Mars, a dusty and quiet planet in its current state, has a surprisingly violent history that could hold important clues about Earth’s own past. According to a recent survey of the Martian surface, the red planet was once filled with volcanoes that resembled the early stages of Earth before the formation of tectonic plates. Planetary scientist Joseph Michalski and his colleagues from the University of Hong Kong studied the Eridania region in the southern hemisphere of Mars and used remote sensing data from orbiters to catalog the scars of volcanic activity. Unlike Earth, which has a crust made up of interlocking continental plates, Mars is considered a one-plate planet. The absence of tectonic plates allowed the volcanoes on Mars to grow larger and more explosive than those on Earth. The largest volcano on Mars, Olympus Mons, is 100 times larger in volume than Earth’s biggest volcano, Mauna Loa in Hawaii.
Mars provides a valuable puzzle piece when it comes to understanding the geological history of our own planet. Roughly 70 percent of the Martian surface is over 3 billion years old, with about 45 percent older than 3.6 billion years. The researchers explain that although the Martian crust is heavily impacted by craters, the ancient geologic record remains mostly intact. This intact record offers a unique window into early Solar System geological conditions and provides clues to the early evolution of Earth’s crust. Michalski and his colleagues believe that studying Mars can help us understand how Earth’s crust might have formed.
Michalski and his colleagues focused their study on the Eridania region of Mars due to its intensely magnetized crust and evidence suggesting the presence of an ancient Martian sea. Using orbital data, the researchers identified four types of volcanoes in and around the Eridania sea: volcanic domes, stratovolcanoes, pyroclastic shields, and caldera complexes. These volcanoes had similar structures to those found on Earth today but with slightly larger diameters, which is attributed to the lower gravity and more explosive volcanism on Mars. Additionally, the volcanoes in the Eridania region showed felsic volcanic compositions that are different from any other recognized volcanic region on Mars, making this area even more unique.
The topography of the ancient Martian landscape provided further insights into the planet’s volcanic history. The thickness of volcanic deposits in the Eridania region, along with sections of warped and folded crust and sagging basins, led the researchers to believe that Mars’ crust might have been slowly overturned by a precursor to plate tectonics called vertical tectonics. This overturning process suggests that the early crust of Mars was constantly changing and dynamic. The researchers also suspect that there could be hundreds more volcanoes in the Eridania region, many of which might have erupted beneath the ancient sea that once existed there. This parallel between Mars and Earth during the Archean period, when Earth was predominantly covered in water and life began to emerge, adds to the intrigue of the Eridania region.
The study of Mars’ violent volcanic history provides valuable insights into the early geological conditions of our own planet. By examining the scars of volcanic activity on Mars, scientists like Joseph Michalski and his colleagues can piece together the puzzle of Earth’s crust formation. The Eridania region of Mars, with its diverse volcanism and evidence of an ancient sea, offers a unique glimpse into the planet’s past. As our understanding of Mars and its geological history deepens, we move closer to understanding the parallels and differences between the red planet and our own blue dot.