I showed up to the interview dressed to the nines, post double shot latte, and mentally prepped only to be ushered to a hallway lined with chairs and a dozen other potential applicants already waiting their turn. I knew I needed something to make me stand out if I had any chance of securing the job.
Answer 1: At plate boundaries where sea-floor spreading occurs, magma wells up to fill the space created by the plates that are moving apart. Check out this United States Geologic Survey (USGS) educational animation to see visually how it works:
The mid-ocean ridges are one of the three basic types of plate boundaries. We call them divergent plate boundaries because the plate material on either side of the margin is spreading apart. The spreading is a result of forces pulling the oceanic lithosphere on either side of the ridge in opposite directions.The forces are produced by mantle convection and gravity.e call that part of the mantle asthenosphere, to indicate that it is a weak zone, that decouples the plate from the overlying mantle (actually, there is undoubtedly some drag forces that act between the two, but the lithosphere can move independently of the deeper mantle.