Gibraltar Subduction Zone Extending Further Into the Atlantic Ocean: Study

Posted 21 Mar 2024

2 min read

Subduction Zones (SZs) or Benioff Zones are locations of convergent plate boundaries where one tectonic plate is pushed below the other tectonic plate and sinks into the mantle (a process called subduction).

Subduction initiation is a cornerstone of the Wilson cycle (repetitive opening and closing of ocean basins due to the seafloor spreading and subduction respectively).

Subduction produces deep trenches, earthquakes, and volcanoes that often form arcs of islands along the convergent boundary.

SZs in Atlantic
- SZ initiation in mature Atlantic-type oceans that have formed from the breakup of a supercontinent is believed to be difficult.
  - This is because the aged oceanic lithosphere is thick and strong, making it resistant to breaking and bending (both are prerequisites for the start of subduction in an ocean surrounded by passive margins).
- Yet, the Atlantic has two fully developed SZs Lesser Antilles and the Scotia arcs.
- Its 3rd such zone, Gibraltar Arc has significantly slowed over years raising a debate whether it is active or not.
  - According to the latest study, the Gibraltar subduction is still active and it will propagate further into the Atlantic after a period of quiescence.
  - Study also reveals that a subduction zone starting in a closing ocean (Ligurian) can migrate into a new opening ocean (Atlantic) through a narrow oceanic corridor.

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