7. Mapping the Mid-Ocean Ridge System

Expedition Menu

1. Introduction

2. Theory

3. Formation

4. Evidence

5. Earth's Interior

6. Heat Engine

7. Mid-ocean Ridge

8. On the Ridge

9. Seafloor Spreading

10. Magnetic Field

11. Magnetic History

12. Magnetic Patterns

13. The Plates

14. More on Plates



Now we know that heat causes movements of the mantle, mainly the upper mantle, within the interior of the earth. Let's return to the surface at the mid-ocean ridges, which we identified in our transect across the Atlantic.

During and after World War II, oceanographers used echo profilers to measure the water depths and identify some of the features on the seafloor.

Remember echo-profiling, or echo-sounding, is where sound is sent out from the bottom of a ship and an echo is returned from the seafloor.  The resulting profiles of the seafloor, although few in number, were used to make the first modern maps of the seafloor around the world.


This information was used by scientists such as Bruce Heezen, Harry Hess and Marie Tharp to reveal a major, continuous ridge of undersea mountains connected together in all of the major ocean basins.

These underwater mountains connect together to form a ridge the extends from one ocean basin to the next. Here is a "fly-over" along the ridge system called the mid-ocean ridge.


Global Ocean Topography
Global Relief Map available from the National Geophysical Data Center of NOAA


The network of mid-ocean ridges, appear as a yellow strip in the map above, which makes its way through all of the major ocean basins, extending around the globe.

From the map above, it is clear that the mid-ocean ridge is not always located in the middle of the ocean. 

Atlantic Seafloor Profile

Here is the seafloor profile across the Atlantic Ocean that you studied in the previous expedition showing the mid-Atlantic Ridge.

Created By:
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Don Reed
Dept. of Geology
San Jose State University
©Copyright 2008
Last Updated on 
Sept. 22, 2008

What lies inside a mid-ocean ridge?