NASA found billions of years of sand dunes on Mars, and they looked familiar


Carried away in a valley on Mars, scientists have discovered a windscreen field of solid sand, which turned into a rock about a billion years ago.

Despite heavy erosion, this frozen plain of paleo-dunes has had a remarkably good time, much more so than fossilized waves of sand on Earth, which are subject to wind, water, and deep time shifting landscapes .

Understanding how these dunforms stood the test of time can give us insight into the sedimentary processes on Mars and reveal something about the geological history of the planet at the same time.

“This level of protection for terrestrial sand dunes is rare due to ongoing erosion and tectonics,” Planetary Scientist Matthew Choznaki explains from the Planetary Science Institute.

“Based on the relationship of other geologic units and the Dunne deposit to modern erosion rates, we estimate these to be about one billion years old.”

(NASA / JPL / University of Arizona)

Today, mounds of sand, blowing through the air, are a common feature, and the shape and arrangement fixed in place in the widest part of the Valse Marinaris Valley – Meles Chasma – looks very similar to the recently built ones .

This indicates that the climate and atmosphere on Mars have changed in a very short, very long time. Astronomers say that the orientation, length, height, shape, and slope of the Melas Chasma Paleo-dunes all resemble sand waves recently seen elsewhere on the red planet.

“This suggests that the major wind directions that are responsible for the size of the dunes have not changed sufficiently over time,” Choznacki told Earthsky.

“We see very similar shapes and sand dunes from the two time periods. This may indicate that atmospheric pressure did not differ significantly.”

Using images from the High Resolution Imaging Science Experiment (HiRISE) and Martian topography data, researchers have documented and dated the bedform properties of Melus Chasma.

Although the topography of this valley is still incomplete, as some of the mounds have been erased or buried, the paleo-dunes do not portray a dramatically different picture than what we “could find from modern counterparts”. We do. Explain.

The authors found that some mounds were buried under tens of meters of material, which came from a catastrophic volcanic event.

Picture 11(Chोजnecki et al., JGR Planet 2020)

Some time later, the authors predict, an unstable compound came into contact with compact sand dunes and helped harden them, freeing them from the waves in time and moving into mellus chasma.

Such a process can be observed on Earth when groundwater strikes partially buried sand dunes, which are like layers of leonified sand such as the famous striped structures seen in Zion National Park. Unlike our planet, however, there are very few elements on Mars to contend with sand dunes.

In the absence of water, vegetation, or plate tectonics, exposure to trade winds on Mars is the main eroder, and in deep times, it has helped to chisel the volcanic shell that once covered these dunes.

Highrise Martian Dunes 1Close the sand dunes taken by HiRISE Camera. (NASA / JPL-Caltech / University of Arizona)

The unit of survival and conservation seen in these mounds shows a significant difference in the landscape development of Earth and Mars.

While ancient lithiated sand dunes are rarely found and much eroded on Earth, Melas Chasma has “extensive paleo-dune fields that appear scattered on the basin floor, where many dunes and their morphology are fairly The extent remains intact. ”

“Water and tectonics that continually reopen the Earth’s surface are not currently a factor on Mars, thus being an opportunity to learn from the geologic record of the red planet,” Choznecki says.

“These results show us that the recent history of Mars has undergone a lot of wind-driven sand transport, deposition and topography and shows how different the evolution of the landscape is compared to Earth.”

The study has been published in JGR Planet.

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