Unit One Flashcards
Name the layers of the earth, starting from the centre.
The inner core, outer core, mantle and crust.
What is the inner core like?
Solid iron and nickel.
What is the outer core like?
Liquid iron and nickel.
What is the name given to where the crust meets the mantle?
Where crust meets the solid mantle is called the ‘lithosphere’.
What is the mantle like below the lithosphere?
A dense, mix of solid rock and molten rock, like very thick, dense, hot porridge.
What is the lithosphere like?
It is made of two types of crust; oceanic and continental crust.
What causes tectonic plates to move?
Tectonic plates are moved by ‘convection currents’ in the mantle.
How do convection currents cause tectonic plates to move?
Magma heated near the core rises, as it rises it loses heat, spreads out, sinks towards the core. As it spreads it pushes and pulls the plates on top of it.
What is oceanic crust like?
Oceanic crust is younger, thinner, denser and made of basalt, which is a dense igneous rock. It is usually between 6-8kms thick.
What is continental crust like?
Continental crust is older, thicker, less dense and made of granite, which is a low density igneous rock. It is usually between 30-50kms thick.
How fast do tectonic plates move?
Usually between 3-5cms per year.
Name the four types of plate boundary.
Constructive, conservative, destructive subduction and destructive collision.
What happens at constructive plate boundaries?
Plates pull apart, magma rises forming volcanoes. Lava flows cool and solidify to create new land. An example is Iceland, on the Mid-Atlantic ridge, where the Eurasian and North American plate are pulling apart.
What happens at conservative plate boundaries?
Plates move alongside one another, in the same or opposite directions. Crust is neither created nor destroyed. Tension is built up in the crust, which is released in earthquakes. An example is the San Andreas fault in California, USA. You do not get volcanoes on this type of boundary.
What happens on destructive subduction plate boundaries?
Continental crust and oceanic crust push into one another. Oceanic crust is denser and heavier so it subducts underneath the continental crust. Earthquakes and volcanoes happen at these boundaries. An example is Mt St Helens in the USA.
What happens at destructive collision plate boundaries?
Continental crust and continental crust push into one another but as they are the same weight and density there is no subduction. They push each other upwards, forming mountains. An example is the HImalayas, at the boundary between the Eurasian and Indian plates meet. Large earthquakes are experienced on these boundaries.
What is the Greenhouse Effect?
It’s the way that gases in the atmosphere trap heat from the sun.
What is Global Warming?
It is the increase in average global temperatures, caused by human activity.
Can you name two periods of climate change in the past?
Medieval Warm period, roughly between 1000AD and 1250AD and the Little Ice Age, roughly between 1500AD and 1800AD.
What is the UK’s climate like today?
The UK has a temperate maritime climate, which means that it is mild, with changing seasons and has moderate rainfall.
How did climate change contribute to species becoming extinct at the end of the last Ice Age?
When temperatures increased at the end of the last Ice Age, animals such as Wolly Mammoths and Sabre-tooth Tigers couldn’t adapt to their changing environment.
What happened in the Medieval Warm Period?
Vikings began to explore further north, into Greenland and the far north, as sea ice melted. They colonised whole new lands, but weren’t able to cope when climate began to cool again, and settlements in colder areas failed.
What happened in the Little Ice Age?
Winters were very cold and growing seasons were much shorter. People’s leisure activities changed, with Winter Fairs and Ice Skating on rivers were common. Farmers had to change the crops that they grew as seasons and land changed. The people of Iceland changed their diet to one largely consisting of fish.
