Water on Mars - Page 7

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MPJ


Posts: 250

Reply: 121



PostPosted: October 26, 2011 3:50 AM 

Something for Fred?
Mars Climate Sounder confirms a Martian weather prediction:
http://www.planetary.org/blog/article/00003234/

So a temperature inversion cause (water ice) clouds to build up high during the night and decent to the ground by morning - poor rocks/soil get a little wet in the morning!? Wink

Fred


Posts: 73

Reply: 122



PostPosted: October 31, 2011 12:27 PM 


It is a dynamic place indeed.

Barsoomer


Posts: 344

Reply: 123



PostPosted: November 2, 2011 11:59 AM 

link

Currently active flow features in Newton Crater

Barsoomer


Posts: 344

Reply: 124



PostPosted: November 2, 2011 12:01 PM 

link

Currently active flow features in Newton Crater.

Barsoomer


Posts: 344

Reply: 125



PostPosted: November 3, 2011 10:58 AM 

http://www.sciencedaily.com/releases/2011/11/111102145736.htm

Warm, wet, mostly underground.

Barsoomer


Posts: 344

Reply: 126



PostPosted: November 3, 2011 11:05 AM 

[link]

Subsurface water and clay mineral formation during the early history of Mars.

New Nature article.

Barsoomer


Posts: 344

Reply: 127



PostPosted: November 3, 2011 11:42 PM 

I can summarize the contents of the article. It concludes that warm wet SURFACE conditions on Mars were confined to a short period near the boundary of the Noachian and Hesperian ages, accompanied by extensive volcanic activity.

However, warm wet SUBsurface conditions were present from a much earlier time and so extended for a lengthy period.

It infers these conclusions from the distributions of different types of clays on Mars. It seems to regard aluminium-based clays as indicative of the warm wet surface conditions, whereas Fe/Mg clays are viewed as indicative of subsurface warm wet hydrothermal alteration. It seems the aluminium-based clays are almost always in a thin layer on top of Fe/Mg clays.

The above is an over-simplification of the paper, but I think gives the flavor of its findings. The paper excludes from its conclusions a Pre-Noachian era for which the crustal record has been disrupted.

Barsoomer


Posts: 344

Reply: 128



PostPosted: November 4, 2011 5:56 PM 

The paper also suggests that the short surface warm wet period may have taken place during a high obliquity excursion and that there were tapering "echoes" of lesser such periods in following high obliquity episodes. This can be seen in figure 4 of the "Figures at a glance" section in the linked page.

Ben


Posts: 2270

Reply: 129



PostPosted: November 4, 2011 8:33 PM 

Barsoomer;THANKS FOR THAT LINK.
It is very close to the Mars history I have been describing for some time.

The melting of polar ice caps could then be explained by obliquity or the period of vulcanism. Also helps explain the air fall scenario Very Happy

Kevin Author Profile Page



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Reply: 130



PostPosted: December 2, 2011 6:24 AM 

Water Ice discovered near the Elysium region in the Phlegra Montes:

[link]

Kevin Author Profile Page



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Reply: 131



PostPosted: December 2, 2011 11:44 AM 

So what did cause these gullies?

http://www.uahirise.org/ESP_023937_2240

Barsoomer


Posts: 344

Reply: 132



PostPosted: December 2, 2011 12:22 PM 

A relatively short (~ 200 MYr) duration of the ancient surface warm wet period does not preclude any of the possibilities for later minor water flows. It seems there were glaciers at low latitudes even during recent high-obliquity periods.

My guess about the gullies, which may be happening even today, is that they are brine runoff from overnight frost deposition on salty rocks.

Kye Goodwin


Posts: 1166

Reply: 133



PostPosted: December 2, 2011 12:59 PM 

Here's another take on how long water acted to produce the Meridiani bright rock sediments, which are thought to include clay minerals. The estimate of these authors is TENS of YEARS, maybe about as long as it would take a fresh wet impact sediment the depth of Meridiani's to cool off and dry out:

http://ammin.geoscienceworld.org/content/94/8-9/1279.abstract

John Henry Dough


Posts: xxx

Reply: 134



PostPosted: December 2, 2011 2:40 PM 

Pristine Sulfuric Acid,,,it says?

Looking at evidence for prolonged rain,,shows no
models for crater rim run-off. (One side bursting to allow water to escape)...so then,,Is one to conclude that the meteorites came after the water? Or perhaps all the existing meteorite circles were perhaps slowly flooded and the water went to evaporation and settlement to bottom of crater.?

Ben


Posts: 2270

Reply: 135



PostPosted: December 2, 2011 5:49 PM 

JHD; I interpret the warm wet period to have been accompanied by rains and the attendant erosion of crater rims has since been obscured by wind and gravity.

Craters which exhibit "splattered" ejecta indicate shallow subsurface water and others indicate impact into dry material.

In most examples, where there are no crater
outlets, water was absorbed by surrounding material or as you suggest, was lost to the atmosphere and returned to the polar ice caps.

Ben


Posts: 2270

Reply: 136



PostPosted: December 2, 2011 5:53 PM 

Tried to reply to 133 but got nowhere. Rolling Eyes

John Henry Dough


Posts: xxx

Reply: 137



PostPosted: December 2, 2011 6:43 PM 

Please try again Ben,,,here is a link I was looking for a place to post here when I saw your reply,,,
Off Topic,but interesting,,,,,,,

http://www.futurespaceusa.com/

Ben


Posts: 2270

Reply: 138



PostPosted: December 2, 2011 10:12 PM 

Thanks JHD; I doubt those guys would like some old geologist interupting their program.

I will attempt to reconstruct my response but remember my short term memory is fading.

Some craters show evidence of channels that could have allowed some water to flow out but I don't recall one that could have been completely drained.

Craters by nature are below the surrounding common level and impossible to drain like a dam bursting.

I see two classes of craters, depending on the climate when they were formed.. Those with splattered ejecta patterns and those with more of a rocky rim.
The difference is the splat (wet) ones encountered fluid on or in the subsurface and have indications of subsequent fluvial erosion both internally and externally.

Those formed during the wet period probably accumulated water ( Endeavour) but during the following colder, dry period (no rain)
the water was absorbed by the surrounding rock or evaporated as you said and wound up as ice in the polar caps where it remains.

Ben


Posts: 2270

Reply: 139



PostPosted: December 2, 2011 10:30 PM 

JHD ; I posted a long reply to 135 which showed up and then went away.

Do we need more funds to get this problem corrected??

John Henry Dough


Posts: xxx

Reply: 140



PostPosted: December 3, 2011 9:16 AM 

Well Mr. Ben,,,I do Thank You for replying,,and I do
like your,analysis...so very very many things to find out about the red planet.
Respectfully
JHD

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