04. Oceanic Trench and Ridges

Refer to the following article on the Mariana trench published on ST.

What is an oceanic trench?

How is an oceanic trench formed?

Where is the oceanic trench mentioned in the article?

Who was the one mentioned in the article?

When did he managed to reach the deepest part our earth surface?

The deepest place on earth - the Mariana Trench.

Activity:

• With the aid of a well-labelled diagram, explain the formation of an oceanic trench and volcanic islands.

How is an oceanic trench formed?

Where can you find an oceanic trench?

What other tectonic landforms are found near an oceanic trench?

Watch this video on sea floor spreading and formation of oceanic ridge.

• With the aid of a well-labelled diagram, explain the formation of an oceanic ridge.

How is an oceanic ridge formed?

Where can you find an oceanic ridge?

What other tectonic landforms are found near an oceanic ridge?

Why are the age of the rocks older away from the oceanic ridge?