New research suggests that ancient Mars may have been more geologically and hydrologically active than we once thought.
Scientists from Rice University have discovered that the thick crust of Mars’ southern highlands, formed billions of years ago, could have produced granitic magmas and supported underground reservoirs of liquid water.
This challenges the long-held belief that Mars has always been a dry, frozen world.
The study, published in Earth and Planetary Science Letters, was led by Professor Cin-Ty Lee.
It focuses on the Noachian and early Hesperian periods of Mars’ history, about 3–4 billion years ago.
During this time, the southern highlands had a crust up to 80 kilometers thick.
The researchers found that this thick crust was hot enough to partially melt at its lower levels, producing rare types of magmas, like granites, and sustaining subsurface aquifers—underground layers of liquid water beneath a frozen surface.
“Our findings show that Mars’ crustal processes were much more dynamic than we thought,” said Professor Lee.
“The thick crust in the southern highlands could produce granitic magmas and create conditions for stable underground reservoirs of water on a planet we often think of as dry and frozen.”
The research team used advanced computer models to recreate the thermal conditions of Mars’ crust during its early history.
They examined factors like crust thickness, heat from radioactive materials, and heat flowing up from the mantle. Their simulations showed that areas with crust thicker than 50 kilometers likely experienced partial melting, which could create felsic magmas, including granites.
This melting didn’t need the plate tectonics that are responsible for granite formation on Earth.
The heat generated by the thick crust also kept underground aquifers warm enough to remain liquid, even beneath a surface covered in permafrost. These aquifers might have stretched several kilometers deep and could have been tapped by volcanic activity or asteroid impacts, causing occasional floods on the surface.
The discovery that Mars may have produced granitic magmas is important because these rocks often contain elements that support life, such as phosphorus and potassium.
Additionally, the presence of liquid water in underground reservoirs increases the chances that Mars’ southern highlands could have been habitable billions of years ago.
“Granites are like time capsules,” explained Professor Rajdeep Dasgupta, one of the study’s co-authors. “They record a planet’s thermal and chemical history. On Earth, granites are linked to water recycling and tectonic activity. The fact that Mars could produce similar magmas highlights its complexity and its potential for hosting life in the past.”
This study also provides clues about where to look for evidence of Mars’ dynamic past. Large craters and fractures in the southern highlands could expose granitic rocks or remnants of ancient water reservoirs. Future missions to these regions might uncover more evidence of Mars’ ability to support life.
“Understanding Mars’ crustal processes brings us closer to answering big questions about its history and habitability,” said Professor Kirsten Siebach, another co-author. “Our research shows where to search and what to look for as we continue exploring the red planet.”
These findings not only reshape our understanding of Mars but also offer hope that one day, we may find signs of life hidden in its ancient rocks and water.
Source: Rice University.
