Home Plate Speculations, Get it in now, before we know the truth! Options

[Bill Harris]

Correct, "analogous mechanism or process" is a better description than "analogy". Of course, the concept of Uniformitarianism can be applied across planetary distances as well as geologic time. Volcanism is volcanism on either planet, but there are environmental and geochemical differences so the fine details can be different, and of course, the weathering processes are quite different. And on Mars, catastrophism also plays a major role, as the effects of catastrophic events are still visible after millions or billions of years, whereas on Earth, those ancient events have been eroded or subducted out of existence. And, likely, on Mars there were more impacts than on Earth with Mars' proximity to the asteroid zone.

In a few Sols we'll be close enough to Homeplate to start collecting more puzzle-pieces and we'll increase our understanding of this small part of the planet.

The sulfates are interesting, but here I look at them more as a weathering byproduct than as a evaporite.

--Bill

[RNeuhaus]

My best guess would be that the Gussev impact hit a thick ice layer, among other terrains. When the whole thing fell back, there was large ice blocks, and the spaces between them filled with loose stones and sand. After, this exposed ice melt or sublimed, lefting those curious small ridges and mounds where there was spaces between ice blocks. 
Another "phantasm" I will add here is that homeplate would be a piece of hard sedimentary rock. When the highland formed, there was perhaps permanent water or things like that. So it would not be a surprise to find hardened sedimentary rocks, hard ones to bear the shattering and keep large dimentions: sandstone, and even limestone. The later would be a good find.

I do believe that the Gusev crater was impacted by an icy asteroide as you tought. The surface Gusev is so plain and has lead me to think that crater was filled by mud (mix of water and sand) and the higher parts of Gusev crater has more boulders or stones than the lower parts, it might be due to the mud water erosion due to the gravity and leave naked stones and boulders.

Rodolfo

[Guest_Richard Trigaux_*]

I already note that the crest of Mitcheltree Ridge is not layered, so it is not a native ground feature. Rather some process gathered rocks here, and there are many similar features in the surrounding terrains (around other hills in the vicinity, in place which were not covered by the mudflow). So I think it is an important feature which existed in many parts of Gussev crater before mud filling. It is too linear to be impacts, it has too large blocks to be dunes, and water erosion cannot give this. It either don't look like cowpats. My best guess would be that the Gussev impact hit a thick ice layer, among other terrains. When the whole thing fell back, there was large ice blocks, and the spaces between them filled with loose stones and sand. After, this exposed ice melt or sublimed, lefting those curious small ridges and mounds where there was spaces between ice blocks. 

After all, ice is not the only possible material for such a process. Many materials would do the same: sandstone, jarosite, limestone... once eroded, dissolved by water or deflated by the wind, only remain those heaps of hard basalt stones we see everywhere.

[Bob Shaw]

Here's a thought: apart from Devon Island, which is rather old, do we know of any Terrestrial impact craters near the poles, where ice/water may have played a part in the surrounding areas? Canadian Shield chappies that are half a billion years old don't count!

A quantifiable analogy might make it all the way up to a genuine analogue...

Bob Shaw

[tty]

Here's a thought: apart from Devon Island, which is rather old, do we know of any Terrestrial impact craters near the poles, where ice/water may have played a part in the surrounding areas? Canadian Shield chappies that are half a billion years old don't count!

A quantifiable analogy might make it all the way up to a genuine analogue...

Bob Shaw

If You mean a major impact into glacial ice or permafrost the answer is, as far as I know, no. The youngest major high-latitude impact is probably Elgygytgyn in Chukotka which is Pliocene (ca 3 million years old), but the climate in the area at that time was probably cool-temperate.

There are a couple small Holocene craters in Estonia, but they are very small and the climate at the time was similar to the present.

There are only a few (deep) ocean impacts known, the youngest is probably the Eltanin impact in the southern Pacific about two million years ago. This was actually too small to cause a crater because of the deep water, but is known from impactor fragments found in seabottom deposits and traces on land in South America and perhaps Antarctica.

Since Antarctica has been at least partly glaciated since the Oligocene (ca 35 million years) there almost certainly has been sizable impacts into glacial ice there, but a crater that does not reach bedrock will disappear in at most a few hundred thousand years, and a crater that does reach bedrock would be quite difficult to find and even more difficult to study! Even so it might be a worthwhile to search for circular subglacial structures in Antarctice, I don't know if anyone has tried.

tty

[imipak]

Do words like 'Silly' 'Mid' and 'On' mean anything to you?

I'm sorry, but you've given me the image of Geoffrey Boycott pushing his car keys into HP... "Well Ritchie, the air's cool and dry this morning, so the ball won't be swinging for Shane Warne. The wicket is very dry, too, so look for the pace men to have the ball lifting sharply off the basalt... especially at the Husband Hill End."

[tty]

I do believe that the Gusev crater was impacted by an icy asteroide as you tought. The surface Gusev is so plain and has lead me to think that crater was filled by mud (mix of water and sand) and the higher parts of Gusev crater has more boulders or stones than the lower parts, it might be due to the mud water erosion due to the gravity and leave naked stones and boulders.

Rodolfo

It might well have been, but that is completely irrelevant to whether Gusev has been filled with mud or not. Any water in the impactor is instantly turned into (very) superheated steam on impact and most of it is dispersed at hypersonic speed. Any mud in the crater would be due to either (1) melting of permafrost by the impact, (2) groundwater, (3) discharge from the Ma'adim valley or (4) rain.

tty

[Shaka]

I'm sorry, but you've given me the image of Geoffrey Boycott pushing his car keys into HP... "Well Ritchie, the air's cool and dry this morning, so the ball won't be swinging for Shane Warne. The wicket is very dry, too, so look for the pace men to have the ball lifting sharply off the basalt...  especially at the Husband Hill End."

Hey, Pal. When The Commonwealth lands a rover on Mars, you can use all the Cricket terminology you want!
Jeez, that game ... They don't even have real pitchers! One of the outfielders gets the ball, runs all the way in to the mound and kinda heaves the ball like a hand grenade! Naturally most of them can't even reach the plate without bouncin' the ball; foul balls count as runs, so naturally one batter can score like 7000 runs! Meanwhile out in the bleachers the elderly are passin' away, pregnant women are being delivered, and their offspring are learning to say "Well bowled." And this can go on for weeks and in the end the game can still end IN A TIE!!! I mean, Gimme a break!
And a tie is a good outcome for England; otherwise they lose to one of the island colonies like New Zealand or The Falklands....keeeriss...

[Bob Shaw]

Hey, Pal.  When The Commonwealth lands a rover on Mars, you can use all the Cricket terminology you want!
Jeez, that game ...  They don't even have real pitchers! One of the outfielders  gets the ball, runs all the way in to the mound and kinda heaves the ball like a hand grenade!  Naturally most of them can't even reach the plate without bouncin' the ball; foul balls count as runs, so naturally one batter can score like 7000 runs!  Meanwhile out in the bleachers the elderly are passin' away, pregnant women are being delivered, and their offspring are learning to say "Well bowled." And this can go on for weeks and in the end the game can still end IN A TIE!!!  I mean, Gimme a break!
And a tie is a good outcome for England; otherwise they lose to one of the island colonies like New Zealand or The Falklands....keeeriss...

It's at times like this that I'm really glad I live in...

...Scotland.

Bob Shaw

[djellison]

I'm sorry, but you've given me the image of Geoffrey Boycott pushing his car keys into HP... "Well Ritchie, the air's cool and dry this morning, so the ball won't be swinging for Shane Warne. The wicket is very dry, too, so look for the pace men to have the ball lifting sharply off the basalt...  especially at the Husband Hill End."

Ritchie "Thank you Geoffrey, that's the forth set of keys of mine you'd got stuck into the pitch. Infact my lovely gold pen is about 6 inches under the popping crease"

I'm sure there was a comedy sketch about that at some point.


/english humour

Doug

[Shaka]

It's at times like this that I'm really glad I live in...

...Scotland.

Bob Shaw

Yeah...Long as you can chuck a few cabers around, you're happy, right?

[Shaka]

/english humour

Doug

Yeah, and we forgive you, Dougie, cause you're such a sweet guy and distinguished role model!

[helvick]

I'm sure there was a comedy sketch about that at some point.
/english humour

As (possibly) the only Irish Cricket fan known to mankind (thanks to 10 years spent in the southern hemisphere) I have to say that there is no finer way to spend an extended weekend than watching a Test. preferably live, and for my part the place to do it is at St George's Park, Port Elizabeth.

[Shaka]

As (possibly) the only Irish Cricket fan known to mankind (thanks to 10 years spent in the southern hemisphere) I have to say that there is no finer way to spend an extended weekend than watching a Test. preferably live, and for my part the place to do it is at St George's Park, Port Elizabeth.

Good show, lads! Look's like you've made a convert.
(Took you 400 years - plus 10 years of the blood rushing to his head!)

[dvandorn]

Speaking of cricket...

I used to live in an integrated neighborhood in north Minneapolis. By "integrated," I mean that there was a good mix of white, black, hispanic and asian ethnicities represented. We were all pretty middle-middle class, and there were no real racial problems in our neighborhood. (In general, I prefer to live in a pretty evenly mixed, integrated area.)

Having said that, a good many of the black youths in the area chose the "urban black" culture and look -- at this point, basically the gangsta rapper look.

So, imagine my stupefaction when I passed a local park, one spring day a few years ago, to see a fair number of local young black males, in the park -- playing cricket! Wearing traditional cricket uniforms of sweaters, white pants, those silly little hats -- the whole nine yards.

It was amusing, heart-warming (in a way), and above all, extremely unexpected. The latter being the reason for the formers, I'm sure.

So, every time I think of cricket, I think of a bunch of young black men, in the park, wearing their cute, oh-so-very-English cricket outfits, bowling and batting...

-the other Doug