‘S

VOCABULARYVOCABULARY

GLACIERGLACIER - - LARGE MOVING LARGE MOVING MASS OF ICE THAT FORMS NEAR MASS OF ICE THAT FORMS NEAR EARTH’S POLES AND IN EARTH’S POLES AND IN MOUNTAINOUS REGIONS AT HIGH MOUNTAINOUS REGIONS AT HIGH ELEVATIONS.ELEVATIONS.

MORAINE –MORAINE – RIDGE OF MIXED RIDGE OF MIXED DEBRIS BEING DEPSITED BY A DEBRIS BEING DEPSITED BY A MELTING GLACIER.MELTING GLACIER.

This is what a moraine looks like

DRUMLIN –DRUMLIN – ELONGATED LANDFORM ELONGATED LANDFORM THAT RESULTS WHEN A GLACIER THAT RESULTS WHEN A GLACIER MOVES OVER AN OLD MORAINE.MOVES OVER AN OLD MORAINE.

Drumlin (shows direction of glacier flow)

OUTWASH PLAINOUTWASH PLAIN – – AREA AT THE LEADING AREA AT THE LEADING EDGE OF A GLACIER, WHERE OUTWASH IS EDGE OF A GLACIER, WHERE OUTWASH IS DEPOSITED BY MELTWATER STREAMS.DEPOSITED BY MELTWATER STREAMS.

KETTLE LAKES –KETTLE LAKES – FORMED WHEN A LARGE FORMED WHEN A LARGE BLOCK OF ICE BREAKS OFF AND FORMS A BLOCK OF ICE BREAKS OFF AND FORMS A LAKE. (VERY COMMON IN NEW YORK LAKE. (VERY COMMON IN NEW YORK STATE)STATE)

Outwash plainKettle Lakes

TILL -TILL - material deposited directly by material deposited directly by the glacier. (UNSORTED, unlayered).the glacier. (UNSORTED, unlayered).

FINGER LAKES –FINGER LAKES – body of water that body of water that forms in a long narrow u-shaped forms in a long narrow u-shaped glacial valley.glacial valley.

till

Notice how its unlayered and unsorted. Different sizes found throughout the sediment. (Big found on top and bottom

GlaciersGlaciers

Two types of glaciers:Two types of glaciers:

1.1. Valley glaciersValley glaciers (or alpine)(or alpine) – covers the – covers the floor of a valley.floor of a valley.

2.2. Continental glaciersContinental glaciers (Ice Sheets)–(Ice Sheets)– covers continents and is thousands of covers continents and is thousands of meters thick. meters thick.

Valley (or Alpine) glacier

Continental Glaciers

Antartica

Birth of a GlacierBirth of a Glacier

As more and more snow falls andAs more and more snow falls and accumulatesaccumulates, the snow will, the snow will compresscompress andand recrystallizerecrystallize into a rough, granular ice into a rough, granular ice material calledmaterial called firnfirn..

The firn will grow and becomeThe firn will grow and become solid icesolid ice..

The ice begins toThe ice begins to flowflow..

This will then become aThis will then become a glacierglacier..

Snow turning into firn

Glacier MovementGlacier Movement Glaciers move more Glaciers move more rapidlyrapidly in the in the

centercenter than the sides. than the sides.

Glacier movementVALLEY (ALPINE) GLACIER

Notice the stakes. Glaciers move fastest in the middle .

Why??

The rate of melting vs. movement may change and make the glacier appear to move backwards.

A typical advance and retreat of a glacierNotice the rock in the glacier. It’s always advancing down

hill even though the glacier appears to be moving backwords

Glacier MovementGlacier Movement

If a glacier reaches a If a glacier reaches a veryvery steepsteep slope, it will slope, it will literally start toliterally start to crackcrack under pressure.under pressure.

These cracks are calledThese cracks are called crevassescrevasses..

Glacial Erosion and Glacial Erosion and DepositionDeposition

Like running water, glaciersLike running water, glaciers removeremove loose rock andloose rock and carrycarry them with them as they move them with them as they move and eventuallyand eventually depositdeposit them.them.

However, unlike running water, However, unlike running water, due to theirdue to their sizesize,, there isthere is no limitno limit to the size rock they canto the size rock they can carrycarry..

ALLALL SEDIMENT DEPOSITED BY SEDIMENT DEPOSITED BY A GLACIER IS A GLACIER IS UNSORTEDUNSORTED AND AND UNLAYEREDUNLAYERED!!!!!!!!!!

Glacial Erosion and Glacial Erosion and DepositionDeposition

The Glacial ValleyThe Glacial Valley

When a glacier hasWhen a glacier has rocksrocks in it, as it in it, as it moves the rocks willmoves the rocks will scratchscratch the valley the valley

floor and leave behindfloor and leave behind striationsstriations – a – a suresure signsign that a glacier was in the area that a glacier was in the area is a rock with striations on it!!is a rock with striations on it!!

Also, the glacier can act likeAlso, the glacier can act like sandpapersandpaper andand polishpolish andand smoothsmooth the valley floor.the valley floor.

Glacial Striations

Glacial Polish

Glacial striations, left by flowing ice, British Columbia

Glacial erosion

Formed by “pluckingFormed by “plucking

THIS IS HOW THEY DO IT

The Glacial ValleyThe Glacial Valley

As the glacier As the glacier moves through moves through the valley and the valley and carvescarves out the out the rock, it leaves rock, it leaves behind a behind a U-U-SHAPEDSHAPED valley!!!!valley!!!!

The diagram to the left shows a mountainous landscape prior to glaciation. Notice the gently rounded mountains and the young, V-shaped valleys (formed by running water).

This diagram depicts the same landscape covered by glaciers. Notice the many alpine glaciers feeding into a large valley glacier. Higher up, a few cirque glaciers are also present.

The last diagram shows the post-glacial landscape. Notice the sculpting of the mountain peaks and the valley’s transformation from V-shaped to U-shaped.(U shaped formed by glacier)

Glacial DepositsGlacial Deposits

1.1. TillTill – – unsortedunsorted, , unlayeredunlayered rock rock material deposited directly from thematerial deposited directly from the glacial iceglacial ice..

MorainesMoraines When glaciers deposit material they When glaciers deposit material they

formform morainesmoraines (piles of sediment and (piles of sediment and rocks).rocks).

At theAt the ice frontice front, a lot of material gets , a lot of material gets deposited and the pile that builds-up deposited and the pile that builds-up there is anthere is an end moraineend moraine..

The veryThe very lastlast end moraine marks the end moraine marks the glaciers farthest advance and that is glaciers farthest advance and that is known as theknown as the terminal moriane.terminal moriane.

Other Glacial DepositsOther Glacial Deposits

ExtremelyExtremely largelarge boulders thatboulders that do do not matchnot match the the bedrock that they bedrock that they are found on are are found on are probably dropped probably dropped by glaciers. These by glaciers. These are calledare called

erraticserratics..

What would make you think a glacier deposited this?

Rock Type does not match - area rock (All the rock around is igneous yet these big rocks are metamorphic

The size of the rock – to big to be carried by running water

Other Glacial DepositsOther Glacial Deposits

Long, smooth,Long, smooth, canoe-canoe-shapedshaped hills made of till hills made of till are calledare called

drumlinsdrumlins..

Drumlins are great for Drumlins are great for telling thetelling the directiondirection the the glacier moved, because glacier moved, because theythey pointpoint in the in the direction itdirection it movedmoved..

Glacial LakesGlacial Lakes

Kettle lakesKettle lakes are are circularcircular hollowshollows that fill in withthat fill in with meltwatermeltwater from the from the glacier.glacier.

Darien LakesDarien Lakes are are kettle lakes!!kettle lakes!!

Esker

TillMoraine-dammed lake

Terminal Moraine

Glacial Stream

Outwash Plain

Kettle Lakes

DrumlinsKames

Glacier

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WRITE THESE DOWNWRITE THESE DOWN EROSIONAL FEATURESEROSIONAL FEATURES

How do you know a glacier has been here??How do you know a glacier has been here??

1.1. U – SHAPED VALLEYSU – SHAPED VALLEYS

2. PARALLEL SCRATCHES ON THE SURFACE OF ROCKS 2. PARALLEL SCRATCHES ON THE SURFACE OF ROCKS (STIATIONS)(STIATIONS)

3. ERRATICS3. ERRATICS - STUFF FOUND IN AREAS THAT IT - STUFF FOUND IN AREAS THAT IT DOESN’T BELONG (METAMORPHIC BOLDER IN A DOESN’T BELONG (METAMORPHIC BOLDER IN A REGION OF IGNEOUS ROCKS REGION OF IGNEOUS ROCKS

4. Drumlins- Show direction of Glacier Movement4. Drumlins- Show direction of Glacier Movement

5. Unlayered unsorted sediment5. Unlayered unsorted sediment