RHNC+1.4

toc


 * mid ocean ridge** - longest chain of mountains
 * sonar** - records objects with sound waves
 * sea floor spreading** - process that adds new material to ocean floor
 * deep ocean trenches** - deep water canyons
 * subduction** - when ocean floor sinks beneath a deep ocean trench

Evidence for sea floor spreading

 * evidence from molten material
 * toothpaste shape rocks
 * must have erupted over and over
 * Evidence from Magnetic stripes
 * reversals of magnetic fields
 * rocks lie in patterns of magnetic stripes
 * evidence from drilling samples
 * farther away from ridge older; closer=younger