Autism and Ancient Oceans

Apart from the arts, I doubt there is any profession that has as many ways to describe the colour grey as geology. For this science, grey is a universe of subtle colour- it shines and sings, eager to spill the secrets of the Earth. For me, though, grey rocks go even beyond that, shaped by my autistic and synesthetic experience, the latter enabling me to literally hear colours.

While an undergraduate student, I visited the Scottish island of Skye, a beautiful wee island built from over three billion years of Earth history. One chilly April morning, our class was trying to decipher the secrets of the Jurassic rocks in front of us. To everyone else the rocks looked grey, their details hidden from rookie students. But I could see a pattern of subtle changes in colour and texture and I could hear the sounds that those colours and textures made.

In one layer, the rocks appeared in deep dark greens, blues, and purples. I had an image in my mind as of fat stacked shapes, like plates or dominos. I could hear the abstract sensation of sounds: low and droning, coming and going in slow lazy cycles that moved back and forth with a pressure that was both gentle and crushing. In another layer, I heard a sound like static mixed with the roar of a distant crowd and a rapid rolling clacking. I could see sparking white and silver glints shooting through a shifting mass of warm yellows and curving pale blue shapes. All this was wrapped up in a feeling of energy and tumbling over and over.

One of our instructors came over to check on our progress. I gave her my interpretation of the rock examination: there was a change in the ancient sea level. The lower layer, the one with the dark colours, was deep water, out at sea. The upper band, with the sensation of tumbling, was shallow water closer to the shore, maybe even a beach. She told me I was pretty much correct and asked how I could know. I tried to explain but, in the end, I simply told her, “it’s just what the rocks are saying”. My friends thought it was a pretty neat trick, and our instructor shrugged and said, “some people are like that”.

Over time, my instructors noticed more interesting traits about me and eventually, I was diagnosed with dyslexia, dyspraxia, dyscalculia, Attention Defcit Hyperactivity Disorder, and sensory sensitivity. I had always struggled with various tasks - my perception of time is fuid at best, and I am unable to perform Maths at a level much above primary school, as the numbers just won’t stay still. It’s one of the reasons why I had to postpone my degree until my late twenties. I still struggle with things like telling the time and often forget how to tie my own shoelaces. But this might just prove to be an asset for my scientifc experience. I started my PhD at Oxford looking at 1300-million-year old piles of mud that cover most of Northern Australia. The project was meant to be a warm-up, as these rocks had already been studied before, so they should have had nothing

new to tell us. I was given a box of black and grey chunks of rock. To me they were a dark rainbow of textures, colours, sounds and sensations that was telling a diferent story to the one in the books.

We sliced the rocks so thin we could push light through them, and we blasted them with X-rays and electrons. They were then digested in acid and evaporated in fames as hot as the sun. Soon we had collected our own pile of chemical evidence that supported the story that my mixture of senses was telling me.

These rocks record the frst appearance and spread of organisms with complex cells like our own. They tell the story of tiny, single-celled creatures called acritarchs, much more complex than bacteria, but not yet at the level of animals and plants. A lack of oxygen and an ocean saturated with toxic sulphur had held them in evolutionary stasis for over a billion years. But our new data showed an ocean with little sulphur, with low but persistent amounts of oxygen and plenty of the nutrients that these organisms needed. The reason the previous studies had not picked up on this was simple - they didn’t listen to the rocks. The ancient Australian mud had been singing its song of early life and no one had picked up on it, because they could not hear the patterns, the clues. I don’t want to make it sound like a cliché maverick story - my advisors, particularly Dr Rosalie Tostevin and our collaborators were at least equal parts of the project’s success - but I believe my experience really helped to uncover something that could have remained hidden, because it needed a diferent perspective. At this time, I had been getting treatment for severe depression, common among neurodiverse people. My psychiatrist suggested that a lot of my traits sounded like autism, so we looked into it. I eventually got the diagnosis and was told I was autistic. At frst, I was upset- I didn’t want to be like this. It felt like a crushing setback, as I was getting my life into shape at last. I thought it meant I would be forever emotionally separated from neurotypical people. But ever since the diagnosis, I’ve learned a great deal about autism and about myself. I’ve been constantly surprised by the traits I thought of as normal, which only people like me can experience, such as hearing colours. The unusual mix-up of senses is known as synaesthesia and there are many types, which are not only restricted to autistic people, but are certainly common among us.

Now that I know, I feel quite lucky to be able to simultaneously see, hear and feel not just the world as it is now, but also the world as it was millions, or billions of years ago, all of these Earths superimposed upon each other in a beautiful, fowing, shifting dance, momentarily frozen in the form of the landscape around us and the rocks beneath us.

I have always felt more at home in the comforting weight of deep time and now that I fnally understand why, I can work on bridging the gap between those ancient oceans and the noisy world of modern humans. The rocks have a story to tell. You just have to listen. Brooke Johnson is studying for a PhD in Earth Sciences at St Edmund Hall.