big boulders left behind by glaciers
they scraped the land down to the bedrock
how did the ice age form the base for skyscrapers in NYC?
how many ice ages have there been in the past million years?
it looked like a bowl because the ice pushed the land down and it digs it out
when the ice was removed from Greenland, what did the island look like and why?
where is the Mendenhall Glacier?
buried mountain peaks in Juneau
What are Nunetaks?
crud- it falls from the valley walls
what are found on the surface of a glacier? how do they get there?
the ice cracks over dips
what causes crevasses to form in the ice?
crystals bigger/air smaller, flat and aligned
what two changes happen to ice crystals as they are buried deeper and deeper in a glacier?
big mounds of soil found at the base of a glacier
where are terminal morraines found? what are they made of?
how many feet a day does a glacier move?
glacier scraped, tells where glacier came from
how were the grooves made at central park? what information did this give scientists?
what group of lakes in NY were made by the last glaciers?
what distinctive shape do glacier carved valleys have?
Malankovitch theory- the earth's orbit does what every 100,000 years?
malankovitch theory- earth's axis does what every 40,000 years?
snow was not melting
how did colder summers give rise to the last ice sheet in Canada?
measures reflectivity, ocean takes longer to cool
what is albeido? how did the effect make the land even colder?
why did the ocean cool slower than the land?
when there is a large temperature difference between Canada (c) and Gulf Stream (w), what is the weather pattern?
1/3 or 1/6
what fraction of the Earth's land was covered by ice during the last ice age?
water erosion, at the top of rocks
what evidence do Sahara desert rocks show about former climate? why could blowing sand not have done this?
river under sand
what did the space shuttle radat show?
change in desert, forests
what do the recent stone paintings show? the older ones?
shrink before, expand after
when an ice age starts what happens to the dry belts above and below the equator? after?
equator, continental drift carry through
what caused african climate to be tropical in dinosaur times?
steadily decreasing by evaporation
what did space shuttle images show happening to lake chad between 1970 and 1980s?