Spacecraft discover evidence of saturation of groundwater on Mars


The red dots represent the basins analyzed by the researchers.
Image: ESA

According to a new study, scientists have found evidence of an old groundwater system covering the entire planet on Mars. The clues appeared in the images taken by the Mars orbiters.

Studies continue to show that Mars was once wet, from the chemical composition of its land to valleys apparently cut by ancient rivers. But how much water and what the effects are are still topics of discussion. The researchers behind the new study have uncovered evidence of fluctuating groundwater levels in the craters of the entire red planet.

"These deep basins (groundwater-fed lakes) will interest future exploration missions as they could provide evidence of favorable geological conditions for life," according to the paper published today in the Journal of Geophysical Research-Planets.

The Martian landscape.
Photo: ESA

The researchers analyzed a sample of impact craters in the northern hemisphere of Mars taken by the HiRISE (high resolution) scientific experiment and the contextual camera (CTX) on the Mars NASA reconnaissance orbiter and the high resolution stereo camera (HRSC) on the European space. The Mars Express orbiter of the agency. They identified 24 craters 1.4 to 3.1 km deep, which they analyzed for evidence of the influence of groundwater.

Several lines of evidence appeared in the analysis. Some of the craters had valleys that appeared to be formed by erosion of water. Some had channels dug into their walls. Some had "terraces", platforms that could have been formed by the presence of stagnant water. Fifteen craters had fan shapes that looked like river deltas. Some had cones that looked like branched tributaries. Their soils were flat, probably due to the sedimentation of the sediments of the water. Sixteen of the craters had piles of debris that appeared to have been caused by landslides

Diagram showing the receding water formation characteristics in the current craters
Graphic: ESA

Taken together, these data points all occurring at similar depths led the researchers to infer that the features observed in these craters "contained water that was gradually withdrawing, leaving behind some relief in a specific chronological order. ", according to the study. More importantly, the same characteristics observed in the northern hemisphere of the planet suggested to researchers that Mars may have been saturated with groundwater in order to produce the results presented in the paper. The water level also aligns with existing evidence of an ancient Martian ocean.

Results like these are exciting and continue to paint Mars, 3.5 billion years old, as a wetland like Earth today, with oceans, rivers and streams. a water table. Of course, they also ask you if the planet has already sheltered life. Future missions, such as the ExoMars Rosalind Franklin rover and the Mars2020 rover, will need to look directly at the clues of life – and this article offers scientists a favorite spot.

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