1) Mid-ocean ridge
2) At B, molten material from the mantle rises and erupts at the mid-ocean ridge, cools, and solidifies to form new oceanic crust. This process results in the continuous creation of new seafloor, pushing older crust away from the ridge.
3) As new molten material rises and forms new crust at the mid-ocean ridge, the older oceanic crust is pushed outward and eventually moves toward a subduction zone where it sinks back into the mantle.
4) The two kinds of evidence are: (1) patterns of magnetic stripes on the ocean floor that mirror each other on either side of the ridge, showing alternating periods of normal and reversed polarity; and (2) the age of the oceanic crust, which becomes progressively older as you move away from the ridge.
5) At C, the process shown is subduction. It occurs because the denser oceanic crust collides with a less dense continental plate or another oceanic plate, causing the heavier oceanic plate to bend and sink back into the mantle.
6) The "newest" rock on the ocean floor would be found at the mid-ocean ridge.
7) The feature on the ocean floor at C is called a(n) trench.
8) The process that continuously adds new material to the ocean floor is called sea-floor spreading.
9) The process by which the ocean floor sinks into the mantle is called subduction.
10) The chain of mountains that extends into all of Earth’s oceans is the mid-ocean ridge.
Parent Tip: Review the logic above to help your child master the concept of seafloor spreading worksheet.
