Groundwater on Mars
Rain and snow were regular occurrences on Mars in the past; especially in the Noachian and early Hesperian epochs.
[2][3][4][5][6][7] Water was theorized to seep into the ground until it reached a formation that would not allow it to penetrate further (such a layer is called an aquitard and is believed to be impermeable).
Some of the minerals were sulfates that were probably produced when water dissolved sulfur from underground rocks, and then became oxidized when it came into contact with the air.
[16][17][18][19][20][21] In August 2024, a reservoir of liquid water was discovered on Mars - deep in the rocky outer crust of the planet.
[22][23] As per estimates, there may be enough water, trapped in tiny cracks and pores of rock in the middle of the Martian crust, to fill oceans on the planet’s surface.
Calculations and simulations show that groundwater carrying dissolved minerals would surface in the same locations that have abundant rock layers.
Martian ground water probably moved hundreds of kilometers, and in the process it dissolved many minerals from the rock it passed through.
On Earth, mineral-rich waters often evaporate forming large deposits of various types of salts and other minerals.
[30] On Earth the hardness of many sedimentary rocks, like sandstone, is largely due to the cement that was put in place as water passed through.
In February 2019, European scientists published geological evidence of an ancient planet-wide groundwater system that was, arguably, connected to a putative vast ocean.
Spacecraft sent to Mars provided a wealth of evidence for groundwater being a major cause of many rock layers on the planet.
[37] Opportunity found hematite and sulfates in many places as it traveled on the surface of Mars, so it is assumed that the same types of deposits are widespread, just as predicted by the model.
A spectroscope, called CRISM, on the Mars Reconnaissance Orbiter found sulfates in many of the same places that the upwelling water model had predicted, including some areas of Arabia.
[43] Other locations predicted to have upwelling water, for example chaos regions and canyons associated with large outflows, have also been found to contain sulfates.
Such tall mounds were formed, according to this model, by layers that first filled the crater, and then continued to build up around the surrounding region.
Strong evidence for groundwater making lakes in deep craters was described by a group of European scientists in February 2019.
[48][46] Some of the craters studied were Oyama, Pettit, Sagan, Tombaugh, Mclaughlin, du Martheray, Nicholson, Curie, and Wahoo.
