Geography Flashcards
What is the structure of the Earth?
Crust, mantle, outer core, inner core
What is the crust?
The thinnest, coldest layer, it is solid rock that is broken up into pieces called tectonic plates
What is the mantle?
It is a liquid layer made up from magma. Thickest layer of the Earth (2,900km)
What is the outer core?
Liquid layer made from iron and nickel, Approx 2,300km thick, max temperature 5000°c
What is the inner core?
In the centre, hottest part of the Earth (5,500°c), solid layer made from iron and nickel
What was Alfred Wegners theory and what was his evidence?
Alfred Wegner believed that all of the 7 continents today were once all joined together to make one continent (Pangaea). There are 4 pieces of evidence backing up this theory: Jigsaw fit, convectional currents, study of fossils, geological patterns.
What is Jigsaw fit?
If you put all of the continents next to each other to create one big continent you can see that they could’ve once been conjoined.
What is the study of fossils?
An animal called the Mesosaurus only lived in fresh, shallow waters, only 2 places in the world have that, Western Africa and Eastern South America, Mesosaurs’ can’t fly and aren’t able to survive in saltwater so it can’t swim across the ocean.
What are geological patterns?
Glacial striations were found in Africa and South America but obviously glaciers weren’t in warm Africa and tropical South America which means that South America and Africa must have been connected with Antarctica which have glaciers
What are the names of the 7 major plate boundaries?
Pacific plate, North American plate, Eurasian plate, African plate, Antarctic plate, Indo-Australian plate, South American plate
Why are earthquakes and volcanoes often found at plate boundaries?
Plates rip apart at divergent plate boundaries causing volcanic activity and shallow earthquakes
What are convection currents and why are they important?
Convection currents drive the movement of Earth’s rigid tectonic plates in the planets fluid molten mantle
What happens at convergent plate boundaries?
2 tectonic plates come together and one goes under the other one called subduction. At this plate boundary many volcanoes form.
What happens at divergent plate boundaries?
2 tectonic plates move away from each other, magma rises from the mantle to the surface and Earthquakes are common
Impacts of Haiti earthquake
Killed more than 250,000, made 1.5 million people homeless
