Glaciers What types are there How do they

Glaciers What types are there? How do they erode material?

Glaciers n Glacier- naturally formed mass of ice and snow that moves downhill under the force of gravity n Carry: unsorted material – Till large boulders – Erratics

Glacier Movement: n n n As more snow and ice accumulate the glacier moves forward As snow and ice melt the glacier retreats Fragments can be carried hundreds of miles The glacier ice acts like a fluid Its sometimes called a “river of ice” Fragments can be as big as a house

Type #1 - Alpine (Valley) Glaciers n glaciers that form in high elevation in mountain valleys around the world Moves in one direction n Covers a small area n Moves fast n Thin n

Characteristics of Valley Glaciers: n n U-shaped Valley- characteristic of glaciers as they erode the valley walls Horns- structures dropped off by the glacier that stick out of the ground

Type #2 - Continental Glaciers n huge sheets of ice that cover huge landmass regions

Characteristics of Continental Glaciers n n n When a glacier moves over land loose rock and material are frozen to the bottom and dragged along This material frozen to the bottom acts like sandpaper and scrapes the bedrock making: Glacial Grooves/Striations/Scratches- grooves in the bedrock that indicate the way the glacier has moved

Characteristics Con’t. n Terminal Moraine - where the glacier stops forward movement sediment is dropped in an unsorted pile n Glacial Till- unsorted pile of sediments dropped off by the glacier n Drumlins- streamlined oval shaped mound created by till and melting of ice to water n Shows a glaciers direction of movement

n Kettle Lakes- formed when a chunk of ice breaks off from the glacier and leave a depression behind Example: Lake Ronkonkoma n Outwash Plain- a broad delta-like feature of sorted sediment deposits Example: Southern LI