New European subduction zone holds key to Atlantic's geological future
The latest geological research has unveiled not just two, but three subduction zones beneath the waters of the Atlantic, with particular attention drawn to the one closest to Europe due to its unique characteristics.
Highlighted in the journal Geology, this near-Europe subduction zone, situated near the Strait of Gibraltar, sits in a narrow pass between Portugal and Morocco. Known as the Gibraltar arc or trench, it is on a westward expansion course, posing the possibility of future engagement with the wider Atlantic Ocean.
New Atlantic subduction zone discovered
Common knowledge previously acknowledged two Atlantic subduction zones: the Lesser Antilles in the Caribbean and Scotia near Antarctica. The discovery of a third, bordering Europe and Africa, is younger and presents an opportunity to gather fresh insights.
"The earlier subduction zones confronted the Atlantic several million years back. Observing Gibraltar now gives us a rare chance to see such a phenomenon from its inception," explains João Duarte, a geologist at the University of Lisbon and leading author of the study.
According to the Portuguese research team, a quiet phase concerning this subduction zone is expected to persist for another 20 million years. Beyond that, the Gibraltar arc may reinitiate its push into the Atlantic, a phenomenon described as "subduction invasion."
What is a subduction zone?
Subduction zones are areas where lithospheric plates move apart, marking the boundaries between these plates. The Gibraltar arc, however, finds itself in a peculiar standstill, having remained inactive for approximately 5 million years.
João Duarte and his team delved into whether this standstill signifies current inactivity. Through sophisticated computer modelling of the arc's origin in the Oligocene epoch and its development up to now, they've tracked its trajectory.
Analysis revealed a stark decrease in activity about 5 years ago as it neared the Atlantic boundary. Projections over the next 40 million years indicate a laborious journey through the narrow Strait of Gibraltar for about 20 million years.
Should the Gibraltar arc engage with the Atlantic, it may herald the formation of an Atlantic subduction system comparable to the one surrounding the Pacific Ocean, potentially reshaping the region, including the elevation of the Strait of Gibraltar.
