Wednesday, February 27, 2008

Picture of the Day - The Airliner Chronicles

One of my favorite aspects of flights to Europe (and there are very few; Europe is great, nine-hour flights are not) is the necessity of crossing over Greenland. When the weather is clear, the views of this icy alien landscape are just stunning. Our flight home from Paris in 2006 was one of those trips, with just a few clouds over the highest part of the (really big) island. So what do you all think of this glacial feature? What's going on here?

7 comments:

Callan Bentley said...

Looks to me like there's an initial left-right extension, which has opened up a series of top-bottom-trending fractures. I can't quite tell, but it looks like the left half is lower-elevation than the right half of the photo, and transverse fractures open up on glaciers as they descend (perhaps from the ice sheet down into one of the valley glaciers leading to the ocean?). My interpretation continues that an overlying layer of snow has sagged down into the crevasses, more in some areas, less in others (so the crevasses' surface expression appears as a "dotted line"). Finally, wind has come along and exploited this topography, and piled up ridges of snow leading from the distant edge of each sag-hole off to the upper-left. Just a guess, but that's my instinct looking at the photo.

Ron Schott said...

Seconded.

Silver Fox said...

I'd just like to say, Wow - to the picture, not to the extensive analysis. I find everything about snow and ice fascinating, and this is an exceptional air-flight photo.

Silver Fox said...

Well, maybe that would be "extensional" ?

Mel said...

I'll third Callan's response. I was going to reply with a simple crevasses explaination, but Callan has done a wonderful job. I'll add that the smaller patch of crevasses about 2/3 up the photo appear to be coming from a glacier at the top of the photo and are "falling" over the rock ledge visible in the photo.

MJC Rocks said...

Thanks for all the comments! This wasn't a quiz where I knew all the answers this time around; I found the feature kind of mysterious as well. Callan is most certainly correct, in that there are clearly crevasses caused by the west to east flow down some kind of declivity, and clearly wind has caused snow to pile up in ridges transverse to the direction of the crevasses. I found myself wondering: did the crevasses collapse, forming icy grabens, or has the blowing snow filled the crevasses, but not completely? I noticed the presence of gaps and holes just to the right where clearly more crevasses are hidden by a smooth surface of snow and ice.

I shiver just thinking about ambient conditions on the ground where the wind blows this much...

Geology Happens said...

...and I thought it was a ski area after hours and before it was groomed.