Glaciers Agent Please view as a slideshow! Ms. Susinno

What are Glaciers?

How do glaciers form?

Glaciers carve u shaped valleys

Plucking Glaciers: Glaciers “pluck” bedrock and transport rocks in rivers of ice. This makes scratches and grooves on bedrock called striations. “rock flour” at the bottom of the ice polishes the bedrock while the bigger rocks and boulders scratch the bedrock.

A roche moutonée is a glacial landscape feature produced as an advancing glacier slides over a hill of surface bedrock. As the glacier advances up the side of the hill, the surface bedrock is abraded and smoothed by rock fragments carried within the base of the glacial ice, creating a more gentle hillslope. As the glacier advances down the opposite side of the hill, chunks of bedrock are broken off and removed by the ice, a process called glacial quarrying (plucking), making this side of the hill steeper. The resulting hill resembles a drumlin, except it is often smaller and is composed of solid bedrock.

is the part of glacial drift deposited directly by the glacier. Till is UNSORTED! till

Alpine Glaciers: Flow from high elevation to low elevation Are also called Valley Glaciers

Are these erosional or depositional features?

Continental glaciers Flow outward from the thickest point Currently exist in Greenland and Antarctica Once existed over NY State! This process is called calving, and forms icebergs!

icebergs Most of the iceberg is underwater. Why? Density of ice g/cm³

Continental glacier features: Once a glacier retreats, many features are exposed. We know that NY state Was covered by a continental glacier, because many of these features still exist!

Can you name them? Recessional moraine Esker Drumlins Kettle lake Terminal moraine Kettle lakes Outwash

Any time sediment comes into contact with running water, it is SORTED! But when left directly by the glacier, it is unsorted For example, an Essssssker is sssssorted.

a rock or boulder that differs from the surrounding rock and is believed to have been brought from a distance by glacial action. Glacial Erratic: Wildwood, Long Island This is gneiss This is not gneiss

How a kettle lake forms: Kettle Lake, Long Island Lake Ronkonkoma Vertical sorting

Drumlins: elongated hills in the shape of an inverted spoon or half-buried egg formed by glacial ice acting on underlying unconsolidated till or ground moraine. (“a hill of till”)

> FROM Remember me? In which direction was this glacier flowing? TO

Sorted or unsorted? Unsorted Sorted On the bottom Sorted On the bottom Sorted And stratified

Erosional or Depositional?

Erosional or Depositional Roche moutonnee in Central Park

What causes ice ages?

Lovely Long Island…

Long Island Formation Video

Why are south shore beaches sandy and north shore beaches rocky?

Unsorted till Sorted outwash

NY Finger lake formation

Ways to tell glacier flow:

Regents questions:

Base your answers to questions 2 through 5 on map A and map B, and map C below, which show evidence that much of New York State was once covered by a glacial ice sheet. Map A shows the location of the Finger Lakes Region in New York State. The boxed areas on map A were enlarged to create maps B and C. Map B shows a portion of a drumlin field near Oswego, New York. Map C, shows the locations of glacial moraines and outwash plains on Long Island, New York.

2. The arrangement of the drumlins on map B indicates that a large ice sheet advanced across New York State in which compass direction? 3.

4. 6. Explain how the effect of global warming on present-day continental glaciers could affect New York City and Long Island. 5. What is the best evidence that a glacial erratic has been transported?

7.The general shape of the Finger Lakes and the pattern of moraine deposits found across Pennsylvania, New Jersey, and New York are evidence that the continental glacier was advancing from:

The terminal Moraine.