[IndianChief]

Cogitator, though I am not on your ping list, I follow your threads regularly. I have been fascinated by this picture, taken in the Spiti valley, Himachal Pradesh State, India. Could you shed light on how it was formed or what forces are at play here?

The copy right is that of the photographer, Mr Sen.

[MHGinTN]

Placemarker ... great question!

[cogitator]

I’m fascinated by geology, but I’m not a practicing geologist. It would help to know the hydrologic setting of the picture. It looks like erosion through a semi-permeable layer (like permafrost) that has been exposed by river cutting? The altitude at which the picture was taken makes a difference. Anyway, why don’t you post it more generally in “Science” and have other people take a shot at explaining it? Maybe you’ll find someone with more knowledge of something like this.

[MHGinTN]

Disclaimer: not a geologist or even a scientist.

If you look at the moutains in the background (on the right of the picture in particular), it would appear that we see erosion of volcanic ash deposit into a valey, then with rains/snow melt, further depositing into the lower wet weather river bed and washed away. Given the state of the deposits, I would questimate approximately 300,000 to one million years of erosion.