Tunnels on Mars natural or what?

I have been browsing through a various pics of the MRO and I find this pictures very interesting, now I dont know much about rock formations or tunnels for that matter, but this tunnels if you look have some sort of what it look to me unnatural layers (like concrete or something else) around them. One of them looks like it has collapse.

Since I dont have a way now to upload tem, Im just going to place the pics links here.

Light-Toned Rock Outcrops in Northeast Sinus Meridiani (looks collapse)

Edge along Gale Crater Interior Mound


[edit on 10-12-2007 by Bunch]

[edit on 10-12-2007 by Bunch]

reply to post by Bunch


Interesting. I imagine the second picture can be ruled natural right off. The first photo seems to need a closer look to determine just what we are seeing. At first glance, it does seem to have an odd look to it.

A good find, and one I'm sure will bring out discussion.

reply to post by Bunch


I'm trying to imagine our cave systems on earth without water over them anymore. And then thousands or millions of years of erosion, but it's to hard to imagine to me.

We have caves that are miles long and underwater. What happens to them when the water's gone? In my opinion they erode away and finally collapse. Newer one's that haven't eroded away yet are there to see.

Just my opinion and I'm not saying those in the pic are eroded caves, but it is a possibilty.

reply to post by Solarskye


I was thinking something along those line too, still those layers look curiously unnatural to my geology deficient eye. I wonder how deep are they.

reply to post by Bunch


That first one does look unnatural, but what's natural on mars? I wonder what a lava tubes looks like uncovered? Here are lava tubes from the inside.