3. What areas of the
Atlantic seafloor have the youngest rocks? ...the oldest?
4. How old are the very oldest rocks on
the Atlantic seafloor? Where are they?
5. Based on the age of the oldest rocks
between South America and Africa, when did the two continents
The location of the youngest rocks on the seafloor shows
that new rocks form in the middle of the ocean, the
same location as the shallowest area of the ocean. This
line of new, relatively shallow rocks is known as the
mid-Atlantic Ridge. New rock material added to the edges
of the South American and African Plates at the mid-Atlantic
Ridge has separated the two continents.
Imagine what the ocean floor would have looked like
150 million years ago, when all the rocks younger than
that did not yet exist. How would things have changed
by 80 million years ago? Visualize how the Atlantic
Ocean floor started separating the continents and grew
to its present size.
6. Based on ages of the oldest rocks in
the North and South Atlantic, describe how and when
the Atlantic Ocean formed, and how its shape has changed