"A planet without plate tectonics can still develop a complex crust."
Key Findings
Researchers from the University of Oxford have discovered evidence that Mars once hosted large magmatic systems similar to those on Earth, despite lacking plate tectonics. The study, published in Nature Astronomy, suggests that Mars may have produced highly evolved crust through internal recycling processes.
Methods
The team analyzed seismic data from NASA's InSight mission, which recorded waves from meteoroid impacts and marsquakes. They investigated a boundary 24 km beneath the Martian surface. Using thermodynamic modeling and statistical techniques, the researchers compared hundreds of rock compositions with the seismic data.
Results
Only 'ultramafic' rocks (rich in iron and magnesium, low in silica) matched properties below the 24-km boundary, while 'mafic' rocks (higher silica) matched above it. The researchers concluded that this layer formed from molten rock pooling underground and separating into different materials, leaving dense crystals at the base and lighter melts rising.
Significance
This phenomenon, known as 'transcrustal magmatism,' was previously thought unique to Earth. The finding suggests that planets without plate tectonics can still develop complex crusts, potentially influencing habitability.