15 April 2007

No Travel Today. SnowSTAR remained at the Daring Lake Camp today, visiting with other researchers, filling fuel containers, and fixing snowmachines. Tonight's soundclip is a greeting from the newest member of the team: Arvids Silis. If you like rocks it sounds like the barrenlands is the place for you! Tonight's dispatch gives a little lesson in barrenlands geology using words and photos.

Click Here for Tonight's Soundclip from Arvids Silis

Moraines, Eskers, Erratics, and Striations

At Daring Lake Research Camp, 15 April 2007

65º 50'N,   111º 35'W

-10ºC.  Sunny and windless


Moraines, Eskers, Erratics, and Striations;

The Barrenlands is a world of rock, some of it the oldest rocks (4 billion
years or more) found in the world.  It is also a land where ice, in the form
of an enormous ice sheet (called the Laurentide Ice Sheet) has ground up,
quarried, and moved the rocks.  Some places the rocks have been arranged in
patterns, other places they are a chaotic mess.  In most cases, while
beautiful to look at, the rocks require careful driving and hard navigating
to get through.  Hitting a rock with a ski on the snowmachine can bend or
break the skis. Enroute to Daring Lake, and around the research camp, we
have found almost all the types of rock deposit the great ice sheet left
10,000 years ago.  The names for these rock features may seem strange, but
then, do the rocks near you look like this?

Moraines:  Jumbles of small to big jagged and angular rocks, usually all
mixed up.  These are carried by the ice sheet and deposited willy-nilly over
the landscape, as if a giant salted the earth with boulders, cobbles, and
pebbles.  See how carefully we are driving around and through these.

Erratics: These are very large boulders, usually as big as a person,
sometimes as big as a house, that have been left by the ice sheet.  They are
often solitary, sitting all by themselves out on the landscape, unlike the
moraine. Erratics got their name because they usually are a different type
of rock than the rock they sit upon.

Eskers:  These are ridges today that were formed as stream beds in under-ice
caverns through which water flowed.  They run for miles, sometimes as far as
50 miles, and winding across the landscape like a sinuous railroad
embankment.  All of the rocks have been rounded by water.

Striations:  The ice sheet flowed over bedrock. The bottom of the glaciers
carried rocks that scratched the bedrock, leaving grooves that show which
way the ice flowed.

Were there ever glaciers where you live? If so, what signs of glaciers can
you see? If there were no glaciers where you live, what other forces shaped
the landscape?