Geology Picture of the Week & Month: Ash and Antarctica

Flickr ^ | February 11, 2010 | Montserrat Volcano Observatory

[cogitator]

I apologize for my inconsistency in posting the Geology Picture of the Week over the past few weeks. I will still be continuing, but my February is disrupted, so I probably won't do one next week. I'll try to return to normalcy in March.

So I thought for this one I'd do a couple of quick-hitters. First is from the Montserrrat Volcano Observatory; they have a Flickr page. The Soufriere Hills volcano had a partial dome collapse on February 11. The picture shows the ash cloud and a pyroclastic flow.

Montserrat Volcano Observatory Flickr page

The second is a shot of a ventifact from the Antarctic Dry Valleys. I've linked to the article that I got it from.

Vacation to Mars: Antarctica's Dry Valleys

I've got a lot of great volcano pictures stored up; more later!

[cogitator]

I *might* post another one this week.

[skr]

Thanks for posting when you are able!

[cogitator]

* ping *

[unkus]

As always, thank you cogitator. Awesome!

[Fred Nerks]

great images from the antarctic, thanks, added them to my collection.

[Joe Boucher]

cogitator,
I have been interested in geology for ever and have NEVER seen the likes of ths from of all places Antarctica.
The Gobi maybe but here?
WOW,
Good job and thanks

[mathluv]

i always enjoy your pings! I appreciate your efforts. I share many with my daughter, who is a science teacher.

[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.

[IndianChief]

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

Thanks, I hope to do it soon.

The Spiti River Valley in HP passes through some of the most rugged (and beautiful) terrain in India. This picture was taken between places called Kaza(3600m+) and Losar (4200m+). I doubt if there whould be no permafrost here, at least now.

These features can be photographed from the road.

[IndianChief]

ooops!

I doubt if there whould be no permafrost here, at least now

I doubt if there would be any permafrost here, at least now

[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.

[IndianChief]

it would appear that we see erosion of volcanic ash deposit into a valey, then with rains/snow melt

Are the Himalayas volcanic in origin?

Not far from here as the crow flies, at 14200 ft near a village called Langzha, is a big plain of fossils which indicate that a few million years ago it was part of the sea bed.

If I start a thread with a link to a page on another site (an Indian motoring and travel site), will it be allowed or will I be zotted? On the same thread, a travelogue of what is called the "Spiti Loop", you can see some of the fossils. The bigger and better ones have already been collected by travellers and the inhabitants of the villages.

[MHGinTN]

With Plate Tectonics, the reality of fossils from rainforests and sea beds--found high up in mountians--began to make sense.

Years ago I worked for a college textbook company. We published a book on plate tectonics ... I spent so much time on the road with those companies that I read practically every good textbook we published. Plate tectonics was not well received thirty-five years ago. Now, it is quite clear that plates subduct and rise. The Appalachians are old mountains, but the Himalayans are new.

More than one massive volcano has erupted in the area which is now Indonesia. A super volcano can send an awful lot of ash to coat the landscape. And as the Himalayas have risen, they have perhaps covered and subducted massive volcanos which ruled prior to the plates forming up the massive risers of the Himalayas. The Yellowstone super volcano may be going extinct due to plates shifting away from the weak spots in sub-crust.

[MHGinTN]

Oh yeah, in answer to your question, IIRC the himalayans are not volcanic in origin, they are the result of a plate over riding another older plate, pushing up material like a ribbon. Place a bath towel on a smooth table top. Push one side of the towel and watch as wrinkles rise up between your hands and the opposite side of the towel. That’s an illustration of how plates rise and subduct.