Why is earth's surface broken into plates?

1 Answer
Feb 17, 2016

Because large convection cells of hot magma in the mantel keep moving upwards toward the crust and thereby break it up.


Mantle plums of hot magma rise as they heat up and as they do they eventually cool and sink back down again producing a convection cell (a little like a pot of bubbling fudge on the stove). This upward motion encounters the crust and tends to pry it open at divergent plate boundaries - such as the one in the middle of the Atlantic Ocean.

See pic.