Starship Asterisk*

It is hard to imagine that the epic magma flows from the Tharsis region, are not partially responsible (perhaps as they cooled or later cracked) for the formation of all the chasms and valleys in this region of Mars. And it certainly looks like water and wind have played a part, too. If all three played a concurrent role at some time in the past, it might explain why some of the chasms are now isolated, without requiring significant groundwater flows. Based on a topographic map of the region, it appears as though Hebes Chasma might have at one time been open to drain (at least partially) westwards into Echus Chasma. And then later an isthmus formed between them. Certainly an interesting puzzle.

My comments above are obviously highly speculative. But I also think that J.B. Adams, et al, may be too quick to dismiss the flood hypothesis in the "hypotheis holds" link of the APOD description:
[url]http://geomorphology.sese.asu.edu/Papers/Adams_etal_hebes_chasma_salt_tectonics_geol.pdf[/url]
[quote]Hebes Chasma (Fig. 1) lacks a surface outflow channel; therefore the flood hypothesis can be eliminated, ...[/quote]

It may not have lacked a surface outflow channel in ages past.

If you look from the OPPOSITE SIDE, the are other "cut out areas"... they have erosion and sand fills the areas. This I think is an extension of that, but being on the "leeward" side the sand filled more, and the slide came from the outer wall... my revised opinion... :wink:

Fun to try to figure out....
:---[===] *

Ummmm.... maybe it was an "excavation site".... :evil:

Nahhhhh....

The fly through video is cool, on that page I left above...

:---[===] *

OMG!!!!! ITS A SAND WORM!!!!!! :lol2:

:---[===] *

[quote="BDanielMayfield"]It looks as if a humongous ice cube once was there[/quote]

You may be right, Ice Cube was there

[img]https://images-na.ssl-images-amazon.com/images/M/MV5BMGFlNzNmY2ItYmZjMi00ZjQ1LWJjMmMtODM5MWQ0NzI3NzBhXkEyXkFqcGdeQXVyNjU0OTQ0OTY@._V1_UY1200_CR108,0,630,1200_AL_.jpg[/img]

Is this image vertical exaggerated? Comparing this image with overhead shots, the rear wall of the collapse appears to be 18 km long. After estimating the height of the debris above the floor of the depression, given the angle of the shot, perspective foreshortening cannot account for the apparent height of the mesa. Yet there is no mention of vertical exaggeration at the [url=http://www.esa.int/spaceinimages/Images/2013/10/Hebes_Chasma_mesa]image source[/url].

[quote="BDanielMayfield"] What strikes me about this image is how square or rectangular the collapse is. It looks as if a humongous ice cube once was there but then it melted or evaporated away. Probably a ridiculous suggestion, but that's just what it looks like to me.

Bruce[/quote]

[float=left][img2]https://i.ytimg.com/vi/ux5IyAmSXdU/hqdefault.jpg[/img2][c][size=85]Homemade excavator for kids.
Source: https://www.youtube.com/watch?v=ux5IyAmSXdU[/size][/c][/float] My thoughts too, Bruce.

Or rather... These are my thoughts!

Ann

[quote="Boomer12k"][quote="RocketRon"]Unusual - certainly a spectacular and distinctive view/feature !

Be helpful to see a before and after shot, with some indication of scale, might emphasize just how material has gone. ?
And also to see a slightly wider view, it looks like some material has flowed towards the bottom of the picture and further.[/quote]

Will this do? Also more info... and possible Solution...

[url]http://www.dailymail.co.uk/sciencetech/article-2458541/Mars-3D-Images-reveal-red-planets-Grand-Canyon-detail.html[/url]

My thought from the article is... it bulged, tore the chasm, the area fell, making a kind of caldera, then the floor lifted from magma bulging from beneath, but did not break the surface as a volcano, so left the inner mound. OR, it was a little harder material... As it bulges, the slides occurred... My opinion.

:---[===] *[/quote]

Interesting, Boomer!

Ann

The larger views posted in Boomer12k's link show that there was a large slide off the outer wall that ran into the mesa. The elevation map shows a low strip just off the mesa, and the raised lobes show that the landslide debris came from out of the picture. If the notch was created by a landslide, the debris was buried by the later slide from the outer wall.

Or maybe the "mesa" is just a sleeping Arrakian sand worm.

[quote="Chris Peterson"][quote="Guest"]Compare this photo to one of Mount Saint Helens. No aquifer needed.[/quote]
Well, something is needed, and we don't see volcanic activity here.[/quote]
And we know that there was plenty of water on Mars in the past, so suspecting subterranean water as a cause is reasonable. What strikes me about this image is how square or rectangular the collapse is. It looks as if a humongous ice cube once was there but then it melted or evaporated away. Probably a ridiculous suggestion, but that's just what it looks like to me.

Bruce

[quote="Guest"]Compare this photo to one of Mount Saint Helens. No aquifer needed.[/quote]
Well, something is needed, and we don't see volcanic activity here.

Compare this photo to one of Mount Saint Helens. No aquifer needed.

[quote="RocketRon"]Unusual - certainly a spectacular and distinctive view/feature !

Be helpful to see a before and after shot, with some indication of scale, might emphasize just how material has gone. ?
And also to see a slightly wider view, it looks like some material has flowed towards the bottom of the picture and further.[/quote]

Will this do? Also more info... and possible Solution...

[url]http://www.dailymail.co.uk/sciencetech/article-2458541/Mars-3D-Images-reveal-red-planets-Grand-Canyon-detail.html[/url]

My thought from the article is... it bulged, tore the chasm, the area fell, making a kind of caldera, then the floor lifted from magma bulging from beneath, but did not break the surface as a volcano, so left the inner mound. OR, it was a little harder material... As it bulges, the slides occurred... My opinion.

:---[===] *

Unusual - certainly a spectacular and distinctive view/feature !

Be helpful to see a before and after shot, with some indication of scale, might emphasize just how material has gone. ?
And also to see a slightly wider view, it looks like some material has flowed towards the bottom of the picture and further.

[url=https://apod.nasa.gov/apod/ap170528.html][img]https://apod.nasa.gov/apod/calendar/S_170528.jpg[/img] [size=150]Collapse in Hebes Chasma on Mars[/size][/url]

[b] Explanation: [/b] What's happened in Hebes Chasma on Mars? Hebes Chasma is a depression just north of the enormous [url=https://apod.nasa.gov/apod/ap140511.html]Valles Marineris[/url] canyon. Since the depression is unconnected to other surface features, it is [url=http://1funny.com/wp-content/uploads/2011/02/confused-dog.jpg]unclear where[/url] the internal material went. Inside [url=http://en.wikipedia.org/wiki/Hebes_Chasma]Hebes Chasma[/url] is [url=http://www.uahirise.org/ESP_016818_1785]Hebes Mensa[/url], a 5 kilometer high mesa that appears to have undergone an unusual partial collapse -- a collapse that might be providing clues. The [url=http://www.esa.int/spaceinimages/Images/2013/10/Hebes_Chasma_mesa]featured image[/url], taken by ESA's robotic [url=http://en.wikipedia.org/wiki/Mars_Express]Mars Express[/url] spacecraft currently orbiting [url=https://solarsystem.nasa.gov/planets/mars]Mars[/url], shows great details of the chasm and the unusual [url=https://apod.nasa.gov/apod/ap170522.html]horseshoe[/url] shaped indentation in the central mesa. Material from the mesa appears to have flowed onto the floor of [url=http://www.esa.int/spaceinvideos/Videos/2013/06/Fly-through_movie_of_Hebes_Chasma]the chasm[/url], while a possible dark layer appears to have pooled like ink on a downslope landing. A recent [url=http://geomorphology.sese.asu.edu/Papers/Adams_etal_hebes_chasma_salt_tectonics_geol.pdf]hypothesis holds[/url] that salty rock composes some lower layers in [url=https://www.google.com/mars/#lat=-1&lon=-76&zoom=8]Hebes Chasma[/url], with the salt dissolving in melted ice flows that drained through holes into an underground [url=http://en.wikipedia.org/wiki/Aquafer]aquifer[/url].

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