Plate Boundaries Goal 2 1 Divergent Boundaries Question

Plate Boundaries Goal 2. 1

Divergent Boundaries Question to Consider - Why do some parts of the Earth have volcanoes and earthquakes and others do not?

Divergent Boundaries Learning Target: I can identify geological activity that occurs at a divergent plate boundary.

What’s really going on. . .

Divergent Boundary ● A boundary where the plates are separating or moving apart. A divergent boundary is considered a normal fault. merlainadiziodiv 1. weebly. com

Geological Processes 1. High Heat Flow - Magma pushes up into the rift valley. slideplayer. com

Geological Processes 2. Volcanoes - Formed by the magma rising at the rift valley www. clipartpanda. com

Geological Processes 3. Earthquakes - caused by the magma breaking rocks on its way to the surface. merlainadiziodiv 1. weebly. com

Divergent Boundary ● The underwater mountain range formed at divergent boundaries in every ocean is… ○ The midocean ridge

Example - Iceland http: //www. uen. org/Lessonplan/preview. cgi? LPid=33078

Convergent Boundaries There are 3 types of convergent plate boundaries - Depends on their location - Ocean/continental - Ocean/ Ocean - Continental/Continental http: //elearning. stkc. go. th/lms/html/earth_science/LOcanada 4/403/html/3_en. htm

Ocean/Ocean Subduction is… ● The process of one plate going under another. It creates a deep-sea trench. ● The underground edge of the subducting plate melts because it is being pulled deep into the Earth’s crust. Melted crust rises to form a volcanic island arc.

Effects of Plate Snapping ● Two effects can occur from Ocean/Ocean plates snapping back ○ Earthquakes ○ Tsunamis

Lesson 2

Ocean/Ocean Boundary ● The types of fault found at a convergent boundary is called ○ Reverse Fault

http: //www. geology. sdsu. edu/how_volcanoes_work/subducvolc_page. html

Examples of Ocean/Ocean Boundaries 1. Mariana Islands 2. Japan 3. Indonesia sablan. house. gov

Ocean/Continental 1. The oceanic plate subducts under the continental plate (because it is more dense) 2. The volcanic mountain range forms on the land above the subduction zone 3. Examples a. Andes Mountains (South America) b. Cascade Mountains (North America)

Continental/Continental 1. A folded mountain range is formed when two continental plates collide. They are both too thick for one to go under the other. 2. Examples a. Himalaya Mountains b. European Alps study. com

The Appalachian Mountains and the Piedmont. . . ● They started as a continental fragment and a volcanic arc about 700 -600 million years ago ○ The continental fragment moved west to become the Blue Ridge Province ○ The island arc moved west and became the Piedmont Province ○ The folded Valley and Ridge (c/c) formed when the North American and African plates collided (most recent at 300 -

Transform Boundaries 1. Transform refers to “moving across” 2. Here, crust is only deformed or fractured 3. No Volcanoes or mountains because there is NO vertical movement of the plates 4. The types of faults formed here are called strike-slip faults 5. Transform boundaries are where you will find shallow earthquakes

Transform Boundaries Examples San Andreas Fault (California) Haiti www. forbes. com

Why do plates move? ● Large-scale motion in the mantle drives the movement of the plates. Definitions (please add to your last vocabulary chart) 1. Mantle - Layer of Earth beneath the crust 2. Asthenosphere - partially molten layer of the mantle https: //honerscience. wikispaces. com/Plate+Tectonics

https: //honerscience. wikispaces. com/Plate+Tectonics Plates move by. . . 1. The rising part of the convection current spreads out and lifts and splits the lithosphere at divergent boundaries 2. The downward part of the convention current creates a sinking force that pulls plates downward at convergent boundaries.

https: //honerscience. wikispaces. com/Plate+Tectonics Plates move by. . . 3. Ridge Push - the force created by the weight of the uplifted ridge which pushes an oceanic plate towards a trench. (subduction zone) 4. Slab Pull - process in which the weight of the subducting plate helps pull the trailing lithosphere into the subduction zone.