Process: Ventifaction Location: Mc Murdo Dry Valley Prevailing winter wind direction: Westerly off...
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Transcript of Process: Ventifaction Location: Mc Murdo Dry Valley Prevailing winter wind direction: Westerly off...
![Page 1: Process: Ventifaction Location: Mc Murdo Dry Valley Prevailing winter wind direction: Westerly off Ice Sheet Dry Valley conditions favour process of ventifaction:](https://reader036.fdocuments.us/reader036/viewer/2022082917/5515bfc255034693758b45c6/html5/thumbnails/1.jpg)
![Page 2: Process: Ventifaction Location: Mc Murdo Dry Valley Prevailing winter wind direction: Westerly off Ice Sheet Dry Valley conditions favour process of ventifaction:](https://reader036.fdocuments.us/reader036/viewer/2022082917/5515bfc255034693758b45c6/html5/thumbnails/2.jpg)
Process: Ventifaction
Location: Mc Murdo Dry Valley
Prevailing winter wind direction: Westerly off Ice Sheet
Dry Valley conditions favour process of ventifaction:
• Desert conditions (lack of precipitation)
• No snow cover and little vegetation, so … plentiful supply of exposed particles of rock and ice
• Frequent strong katabatic (gravity driven) winds.
![Page 3: Process: Ventifaction Location: Mc Murdo Dry Valley Prevailing winter wind direction: Westerly off Ice Sheet Dry Valley conditions favour process of ventifaction:](https://reader036.fdocuments.us/reader036/viewer/2022082917/5515bfc255034693758b45c6/html5/thumbnails/3.jpg)
Ventifact rock - often weird and wonderful
shapes
![Page 4: Process: Ventifaction Location: Mc Murdo Dry Valley Prevailing winter wind direction: Westerly off Ice Sheet Dry Valley conditions favour process of ventifaction:](https://reader036.fdocuments.us/reader036/viewer/2022082917/5515bfc255034693758b45c6/html5/thumbnails/4.jpg)
Loose, exposed rock and snow particles
Abrasion erosion: wind carried particles are ‘sand blasted’ against facing rock surface
![Page 5: Process: Ventifaction Location: Mc Murdo Dry Valley Prevailing winter wind direction: Westerly off Ice Sheet Dry Valley conditions favour process of ventifaction:](https://reader036.fdocuments.us/reader036/viewer/2022082917/5515bfc255034693758b45c6/html5/thumbnails/5.jpg)
Katabatic (gravity driven) winds carrying rock and snow particles
(eolian transport)
Even in strong winds, particles can’t be continuously held in the air. Instead, particles bounce along ground - saltation.
This erosion is focused on base of ventifact, resulting in mushroom shaped rocks
Side of rock facing prevailing wind may become grooved or polished
![Page 6: Process: Ventifaction Location: Mc Murdo Dry Valley Prevailing winter wind direction: Westerly off Ice Sheet Dry Valley conditions favour process of ventifaction:](https://reader036.fdocuments.us/reader036/viewer/2022082917/5515bfc255034693758b45c6/html5/thumbnails/6.jpg)