Dry Valleys of Antarctica
|[Note Guidelines] Photographer's Note|
|I claim no photographic merit for this shot - it was taken at around 2am in the morning under very overcast conditions - it is also a scanned slide. However, the location is unique and intersting and very difficult to get to. We accessed the Valleys by helicopter and then had an ultra-strict visiting route. It was weird seeing glacial and desert landforms side by side. In some places we could see lichens growing iside the rocks.|
WHAT ARE THE DRY VALLEYS?
The Dry Valleys are a row of valleys in Antarctica located within Victoria Land west of McMurdo Sound. The region includes many interesting geological features including Lake Vida and the Onyx River, Antarctica's longest river. It is also one of the world's most extreme deserts. From north to south, the three main valleys are Victoria Valley, Wright Valley and Taylor Valley.
The Dry Valleys are so named because of their extremely low humidity and their lack of snow or ice cover - they are reputedly, one of the driest places on earth. Together, at 4800 square kilometers, they constitute around 2% of the continent, and form the largest relatively ice-free region in Antarctica. The valley floors are covered with a loose gravelly material, in which ice-wedge polygons may be observed.
HOW WERE THEY FORMED?
The unique conditions in the Dry Valleys are caused by a combination of Fohn (like the Chinook Wind in N America) and katabatic winds (from the Greek word for 'going down'). These occur when cold, dense air is pulled downhill simply by the force of gravity. However, before this the air has risen over a mountain range, cooling further and dropping any moisture, when it descends it is drier and warms (not that we would notice it). Because it is so dry, any moisture in the valleys is 'sucked - up' making them 'super-dry'. The winds can reach speeds of 320 km/h (200 mph) evaporating all moisture - water,ice and snow - in the process.
The gravel is often derived from two sources. The first is the terminal moraines which have formed at the end of glaciers which descend into the Dry Valleys but then mostly sublime (evaporate) directly to air. Thus very little liquid water is added. The second source of terminal moraines comes from a rather unusual source. It is believed that during some glacial periods, the quantity of ice in the nearby Ross Sea was so great that it forced its way inland into some of the Dry Valleys, in a kind of reverse glacier and deposited its own terminal moraine.
Endolithic plants have been found living in the Dry Valleys, sheltered from the dry air in the (relatively) moist interior of rocks. Summer meltwater from the Valleys' overhanging glaciers provides the primary source of soil nutrients. Scientists consider the Dry Valleys perhaps the closest of any terrestrial environment to Mars, and thus an important source of insights into possible extraterrestrial life.
Part of the Valleys was designated an environmentally protected area in 2004.
WHY IS THE GLACIER EDGE SO SHARP? - the wind funnelling down the valley sucks up moisture from the glacier flowing down the side valley, so sculpting the snout.
PaulH, SunToucher, saguzar, sandpiper2, gracious, Matt-Bird, Kathleen, gannu, lovenature has marked this note useful
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- [2007-08-15 2:31]
who cares whether this is 'visually stunning' when we get to see a place most of us will never see in our lifetimes. Facinating natural processes involved here, your inclusion of the figures helps add scale and depth. Thanks for sharing this with us.
I think it is visually stunning. Just look at the size of the glacier compared to the very tiny looking humans. What a baren looking place with all these rocks and ice. Surely not a place to get a tan. The sculpture by the wind on the glacier is very interesting and beautiful. Love the texture on the mountain.
Excellent landscape, I like the entire composition is marvelous, combining well with the cold we have now in Argentina, brrrr...
It's curious to me the snow pale band in the mountain, I never see something like this.
Definately learnt something today, I didn't know there were deserts in Antartica. Great note.
Well composed shot and nicely exposed in such a cool environment.
Hello my friend,
Thank you so much for the effort for showing us the hard-to-see scene of the Antarctica!
especially such a huge Glacier with sharp edge!
good clarity with details
thanks for sharing
- [2007-08-15 8:29]
Merci de partager ta passion avec cette aventure en Antarctique, tu dois faire beaucoup de jaloux.
You are one Lucky man, this would have been an awesome place to go. As Paul said most people will never go there. Its a good photo. They are people standing right up against the side of the glacier, those tiny little thing? Fantastic landscape, thankyou for sharing it.
Wow, the contrast between ice and valley. Exposure was handled excellent as not to blow out the ice or to dark on the valley. Having the people in there really gives the scale of this place perspective.
Wonderful image for showing it how it is with great notes.
- [2007-08-16 7:10]
Hi James, Lovely note and wonderful shot. WOW amazing landscape. TFS Ganesh