Chloe Griffin
Tell us about yourself:
Hi, I’m Chloe, and I’m in the final few months of my PhD at the University of Liverpool in the UK where I’ve been working with Dr. Rob Duller and Dr. Kyle Straub. I’m originally from Cambridgeshire in East England, but I moved up to Liverpool 8 years ago when I started university and I’m yet to leave! I graduated in 2019 with an integrated master's degree in Geology and Physical Geography and after finding a love for sedimentology/geomorphology during my degree I stayed on at Liverpool to start my PhD that autumn.
What is your research about?
My research focuses on the nature of autogenic processes which operate internally within all sediment transport systems and control the transport of sediment across landscapes. Even under constant external forcing, these processes induce episodes of sediment storage and release over a range of space and timescales which means that sediment is not transported linearly through a system. These processes contribute noise to measures of sediment flux, which will also impart variability to strata, and can promote or hinder the propagation and preservation of sediment flux signals generated by environmental change (e.g. climate change, tectonic uplift or anthropogenic change). This means that environmental signals can be difficult to detect from a time series of sediment flux, as they can be modified or obscured by autogenic processes. My research aims to quantify the nature and timescales of autogenic processes operating in different sediment routing systems so we can understand which signals may be preserved in the sedimentary record. To do this, we use a pile of rice which acts as a really simple lab-scale sediment transport system. Within the rice pile, storage and release events occur along a 1D transport path, which is analogous to sediment transport in a 2D path in natural systems, and as a result can produce a diverse range of autogenic dynamics. Using the rice pile, we first characterize the structure and timescales of autogenic processes operating within the Earth surface active layer, where we’ve found that two autogenic timescales exist that control the degradation and detection of environmental signals. More recently we’ve removed time from the sediment flux time series as a proxy for stratigraphic incompleteness, to explore how incompleteness influences the structure of autogenic noise preserved in the sedimentary record and hence the detectability of past environmental signals.
What excites you about your research?
The distinctive temporal structure and two autogenic timescales we’ve found in the rice pile are present within natural sediment transport systems, however the exact processes which control these will differ between geomorphic environments. Whilst we have evidence of what causes these in the rice pile, its been a complex but exciting thought process to try and delimit what could cause these in different natural systems. To try and understand this I’ve really had to get down to the fundamental sediment transport processes operating in different segments of a sediment transport system, where one day I’m thinking about processes operating on hillslopes and the next those controlling delta evolution and morphology; it really keeps me thinking. It then gets even more of puzzle when different environments become linked together (e.g. hillslopes and fluvial systems) which is where the brainteaser really starts. Also, one of the best parts of the experiments was imposing signals onto the rice pile and waiting in suspense to see whether there was still a signal at the other end!
What broader importance does your research have for society?
In geological history, the Earth has been subjected to many large climatic events (e.g. the PETM), which have left imprints in the Earths sedimentary archive. Providing evidence of these signals is preserved in the sedimentary record, this allows for the reconstruction of past environmental perturbations and provides important insights into the response of landscapes to future environmental change. However, anthropogenic forcing is becoming an increasingly dominant mechanism of environmental forcing worldwide, where the intensity of modern anthropogenic activities can trigger more drastic geomorphic change than natural forcing mechanisms. Hence human activity has great potential to impact landscape morphology and be preserved in the future rock record. Understanding the thresholds for the preservation of environmental signals within landscapes can provide crucial insight into landscape sensitivity and resilience and also understanding of which environments evidence of both palaeo-surface processes and environmental signals is best preserved.
What inspired you to pursue a career in Earth Science?
Growing up, I was lucky to get the opportunity to travel around the world and experience different countries all with individual climates and landscapes, which sparked my interest in geography. This interest in all aspects of physical geography continued through school, and inspired me to apply to study physical geography at university. I’d never got the opportunity to study geology during school, but an impulse decision a few weeks before starting university saw me switch course to geology and physical geography and I’ve never looked back. During my masters year, I did a fieldwork project looking at the sedimentological and geomorphological evidence for a drainage capture event and I realized that I enjoyed process sedimentology and connecting surface processes to the sedimentary record, which then inspired me to apply for this PhD.
What are you looking to do after you complete your PhD or postdoc?
I’m now very close to the end of my PhD so I’m currently looking for a postdoc or a research position in industry which would allow me to continue my research interests in sedimentology and/or geomorphology and develop the skillset I’ve gained during my doctoral training. Long term, I think I'd like to stay in academia and find a permanent position, but who knows what unexpected opportunities will be thrown my way and I'm excited for the unknown.
Given unlimited funding and access to resources, what is your dream project that you would pursue?
With more time and funds, I’d love to start taking some of the theory I’ve developed during my PhD and applying it to modern field systems. Whilst the rice pile is a great analogue for sediment transport systems, the complexity of natural systems cannot be replicated in a simple experiment. In order to understand the nature of sediment transport and as a result what signals will be detectable, we must quantify the processes which define and influence the extent of correlation and the duration of the longest duration autogenic event in each specific sediment transport system. If we could generate a quantitative estimate of this event timescale within different sediment transport systems, we could eventually construct a database encompassing all geomorphic environments and provide estimates of the temporal range present depending on a variety of other factors. This would improve our understanding of the nature of sediment transport across the Earth's surface, but also define the ability of environmental perturbations to cause geomorphic change and influence landscape morphology, which could aid the search for evidence of signals within the resultant sedimentary record.
What else do you do? Any hobbies or interests outside of work?
I have 2 horses which take up a lot of my time outside work! I love taking them out for rides around the countryside and along the beach, but I also regularly spend my weekends competing in dressage. I also enjoy hiking in various locations around the UK with my family, friends and my dog.