A recent study published in the journal Geology suggests that a dormant subduction zone beneath the Gibraltar Strait could be active and may eventually penetrate into the Atlantic Ocean, potentially leading to the formation of an Atlantic “Ring of Fire.” This subduction zone, also known as the Gibraltar arc or trench, has been slowly migrating westward for millions of years, originating along the northern coast of the Mediterranean Sea. While it has appeared to stall in recent history, researchers believe it is merely in a period of dormancy, with the potential to resume activity in approximately 20 million years.
Lead author João Duarte, an assistant professor at the University of Lisbon, and his team utilized computer modeling to simulate the evolution of the Gibraltar arc from its inception in the Oligocene epoch to the present day. Their findings indicate a significant slowdown in the subduction zone’s movement around 5 million years ago as it approached the Atlantic boundary, suggesting a potential future invasion of the ocean.
Should the Gibraltar arc breach into the Atlantic Ocean, it could trigger the formation of an Atlantic subduction system akin to the Pacific’s Ring of Fire. This chain of subduction zones circling the Atlantic would result in the recycling of oceanic crust into the mantle through subduction, gradually closing up the Atlantic Ocean over time.
Despite the relative absence of seismic and volcanic activity in the region in recent millennia, attributed to the subduction zone’s stalled movement, researchers argue that this does not discount its potential activity. The lack of significant seismic events since the 1755 Great Lisbon Earthquake is attributed to the prolonged period of inactivity rather than an indication of permanent dormancy.
The study underscores the importance of advanced computer modeling in understanding the evolution of geological phenomena and highlights the potential long-term geological consequences of subduction zone dynamics in the Atlantic Ocean.
