Mars' relatively well-preserved ancient crust provides a natural window into early planetary evolution not visible on Earth. Mars has generally been thought to be a monolithic basaltic planet, but recent evidence suggests that magmatic evolution leading to a felsic crust may have occurred sporadically. A new study shows multiple lines of evidence for diverse volcanic activity and complex volcanic tectonics in Mars' southern highlands in and around the Eridanian basin 3.5 to 4 billion years ago.
Topographic map of the Eridanian region of Mars. The volcanic structure described by Michalski et al. Classified by morphology and morphometrics. Image credit: Michalski other., doi: 10.1038/s41550-023-02191-7.
In contrast to Earth, Mars today has little volcanic or tectonic activity.
Additionally, nearly half of Earth's surface is more than 3.5 billion years old, and since then it has undergone extensive tectonic recycling (a phenomenon typically caused by Earth-like tectonic movements, in which surface material is recycled into the mantle). This shows that there is no such phenomenon.
Recent discoveries suggest that this is not always the case, but geological activity during the first billions of years after Mars' formation is still unknown.
“Geological exploration of other rocky planets provides clues to early crustal evolution and volcanic tectonic processes,” said Dr. Joseph Michalski of the University of Hong Kong. “This is an example of an equivalent Earth system with a changing composition.”
“Looking through the lens of different gravitational fields, bulk planetary compositions, and heat flows allows us to test models of crustal resurfacing and discover the steps that led to plate tectonics and other forms of crustal recycling.” It will be possible to do so.”
“Mars represents a particularly valuable piece of the puzzle in this regard.”
The authors studied the morphology and mineralogy of the Eridanian region in Mars' southern hemisphere.
They analyzed remote sensing data from a variety of orbiting satellites, including NASA's Mars Global Surveyor, Mars Odyssey, and Mars Reconnaissance Orbiter.
The Eridanian region contains the most powerful crustal remains of Mars' ancient magnetic field and various traces of volcanic activity.
The researchers identified 63 examples of four different types of volcanoes (volcanic domes, stratovolcanoes, pyroclastic shields, and caldera complexes), and there are likely hundreds more in the Eridanian region alone. , these are probably the remnants of a period of active geological activity about 3.5 billion years ago.
This set of observations is consistent with the existence of early Martian tectonic cycles driven by vertical tectonics, a type of tectonic process precursor to full plate tectonics on Earth.
Such diverse volcanic structures may be more widespread on ancient Mars than previously thought.
“The observed remnants of this activity may be the closest analog on Earth to the proposed hydrothermal origin of life scenario for Earth,” the scientists said.
Their paper Published in an online journal today natural astronomy.
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JR Michalski other. Diverse volcanic activity and crustal circulation on early Mars. Nat Astron, published online on February 12, 2024. doi: 10.1038/s41550-023-02191-7
Source: www.sci.news
