropogenic rocks. For these case studies, the following research question will be addressed:

• What are the geological mechanisms and causes of lithification of artificial ground?

• What challenges and opportunities are presented by typical types of anthropogenic rocks?

Samples of already lithified artificial ground will be collected from case study sites for microanalysis. Scanning electron microscope imaging and chemical mapping will be used investigate mineralogical and chemical changes with lithification. X-Ray Diffraction will be used to determine anthropogenic rock mineralogy and laser ablation mass spectrometry will fingerprint microchemistry. There is also scope for various other types of geochemical analysis, e.g. carbon isotopes, depending on the outcomes of the other analyses.

How to Apply: Please refer to the following website for details on how to apply: http://www.gla.ac.uk/research/opportunities/howtoapplyforaresearchdegree/.