how do glaciers effect the land? by erosion & deposition

How do Glaciers Effect How do Glaciers Effect the Land?the Land?

By erosion & depositionBy erosion & deposition

Glacial erosionGlacial erosion forms when forms when glaciers sculpt, carve and carry glaciers sculpt, carve and carry away the land beneath them. away the land beneath them.

Glacial depositionGlacial deposition is created is created by deposition, or what a by deposition, or what a glacier leaves as it retreats or glacier leaves as it retreats or melts away. melts away.

Glacial ErosionGlacial Erosion

A glacier's weight and A glacier's weight and movement, can re-shape the movement, can re-shape the landscape. (this takes hundreds landscape. (this takes hundreds or thousands of years) or thousands of years)

The ice erodes the land surface The ice erodes the land surface and carries the broken rocks and carries the broken rocks and soil debris away.and soil debris away.

Types of Glacial ErosionTypes of Glacial Erosion

Glacial Valleys Horns FjordsCirques Aretes

Glacial ValleysGlacial Valleys trough-shaped, with trough-shaped, with

steep vertical cliffs where steep vertical cliffs where entire mountainsides entire mountainsides were removed by glacial were removed by glacial action.action.

Ex: Yosemite National Ex: Yosemite National Park. glaciers sheared Park. glaciers sheared away mountainsides, away mountainsides, creating deep valleys creating deep valleys with vertical walls. with vertical walls.

Yo

Hanging ValleyHanging Valley Forms when small tributary glaciers join larger Forms when small tributary glaciers join larger

glaciersglaciers Since small glaciers are unable to erode down into Since small glaciers are unable to erode down into

the landscape very far a hanging valley formed.the landscape very far a hanging valley formed. The larger the glacier, the deeper the valley it can The larger the glacier, the deeper the valley it can

erode. erode.

Look at the hanging Look at the hanging valley!valley!

Fjords Long, narrow coastal Long, narrow coastal

valleys with steep valleys with steep sides & rounded sides & rounded bottoms.bottoms.

Fjords form when a Fjords form when a glacier erodes the glacier erodes the land below sea level. land below sea level. When the glacier When the glacier melts, the ocean melts, the ocean water fills in the water fills in the valley floor.valley floor.

CirquesCirques Created when glaciers erode backwards Created when glaciers erode backwards

into mountainsides, creating rounded into mountainsides, creating rounded hollows shaped like shallow bowls.hollows shaped like shallow bowls.

Tarn LakeTarn Lake A tarn is a mountain lake or pool, formed

in a cirque after the glacier melts.

AretesAretes Jagged, narrow ridges created where Jagged, narrow ridges created where

the back walls of two cirque glaciers the back walls of two cirque glaciers meet, eroding the ridge on both sides. meet, eroding the ridge on both sides.

Arete

HornsHorns

Matterhorn in Switzerland

Created when several Created when several cirque glaciers erode a cirque glaciers erode a mountain until all that is left mountain until all that is left is a steep, pointed peak with is a steep, pointed peak with sharp, ridge-like aretes sharp, ridge-like aretes leading up to the top.leading up to the top.

Types of Glacial ErosionTypes of Glacial Erosion

Glacial DepositionGlacial Deposition

Landforms are also created by Landforms are also created by deposition, or what a glacier leaves deposition, or what a glacier leaves as it retreats or melts away.as it retreats or melts away.

Kettle LakesKettle Lakes KamesKames

Moraines Moraines Till Till DrumlinsDrumlins

Erratic BouldersErratic Boulders

TillTill Material that is Material that is

deposited as deposited as glaciers retreat, glaciers retreat, leaving behind leaving behind mounds of gravel, mounds of gravel, small rocks, sand small rocks, sand and mud. and mud.

It is made from the It is made from the rock and soil ground rock and soil ground up beneath the up beneath the glacier as it moves. glacier as it moves.

MorainesMoraines Material a glacier picks up or pushes as Material a glacier picks up or pushes as

it moves.it moves. They form along the surface and sides of They form along the surface and sides of

the glacier. the glacier. As a glacier retreats, the ice melts away As a glacier retreats, the ice melts away

from underneath the moraines, leaving from underneath the moraines, leaving long, narrow ridges that show where the long, narrow ridges that show where the glacier used to be. glacier used to be.

Glaciers don't always leave moraines Glaciers don't always leave moraines behind, because sometimes the glacier's behind, because sometimes the glacier's own meltwater carries the material away. own meltwater carries the material away.

Types of MorainesTypes of Moraines

Medial Moraine

Kames Small steep-sided mounds of soil and Small steep-sided mounds of soil and

gravel that form adjacent to the gravel that form adjacent to the glacier. glacier.

They form from streams flowing out They form from streams flowing out of the glacier that carry rock and of the glacier that carry rock and soil.soil.

Kettle lakes Form when a piece of glacier ice breaks Form when a piece of glacier ice breaks

off & becomes buried by glacial till or off & becomes buried by glacial till or moraine deposits. moraine deposits.

Over time the ice melts, leaving a small Over time the ice melts, leaving a small depression in the land, filled with water. depression in the land, filled with water. very small, more like ponds than lakes. very small, more like ponds than lakes.

Erratic Boulders Glaciers pick up rocks Glaciers pick up rocks

as they slowly move as they slowly move along. The glaciers along. The glaciers carry the rocks far carry the rocks far away from their away from their source.source.

When glaciers melt When glaciers melt they leave behind they leave behind anything they pick up anything they pick up along the way (huge along the way (huge rocks, called rocks, called erratic erratic boulders)boulders)

Drumlins long, streamlined tear-drop-shaped long, streamlined tear-drop-shaped

formations. formations. They form when a glacier deposits material They form when a glacier deposits material

as it is flowing and then moves over it. as it is flowing and then moves over it. Because they are deposited and shaped by Because they are deposited and shaped by

glacier movement, all the drumlins left by glacier movement, all the drumlins left by a particular glacier will face the same a particular glacier will face the same direction. direction.

Often, groups of several thousand drumlins Often, groups of several thousand drumlins are found in one place, looking very much are found in one place, looking very much like whalebacks when seen from above. like whalebacks when seen from above.

Drumlins

Glacial StriationsGlacial Striations

are scratches or gouges cut into the are scratches or gouges cut into the bedrock by process of glacial abrasion. bedrock by process of glacial abrasion.