Plate boundaries Flashcards
(12 cards)
What are the four main types of plate boundary?
Destructive, constructive, conservative, and collision.
What happens at a destructive plate boundary?
An oceanic plate subducts beneath a continental plate due to density differences, leading to earthquakes, volcanoes, and ocean trenches.
Name an example of a destructive plate boundary.
Nazca Plate subducting beneath the South American Plate (Andes Mountains).
What occurs at a constructive plate boundary?
Two plates move apart, causing magma to rise and form new crust, resulting in mid-ocean ridges or rift valleys.
Give an example of a constructive plate boundary.
Mid-Atlantic Ridge – Eurasian Plate and North American Plate moving apart.
What happens at a conservative plate boundary?
Plates slide past each other horizontally; no crust is created or destroyed. This can cause strong earthquakes.
Name an example of a conservative plate boundary.
San Andreas Fault – Pacific Plate and North American Plate.
What is a collision plate boundary?
Two continental plates collide, neither subducts, causing uplift and forming fold mountains.
Give an example of a collision plate boundary.
Indo-Australian Plate colliding with the Eurasian Plate – forms the Himalayas.
What type of plate boundary is associated with island arcs?
Destructive boundaries – subduction causes melting and formation of volcanic island arcs.
GPS (measuring plate movement)
GPS - (Global Positioning System) Scientists place GPS receivers on the Earth’s surface. By tracking their positions over time, they can detect even very small movements (as little as a few millimetres per year).
Magnetic Stripes in Ocean Crust (measuring plate movement)
Patterns of magnetic minerals in oceanic crust record Earth’s magnetic field reversals. These symmetrical stripes on either side of mid-ocean ridges help estimate the rate of seafloor spreading over millions of years.
