internal dynamics

Autora: Marta García T.

The interior of the Earth is hotter than the exterior (6000 ºC). The temperature increases by about 33 ºC for every Km in depth.

The lithosphere (cold and solid) floats over the asthenosphere (hot and molten).


1. Can you guess what is happening in this image?

2. What would happen with a floating piece of cork?


The lithosphere is broken into sections called Tectonic Plates.

What do you think is going to happen in these conditions?


Tectonic Plates move slowly over the asthenosphere, due to the convection currents (they carry plates).


Investigate about Tectonic Plates…

1. How many tectonic plates are there?2. What are their names?3. How many types of plates can we find?4. How many types of movement can plates have?

http://www.brainpop.com/science/earthsystem/platetectonics/




• There are twelve main tectonic plates.• There are three types of plates:

– Continental Plates: plates below the continents.– Oceanic Plates: plates below the oceans.– Mixt Plates: plates below oceans and continents.

Can you give an example for each one?• Plates can move in three ways, carried by the

convection currents:

– They can move apart.– They can move together.– They can move sideways past each other.


So, there are three types of PLATES BOUNDARIES:

1. Divergent Boundary: plates move apart.

2. Convergent Boundary: plates move together.

3. Transform Fault Boundary: plates move sideways past each other.


• Divergent Boundaries: as plates move apart, new material is erupted to fill the gap. The fissure between plates is called Rift.

http://www.juntadeandalucia.es/averroes/manuales/tectonica_animada/tect_swf_files/01[1].swf


http://www.juntadeandalucia.es/averroes/manuales/tectonica_animada/tect_swf_files/01%5B1%5D.swf

Convergent Boundaries: if plates have different density, the more dense slides under the less dense. This area is called Subduction Zone.

Volcanoes and volcanic island are formed.http://www.juntadeandalucia.es/averroes/manuales/tectonica_animada/tect_swf_files/02[1].swf

http://static.howstuffworks.com/flash/volcano-eruption.swf


http://upload.wikimedia.org/wikipedia/commons/2/29/Active_Margin.svg

If plates are both continental plates, none of them slides under the other one. They collide and mountains are formed.


Transform Fault Boundary: plates slide past each other.


CONVERGENT DIVERGENT TRANSFORM FAULT

VOLCANOESEARTHQUAKES

CONVERGENT DIVERGENT TRANSFORM FAULT

VOLCANOES It depends YES NOEARTHQUAKES YES YES YES


If you look at a map of the world, you may notice that some of the continents could fit together like pieces of a puzzle.


About 200 million years ago, all the continents on the Earth were one huge "supercontinent" surrounded by one enormous ocean. This gigantic continent was called Pangaea.


Pangaea slowly broke apart and spread out to form the continents we know today. http://www.eduplace.com/kids/socsci/ca/books/bkf3/imaps/AC_01_005_drift/AC_01_005_drift.html


A volcano is a place on the surface of the Earth where molten rock (Magma), solids, and gases are ejected through the crust.

When magma reaches the surface, it is called Lava.


Parts of a volcano:

Go to this web and look for information about the three main types of volcanoes:

http://www.guardian.co.uk/world/interactive/2007/jan/25/volcanos


Volcanoes eject different materials:

◦Liquids: Lava (molten rocks).◦Gasses: CO2, SO2, CH, H2O.◦Solids: called Piroclasts. Depending on their

size, they have different names:

Bombs: until 1m diameter. Lapilli: gravel. Ash: (the smallest).


Look at this map. You can see plates boundaries and main volcanoes locations. Just to think a bit….

Why can we find volcanoes far away from plates boundaries? How do you think they are formed? Why are they in line?

http://www.wwnorton.com/college/geo/egeo/flash/2_10.swf


An earthquake is a violent trembling of the Earth’s crust. When it is origined under the sea, it is called a Seaquake, and may produce a Tsunami.

The point in the crust where the earthquake is origined is the Hypocentre.

The point on the surface which is directly above the hypocentre is the Epicentre.

http://www.cienciasnaturales.es/TERREMOTO.swfAutora: Marta García T.

They are produced by the plates’ movement. Earthquakes are measured on the Richter

Scale, numbered from 1 to 10, which reflects the amount of energy released at the hypocentre.

http://www.ucoerm.net/public/terremoto.swf

The energy travels through the rocks in seismic waves. There are four types of seismic waves: P, S, R, L.http://cienciasnaturales.es/TERREMOTOSONDAS.swf


Seismographs are instruments that record earthquake waves. They make a graphic called Seismogram.

http://www.ucoerm.net/public/terremoto.swf


They are rocks formed when magma cools and solidifies. This process is called Magmatism. There are two types of igneous rocks:

◦ Plutonic: formed when magma cools and solidifies slowly beneath the Earth’s surface. So, they have large, visible crystals.

◦ Volcanic: formed when lava cools and solidifies quickly on the Earth’s surface. So, they have very small crystals (sometimes non visibles).


http://geology.com/rocks/igneous-rocks.shtml

Granite Andesite Obsidian Diorite Pumice Basalt


They are formed from the transformation of other rocks, due to increases in temperature or pressure. This process is called Metamorphism and is very, very slow. There are two types of these rocks:

◦Foliated: formed due to pressure increases.◦Non Foliated: formed due to

temperature increases.


internal dynamics

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