Earth’s Forces
What is Plate Tectonics? Movement of large plates (crust) above magma in the mantle What proof is there? Fossils, plants and animals along coastlines of separated continents
What is the theory of Continental Drift? 1912 theory by Alfred Wegener Earth once had a supercontinent (all connected) Called “Pangea” What is the theory of Continental Drift?
What type of movements are there? Divergent Convergent: Subduction Convergent: Collision Transform
Sub-Duction Zone Two tectonic plates meet and one bends and slides under the other. Continental and oceanic plates
Convergent: Collision Continent-continent Collide without subducting India slammed into Asia; ex: Himalayas
Divergent Boundaries Oceanic plates move apart and create cracks in ocean floor Magma rises from mantle through cracks; forms new crust of igneous rock. Example: Sea Floor Spreading
Transform Boundary Two plates move horizontally Friction in rocks causes plates to lock. Rocks fracture and the sudden release of energy is what we feel during earthquake. Ex: San Andreas
Volcanoes What is the Ring of Fire? Most volcanoes located around the rim of the Pacific Ocean
How does erosion shape our land? Bellringer #6 How does erosion shape our land?
What is Weathering? Types of Weathering are… Mechanical – When rocks and other minerals are broken into smaller pieces. Chemical – When minerals are changed completely when they mix with water and air. Like metal changing to rust.
What is Wind Erosion? Loess is wind-blown silt, sand, and clay. Can form sand dunes 100’s of feet deep!
What is Water Erosion? Precipitation Mudslides Avalanche
What is Glacial Erosion? Glaciation – changes in a landform made from a slowly moving sheet of ice (glacier) Moraines – rocks left behind after a glacier moves Creates new valleys, hills, or ridges
ASSIGNMENT What is this force? EROSION WEATHERING What is this force? How does it change the physical surface? What are the different ways this external force can occur? What type of landforms does it affect? What are some examples?