Researching Submarine ‘Rivers’ and Salt Topography

Introduction

My name is Zoë Cumberpatch and I’m half way through a PhD in Basin Studies at the Department of Earth and Environment, University of Manchester. From a young age I loved the outdoors and wanted to understand ‘why is that hill there?’, ‘why does one river flow faster than another?’ and ‘why do the rocks in Nottingham (where I’m from) look so different to the rocks in holiday destinations?’

My enjoyment and interest of Maths, Science and Geography at school led me to study Geology, Geography, Biology and Maths at A-level, before going on to study Geological Sciences at the University of Leeds. At Leeds, I preferred sedimentary rocks rather than igneous and metamorphic rocks and that fuelled my desire to study the applied side of sedimentology (with an MSc in subsurface energy at Imperial College London). 

During my MSc I was exposed to lots of different geological techniques and methods, and I wanted to integrate a number of these techniques to answer a research question. This led me to apply for multiple PhD projects and eventually I settled on my current project at the University of Manchester. My project looks at how deep marine landslides and ‘rivers’ can be controlled and re-routed by growing ‘salt diapirs’ (which are essentially hills made of salt). The properties of the rocks deposited by these flows can be very optimal for both producing hydrocarbons and storing carbon dioxide. Geologists are the experts of the earths subsurface and are vital for the ‘global energy transition’.

My PhD combines subsurface data (think of it as an ultrasound of the earth), fieldwork (travelling the world to study analogous exposed rocks), numerical modelling (creating geology using ‘ping pong balls’ and simulating geological time) and physical modelling (literally building hills in a flume tank and letting the water in).


My PhD has given me some incredible experiences; my highlights so far include:

1) Leading a field trip to my field area (northern Spain) for 10 industrial sponsors of our research group (picture of me in a hi-vis)
2) Winning best student poster at an International Conference in Salt Lake City
3) Spending my entire August 2019 doing fieldwork in Azerbaijan, after successfully winning a grant with a colleague
4) Working as a team to construct valid flume tank experiments in Utrecht
5) Being part of a NERC CDT (Centre of Doctoral training) which gives me a cohort of like-minded researchers, and 20 weeks of broad geological training (picture below shows a group of us in the Alps on a field course).

In depth (PhD Project Summary)

Layers of sedimentary rock form much of the Earth’s continental crust. These rocks are laid down in different depositional environments (e.g. terrestrial or marine). Layers of salt accumulate in regions where seawater incursions evaporate. Due to salt’s mechanical properties it becomes buoyant when sufficiently buried and can flow over geological time (much like glass), forming salt-cored ridges and domes on the ocean floor. Gravity moves sediment from the continents to the deep ocean basins, resulting in the deposition of rocks around the salt bodies. These salt bodies, which can be growing during deposition can cause deep water gravity flows to terminate completely or reroute their course. Geophysical ‘ultrasounds of the earth’ (seismic imaging) make it possible to study the subsurface, however areas around salt remain difficult to image in these data sets due to the chaotic representation of salt on seismic. Cliff sections in the Basque Country, Spain reveal ancient deep-marine rocks originally deposited next to salt-cored topography; these are used to understand sedimentary processes operating in deep-water and their effect on the sedimentary record. Fieldwork observations are combined with subsurface seismic data from the UK North Sea and numerical and physical models to appreciate the distribution of these sediments on a variety of scales and explore how this may influence potential hydrocarbon or carbon storage distribution and quality around salt bodies.

Going Further

For more information about all things geological, including resources for schools and colleges see the Geological Society: https://www.geolsoc.org.uk/

To learn more about the research happening in my department: https://www.ees.manchester.ac.uk/research/themes/

To learn more about the research happening in my research group: http://stratleeds.org.uk/

If you’re interested in sedimentology, look no further than: https://www.sepm.org/


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