Layers of the earth

1. Layers of the earth We’re standing on a rock raft floating on lava! spinning around a fusion reaction (sun). ...zooming through space at 492,000 miles/hr around a black hole! Who wouldathunk?

2. Earth is layered like an egg • Crust • Mantle • Liquid outer core • Solid inner core

3. Crust • The crust is the outermost layer of the Earth. It is the familiar landscape on which we live: rocks, soil, and seabed. • It ranges from about five miles thick beneath the oceans to an average of 25 miles thick beneath the continents.  Oceans under our oceans

4. Composition of the crust • Earth's crust is made up of several elements: • iron, 32 % • oxygen, 30 % • silicon, 15 % • magnesium, 14 % • sulfur, 3 % • nickel, 2%

5. Crust (continuted Earths crust in motion • The crust is divided into huge plates that float on the mantle (the next layer of earth). • Hot moving currents (convection currents) within the mantle have broken the crust into blocks, called plates.  • The plates are constantly in motion; • they move at about the same rate as fingernails grow. • Earthquakes occur when theseplates grind against each other. • They create mountains when they collide together. We’ll talk more about this later. Bedrock and skyscrapers. How are skyscrapers able to be built so tall without falling over?

6. Mantle • Found under the crust • Largest layer • Mostly solid, but behaves like a very thick liquid. • Has the texture of hot black road tar. • 1,800 miles thick • 2 layers. • Hot layer (outer layer) • Hotter layer(inner layer) • Intense heat causes the rocks to rise. They then cool and sink back down to the core (convection current). • When the mantle pushes through the crust, volcanoes erupt. Volcanoes

7. Composition of mantle • Made of rock that is rich in: • Magnesium • Iron • The 7 continents are composed of relatively light blocks that float high on the mantle, like gigantic, slow-moving icebergs. • Seafloor is made of a denser rock called basalt. This is why the oceans are able to fill with water. • Basalt is a very hard rock that formed from volcanoes

8. The earth’s core Does the moon have a liquid core? • At the center of the earth is the core. • 2 parts: • Inner core: The solid core of iron has a radius of about 760 miles. 12,000 degrees Fahrenheit • Outer core: Liquid core composed of nickel 1,355 miles thick.

9. The earth’s core Northern lights • Cool fact:Theinner core spins at a different speed than the rest of the planet. This is thought to cause Earth's magnetic field. • Aurora Borealis (northern lights) • Caused by solar winds (from sun) traveling at 1 million miles/hour and follow the magnetic field.

10. Plate Tectonics! • The earth’s surface (crust) is broken into large, rigid pieces that move with respect to each other. • Floating on top of the mantle. • The movement of the plates causes: • Formation of volcanoes • Mountains • Earthquakes • Causes the continents to move slowly • Pangea

11. Major tectonic plates • Scientists have identified 15 major plates on earth. • Some are very large. An entire continent can be on one plate. • Some are very small. • We live on the “North American Plate” • Some others include: • Eurasian plate • African plate • South American plate Tectonic Plates

12. Why do the plates move? • As we stated before, it’s due to CONVECTION CURRENTS. • As fluids heat up, molecules spread apart (they’re moving faster). • Fluid becomes less dense • As fluids cool down, molecules move closer (they’re moving slower) • Fluid becomes more dense • Warm fluids rise upwards and cooler fluids move downwards.

14. Joke of the day:What did one tectonic plate say to the other tectonic plate when it accidentaly bumped into it? • “Sorry, my fault” HA!

16. Plate boundaries • How do we describe the movement of tectonic plates? • By the way that they move in relation to each other. • 3 types: • Divergent boundaries- When 2 plates move away from each other. • Convergent boundary- when 2 plates move toward eachother • Transform boundary- When 2 plates slide past eachother.

17. New ocean floor, underwater volcanoes (Hawiian islands), or valleys • Creates new mountains and volcanoes • Earthquakes

18. Geosphere • Refers to the solid part of the earth • Basically the crust. The rocks and soil on land and beneath the oceans. • Materials in geosphere: • Soil • Rock • Metal -all made of smaller particles…

19. Minerals • Naturally occurring, inorganic solids that have crystal structures and definite chemical compositions. • Cannot be made by people • Materials that were once alive are considered organic and cannot be minerals • Must be solid • Examples: • Diamond • Quartz • hematite

20. Rocks • Naturally occurring solid composed of minerals and sometimes other organic matter. • Minerals are the building blocks of rocks. • 3 major types of rocks: • Igneous rocks • Sedimentary rocks • Metamorphic rocks.

21. Igneous Rock • Form directly from the cooling of magma(liquid rock, lava) • When the magma cools off and hardens, it turns to igneous rock.

22. Sedimentary Rock • Form when forces such as water, wind, and ice break down rocks into small pieces called sediment. • These little bits of our earth are washed downstream where they settle to the bottom of the rivers, lakes, and oceans. • Layer after layer of eroded earth is deposited on top of each. These layers are pressed down more and more through time, until the bottom layers slowly turn into rock.

23. Metamorphic Rock • These rocks “morphed” into a new type of rock. • They were once igneous or sedimentary • Form under extreme temperatures and pressure. • Usually when tectonic plates get buried deep under earth and volcanoes form.

24. Rock Cycle • It may not be as obvious as the water cycle but all the rocks on earth are in a continuous cycle as well. • It’s a series of processes that transport and continually change rocks into different forms. • Some of the changes happen deep within the earth. • Some happen on the surface of the earth

25. Rock Cycle (continued) • Cooling and Crystalization • When magma flows out of the earth’s surface it’s called lava. • When lava cools it turns into igneous rock. • Uplift • Process that moves large bodies of earth to higher elevations. • Rocks that form deep within the earth can eventually be exposed at the surface. • Mountain building.

26. 3. Weathering and Erosion • Rocks that are exposed to weather break down into sediment. • Can be seen in mountains where uplift has occurred. • We can see this on Presque Isle in Marquette. • Reason that we have beaches (sand)

27. 4. Deposition • The agents of erosion lose their energy and slow down or stop. Either falling from mountains or deposited into lakes from rivers. • More and more layers form over time.

28. 5. Compaction and cementation • As more and more layers of sediment are deposited, their weight pushes down on underlying layers.