Boundaries
#22 At the edges or boundaries of the plates, the earth's crust is in motion.
Boundaries Divergent Convergent Transform Plates move apart Plates push together Transform Plates scrape past one another
#24 At divergent plate boundaries such as the mid-Atlantic ridge, new ocean floor is created.
Convergent Boundaries 3 types Continental-Continental Collision Oceanic-Oceanic Subduction Ocean-Continental Subduction
Continental-Continental Collision Both crusts push together Crusts are same density so neither plate can sink #26 When continental crust meets continental crust at a convergent boundary, a collision occurs, resulting in folds, faults, and high mountains.
Oceanic-Oceanic Subduction One plate with oceanic crust sinks (subducts) A result of being cooler, older and more dense Crust melts when it reaches Mantle Forms: Deep-ocean ridges Island Arcs Ex. Japan and Philippines
Ocean - Ocean A location where two plates of oceanic crust are coming together.
Subduction Why does one plate usually sink below another plate? The more dense plate sinks below the less dense plate. Continental crust = 2.8 g/cm3 Oceanic crust = 3.0 g/cm3
Oceanic-Continental Subduction Oceanic crust sinks under continental crust Ocean crust = cooler, older and more dense Forms: Deep ocean trenches Coastal mountains
Continent - Ocean A location where continental crust is colliding with oceanic crust
#25 At convergent plate boundaries known as subduction zones, a trench and deep earthquakes mark the zone where a slab of oceanic lithosphere descends into the mantle, and volcanoes and mountain ranges form on adjacent land.
Transform Boundaries Crust isn’t formed or destroyed Crust can move past one another in opposite directions
#27 Transform boundaries are where plates slide past each other #27 Transform boundaries are where plates slide past each other. They connect other plate boundaries and are characterized by earthquakes.
Transform boundary A location where two plates are sliding past one another.
Review What are the 3 types of boundaries and what do they do? Divergent-pull apart Convergent-push together Transform-scrape past one another What are the 3 types of convergent boundaries? Continental-Continental Oceanic-Oceanic Oceanic-Continental