The relatively well-preserved ancient crust of Mars provides a natural window into early planetary evolution that is not available on Earth. Mars has generally been considered a single-plate basaltic planet, although recent evidence suggests that magmatic evolution that gave rise to a felsic crust may have occurred sporadically. New research shows multiple lines of evidence for diverse volcanism and complex volcanctonics in the southern highlands of Mars in and around the Eridania Basin, 3.5 to 4 billion years old.
Unlike Earth, today’s Mars has little or no volcanic or tectonic activity.
Furthermore, almost half of the planet’s surface is more than 3.5 billion years old, indicating that there has not been extensive recycling of the Earth’s crust (a phenomenon generally driven by Earth-like tectonics, in which material of the surface is recycled in the mantle) since then.
Recent discoveries suggest that this was not always the case, but the geological activity of Mars in the first billion years after its formation is still unclear.
“Geological exploration of other rocky planets provides clues to early crustal evolution and volcanoctonic processes because other bodies exemplify comparable geosystems with variable mass, gravity and composition,” said Dr. Joseph Michalski of the University of Hong Kong and his colleagues. colleagues.
“Looked at through the lenses of different gravity fields, massive planet compositions, and heat flow, it is possible to test models of crustal resurgence and thus uncover the steps that led to plate tectonics and other forms of recycling. Earth’s crust”.
“In this sense, the planet Mars represents an especially valuable piece of the puzzle.”
The authors studied the morphology and mineralogy of the Eridania region in the southern hemisphere of Mars.
They analyzed remote sensing data from several orbiters, including Mars Global Surveyor, Mars Odyssey and NASA’s Mars Reconnaissance Orbiter.
The Eridania region offers the strongest crustal remains of Mars’ ancient magnetic field and several signs of volcanism.
The researchers identified 63 cases of four different types of volcanoes (volcanic domes, stratovolcanoes, pyroclastic shields and caldera complexes) and possibly hundreds more in the Eridania region alone, probably remnants of a vigorous period of geological activity about 3.5 billion years ago. .
This set of observations is consistent with the presence of crustal recycling on early Mars driven by vertical tectonics, a kind of tectonic process precursor to full plate tectonics on Earth.
This variety of volcanic structures could be more widespread on ancient Mars than previously thought.
“The observed remains of this activity may be the closest analogue on the planet to the hydrothermal origin of life scenarios proposed for Earth,” the scientists said.
His paper was published online today in the magazine Nature Astronomy.
JR Michalski et al. Diverse volcanism and recycling of the Earth’s crust on early Mars. Nat Astron, published online February 12, 2024; doi:10.1038/s41550-023-02191-7