Billions of years ago, Mars was a planet where rain fell, rivers flowed, and water collected in vast valleys and canyons. This water might have even reached a large Martian ocean, creating environments where life could potentially thrive. Now, for the first time, researchers have mapped the large river drainage systems on Mars, providing new insights into the planet’s ancient hydrology and its potential for harboring life.
A groundbreaking study published in the Proceedings of the National Academy of Sciences by researchers from The University of Texas at Austin has defined 16 large-scale river basins on Mars. These areas are where life would have been most likely to develop during the planet’s wetter periods. “We’ve known for a long time that there were rivers on Mars,” said Timothy A. Goudge, a co-author and assistant professor in the Department of Earth and Planetary Sciences at the UT Jackson School of Geosciences. “But we really didn’t know the extent to which the rivers were organized in large drainage systems at the global scale.”
Unveiling Mars’ River Basins
Goudge, along with postdoctoral fellow Abdallah S. Zaki, synthesized previously published datasets of Mars’ valley networks, lakes, and rivers to outline these drainage systems. They identified 19 significant clusters of valley networks, streams, lakes, canyons, and sediment deposits, 16 of which formed watersheds of 100,000 square kilometers or larger. This size is the threshold for what is considered a large drainage basin on Earth.
“We did the simplest thing that could be done. We just mapped them and pieced them together,” said Zaki, who led the research.
On Earth, large watersheds are more common, with 91 systems spanning at least 100,000 square kilometers. The Amazon River basin, the largest on Earth, covers about 6.2 million square kilometers, while Texas’ Colorado River basin just qualifies as large at 103,300 square kilometers. These large river systems are often ecological hotspots, rich in biodiversity and nutrients.
The Significance of Large Drainage Systems
Large river basins on Mars, although less common, are significant. They account for about 42% of the total material eroded by rivers on the planet, despite only covering 5% of Mars’ ancient terrain. This erosion is crucial because sediment often contains nutrients, making these areas prime candidates for finding signs of past life.
“The longer the distance, the more you have water interacting with rocks, so there’s a higher chance of chemical reactions that could be translated into signs of life,” Zaki explained.
Unlike Earth, Mars lacks tectonic activity, which limits the number of large drainage systems. However, the identified basins could still provide vital clues about the planet’s habitability. “It’s a really important thing to think about for future missions and where you might go to look for life,” Goudge emphasized.
Implications for Future Exploration
The findings of this study have significant implications for future Mars missions. The 16 large drainage areas identified could be key targets for exploration, offering the best chance of discovering evidence of past life. Department Chair Danny Stockli highlighted the importance of this research, noting, “Tim Goudge and his team continue to be leaders in the field, making groundbreaking contributions to the understanding of Mars’ planetary surface and hydrologic processes.”
This study, co-authored by David Mohrig, a professor in the Department of Earth and Planetary Sciences, marks a significant advancement in our understanding of Mars. As researchers continue to explore these ancient river systems, they hope to uncover more about the planet’s history and its potential to support life.
The mapping of Mars’ large river drainage systems opens a new chapter in planetary science, offering a detailed look at the red planet’s past and guiding future exploration efforts in the search for life beyond Earth.
