ChaSE student focus: Alex Hands

Alex Hands and Dr James Witts collecting fossil brachiopod samples from the Cenomanian-Turonian chalk succession at Eastbourne, East Sussex.

Who are you? What course are you on? Who is your supervisory/advisory team?

I am Alex Hands, a 22-year-old geologist who previously studied Geology for three years at the University of Durham and is now based in St Andrews, Scotland. At the University of St Andrews, I am on a year-long taught Master’s in Geochemistry where I have been supported by my academic supervisor Dr Eva Stueeken and my dissertation supervisor Dr Hana Jurikova. I have been given the opportunity to really tailor my project to my own interests and work with other researchers as part of the ChaSE project.

Tell us about your project?

Ocean Anoxic Event 2 (OAE-2) is the focus of my research which was a short-lived period where the oceans were depleted in dissolved oxygen during the Late Cretaceous spanning the Cenomanian-Turonian boundary. Lasting approximately from 93.97 Ma to 93.49 Ma, OAE-2 was also associated with second order mass extinction in the marine realm claiming 8% of marine families and 26% of marine genera. My dissertation project involves the reconstruction of the ocean pH and atmospheric CO₂ from boron isotopes (δ¹¹B_Borate) in Cenomanian-Turonian brachiopods spanning across OAE-2. This reconstruction will help to determine the role of ocean acidification in the second order mass extinction and solve the contradiction between extensive Large Igneous Province (LIP) activity at the time and existing invariable CO₂ records from stomata.

With help from collaborators the brachiopods will also provide a δ¹³C, δ¹⁸O and an ⁸⁷Sr/⁸⁶Sr record. These records will help to assess the dominant disruptor to the carbon cycle, the effect on climate-weathering feedback and hopefully the ultimate cause of OAE-2. This research is exciting as using brachiopods instead of planktic foraminifera (Cenozoic) is a relatively new method that has unlocked the rest of the Phanerozoic. The method has been tested successfully on both the Permian-Triassic mass extinction and the early Jurassic (Toarcian-OAE) respectively.

What is the most exciting part so far? And/or: what is one interesting fact about chalk you’ve learned from your project that you didn’t know before?

The most exciting parts so far have been the lab work in the clean labs on cleaning, dissolving and Boron purification for Boron isotope analysis, and the ChaSE fieldwork in Eastbourne, where I learnt a huge amount about the Cenomanian-Turonian succession and OAE-2 from the brilliant Prof. Andy Gale. Chalk is a rock that surprisingly despite being an Earth Scientist for over four years now I have had limited experience with up until now. I had perhaps naively never realised that it could host so many exciting macrofossils like brachiopods, echinoids and ammonites, I had assumed it was all just microfossils!