Inside The Earth Flashcards Preview

Geography > Inside The Earth > Flashcards

Flashcards in Inside The Earth Deck (39)
Loading flashcards...

Facts about the crust

50km deep
Formed when earth cools down
Split into lithosphere and asthenosphere
The lithosphere is split into tectonic plates and move very slowly on a layer called the asthenosphere


Facts about the mantel

2900 km deep
Consists of upper and lower mantle
Upper mantle carry the crust and is viscous
Lower mantle is solid


Facts about inner core

1200km deep
Mostly solid
Creates a magnetic field


Facts about outer core

Temperatures vary from 4000*c to 5,700*c
Made of liquid iron and nickel


Facts about oceanic crust

1-3 miles, very thin basalt rock, same rock as I'm the mantle
Basalt rock is chemically different to mantle basalt, this allows the oceanic crust to be less dense than the mantle basalt, so it floats on top
Under the oceans


Facts about continental crust

Made of 10-50 miles of thick granite
Low density, so it floats high on the mantle
Floats on the mantle because it is less dense rock than mantle basalt
Thicker but less dense
Forms the land


What is the lithosphere

The uppermost layer of the earth. It is cool and brittle. It includes the very top of the mantle and above this is the crust


What is the asthenosphere?

It is part of the earths mantle. It is a hot semi molten layer that lies beneath the tectonic plates


What are tectonic plates

The earths surface is Brocken into large pieces and are called plates


What is the evidence that the earths core is metal

From meteorites


What is the evidence that the earth is hot

Molten lava spewing from active volcanoes
Hot springs and geysers


What is geothermal and how is it produced

Geothermal Is the heat from inside the earth and is produced by radioactive decay and raises the core by 5000 degrees


What is radioactive decay

Some element are naturally unstable and radioactive such as uranium and thorium. Atoms of these elements release particles from their nuclei and give off heat


What is wegeners theory

That the earths continents were once joined together but gradually moved apart over millions of years. Mountains were formed when the edge of a drifting continent collided with another causing it to crumble and fold.


Wegeners evidence for continental drift

The same types of fossilised animals and plants are found in South America and Africa
The shape of the east coast of South America fits the west coast of africa like a puzzle
Matching rock formations and mountain chains are found in South America and Africa


What is continental drift

250 million years ago the land masses of earth were clustered into one super continent called Pangea. As millions of years passed Pangea broke apart and large prices of land slowly moved away to form continents


What is the mesosaurus

A small freshwater reptile that is not able to swim long distances in salt water. Fossils were found in Southern Africa and South America


Stages of continental drift

220 m- one supercontinent called Pangea
200 m- 2 large continents
135 m- when dinosaurs ruled the earth
65 m - dinosaurs become exist


How does the continental jigsaw link to continental drift

Researchers found that continents fit together like a jigsaw. Rock layers in mountain ranges match perfectly when the coastline of countries match up


How does the mesosaurus link to continental drift

Fossils were found in South America and Africa also they couldn't swim in long distances so it shows that the continents were connected


How does coal link to continental drift

Because coal is found in wales which is cold, however coal needs to from in warm climates so The continents must of been connected


Information about divergent plate boundaries

Between oceanic and oceanic crust
The plates move apart from each other
Earthquakes are gentle, volcanoes are less violent than destructive


Info about convergent plate boundaries

Forms between oceanic and continental crust.
Moving towards each other and oceanic is forced underneath
Example is the Andes
Both volcanoes and earthquakes


Info about collision plate boundaries

Forms between 2 continental plates
The 2 plates collide
Big earthquakes and no volcanoes


Info about conservative plate boundaries

2 continental plates
The plates move along side each other
Only earthquakes and no volcanoes


What is a hot spot

A place in the centre of a plate where magma rises. This causes the lithosphere to melt and magma pushes through the crust to form volcanoes


Properties of a shield volcanoes

Broad or wide peak
On divergent plate boundary
Release runny lava that isn't viscous
VEI: 1/2


Properties of composite volcanoes

Convergent plate boundary
Steep slopes
Releases viscous lava


Volcanic explosively index and example and volume of erupted lava

1-small-0.00001 km3- mono inyo craters
2-moderate-0.001 km3- mono inyo craters
3-moderate-0.01 km3 - mono inyo craters
4-large-0.1 km3- mount st Helens
5-very large- 1 km3 - pinatubo, 1991
6- very large- 10km3 - tamboura, 1815
7- very large- 100km3 - Yellowstone caldera 600,000 years ago


How can you reduce the effects of a tsunami

Avoid building sites or infrastructure to avoid being hit with loose bricks
Make a tsunami emergency kit
Move away from beaches and always save yourself first and not possessions