What was Mars like billions of years ago? The presence of liquid water is undeniable, but there are many open mysteries about how the water moved around the planet. New research argues that Mars might have been a planet of rivers, suggesting that there are more fluvial structures on the Red Planet than previous observations might have suggested.
The team set out to understand how erosion has shaped Mars across geological epochs. They trained a computer model on images from NASA’s Curiosity together with satellite data and 3D scans of layers of rocks from Earth. The first to map erosion of ancient Martian soil, the findings suggest that the common "bench and nose" landforms are related to river erosion.
“We have everything to learn about Mars by better understanding how these river deposits can be interpreted stratigraphically, thinking about rocks today as layers of sediment deposited over time,” lead author Benjamin Cardenas, from Pennsylvania State University, said in a statement.
“This analysis is not snapshot, but a record of change. What we see on Mars today is the remnants of an active geologic history, not some landscape frozen in time.”
Previous river structures known as fluvial ridges have been found around Mars, but Curiosity has found these river deposits also in the bench landforms and in the nose landforms. These are not associated with fluvial ridges. Their model showed that in craters, fluvial ridges can turn into benches and noses due to erosion.
“This suggests that there could be undiscovered river deposits elsewhere on the planet, and that an even larger section of the Martian sedimentary record could have been built by rivers during a habitable period of Mars history,” Cardenas said.
“On Earth, river corridors are so important for life, chemical cycles, nutrient cycles and sediment cycles. Everything is pointing to these rivers behaving similarly on Mars.”
NASA’s other rover Perseverance might have some answers about the possibility of life in ancient Martian rivers. The rover is exploring the delta of an ancient river inside Jezero Crater.
“Our research indicates that Mars could have had far more rivers than previously believed, which certainly paints a more optimistic view of ancient life on Mars,” Cardenas said. “It offers a vision of Mars where most of the planet once had the right conditions for life.”
The study is published in the journal Geophysical Research Letters.