The bottom of the sea
Have you ever wondered what’s at the bottom of the sea? Well, it’s land,
of course.
When the sea was formed, water filled the low parts of the earth and
covered much of the land. So, there is land beneath the sea. This land
is much like the land above the sea.
However, the land beneath the sea is really grander than that above!
Beneath the sea are
ranges of mountains that are longer and wider than any mountain ranges
on land. There are longer, deeper valleys, too. In the Pacific Ocean
there are many great valleys in the ocean floor. The water in some
valleys is so deep that if Mount Everest, the highest mountain on land,
were put into one of them, its top would be more than a mile below the
surface!
There are volcanoes on the sea bottom, too. Sometimes these volcanoes
erupt, pouring out tons of red-hot, liquid rock that makes the water
boil. As the liquid rock cools and grows solid, it makes the volcano
taller. Many of the underwater volcanoes have grown so high that they
stick up out of the water. We call the part that sticks out an island.
The Hawaiian Islands are really the tops of huge underwater volcanoes.
All of the broad plains and deep valleys of the ocean floor are covered
with layers of mud. In most places the mud is hundreds of feet (meters)
deep. This mud has been building up for millions of years. It is made up
of bits of sand, clay, and other material that has drifted down from the
surface, together with the shells and skeletons of billions of dead sea
creatures. But beneath all the mud there is hard rock.
