Mars is often compared to Earth as a potential destination for human exploration and colonization. Both planets share a similar early history, including the presence of water and volcanic activity. However, a new study reveals that Mars has far fewer minerals than Earth, despite their common origins.
According to the study published in the Journal of Geophysical Research-Planets, Earth has about 6,000 different minerals, while Mars has only 161. That is a huge difference that reflects the divergent evolutionary paths of the two planets.
What Causes Mineral Formation?
Minerals are natural substances that form through various physical and chemical processes. The study identified 57 primary and secondary mechanisms of mineral formation on Earth, but only 20 on Mars.
The researchers traced the mineral evolution of both planets back to their formation in the protosolar nebula, where they inherited a dozen primitive minerals from the dust and gas that surrounded the young sun. As the planets grew through collisions and accretion, they developed more complex minerals from the melting and crystallization of rocks.
The study found that the earliest minerals on Earth and Mars were similar, mostly mafic igneous rocks such as basalt. Hydrothermal activity also played a role in creating new minerals on both planets.
What Made Earth More Mineral-Rich Than Mars?
The study suggests that two major factors contributed to Earth’s mineral diversity: plate tectonics and life. Both processes are not known to have occurred on Mars, at least not to the same extent as on Earth.
Plate tectonics is the movement of large segments of Earth’s crust over its mantle. It creates zones of subduction, where one plate sinks beneath another, and zones of rifting, where plates pull apart. These processes recycle rocks and minerals between the surface and the interior of the planet, exposing them to different temperatures, pressures, and fluids. Plate tectonics also drives volcanism, which produces new magmas and minerals.
Life is another source of mineral diversity on Earth. Living organisms can alter the chemical composition of their environment through metabolism, photosynthesis, respiration, decomposition, and biomineralization. Life can also influence the physical conditions of mineral formation by creating habitats such as shells, bones, coral reefs, caves, and soils.
The study estimates that plate tectonics and life account for more than 4,000 minerals on Earth that are absent or rare on Mars.
What Does This Mean for Mars Exploration?
The study provides a new perspective on the geology and history of Mars. It shows that Mars is not just a smaller version of Earth, but a fundamentally different planet with its own mineralogy.
The study also has implications for the search for life on Mars. If life ever existed or still exists on Mars, it might have left behind traces of biogenic minerals that could be detected by future missions. However, finding such minerals might be challenging due to the limited diversity and abundance of Martian minerals.
The study also suggests that there might be more minerals on Mars than we currently know. Some minerals might be hidden below the surface or in regions that have not been explored yet. Future missions could reveal new discoveries that would enrich our understanding of Mars and its evolution.
