Convergent Boundaries
Dec 22, 2015
What happens at Convergent Boundaries?
(Continental plate – Continental plate)• A collision boundary (continental to continental) is when two plates carrying continents are welded together to form one continent– Will not subduct
(go under)– Creates folded
mountains– Regional
metamorphism occurs here
What are Examples of a Continental Plate converging with a continental
plate• Himalaya
mountains (India + Asia)
• Ural Mountains (Europe + Siberia)
• Appalachian mountains (N.A.+Europe) – now split from a spreading center known as the mid-Atlantic ridge
What is a subduction zone Boundaries?
• A subduction zone is when an oceanic plate plunges beneath another overriding plate
• Subducting zones create the deepest places on the ocean floor called deep-sea trenches
Subduction zone
What is a convergent Boundary?(Oceanic-Continental)
• Oceanic crust subducts under continental crust plate---MORE DENSEPLATE GOES DOWN!
• Volcanoes form on the continent – volcanic arc
• Deep sea trench is formed
O-C Convergent Boundary cont’d
• deep sea trench results• mountain chain and
volcanoes form inlandon overriding plate
What happens at Convergent Boundaries
Oceanic-Oceanic crustWhen two
oceanic plates converge:
1) Deep- sea trench is created
2) A chain of volcanic islands is formed-island arc
Island arc
Deep-sea trench
Convergence-Mariana Trench• Deepest location on Earth’s
surface ~6.8mi
Farther below sea level than Mt. Everest is above it!
What Other Phenomena that occur in all types of subduction
zones?
• Earthquakes occur at greater depths
• Lithosphere is destroyed (it melts)
What happens at Transform-fault Boundaries?
• Lithospheric plates slide past each other
• Example: San Andreas Fault
• A fault is a break in Earths crust along which movement has occurred– *shallow earthquakes
occur here
Transform Boundary• The San Andreas Fault, California• N. American plate
and Pacific plateare sliding pastone another
• SW Ca. –Pacific Platemoving NW
• Rest of U.S. is onN. American platemoving SE
Earthquake Trail, San Francisco area, California
ReviewReview
What is a fault?
What happens at Transform-fault boundaries?
Are earthquakes at sliding boundaries (transform-fault ) deep or shallow?
How do plate interactions affect the world?
Tectonic Plates grow and split at Mid-Oceanic Ridges (sea floor spreading); they melt and shrink at subduction zones
ReviewReviewWhich type of crust is involved in a collision
boundary?
What feature is created there?
Which type of rock is associated with a collision boundary?
What is an example of a collision boundary?
ReviewReviewWhat is a subduction zone?
Which type of crust will not subduct?
What feature are formed at a subduction zone?
What feature is formed on the continent at subduction boundaries?
ReviewReviewWhat is an example of a volcanic arc?
What type of volcanic chain is formed when two oceanic plates converge?
What is an example of a place formed by two oceanic plates colliding?
Where do earthquakes occur in a subduction zone?