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Reservoir of liquid water found deep in Martian rocks (bbc.co.uk)
18 points by _____k on Aug 12, 2024 | hide | past | favorite | 6 comments


Article: "Liquid water in the Martian mid-crust" (2024) https://www.pnas.org/doi/10.1073/pnas.2409983121

- "Mars may host oceans’ worth of water deep underground" [according to an analysis of seismic data] https://www.planetary.org/articles/mars-may-host-oceans-wort... :

> Now, a team of scientists has used Marsquakes — measured by NASA’s InSight lander years ago — to see what lies beneath. Since the way a Marsquake travels depends on the rock it’s passing through, the researchers could back out what Mars’ crust looks like from seismic measurements. They found that the mid-crust, about 10-20 kilometers (6-12 miles) down, may be riddled with cracks and pores filled with water. A rough estimate predicts these cracks could hold enough water to cover all of Mars with an ocean 1-2 kilometers (0.6-1.2 miles) deep

> [...] This reservoir could have percolated down through nooks and crannies billions of years ago, only stopping at huge depths where the pressure would seal off any cracks. The same process happens on our planet — but unlike Mars, Earth’s plate tectonics cycles this water back up to the surface

> [...] “It would be very challenging,” Wright said. Only a few projects have ever bored so deep into Earth’s crust, and each one was an intensive undertaking. Replicating that effort on another planet would take lots of infrastructure, Wright goes on, and lots of water.

How much water does drilling take on Earth?


Water is used to displace debris and to carry it up to the surface.

A cylinder of 30cm diameter and 10km deep would hold around 700k litres.


1 US gal = 3.785 litres

700k litres = 0.184920437 million US gallons

"How much water does the typical hydraulically fractured well require?" https://www.usgs.gov/faqs/how-much-water-does-typical-hydrau... :

> Water use per well can be anywhere from about 1.5 million gallons to about 16 million gallons

https://www.epa.gov/watersense/statistics-and-facts :

> Each American uses an average of 82 gallons of water a day at home (USGS, Estimated Use of Water in the United States in 2015).

So, 1m gal / 82 gal/person/day = 12,195 person/days of water.

Camping guidelines suggests 1-2 gallons of water per person per day.

1m gal / 2 gal/person/day = 500,000 person/days of water

The 2016 Mars NatGeo series predicts dynamics of water scarcity on Mars.

Water on Mars: https://en.wikipedia.org/wiki/Water_on_Mars


How much does this finding increase the likelihood of finding life on Mars? Liquid water in cracks sounds like a positive. But then what energy source could there be? No light for photosynthesis 6 miles down. No hydrothermal vent like things.


From the paper, here is the core of the research:

We use rock physics models and Bayesian inversion to identify combinations of lithology, liquid water saturation, porosity, and pore shape consistent with the constrained mid-crust (∼11.5 to 20 km depths) seismic velocities and gravity near the InSight lander. A mid-crust composed of fractured igneous rocks saturated with liquid water best explains the existing data.

https://www.pnas.org/doi/10.1073/pnas.2409983121





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