Study reveals new way to reconstruct past climate on Mars

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A study by a Monash University geologist has provided new evidence for when high rates of erosion have occurred throughout Mars’ history.

The findings, published today in Geology date when the climate was much more erosive in Mars’ past – with the implication that there were extended periods of liquid water moving across the planet’s surface.

Scientists have long wanted to understand how Mars went from a state potentially closer to modern Earth to the desolate and inhospitable place it is today.

“If we want to know if there was life on Mars, we need to understand the sedimentary rock record,” said study lead author Dr Andrew Gunn, of the Monash University School of Earth, Atmosphere and Environment.

“Our study determines the timing and rates of sediment erosion and accumulation over the geologic history of Mars in a completely new way, and for the first time quantifies a measure of the erodibility of each of the types of rocks that we see on the surface of Mars,” he said.

“This is important because we show that the abundance of windblown sand in craters on the surface of Mars may be linked to the planet’s climatic history, opening up a new way of understanding when, in time geologic, Mars may have been habitable.”

The researchers relied on several datasets to estimate the size of the crater sand deposits and what produced them, including geological maps, climate simulations and satellite data. They synthesized and interpreted this data to understand the controls and timing of erosion on Mars.

On Earth and Mars, there is a sedimentary cycle where surface rocks are slowly eroded into sediment, sediment sinks, new rock forms, and the process continues. On Earth, the surface is recycled by tectonics, erasing ancient sediments over most of the planet, but on Mars, accumulations of surface sediments are mostly preserved to the present day.

Erosion of rocks occurs much faster when they collide in a liquid compared to gas, because liquids can carry larger and heavier rocks. To produce sediments that can be moved by the wind, they often must first be broken down into smaller particles by rivers.

“Seeing high rates of accumulation during a certain period of Mars history indicates that it was much more likely that there were active rivers then eroding material,” said Dr. Gunn.

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


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More information:
Andrew Gunn et al, Accumulation of Windblown Sand in Impact Craters on Mars, Geology (2022). DOI: 10.1130/G49936.1

Provided by Monash University

Quote: Study Reveals New Way to Reconstruct Past Climate on Mars (May 13, 2022) Retrieved May 14, 2022 from https://phys.org/news/2022-05-reveals-reconstruct-climate-mars.html

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