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the earths crust
Transcript of the earths crust
The movement of rock by convection currents in the outer core can help to explain the earths magnetic field. a magnetic field is a region of force around a magnet. for an example of this, when you use a thecompass needle pointing toward north, you are seeing evidence of earths magnetic field. Igneous Rock: The igneous rock is one of the three main types of rocks. Also, the igneous rock is formed when magma or lava becomes solid, the rock can also be formed with or without crystals. and can also be extrusive which is formed above the surface and intrusive which is formed below the surface. Igneous
rocks Sedimentary rocks are formed by sediment that is deposited over time, usually as layers at the bottom of lakes and oceans. Sediment can include minerals, plant and animal remains, and bits of rock.
The sediment is pressured over a long time before turning into solid layers of rock. Sedimentary rocks form layers called strata which can usually be found in open cliffs. Sedimentary rocks are the only rocks which contain fossils this is because sedimentary rocks are partly made of sediments and sediments contain animal and plant remains. The end By Brittney and Josie By Brittney and Josie By Brittney and Josie In this presentation you will learn about the four layers of the earth, the three types of rocks, convection currents and magnetic fields So now you have learned that there are four layers of the earth, each one made up of different rocks and minerals. There are three types of rocks which are each formed differently and you know what magnetic fields and convection currents are. Metamorphic rock: Metamorphic rocks come from transformations of an already existing rock.The process that makes a rock change into a metamorphic rock is when heat,pressure, or fluids change it into another. The original rock before it transformed is called the parent rock! Some examples of metamorphic rock are slate, marble, gneiss and quartzite. Convection Currents Magnetic Field The Inner Core The Crust The Earths crust is the first layer of the earth. There are two types of crust, oceanic crust and continental crust.
The oceanic crust covers around 60% of the earth. It is very thin ( no more than 20 km ) and never older than about 180 million years. This is because everything older than that has been pulled under the continents by subduction. The oceanic crust is made of basalt rock with a thin layer of sedimentary rock on top.
The continental crust covers about 40% of the planet. It is made of granitic rock with a thin layer of sedimentary rock covering most of the surface that you can see. The Asthenosphere Lithosphere The lithosphere is made up of the crust and the upper mantle. It is is split into about 12 huge pieces called plates. It is composed of brittle rock and magma. The crust is about 80 km thick The mantle is the second layer and is right under the earths crust and is the biggest layer of earth.it is semi-molten.The type of rocks that make up the mantle are mostly olivine, pyroxenes, spinel, garnet, peridotite, dunite and eclogite. the temperature of the upper mantle is about 1000 degrees Celsius. the temperature in the lower mantle is about 2500 degrees Celsius.The boundary separating the crust from the mantle is the Moho The Mantle The semi molten part of the mantle just below the lithosphere is the asthenosphere.The asthenosphere is about 180 km thick. It is liquid in places, and solid rock in others.The asthenosphere is located about 6000 miles below the earths surface. It is made mostly of olivine, magnesium and silicon. The asthenosphere can move tectonic plates, this is because a large part of them is fluid and the plates float on the asthenosphere. Many people think the inner core is liquid like magma but it is really solid because of all the pressure coming from the other layers. The inner core is the last layer of the earth and is right in the middle. It is dense and solid and is about 1200 km thick. This layer is made of iron and nickel and is a solid ball of metal. It's also the hottest layer of the earth. The Earth is made up of four layers.The first layer is the crust, the second is the mantle and after that there is the third layer which is the the outer core and right in the middle there is the inner core. Convection currents happen in the Lithosphere. When the rocks within it become hot and molten from the heat of the inner core they start moving. Some of the molten rocks become less dense and float up to the top while the cooler rocks sink back towards the bottom creating a circular motion between the different temperatures And that is what makes convection currents. Metamorphic
rock The outer core is a layer of mostly liquid iron and nickel and some other elements that surrounds the inner core. This layer is about 2,266 km thick and is above the Earth's solid core and below its mantle. The temperature of the outer core ranges from 4400 °C in the outer part to 6100 °C near the inner core. Did you know that it makes up about 30.8 of the earths mass? The Outer Core Interesting facts Did you know? - Hot springs are made from geothermal ground water from the earths crust - We use pumice stones ( from volcanic eruptions ) to smooth the soles of our feet. -Hawaii is created from volcanic eruptions, so each time a volcano erupts there more land is created! - Natural gas does not have an odour. Strong smells are added by humans so they will know when there is a gas leak. -The pumice rock is the only rock that can float in water Our sources www.wikianswers.com www.ehow.com www.kidsgeo.com wikipidia www.sciencekids.com www.rocksforkids.com google images