ASU/UBC/WU: Early Mars Was Covered in Ice Sheets, Not Flowing Rivers

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ASU/UBC/WU: Early Mars Was Covered in Ice Sheets, Not Flowing Rivers

Post by bystander » Mon Aug 03, 2020 6:58 pm

Early Mars Was Covered in Ice Sheets, Not Flowing Rivers
Arizona State University | University of British Columbia | Western University of Ontario | 2020 Aug 03
A large number of the valley networks scarring the surface of Mars were carved by water melting beneath glacial ice, not by free-flowing rivers as previously thought ... The findings effectively throw cold water on the dominant “warm and wet ancient Mars” hypothesis, which postulates that rivers, rainfall and oceans once existed on the red planet. ...

The similarity between many Martian valleys and the subglacial channels on Devon Island in the Canadian Arctic motivated the authors to conduct their comparative study. ... In total, the researchers analyzed more than 10,000 Martian valleys, using a novel algorithm to infer their underlying erosion processes. ...

Valley Formation on Early Mars by Subglacial and Fluvial Erosion ~ Anna Grau Galofre, A. Mark Jellinek, Gordon R. Osinski
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Re: ASU/UBC/WU: Early Mars Was Covered in Ice Sheets, Not Flowing Rivers

Post by BDanielMayfield » Tue Aug 04, 2020 12:49 am

This makes a great deal of sense. When considering the Faint Young Sun Problem, it has been even harder to explain abundant liquid water on early Mars than a warm early Earth. At 50% farther from the Sun than Earth, Mars only receives 1/1.5^2 or 44.4% of Earth's solar energy.

There still likely was a vast Martian ocean in its Northern hemisphere, but most of it was probably always frozen.

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Re: ASU/UBC/WU: Early Mars Was Covered in Ice Sheets, Not Flowing Rivers

Post by Ann » Tue Aug 04, 2020 6:29 pm

BDanielMayfield wrote:
Tue Aug 04, 2020 12:49 am
This makes a great deal of sense. When considering the Faint Young Sun Problem, it has been even harder to explain abundant liquid water on early Mars than a warm early Earth. At 50% farther from the Sun than Earth, Mars only receives 1/1.5^2 or 44.4% of Earth's solar energy.

There still likely was a vast Martian ocean in its Northern hemisphere, but most of it was probably always frozen.

Bruce
Exactly, Bruce. So "warm and wet Mars" probably never existed.

All is not lost for those who hope to find (remnants of past) life on Mars:
The University of British Columbia wrote:

These environments would also support better survival conditions for possible ancient life on Mars. A sheet of ice would lend more protection and stability of underlying water, as well as providing shelter from solar radiation in the absence of a magnetic field—something Mars once had, but which disappeared billions of years ago.
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Re: ASU/UBC/WU: Early Mars Was Covered in Ice Sheets, Not Flowing Rivers

Post by neufer » Wed Aug 05, 2020 2:44 am

Ann wrote:
Tue Aug 04, 2020 6:29 pm
BDanielMayfield wrote:
Tue Aug 04, 2020 12:49 am

This makes a great deal of sense. When considering the Faint Young Sun Problem, it has been even harder to explain abundant liquid water on early Mars than a warm early Earth. At 50% farther from the Sun than Earth, Mars only receives 1/1.5^2 or 44.4% of Earth's solar energy.

There still likely was a vast Martian ocean in its Northern hemisphere, but most of it was probably always frozen.
Exactly, Bruce. So "warm and wet Mars" probably never existed.
Hamlet: V, i
--------------------------------------------------------------------------------------

First Gravedigger: [Throws up another skull]

HAMLET: There's another: why may not that be the skull of a
  • lawyer? Where be his quiddities now, his quillets,
    his cases, his tenures, and his tricks? why does he
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Where be Mars's Moraines now, his Drumlins, his Roches moutonnées, his Alluvial stratification, his Glacial deposits, his Loess deposits, his Glacial valleys, his cirques, his arêtes, his and pyramidal peaks? (The very conveyances of his lands will hardly lie in these posts.)
https://en.wikipedia.org/wiki/Glacier#Glacial_geology wrote:


7 Glacial geology
  • 7.1 Moraines
    7.2 Drumlins
    7.3 Glacial valleys, cirques, arêtes, and pyramidal peaks
    7.4 Roches moutonnées
    7.5 Alluvial stratification
    7.6 Glacial deposits
    7.7 Loess deposits
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Re: ASU/UBC/WU: Early Mars Was Covered in Ice Sheets, Not Flowing Rivers

Post by Ann » Wed Aug 05, 2020 5:10 am

Funny, Art, and a good point.

Does that mean that you believe that Mars really was warm and wet in the past, with exposed rivers happily burbling and surging (or just rolling along, like old man river Mississippi) over the Martian plains?

So Percival Lowell was "half right" about the rivers of Mars after all?

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Re: ASU/UBC/WU: Early Mars Was Covered in Ice Sheets, Not Flowing Rivers

Post by neufer » Wed Aug 05, 2020 1:10 pm

Ann wrote:
Wed Aug 05, 2020 5:10 am

Funny, Art, and a good point.

Does that mean that you believe that Mars really was warm and wet in the past, with exposed rivers happily burbling and surging (or just rolling along, like old man river Mississippi) over the Martian plains? So Percival Lowell was "half right" about the rivers of Mars after all?
.
Click to play embedded YouTube video.
I find the whole issue way out of my area of expertise.

There seem to be plenty of examples (from both orbit & rovers) for running water and that is what's critical for the possibility of ancient life.

If there is also good evidence for ancient Martian Yosemites I'm all ears.
Art Neuendorffer