Oceans Apart -
How These Rocks Will Never Meet Again
Iceland on a Mid-Ocean Ridge
The earth's crust underneath the sea is much younger than the crust of the
continents. Down the middle of most oceans new crust is being formed.
Like on a very slow moving conveyor belt, as even newer crust pushes it
aside, it move towards the continents at about 25km every 1 million years.
. When it reaches the continents the ocean crust is pushed underneath the
continent ( geologists call this process subduction).
So our two little pieces of lava both formed in Iceland are destined to
never meet again. Each rock travelling away from the other until they
disappear under continents on opposite sides of the ocean in 100-200
million years time!
You can read more on this website PLATE
TECTONICS / HOT SPOTS and EARTHQUAKES
AND THE EARTH'S INTERIOR