EARTH Magazine: New subduction zone may close Atlantic Ocean

Throughout the history of Earth, supercontinents have formed and ocean basins have opened and closed over timescales of 300 million to 500 million years. But scientists haven't found direct evidence of the in-between phase—an ocean basin that was opening, starting instead to close—until now. Thanks to new high-resolution surveys of the seafloor, scientists think they have evidence of that process starting in the Atlantic Ocean off the coast of Portugal. If they are right, this nascent subduction zone could close the Atlantic Ocean—in roughly 200 million years.

Geoscientists have hypothesized the existence of an earthquake-causing, volcano-forming subduction zone along the Portuguese coast. Now, based on new analyses of a series of faults and regional tensions, João Duarte, the principal investigator, suggests that his study supports that hypothesis and identifies the main tectonic mechanisms. However, this conclusion has garnered some controversy from fellow scientists, mainly because it may still be too soon to tell.

Read more about how passive margins may become active margins in this month's issue of EARTH Magazine: http://bit.ly/1bV6YLU. For other stories on Ireland's volcanic winters, how Northern Hemisphere sulfate emissions shifted tropical precipitation patterns, and the feldspar linings of clouds, visit the digital bookstand at: http://www.earthmagazine.org/digital.

Provided by American Geosciences Institute