3.2 C: Geology = the Changing Earth 3.2 The Icy Epoch Flashcards
(66 cards)
What is the Athabasca Dunes?
Alberta’s largest actively migrating sand dune
Located in northeastern Alberta, close to the Athabasca River
How long and wide is the Athabasca Dunes?
7 km long, 1.5 km wide, and up to 35 m deep
This vast size can create a sensation similar to being in the Sahara Desert
At what rate does the Athabasca Dunes migrate?
1.5 m per year
This migration is caused by prevailing winds and results in sandstorms
What natural features does the migrating sand bury?
Trees, ponds, streams, and lakes
The advancing sand creates a seemingly lifeless desert environment
What process created the Athabasca Dunes?
The movement of ice sheets
A sheet of ice over 1 km thick shaped Alberta’s landscape over the last 1.7 million years
How long ago did glaciers begin to advance on Alberta?
1.7 million years ago
This advance of glaciers significantly impacted the region’s geography
What period marks the beginning of the icy Pleistocene Epoch?
The end of the Tertiary Period, around 7 million years ago
This period is characterized by accumulating snow in polar regions
What is a glacier?
A large river of ice that forms on land and moves under the influence of gravity
Glaciers are formed from compacted layers of snow
What happens to snow in polar regions during the early Pleistocene Epoch?
Snow accumulates year after year and compacts into ice
This process leads to the formation of glaciers
What ironic relationship exists between the advancing sand and the ice sheets?
The advancing sand mimics the ice sheet that created it more than 18,000 years ago
This reflects the cyclical nature of geological processes
Where can Earth’s largest glaciers be found?
In the polar regions - the Greenland and Antarctic continental ice sheets.
What happens to ice sheets during the Pleistocene Epoch?
They reached a critical mass and began to slowly flow outward toward the equator like a viscous fluid.
What is the depth of ice accumulation at the centers of current massive continental ice sheets?
Over two kilometers.
What is the process called when huge chunks of ice break off and float away?
Calving.
During the Pleistocene Epoch, where else did snow accumulate besides the continental ice sheets?
In mountainous regions, resulting in mountain glaciers.
Fill in the blank: Ice accumulates at the centers of ice sheets to depths of over _______.
two kilometers
True or False: Icebergs are formed from the calving process of ice sheets.
True.
What is the characteristic behavior of ice sheets when they reach a critical mass?
They begin to flow outward.
What significant geological period is associated with the accumulation of ice in mountain regions?
Pleistocene Epoch.
Fill in the blank: The continental ice sheet covers most of _______.
Greenland
What is the visual analogy used to describe the process of calving?
As if the ice sheet were giving birth.
Where can Earth’s largest glaciers be found?
In the polar regions - the Greenland and Antarctic continental ice sheets.
What happens to ice sheets during the Pleistocene Epoch?
They reached a critical mass and began to slowly flow outward toward the equator like a viscous fluid.
What is the depth of ice accumulation at the centers of current massive continental ice sheets?
Over two kilometers.
