1.1.2 Option B OCR - Glaciated Landscapes

cryosphere

the frozen part of the earth’s surface (e.g. polar ice caps, continental ice sheets, glaciers, sea ice, permafrost)

glacial landscape areas

1. Andes - located on the West coast of South America

2. Rockies - North West coast of North America

3. Himalayas - Central Asia, North of India

glacial periods temp fluctuations

global temperature fluctuates between 5°C and 6°C between glacials (cold periods, e.g. the Pleistocene) and interglacials (warmer periods, e.g. Holocene)

the different types of glaciers

• ice sheets

• ice caps 

• ice shelf

• valley glacier

types of valley glacier

• niche

• corrie

• piedmont

• outlet

glacier

it is a permanent body of ice (on a human timescale), consisting largely of recrystalised snow which shows evidence of downslope or outwards movement due to the pull of gravity

what are ice sheets?

• they are the largest glaciers

• they are continental glaciers, with a large flat appearance

• covers large areas of land

• e.g. Greenland and Antarctica which cover 96% of all glacial ice on earth

what are ice caps?

• they sit across mountains and mountain ranges

• they have exposed summits of high mountains (called nunataks)

what is a valley glacier?

• the most common glacier 

• it is a flowing stream or tongue of ice

• it is restricted by surrounding relief mountains

• carves out landscapes

what is a niche?

a small version of a corrie which occupies hollows on North facing slopes in the Northern Hemisphere

what is a corrie?

masses of ice which fills armchair shaped hollows in mountains. they can overspill and fill valley glaciers.

aspect

the direction something faces in

piedmont

• can make up the bottom stretches of a valley glacier.

• the ice becomes broader and shallower as it spreads out onto the land.

• it looks like a spoon

outlet

• is a valley glacier that has its source from a icesheets

• e.g. the Beardmore on Antarctica (extends over 200km and is up to 20km wide) 

what is a glacial environment?

an environment which contains snow and ice all year round

active glacial environments

means the environment is currently covered in ice

relict glacial environments

old, no longer covered in ice

process of diagenesis

• glaciers form when snowfall in 1 year remains frozen throughout the year

• fresh snow falls on top of last years snow

• snow that survives a summer is called névé/ firn ice which has a density of 0.4g/cm³

• fresh snow has low density

• each layer of fresh snowfall compresses and compacts the layer beneath, squeezing out air

• low density snow becomes higher density ice

• glacial ice has a density of 0.83 - 0.94g/cm³