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Introduction to Geology Hello class Today we are going to be talking about one of my favourite subjects, which is Geology. Can anyone of you tell me what does Geology mean? What does the word geology mean?


What is geology ? The best definition for the word geology that I can find is “the science that deals with the Earth’s physical structure and substance, its history and the processes that act on it”


While talking about Geology, it’s best to start from the inside of the Earth and work our way out. There are many different layers of the Earth so we are going to watch this short little video that talks about the different layers inside of the Earth


What are the two types of crust? Is the mantle solid or liquid? What is the core made out of? What is the largest part of the earth? So, after watching that wonderful video that gave you a nice introduction to the different layers of the Earth. We are going now to answer few questions regarding the information. The first question: What are the two types of crusts? The second question: Is the Mantle solid or Liquid? The third question: What is the core made out of? And, finally, the fourth question: What is the largest layer within the Earth?


What are the two types of crust? The first question, what are the two types of crust. Well, there are two types of crust and they are called continental crust and oceanic crust. The continental crust is a granitic crust which has a low density; whereas the oceanic crust is more basaltic and has a higher density.


Is the mantle solid or liquid? The second question: Is the mantle solid or liquid? Well, this is actually a trick question because it kind of behaves a little bit as both. The mantle behave is a viscous liquid it means it’s composed of a plastic flowing rock


What is the core made out of? For the third question: What is the core made out of? This is another little bit trick question because the core consists of two different parts: the inner core and the outer core. The inner core is a solid and it is composed of iron and nickel; however, the outer core is more of a liquid


What is the largest part of the earth? The final question, what is the largest part of the Earth? Out of the different layers of the earth, the mantle occupies the most space


Plate Tectonics So, now we are going to talk a little bit about plate tectonics. Plate tectonics occurs on the top layer of the earth, the crust. Plate tectonics are fragmenting pieces of the crust; that kind of move float around the top layer of the earth


Plate Tectonics Looking at this map of plate tectonics. Can you tell me which plate do you guys live on? Which plate is Spain on?


Plate Tectonics Of course, looking at this map, we can tell that Spain is on the Eurasian plate. This plate consists of both continental crust ad oceanic crust.


Pangea As I mentioned earlier, the plates are constantly in motion. They move very little but they are constantly moving. Each year the plates separate or come together about the distance how your finger nail grows each year. It’s a very short distance but over millions and millions of years it makes up a very large distance


Types of Plate Boundaries Since the plates are constantly in motion, and they are all completely separate from each other, there are boundaries that exist between the plates. There are three types of boundaries that exist: the first one is called divergent boundaries, the second one is convergent boundaries and the third one is transform boundaries


Divergent Boundaries Let’s now talk about divergent boundaries. Divergent boundaries are where two plates are spreading apart. They are separating from each other. At the point where these two plates are separating, there is often a Rift or a Ridge that it is created. There is also a lot of volcanic activity in these zones, A great example is the Mid Atlantic Ridge and Iceland. You can see where the plates have separated and volcanic activity has occurred and, eventually, created an island.


Convergent Boundaries The second type of boundaries is convergent boundaries. This occurs where two plates are coming together. When two plates come together, there is usually a subduction zone that is created. This is when one plate goes underneath the other one. These create tranches usually, like the Mariana Trench in the Pacific Ocean. Also in these spots there is a lot of volcanic activity that is involved. You can see this, for example,where the Pacific plate and the South American plate are coming together. We have an entire mountain range called the Andes which have been created because of this convergent boundary


Transform Boundaries And finally, the third type of boundariesis transform boundaries. These are where two plates are sliding against to each other. One of the main deference between this boundary and the other two is there’s not typically volcanic activity involved, but there are a lot of earthquakes. One great example of transform boundaries is the Saint Andres Fault, in North America


Mid Oceanic Ridge and Rift Valleys This geologic activity occurs where there is a divergent boundary. These formations happen where the earth’s crust is pulling apart. The two best examples of these formations are the Mid-Atlantic Ridge and the East African Rift. The Mid-Atlantic Ridge is where the North and South American plates are separating from the Eurasian and African plates. The East African Rift is an active continental rift zone in Africa. The African plate is splitting into two new plates and will create a new oceanic basin.


Trenches This geologic formation occurs where there is a convergent boundary. These occur at subduction zones where one tectonic plate is going under another tectonic plate. This geologic activity forms a trench. The most famous trench is the Mariana Trench in the Pacific Ocean where the Pacific plate is going under the Mariana plate. This is the deepest point in all of the oceans on earth

Transform Boundaries:

Transform Boundaries Unlike divergent and convergent boundaries, no land is formed nor lost with this type of boundary. This is where two plates slide past each other horizontally. The most famous example on a transform boundary on land is the San Andreas Fault in the western United States. This occurs where the Pacific plate is sliding past the North American plate


Volcanoes Volcanoes are a point on the earth’s surface where magma escapes from within the earth to the earth’s surface. These often occur on divergent and convergent plate boundaries, but they can also occur on Hot Spots. There are six types of volcanoes. They are: fissure volcanoes, shield volcanoes, dome volcanoes, ash-cinder volcanoes, composite volcanoes, and caldera volcano.


Fissure volcanoes Fissure volcanoes are basically a crack in the earths core where the magma escapes. Many examples of this type of volcano can be found in Iceland.


Shield volcanoes Shield Volcanoes are volcanoes that typically do not have very violent eruptions and form with a very gentle slope. The best example of this type of volcano is the Hawaiian Islands.


Dome volcanoes Dome volcanoes are formed by slow eruptions with slow moving lava. These have steep slopes from the cooling lava.


Ash-cinder volcanoes Ash-Cinder volcanoes form from pieces of rock accumulating around the volcano. They often only erupt once.


Composite volcanoes Composite volcanoes are usually tall mountainous volcanoes with violent eruptions. Some famous examples of this type of volcano are Mount Fuji in Japan or Mount Vesuvius in Italy.


Caldera volcanoes Finally Caldera volcanoes are formed after a previous volcano has erupted and the surround land has collapsed into the magma chamber of the original volcano. These volcanoes usually have a very destructive eruption as well.


Hot Spots-Canary Islands These are geologic regions of weak crusts with extra hot mantle underneath. They form magma in plumes which rise to the earth’s surface and create volcanoes. These volcanoes do not occur on plate boundaries. Some of the most famous hotspots are Yellowstone in the United States and the Canary Islands in Spain.


Earthquakes An earthquake is the violent shaking of the earth’s surface resulting from movement on the earth’s crust. Earthquakes often occur on tectonic plate boundaries, but it is possible that they can be caused by humans too. Earthquakes are measured on a seismic scale from 1-no limit. However, the strongest recorded earthquake was a 9.5 in Chile.

Types of Faults:

Types of Faults Faults are fractures in the earth’s surface which cause earthquakes when there is a large movement. There are three types of faults that cause earthquakes. These are called normal faults, thrust faults, and strike-slip faults. In this image you can see how the different types of faults operate.


Ring of Fire The Ring of Fire is located around the Pacific Ocean where a large amount of volcanic and earthquake activity occurs. More than 75% of volcanoes and 90% of earthquakes happen in the Ring of Fire. The worst earthquake ever measured was in this area as well..


Earthquakes and Volcanoes in Spain Volcanoes Earthquakes Even though Spain is located far from the Ring of Fire, it still has some earthquakes and volcanoes. Most of the volcanoes and earthquakes occur in the Canary Islands due to its location above a Hot Spot. The mainland has very little seismic activity and no volcanic activity.


Types of rocks Now I am going to tell you about the different types of rocks. There are three different types of rocks and each type has a different origin. The types of rocks are: sedimentary, igneous, and metamorphic

Sedimentary Rocks:

Sedimentary Rocks These are the most common types of rocks that you can see on the earth’s surface but actually only make up a small portion of the crust. They are made up of particles of sand, clay, and sea creatures that have accumulated in low lying areas on the earth’s surface and in bodies of water. The different materials are then cemented together. Typical types of sedimentary rocks are sandstone and limestone

Igneous Rocks:

Igneous Rocks This type of rock is created by the cooling of magma or lava. If this occurs on the earth’s surface, it is called extrusive. If it cools within the earth, it is called intrusive. The most popular types of igneous rocks are granite and basalt

Metamorphic Rocks:

Metamorphic Rocks Finally, the last type of rocks is called metamorphic rocks. These rocks exist from the transformation of existing rocks through intense heat and pressure. This causes a change in the physical and chemical makeup of the rock. Slate and Marble are both examples of metamorphic rocks

Rock Cycle:

Rock Cycle Finally, the last type of rocks is called metamorphic rocks. These rocks exist from the transformation of existing rocks through intense heat and pressure. This causes a change in the physical and chemical makeup of the rock. Slate and Marble are both examples of metamorphic rocks


What is erosion ? Erosion is defined as removal of rocks and soil by wind, water, ice and gravity. Wind, water, ice and gravity are also known as the agents of erosion. Now let’s take a look at erosion a little more closely

Difference Between Weathering, Erosion and Deposition:

Difference Between Weathering, Erosion and Deposition BREAKS TAKES MAKES Weathering breaks down earth´s surface into sediment. BREAKS Erosion is when sediments are transported. TAKES Deposition is when sediment is dropped by whatever is carrying them s ometimes creating new formations. MAKES


Water Erosion Rain Rivers/Lakes/Oceans This type of erosion can be caused by rain, rivers, lakes, oceans, and even floods. Dramatic coastlines with cliffs and grottos are caused by oceans. Deep river valleys and canyons are caused by rivers. The Grand Canyon was formed by water erosion


Ice Erosion This is caused by glaciers. The glaciers pick up rocks and drag them along the ground under intense pressure. It acts very much like sandpaper on the earth’s surface. It creates large U shaped valleys and even glacial lake basins like the Great Lakes


Wind Erosion There are two types of wind erosion. The first example is when the wind picks up pieces of sand, carries them away and eventually deposits them in a different location. The second is the effect the blowing sand has on anything it comes in contact with


Online Activity Whats on Earth made this? Now we are going to do a little activity. We are going to look at pictures of different rock formations and determine what type of erosion took place

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