Canadian Geo demo for the earth Flashcards
How many layers in the earth? and what are they?
3, core, mantle, crust
What is the mantle?
Primarily composed of silicate, (rocks rich in magnesium and iron and poor in silica; mostly peridotites)
What is the core (including inner and outer)?
Composed primarily of a iron alloy (along with abundant platinum group elements)
Two main parts (Inner core and outer core)Outer core
Mostly iron nickel - 90% iron
2250 km thick
1 900 C - 6 000 C
Inner core
Solid nickel
1300 km thick
6 000 C - 10 000 C
The lithosphere consist of the earth’s crust and upper mantle
The division between the crust and the mantle is called the Moho
What is the crust?
The crust is where we live - it is the surface of the earth
The earth is made of two types of crust: Continental and oceanic
Continental crust is thick mostly formed of various types of rock
Oceanic crust is found 5-10KM below sea level and is formed of minerals -mostly magnesium and silicate
What are tectonic plates?
A tectonic plate is a massive irregular shaped slab of rock composed of continent and oceanic lithosphere
The theory about tectonic plates is…
A theory that earth’s outer shell is made up of individual plates that move
This explains why we have earthquakes volcanoes mountains and the formation of a new crust
What is the lithosphere?
The lithosphere is a rigid outer layer of the earth composed of rocks and minerals. Made up of entire crust as well as the upper part of the mantle
Why are tectonic plate significant?
Plate boundaries are important because they are often associated with earthquakes and volcanoes, when earth’s tectonic plates grind past one another, enormous amount of energy can be released in the form of earthquakes
What are the three different types of plate movement and explain what they mean…
Divergent —- move apart
Convergent —- come together
Transform —- rubbing side to side — tends to create earthquake
3 types of convergence….
Continental plate meets oceanic plate: The rocks that make up oceanic plates are denser than continental, therefore, oceanic plates slide underneath a continental plate.
Oceanic plates meet oceanic plates: the older and denser oceanic crust will subduct. This will cause an ocean trench to form.
Continental plate meets continental plate: when two continental plates collide, massive layers of rock are folded, broken, and forced upwards.
Alfred Wegner and the continental drift
Suggested all earth’s land masses collide 300 million years ago to form one supercontinent called pangea
The theory of the drift is called the continental drift. It was proved by the fact that the continents fit together like a puzzle
There were fossils of the same plants and animals were located on two continents
South africa and africa
Ice sheets covered southern Africa, India, Australia and South America 300 million years ago.
