Our Community Is Moving

1. Our Community Is Moving With GPS (Global Positioning System) geoscientist are able to see how the surface of the Earth is moving. GPS consists of 24 satellites that go around the Earth. Receivers on Earth can calculate the location at stations. Geoscientist have set up targets all around world to monitor the movement of lithosphere plates. Steel tripods mounted in the ground act as targets. On top sits a high-precision GPS receiver. The receiver then measures the distance to four or More GPS satellites and uses stored data on satellite location to compute the location of the target. Changes in horizontal and vertical positions can be detected within several millimeters. All the data collected from stations all around the world confirm that the surface of the Earth is moving.

2. Plate Movements and Their Interactions at Plate Boundaries 3 types of Boundaries Divergent Boundaries Convergent Boundaries Transform Boundaries

3. Divergent Boundaries Where two plates move away from each other. Involves Mid-Ocean Ridges A mid ocean ridge is where mantle athenosphere rises slowly upward. As it rises, some rock melts to form magma. The magma then rises, because it is less dense than the rock. It forms volcanoes in the central valley of the mid ocean ridge. Continents move farther and farther from the spreading ridge.

4. + In both the north and southern Atlantic ocean there isn’t a plat boundary along the coastlines on either side of the ocean. This means that the Atlantic is getting wider as time passes by. If you were to go back in time there wouldn’t be an Atlantic Ocean. -A new ocean begins when mantle material begins to move upward beneath a continent. The lithoshere of the continent goes upward and is stretched sideways. Then it breaks along a crack and forms a rift valley. As it gets wider, the ocean invades the rift.

5. Convergent Boundaries • When two plates are moving toward each other. One eventually goes under the other. One plate stays at the surface, and the other plate dives down beneath it at some angle. This is called subduction. Where the downgoing plate bends, a deep trench is formed on the ocean floor. As the plate later keeps on sinking, magma is produced and rises to form a volcanic arc. 3 Places Where This Happens -Two Oceanic Plates -Edges of Continents -Two Continental Lithospheric Plates

6. Transform Boundaries • Where plates slide past one another • Land moves out in opposite directions. Like cutting it in half and moving one to the right and the other to the left.

7. Earth’s Interior Structure and the Flow of Matter and Energy within the Earth

8. Density • The mass per unit volume of a material or substance

9. Density Varies within the Earth • Rocks deep in the Earth are more dense than the same rock when they are at the surface. The Most dense material should be at the center of the Earth.

10. 4 Main Layers of Earth • Inner core • Mantle • Outer core • Crust

11. The Core is made up of mostly iron, its so hot that the outer core is molten • The Inner Core is also hot but because of so much pressure it remains solid. • Mantle is where the most mass is. The mantle is composed of iron, magnesium, and aluminum silicate materials. The mantle is solid rock at 1000 c, but it can deform slowly in a plastic manner • The Crust is much thinner than the other layers, and it is made of the least dense rocks.

12. Thermal Convenction A pattern of movement in a fluid caused by heating from below and cooling from above. Thermal convention transfers heat energy from the bottom of the convection cell.

13. Mantle Convection Material is heated at the core-mantle boundary. Rises up, spreads out horizantally, cools, and sinks back into the interior.These might provide the driving force that moves the lithospheric plates.

14. Building Features on the Earth’s Sruface Plate Tectonics, tectonics comes from the Greek word tekton,which means builder. It refers to the building of the features on Earth’s surface.

15. Features on Earth Surface from Plate Tectonics • Oceanic Trenches • Volcanoes • Hot spots • Mountain ranges • Growth of continents • Earthquakes

16. Arrangement of continents and oceans in the goelogic past Geoscientist have reconstructed the break up of Pangea.

17. Using Evidence of… • Magnetic striping on the ocean floor • Ages of ocean floor basalts • Outlines of continental plates • The location of similar fossils and rock types on widely spread continents

18. Pangea started to break up about 200 million years ago. As continental rifts began to open and oceanic crust began to form. Pangea continued to rift apart, and oceanic crust then formed between the northern and southern continents. Also between antartica and Australia and between Africa and S. America. India Started to separate from antartica and headed upward.