I look for the mineral equivalent of tree rings
Yang Li’s research has developed a high-precision chronology of rocks
“Early in my career, as I studied at the China University of Geosciences in Wuhan, I wanted to discover where and how minerals formed. Now, I develop geochemical tools to explore how minerals form in the crust — which could help to guide more cost-effective mining.
During my PhD at Durham University, UK, I learnt that mineral formation was much faster than the continuous process over several millions of years it had been thought to be. My geochronology data suggest that minerals can form much more quickly, in spurts, over a few tens of thousands of years or less. The mineral zones that form during these spurts are akin to the seasonal growth rings of trees, but they’re much smaller, usually only a few millimetres to micrometres wide.
My current research at Peking University in Beijing focuses on identifying what controls this rapid and pulsing nature of mineral ore formation so that we can identify where metals in Earth’s crust are enriched and can be mined economically.
In this image, I’m collecting granite rock samples in the coastal Hainan region of China. It takes hundreds to thousands of years for magma to cool and solidify into granite, during which valuable minerals, such as iron or copper, form from the fluids released by the cooling magma.
In the laboratory, we polish thin layers of rock to analyse their elements and isotopes. Oxygen isotopes can indicate what types of fluid the metals came from and how the minerals interacted with groundwater. By analysing the mineral’s rings of oxygen isotopes, I can reconstruct the history of mineral growth, and therefore the history of the geological event that led to ore formation. I can also track the diffusion of elements, such as aluminium in quartz, to estimate the dynamics of geological events.
Last summer, I travelled to Iceland and saw my first volcanic eruption. I finally got to see how magma bursts into the world.”
Nature 627, 236 (2024)
doi: https://doi.org/10.1038/d41586-024-00647-y
This interview has been edited for length and clarity.
This story originally appeared on: Nature - Author:Virginia Gewin
