Recent research conducted by geologists in Australia's Monash University reveals that a passive margin in the Atlantic Ocean is starting to become active. Scientists are now looking at this occurrence as an early stage of the Wilson Cycle--a phenomenon wherein the movements among tectonic plates break up large continents--such as Pangea--while also closing old oceans and opening new ones.
The team mapped a subduction zone near Iberia and found out that the ocean floor underneath the Atlantic is beginning to show signs of fracture.
Research leader, Dr. João Duarte of the School of Geosciences, says "What we have detected is the very beginnings of an active margin - it's like an embryonic subduction zone."
Duarte explains that the underwater mountain, Gorringe Bank, looks a lot like a nascent subduction zone based on the newly discovered fault lines in the area. He says the nascent subduction zone in the underwater mountain could split the Eurasian plate, which extends to the mid-Atlantic ridge. When this happens, one of the plates would remain oceanic while the other would surface as a continental plate.
The geologist also cited the 1755 earthquake that devastated Lisbon as an evidence that there may be convergent tectonic activities around the area. Along the process, Iberia would be gradually pulled towards the United States, and the Atlantic Ocean would become narrower until it finally closes.
Duarte says that the new Wilson Cycle could have started because the African and Eurasian subduction zones cycle had just ended, creating the mountains from Gibraltar to the Himalayas. He supports this hypothesis by noting that when the Pacific plates settled down, two new zones were spotted in the East Atlantic area --one is in the North Atlantic, around the area of the Caribbean Sea and the other between Antarctica and South America.
The features seen in these new zones are said to be very much similar to the ones in the Gorringe Bank.
While this process may already be under way, the team emphasized that the Wilson Cycle actually takes millions of years to complete. This means that the major changes in the geography of the area would only take place after 20 million years or so. And it would take ten to eleven times that duration before the Atlantic Ocean is completely gone.
Nonetheless, geologists continue to study activities in the Atlantic Ocean floor. Duarte says that this is a good opportunity to have a closer look at how the Wilson Cycle takes place from the very beginning.