Structural Map of the Atlantic Ocean

Quick Answer: The Structural Map of the Atlantic Ocean is a geological map of the Atlantic floor that shows the Mid-Atlantic Ridge, the fracture zones that offset it and, typically, the age of the oceanic crust in bands on either side, together with the continental margins. It is used to study seafloor spreading in secondary and university geology.

The Atlantic Floor as Evidence

The Atlantic is the textbook ocean for plate tectonics because it is still opening and has few subduction zones to destroy its record. A structural map of the Atlantic Ocean shows the Mid-Atlantic Ridge winding down the centre, cut into segments by transform faults and fracture zones that run roughly east to west. Maps of this kind usually colour the crust by age, and the bands form an almost mirror-image pattern: youngest along the ridge, older towards the Americas on one side and Europe and Africa on the other.

That symmetry makes the map a working tool, not just a display. Students can measure the distance from the ridge to a band of known age and divide to estimate how fast the ocean has widened, typically a few centimetres a year for the slow-spreading Atlantic. The oldest crust, from the Jurassic, lies next to the continental margins where the ocean first opened, for example off eastern North America and north-west Africa.

Iceland, where the ridge rises above sea level over a hotspot, and the sediment-covered passive margins along the coasts complete the picture.

Specifications

Applications

• Calculating spreading rates from distance and crustal age
• Demonstrating the symmetry of ocean-floor ages about the ridge
• Studying how transform faults offset ridge segments
• Reconstructing the opening of the Atlantic by closing the age bands step by step

Care & Handling

• Mount the map under a clear sheet so students can measure distances with a ruler and wipe-off pen.
• Keep the scale bar visible when framing, since spreading-rate exercises depend on it.
• Store the map flat to avoid creases along the ridge axis.

Why Choose LabEquip

Geology lecturers and senior-school teachers often use it after the Divergence and Oceanic Opening poster, which explains the process this map records. Both are in Educational Charts, and orders can be placed through the LabEquip contact page.

Frequently Asked Questions

Why is the Mid-Atlantic Ridge in the middle of the ocean?

The ridge is where new crust forms as the plates move apart, and spreading has been roughly equal on both sides. As a result the ridge stays near the centre while the continents on either side move away from it.

How do I calculate a spreading rate from the map?

Measure the distance from the ridge axis to a crustal age boundary using the map scale, then divide by the age of that boundary. For example, 100 km of crust formed in 5 million years gives 2 cm per year.

What are fracture zones?

They are long scars on the ocean floor that extend from the transform faults offsetting the ridge. The active part lies between ridge segments; beyond it, the fracture zone is an inactive trace that records the direction of spreading.

Where is the oldest crust in the Atlantic?

Next to the continental margins, where the ocean first opened in the Jurassic, for example off eastern North America and north-west Africa. The crust becomes steadily younger towards the ridge.

Why is Iceland above sea level if it sits on the ridge?

Iceland lies where the Mid-Atlantic Ridge crosses a hotspot, an area of unusually hot mantle that produces extra magma. The thick crust built by that volcanism rises above the sea.

Why does the Atlantic have few deep trenches compared with the Pacific?

The Atlantic is bordered mostly by passive margins, where ocean and continent belong to the same plate, so there is little subduction. The exceptions, such as the Puerto Rico Trench and the South Sandwich arc, lie at its edges.

Last Updated: September 2026