Rocks keep time. Not on our human-scale time, but deep time: the almost unimaginable span of billions of years which have already come and gone.
Let’s say you’re in the far future and you’re looking for evidence of previous civilisations. Where would you look? The first place would be in the rocks.
For decades, experts have debated whether our world-spanning impact on the planet represents the sign of a new geological period, the Anthropocene. Only recently, scientists selected a small lake in Canada as the site that best records our impact.
