Landscape

Yellowstone national park is an alpine glacial landscape and the glaciers are responsible for shaping the beautiful scenery and landscape we see today. The park has been through at least 3 major glaciations. The last period, the Pinedale glaciation period ended about 14,000 years ago. Even though the ice has long been melted, the land still bears evidence of its existence. Glaciers result in depositional and erosional forms, both of which are abundant in the park. Depositional forms from the ablation zone are the result of the glacier front retreating. Till is a mixture of gravel, boulders, clay and sand left behind by a glacier. Often till is deposited in ridges known as moraines. 

A terminal moraine near Bannock Peak. From this ridge of till we know the maximum extent of the glacier before it receded.

http://www.nps.gov/features/yell/slidefile/geology/glacial/Inside%20Yellowstone%20Park/Page.htm

 Erosional forms result from the glacier sliding along the landscape. One of the most telling forms of a glacial landscape are parabola valleys. As the glacier slides along the land, it carves out the landscape into a u-shape, as opposed to the v-shape that rivers carve out in fluvial landscapes.

Can you see the u-shape of the valley?

http://www.nps.gov/features/yell/slidefile/geology/glacial/Inside%20Yellowstone%20Park/Page-1.htm

Hanging valleys are a formed when a glacier in a u-shaped valley at a higher elevation feeds into a glacier of larger volume at a lower elevation. A perfect example of this is Bridal Veil Falls. 

The waterfall is flowing from the hanging valley into the other deeper valley. 

http://lurbano-6.memphis.edu/Classes/index.php/Alpine_glacial_features

As the glacier moved it picked up large boulders and rocks and when the glacier melted, it deposited them across the landscape. These scattered boulders are known as erratics.

A large erratic along the road to Inspiration Point. This particular boulder was carried here 15 miles by the glacier.

http://travellogs.us/Miscellaneous/Geology/Glacial%20erratics/Glacial%20Erratic.htm

http://lurbano-6.memphis.edu/Classes/index.php/Alpine_glacial_features

http://www.geocaching.com/seek/cache_details.aspx?guid=8be93682-6e8c-4cf7-97b4-af94f5d678d8

http://travellogs.us/Miscellaneous/Geology/Glacial%20erratics/Glacial%20Erratic.htm

http://www.nps.gov/archive/yell/insideyellowstone/0043general.htm

Casey Allen class lectures