Subduction zone detected beneath Gibraltar Strait

  • Scientists in Portugal have discovered a disturbing revelation about the fate of the Atlantic Ocean, pointing to a possible ‘Ring of Fire’ (a Subduction Zone).
  • Researchers warn that the Atlantic may be on the verge of closing owing to subduction activity. 

About Gibraltar Strait

LocationIt connects the Atlantic Ocean to the Mediterranean Sea, separating Europe’s southern Iberian Peninsula from Africa’s northern coastline. 
WidthAt its narrowest point, it measures around 13 kilometres (8.1 miles).
DepthVaries, with the deepest point reaching approximately 300 metres (984 ft).
FormationThe convergence point of the Eurasian and African plates.Around 5.33 million years ago, during the Messinian salinity crisis, the Atlantic Ocean overcame the barrier separating it from the Mediterranean Sea, causing a catastrophic deluge known as the Zanclean flood.The current shape and depth of the strait have been impacted by tectonic movements and erosional processes throughout geological time.
Historical SignificanceServes as an important marine route for trade and military objectives.
DisputesGibraltar is a disputed territory between Spain and the United Kingdom. It is now under British administration. 

What are Subduction Zones?

  • Subduction zones form at convergent plate borders, where two tectonic plates move closer together.
  • This convergence typically occurs between an oceanic plate and a continental plate, or between two oceanic plates.
  • Subduction Process: 
  1. When two tectonic plates collide, the denser oceanic plate is pushed beneath the less dense continental plate or another oceanic plate.
  2. Partial Melting: As the oceanic plate descends into the mantle, it generates great heat and pressure, resulting in partial melting of the mantle material.
  3. Volcanic Activity: Molten material created during the subduction process rises through the Earth’s crust, causing volcanic eruptions at the surface.
  4. Volcanic Arc Formation: These eruptions frequently occur in long chains known as volcanic arcs that run parallel to the subduction zone. For example, consider the Andes in South America and the Cascade Range in North America.

Implications for this Activity

  • Earthquakes in subduction zones can be especially damaging, triggering tsunamis due to the displacement of massive volumes of water.
  • Trench Formation: A subduction zone’s surface representation is frequently a deep oceanic trench where the descending plate bends and plunges into the mantle.
  • Mountain construction: Over time, the ongoing subduction of oceanic crust can cause uplift and deformation of the overriding plate, leading in the construction of mountain ranges around the subduction zone. These mountains may have complicated geological formations, such as folds and faults.
  • Recycling of Oceanic Crust: As oceanic plates subduct, the mantle gradually consumes them, releasing minerals and elements that are eventually reintroduced to the surface via volcanic activity. 

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