As a geologist, I have studied various types of natural rocks, but recently I have become interested in ‘anthropogenic geomaterials’ – things like industrial slag – and how they become entwined in geological and environmental processes. I came to Workington originally to look at the slag, because I was interested in its potential to scrub-capture carbon dioxide out of the atmosphere. However, when encountering the rock platform with the wheel in it, I was drawn by its incongruity. After studying the geomaterials of Workington more closely with my colleagues Amanda Owen and David Brown, we believe that this little-known section of the English coastline represents a tangible and potentially long-lasting signature of the impact humans are having on the planet.

Unlike many industrial landscapes, nature here has mostly returned, so it would be easy to miss that the beach is composed of human materials. Here a process that normally takes millennia or aeons has happened in a matter of decades. And it’s not the only example: new forms of anthropogenic geology are emerging around the world. These new materials are blurring the borderline between the natural and unnatural. They are also raising a rather fundamental question for geology: what actually is a rock?