Study offered fresh evidence when the climate was far more erosive in Mars’ past

Mars may have had a denser atmosphere and greater surface temperatures before 3.8 billion years ago. However, the Martian atmosphere is now too thin and frigid to support liquid water. Furthermore, the atmospheric pressure is less than 1% of that of the Earth's atmosphere.

How did Mars evolve from a state that resembled modern Earth to the barren, inhospitable place it is now?

The answer could be found in Mars' former climate. The time and rates of sediment erosion and deposit during Mars' geologic history are determined in a study by a Monash University geologist.

It adds to the growing body of evidence linking the amount of sand blasted into craters on Mars' surface to the planet's temperature history. It could reveal fresh information on when Mars was habitable in geologic time.

The study also calculates the erodibility of each of the several types of rocks found on Mars' surface.

Scientists examined a variety of datasets to determine the amount of crater sand deposits and what caused them. Geologic maps, climate simulations, and satellite data are among the databases. Scientists were able to understand the controls and timing of erosion on Mars after synthesizing and analysing the data.

The sedimentary cycle on Earth and Mars slowly erodes surface rocks into sediments. The sediments bury each other, forming new rocks, and this process continues. Plate tectonics recycles the Earth's surface, removing old deposits across the majority of the world. On the other hand, sediment accumulations on Mars surface have largely survived to the present day.

Because liquids can carry larger, heavier boulders, rocks colliding in a liquid erode far faster than rocks colliding in gas. Rivers must often break down silt into tiny particles before it can be transported by wind.

“Seeing high rates of accumulation in a certain period of Mars’ history indicates that it was much more likely there were active rivers eroding material than,” study author Dr. Andrew Gunn of Monash University's School of Earth, Atmosphere, and Environment said.

“Plenty of evidence for surface water in Mars’ past has been published before—meaning there was liquid water on the surface and an atmosphere to sustain it (i.e., conditions more conducive to life)—but the jury is still out on when exactly, and for how long, this occurred.”