Fissures/channels
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angi60
A fascinating image!
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p.titchin
in response to angi60's comment.
Have a look at the HiRISE RGB col. strip for this image (bottom fifth of the strip) It truely is fascinating. These channels run in continuous straight lines across the surface like a giant tyre track + lots of venting activity. I'd love some insight on their evolution!
Pete
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Kitharode
moderator
The HiRise image is centred at -86 deg and 178 deg E on the polar layered deposits. http://www.nasa.gov/images/content/171411main_pia09224-thick-annot-516.jpg
"Both polar caps show layered features, called polar-layered deposits, that result from seasonal melting and deposition of ice together with dust from Martian dust storms. Information about the past climate of Mars may be eventually revealed in these layers, just as tree ring patterns and ice core data do on Earth". (Wikipedia)
Posted
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angi60
Pete: Thanks, I'm glad you pointed that out - I'd looked at the RGB, but hadn't scrolled right down, so missed the best bit!! It certainly does resemble a giant tyre track! Kitharode's comment above might be useful for you concerning their evolution 😃
Kitharode: Thanks for the pointer. Very helpful. Looks like I have more reading to do!! :-X
Posted
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wassock
moderator
try the grey scale image - looks like a chunk of tree trunk
Posted
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angi60
in response to wassock's comment.
Oh yes, so it does Wassock! Trees on Mars - who'd have thought it!!
Posted
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Kitharode
moderator
It's only a gut feeling at the moment, but this sort of surface topology might well be just the sort of thing required to make a start on "chain spiders" as I call them which, in certain areas, might lead to 'networks' of spiders as in this image from A0087779's 'Any Ideas' thread. http://planetfour.org/subjects/standard/50e741835e2ed212400035d0.jpg
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angi60
in response to Kitharode's comment.
That's interesting. I won't ask you what the gut feeling is, but let us know if you advance it to a theory!! 😃 Gut feelings are often accurate though.
Posted
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p.titchin
in response to Kitharode's comment.
Are you thinking that this topology eventually allows the formation of polygonal fractures in the covering ice which then leads to the spider networks, or that the chain spiders form, and in subsequent ice cover influence the formation of polygonal fractures which are then allowing the further development of the networks, or are you thinking two different processes both leading to networks?
Posted
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Kitharode
moderator
in response to p.titchin's comment.
On the assumption that most spiders are formed in the same way, I'm struck by the fact that 'true' spiders and 'chain/web' spiders are wildly different in form. My feeling is that, amongst other things, topology shapes spiders. Therefore I think that chain/web spiders are a consequence of 'linear features' on the martian surface. The 'tyre tracks' in the image above might not be a good example, but something similar would work for me.
I did think about ice polygons shaping some spiders, but I gave up the idea because I didn't think the seasonal icelayer would shrink/crack in exactly the same fashion year by year. Linear/polygon cracks in the surface however might easily do this. As usual, all a bit vague ... ** 😛 **
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wassock
moderator
think the idea is that the surface has long since 'dried out' to leave polygonal cracks which stay put and get sculpted by the spiders over the years
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