Ice Ages Flashcards
True or false
We are still in an ice age?
True
What is an ice age?
A period of cooling, marked by the presence of glaciers and ice sheets, such as those currently found in Antarctica and Greenland .
Name the cold periods and warm periods of an ice age?
Cold-Glacial
Warm-Interglacial
How many years has the earth been around for?
4.6 billion years
How major ice ages have their been ?
7
The ________ Ice Age being the recent one and the period covers __ Million years of the earth’s history.
Quaternary
2
What period is earth in at the moment?
Interglacial
Inter glacial period refers to the ______ in the longer period of glaciation known as the Quaternary Ice Age.
Interval
How many periods of cooling and subsequent glaciations have there been in the Quaternary Ice Age?
20
What was the most recent glaciation period?
Pleistocene
What is the climate like during a period of glaciation?
Cooler and drier
What is a glaciation?
A cold period marked by glacier and ice sheet cover.
The glaciation began _________,reached its peak _____ and was ended ________.
70000
20000
10000
What is meant by the term Albedo?
The amount of reflectivity surfaces have
Albedo for light and dark surfaces?
Light -high
Dark-low
How Ice ages begin?
- As the climate cools at the start of glacial period, snow fallen in mountainous areas in winter will not melt completely in the following summer.
- snow patches remain, this is then repeated over the years
- glaciers will begin to develop in mountain valleys and on high land surface
- If this continues, valley glaciers will extend into lowland areas and will eventually become large ice sheets covering vast areas of land
What is a glacier?
A glacier is a persistent body of dense ice that is constantly moving under its own weight.
How do glaciers form?
If forms where the accumulation of snow exceeds its ablation over many years,often centuries.
During the Quaternary period ice-sheet growth must have occurred on many occasions. In the Northern Hemisphere, major ice sheets covered both _______ America and Northern _________. Smaller glaciers covered _______ and _______.
North
Europe
Britain
Iceland
Sea levels dropped by 130m and the world’s land area increased by ____. America and ______ as well as Europe and _______.
8%
Asia
England
What is the greenhouse effect?
The greenhouse effect is the process by which radiation from a planet’s atmosphere warms the planet’s surface to a temperature above what it would be without its atmosphere.
Between the 15th and 19th centuries there was significant cooling in the northern hemisphere. The 20th century saw an ______ in temperature especially from 1990. The _______ effect on earth’s temperature is suspected of being responsible for this.
Increase
Greenhouse
What causes Ice Ages?
- Changes in the earth’s orbit
- The tilt of the earth’s axis. Varies between 21.8 and 24.4
- The Time Of year when the earth is closest to the sun.
During an ice age ____ levels change substantially as can fall by as much as 130m.
Sea
