Minnesota - ice sheet glacier Flashcards
1
Q
A
2
Q
Where is Minnesota?
A
Midwestern Us state
Borders Canada and the Lake Superior - the largest of the Great Lakes
3
Q
What was the name of the glacial sheet?
A
Laurentide ice sheet centred around the north extending from around Hudson bay.
4
Q
Glaciation
A
- Was impacted with Glaciation during the quaternary period
- Saw many advancements and retreats of continental ice sheets such as the Lauren tide Ice Sheet
- Lauren tide ice sheet transported and deposited glacial till from different areas
5
Q
Geology
A
- Belts of volcanic and sedimentary rock it’s Granitic rock material lying in between the belts.
- Volcanic and sedimentary rock began to form 2700 million years ago
- Volcanic debris released into the nearby seas – later settled on the seafloor forming massive layers of sedimentary rock
6
Q
Erosional impact
A
- High mountains were worn down
- Large ellipsoidal basin formed – which now holds a large number of lakes
- As the lobes advanced bold striations – in the metamorphic gneiss and green stone ( gives indication of the direction of the ice movement)
7
Q
Depositional impact
A
- Wadena lobe extended from North East Canada deposited till – red and sandy → It deposit moraine and drumlin fields
- Extension of lobes – left a wide range of terminal moraine made up of different rock dependent upon the origin of the lobe
8
Q
What is a proglacial lake?
A
are lakes that form behind a moraine of ice damn.
9
Q
How are proglacial lakes formed?
A
- May form behind moraine left by a retreating glacier
- Glacial ice can also create a dam to block the flow of water from a river or melting glacier
When the damn breaks catastrophic flooding can occur and carve areas down stream
10
Q
Pro glacial lakes in minnesota
A
he edge of a giant ice sheet and its associated loops also down to the natural drainage of the area – this created a number of pro glacial lakes
11
Q
What is the largest proglacial lake in minnesota ?
A
Lake Agassiz
