Evidence of Plate Tectonics
Fossils of the same species are found on the coasts of South America and Africa. What does this support?
The continents were once joined together.
What boundary forms when two plates pull apart?
Divergent boundary
What feature forms at a divergent boundary on the ocean floor?
Mid‑ocean ridge
A family moves near a transform boundary in California. What natural disaster is most likely there?
Earthquakes
What process forms new seafloor at mid‑ocean ridges?
Seafloor spreading
A research ship finds that ocean‑floor rocks get older as they move away from a mid‑ocean ridge. What theory does this support?
Seafloor spreading
What type of fault is most common at a divergent plate boundary?
Normal fault
What feature forms when two continental plates converge?
Mountain range
Double Jeapordy
Why are there many volcanoes in the Ring of Fire?
What process pushes old seafloor back into the mantle?
Subduction at deep‑ocean trenches
According to radioactive dating of seafloor rocks, which location is youngest?
Closest to the mid‑ocean ridge
Double Jeapordy
If spreading occurs faster than subduction, what happens to Earth’s size?
What feature forms where plates collide and one is forced downward?
Deep‑ocean trench (subduction)
What occurs where two plates slide past each other?
Earthquakes (transform motion)
What process moves tectonic plates by circulating hot mantle material?
Mantle convection currents
What evidence shows the Atlantic seafloor is spreading?
Rock samples farther from the ridge are older
What boundary causes mountains to form when two continental plates meet?
Convergent boundary (same density → mountain building)
Which plate boundary is most likely to cause a rift valley?
Divergent boundary
When older, cooler oceanic crust meets younger oceanic crust, what occurs?
The older plate subducts under the younger plate
What boundary creates new igneous rock on the ocean floor?
Divergent boundary (oceanic crust separating)