Ancient Oceanic Crust Found in Mediterranean Sea 70 Percent Older Than Any Known Seafloor

Dr. Roi Granot, a senior lecturer in the Department of Geology and Environmental Sciences at Ben-Gurion University of the Negev (BGU), has identified an ancient oceanic crust below the eastern Mediterranean Sea that is about 70 percent older than any known seafloor.

The seafloor slab, described in a paper published in the journal Nature Geoscience, is about 340 million years old, approximately 150 million years older than the previous record holder located east of Japan. Dr. Granot believes that the 60,000 square mile piece of crust was a remnant of the Ancient Tethys Ocean, which existed long before the Atlantic and Indian Ocean.

"[W]e don't have intact oceanic crust that old ... It would mean that this ocean was formed while Pangaea, the last supercontinent, was still in the making," Dr. Granot told Business Insider.

Pangaea is known to be a supercontinent before newly forming ocean split it apart less than 300 million years ago. However, the discover of the 340 million years old oceanic crust suggests that the supercontinent started breaking apart before it was fully formed or that the section where the crust was found is already existing even before Pangaea arose.

Due to the extremely thick sediments covering the crust in the eastern Mediterranean and small size of the basin, the seafloor slab remained to be unnoticed until now.

To determine if an oceanic crust is hiding below the Mediterranean Sea, Dr. Garot and his team collected marine magnetic profiles across Herodotus and Levant Basins using magnetic sensing equipments.

After analyzing the nature of the magnetic data in the crust of Herodotus Basin, Dr. Garot discovered that the rocks are characterized by magnetic stripes.

Magnetic stripes is the striped pattern in mineral orientations formed when molten magma cools down, making the magnetic minerals within it to align themselves Earth's geomagnetic field. The flipping of the Earth's north and south magnetic poles forms the magnetic stripes for over millions of years.

Dr. Garot noted the future studies are still needed to confirm his discovery.