Physics Photo of the Week
September
4, 2009
Victoria Glacier, Lake Louise, Canada
Lake
Louise in Banff National Park, Canada is one of the most picturesque
views of nature on the North American continent. The backdrop of
extremely high massive snow-packed cliffs, the narrow, symmetrical
V-shaped valley beyond the lake, and the Victoria glacier visible in
the upper valley makes easy composition for a novice
photographer.
Lake Louise was created by the Victoria Glacier back in the last ice
age abour 10,000 to 20,000 years ago. We see the still active
Victoria Glacier in the center of the photograph. It doesn't look
like many photographic glaciers because it is covered with debris
(rocks having fallen onto it along its journey through the
valley). The snowfields half-way up the steep sides of Mount
Victoria in the background contribute to the rock debris falling onto
the glacier, thus making the ice of the glacier all but invisible.
The close-up image (right) outlines
the current terminus for Victoria Glacier. The photo also shows a
lateral moraine on the right side of the photo. A lateral moraine
is a ridge of debris left on the lateral edge of the glacier.
Since the glacier has retreated during the past several thousand years,
the lateral moraine is considerably higher than the current glacier.
Another feature of the Rocky Mountain ranges shows clearly in these
photos of Lake Louise. Notice that the rock strata of Mt.
Victoria in the background appear to be horizontal. Wherever we
see stratified rock, that indicates that the rocks were at one time
formed as sediments at the bottoms of oceans, seas, or lakes. The
sedimentary rocks may be sandstones - sediments that have solidified
due to time and pressure. If the sediments
have undergone extreme heat as well as pressure, they form metamorphic
rocks. Metamorphic rocks are much harder as a result of the
particles becoming sintered together, similar to the hardening of clay
into pottery in a kiln. The results of the Earth's tectonic
plates colliding together has caused one plate to be thrust on top of
another plate, thus causing elevated mountains that become easily
eroded to form the picturesque glacier-formed lakes and valleys.
Physics
Photo of the
Week is
published weekly during the academic year on Fridays by the Warren
Wilson College Physics
Department. These photos feature interesting phenomena in
the world around us. Students, faculty, and others are invited to
submit digital (or film) photographs for publication and
explanation. Atmospheric phenomena are especially welcome.
Please send any photos to dcollins@warren-wilson.edu.
All photos and discussions are copyright by Donald
Collins or by the person credited for the photo and/or
discussion. These photos and discussions may be used for private
individual use or educational use. Any commercial use without
written permission of the photoprovider is forbidden.
Click
here to see the Physics Photo
of
the Week Archive.
Observers are invited to submit
digital photos to:
