Features of the Seafloor

The Deepest Part of the Ocean

You learned about how subduction zones formed on the Plate Tectonics: Convergent Plate Boundaries page.  Trenches occur along some continents and are the surface expression of a subduction zone. 

Image source:  "plates-jigsaw-puzzle-crust-Earth-types-motion.gif" by Encyclopædia Britannica is licensed under CC BY-NC 4.0

Their length varies depending upon what two plates are colliding, but their width and depth are fairly similar.  The Mariana trench the deepest (11,020 m) and the Peru-Chile trench the longest ( 5900 km). 

How deep is the Mariana Trench?  Deep enough that Mt. Everest would fit with some room to spare.  Visit The Deep Sea for a cool virtual trip to the deepest part of our oceans.

The deepest point in the Mariana Trench is called the Challenger Deep.  As noted in the image above, it's very deep and very remote; so much so that only seven people (6 men and 1 woman) have ever been there.  The most recent was James Cameron in 2012.  Below is a short clip promoting the movie he made about his experience.   As you watch, note the following:

• Conditions in a submersible are very, very cramped.  Imagine being in there for several hours - one way.
• At the beginning of the video, you can see the first submersible to descend into the Challenger Deep - the Trieste.  Is it bigger or smaller than Cameron's Deepsea Challenger (DCV 1)?
• How does this method of exploration differ from the one used by the Okeanos Explorer?  Is one better than the other?
• Would you make this trip?