Erosion and Depistion BY GLACIERS!

What is a Glacier? a. A glacier is ________________ ___________________________ ___________________________ Glaciers occur in the polar regions and at high altitudes a large mass of slowly flowing ice and snow that formed from the compaction and re-crystalization year after year.

b. Types of glaciers 1. _____________- glaciers that form in mountain valleys at high elevations Ex: _______________ , _____________ ______________ , ____________ 2. __________- glaciers that form over vast areas of land. –Like Ice Sheets Ex: ____________, _____________ Valley / Alpine Alps (Europe) Himalayas (Asia) Rockies (N.A) Andes (S.A) Continental Greenland Antarctica

Glacial Movement Movement occurs due to gravity down a slope or outwards under it’s own pressure

3. Profile of a valley glacier alpine Valley glaciers are called _________, and like a stream, valley glaciers move fastest in the ________. ______ moraine is rock material pushed along the front edge of a glacier. middle End

Lateral ___________- moraine is rock material on the sides of a glacier along the valley walls __________- moraine is rock material in the middle of a valley glacier formed when the inside lateral moraine combine when two valley glaciers merge as one __________- moraine is rock material trapped on the bottom of a glacier. Medial Ground

Moraine’s can be seen by “dirty” streaks in the glacier medial moraine lateral moraine

Erosion by glaciers Till 1. 2. As a glacier moves, it plucks up loose rock material (E) . ____- is all the unsorted rock material carried by a glacier. The glacier, with pieces of rock within the ice, acts like a piece of sandpaper! Can grind down mountains (E). Results: Polished and rounded mountaintops, and scratched bedrock Till

Deposition: When the Ice melts the till just drops on out!

Boulders from the last Wisconsin Ice advance are pushed as far as NYC Boulders from the last Wisconsin Ice advance are pushed as far as NYC!- Shawangunk ridge, Gardiner NY

Glacial Erosion: Stream Valleys vs. Glacial Valleys V-shaped valley eroded by a __________ U-shaped valley eroded by a __________ stream glacier

BANFF National Park, Canada

4. Stream Valleys vs. Glacial Valleys U-shaped V-shaped

Post Glacial Landscape Features, Depositional or Erosional Post Glacial Landscape Features, Depositional or Erosional? Formation of Long Island: Lesson Interactive: Moraines and outwash plains

Esker- long winding ridge of sediment. Drumlins- elongated hills formed when a glacier slides over a pile of sediment. (looks like spoons-D) Esker- long winding ridge of sediment. - SORTED and layered because it is deposited by running water under glacier

Kame- irregular shaped hill of unsorted sediment Kettles & Kettle-Lakes- when a block of ice indents the soil to create a depression. If it melts it forms a “kettle” lake (D) Kame- irregular shaped hill of unsorted sediment (forms when sediment flows into cracks of glacier) (D)

Erratics- a large rock plucked up and dropped off by the glacier (D) Striations - parallel lines in the bedrock caused by rock fragments scratching (E) Erratics- a large rock plucked up and dropped off by the glacier (D)

MORAINES: Depositional

How glaciers move - budget

Ablation vs. Accumulation A glacier gains and loses ice each year Ablation= the amount lost due to melting Accumulation= the amt. of snow and ice added at the end of the year

Relationships of Ice gain/loss If the net accumulation > ablation= Glacial Advance If net accumulation < ablation= Glacial Retreat If there is no net gain or loss of ice (accumulation= Ablation) the glacier is stationary (NOT MOVING )

Recognizing a net loss graphically

Most Glaciers are retreating globally at this moment in time 