A Vanished Martian Oasis Holds Clues to How the Red Planet Dried Out

[Judi Lynn]

By Joel Hruska on October 9, 2019 at 7:27 am



The prevailing scientific wisdom on Mars, based on information gathered by the Spirit, Opportunity, and Curiosity rovers, as well as via multiple orbiting satellites, is that the planet once had substantial reserves of liquid water on its surface. The question of what happened to those reserves, and how Mars transitioned from a warmer, wet world to the frozen arid desert of today, is still a topic of active study and consideration.

We know that Gale Crater, where Curiosity landed, is virtually guaranteed to have been a lake at one point. There are extensive examples of both clay and sulfate mineral types that form in water, as well as visual evidence for features like fans and deltas — two features that are associated with the flowing of liquid water on Earth. Gale itself is believed to have been a freshwater lake that may have been pure enough for humans to drink from it, at least at one point in time. The video below is a good introduction to Gale Crater and the prevailing conditions that Curiosity has been researching, though it predates this paper:

At the lowest levels of Mount Sharp (a raised peak inside Gale Crater), Curiosity found evidence of a long-existing lake. As the rover picks its way up the slopes, it found evidence of rocks enriched in mineral salts, implying these deposits were laid down in briny ponds that underwent repeated episodes of drying and wetting — exactly what you might expect in an area where the hydrological cycle is failing, but not yet failed completely. Curiosity will head for a rock outcrop known as the “sulfate bearing unit” at some point in the future to test it and determine what its composition can tell us about the beginning of the Red Planet’s long dry spell.

As Curiosity climbs, the rock layers it has access to become younger, meaning that the rover is essentially traveling forward into Mars’ present from a starting point in its most distant past. If the sulfate-bearing unit shows strong and increasing concentrations of sulfates, it will imply that Mars’ aridity was a consistent progression, with no significant reversals over time. If the sediment layers the rover finds are thin, with alternating patterns of aridity and moisture, it will imply that Mars’ drying happened in a stepwise fashion over a long period of time.

More:
https://www.extremetech.com/extreme/299863-a-vanished-martian-oasis-holds-clues-to-how-the-red-planet-dried-out

[at140]

1. No scotch and water for astronauts landing on mars!

And without ice made of water available, better carry some cognac on board which I like sipping straight without dilution.

[ret5hd]

2. Heathen. Disgusting savage.