Congratulations to Alexandra Turchyn and Rich Harrison, who have each been awarded prestigious ERC Advanced Grants to investigate fundamental questions about Earth’s climate, its long‑term habitability and the origins of life in the universe.
Earth’s geological thermostat and the role of the ocean crust weathering
Alexandra Turchyn’s project investigates how the breakdown of submarine rocks may have helped stabilize Earth’s climate over geological time to create a habitable environment.
Earth has remained a habitable planet for most of its 4.5 billion years, never getting too hot or too cold, allowing life to evolve.
The breakdown of rocks on-land is thought to be key in stabilizing Earth’s temperatures – acting as a geological thermostat. Continental, silicate rocks such as granite react with acidic rainwater, drawing CO2 down from the atmosphere in the process. This CO2 is then converted into carbonate minerals and washed away into the oceans, where it is locked away in rocks.
“The premise is that, if atmospheric CO2 increases then temperatures and rainfall will also rise – driving more continental silicate weathering, removing more carbon and in turn bringing temperatures down,” explained Turchyn. “However, decades of research have shown that the rates of continental silicate weathering depend only weakly on temperature and, indeed, the overall controls remain enigmatic.”
Turchyn’s new project investigates another frequently underappreciated player in the global thermostat: the breakdown of seafloor basalt. When seawater circulates through basaltic crust at mid‑ocean ridges and ridge flanks it dissolves the silicate minerals, consuming CO2 and precipitating it as carbonate minerals.
She and a team will run a series of lab experiments that mimic submarine basalt weathering, up scaling these observations using computer models to understand the relative role of this process in the global carbon cycle.
“Understanding how submarine basalt weathering interacts with Earth’s climate system over a range of temperature and chemical conditions could transform our understanding of one of the most fundamental questions – how our planet achieved a stable climate and thus became habitable,” said Turchyn.
Peering into magnetic minerals to redefine our understanding of planetary formation
Richard Harrison and collaborators will use a newly developed technique for imaging magnetic minerals to advance our understanding of the early solar system and life-building processes on Earth.
Scientists have been using ancient magnetic signals preserved in rocks to investigate Earth’s dynamic history for decades. More recently, palaeomagnetism has been used to ask questions about the early solar system, with, for example, magnetic information within meteorites providing clues about how rocky worlds formed.
“Traditionally, scientists had thought that magnetic grains smaller than 100 nanometres record the best signals of past magnetic field,” said Harrison. “But recent studies have in fact shown that particles up to several 1000 nanometres in size are not only more commonly found in rocks but could track magnetism just as faithfully.”
However, measuring the magnetic properties of these larger particles has been challenging because X-rays couldn’t penetrate far enough to create an image of their internal structure.
That changed recently, when Harrison and colleagues from Germany and China developed a new technique for visualizing the interiors of magnetic particles – including those larger grains typically containing magnetic moments (tiny magnetic fields generated by spinning electrons) arranged in a complex, vortex‑like pattern.
Harrison’s new project will develop methods to observe how these vortices respond to changes in temperature, magnetic field and time, enabling scientists to understand how they retain the magnetic information through time.
Using the new 3D imaging technique, Harrison said they will now be able to tackle wide-ranging problems from reconstructing the distribution of magnetic fields in the early solar system to modelling the interaction of magnetic particles with pre-biotic chiral molecules – proposed to be a critical step in the origin of life – and extracting reliable paleomagnetic data from the early Earth.