World's Oldest Oceanic Crust Found Underneath The Mediterranean Sea

Experts have recently found that the oldest patch of undisturbed ocean crust on Earth is located under the Eastern Mediterranean Sea which is estimated to be at least 340 million years old. It is believed to be broken the record of a previous discovery by more than 100 million years.

According to phys.org, a researcher at Ben-Gurion University of the Negev (BGU) has discovered that the eastern Mediterranean Sea has the world's oldest oceanic crust still in place which could be almost 340 million years-old.

The study published in Nature Geoscience was spearheaded by Dr. Roi Granot, a senior lecturer in the BGU Department of Geology and Environmental Sciences. It has been said that the Earth's outermost layer can be billions of years old on land, however most oceanic crust are said to be younger than 200 years old. Experts are using these oceanic formation to figure out what the Earth looked like during the formation of continents, when it broke apart and when it shifted around the globe hundreds of millions of years ago.

"The Mediterranean Sea is one of them," Granot said. "And now it seems that we know what it is." Yahoo News reported that Dr. Granot used the magnetic data to study the nature of the crust in the Herodotus Basin, and found that the rocks are defined by magnetic stripes, which is the hallmark of ocean crust formed at a mid-ocean ridge.

Experts explained that as magma at a mid-ocean ridge axis cools, magnetization of the minerals in the newly formed rocks align with the direction of the Earth's magnetic field.

Meanwhile, Dr. Granot tugged magnetic sensors behind a boat on four different trips over the area between Turkey and Egypt. The magnetic signals showed stripes which is an indication of a previously unknown mid-ocean ridge, New Scientist reported.  "Here I am in the middle of the eastern Mediterranean and I see this beautiful feature that crosses the entire sea, from north to south," Dr. Granot says. "That feature can only be created by oceanic crust."

Dr. Granot estimated the age of the oceanic crust by comparing the magnetic signals with predictions based on the northward drift of the African continental plate over the past 400 million years.  He knew where and when tectonic plates shifted Africa, so he could somehow calculate the expected amount of magnetic signals of the nearby oceani crust as time pass. After careful examination, it was revealed that the best match between Granot's observations and the model estimates suggest the oceanic crust formed about 340 million years ago.

"The area is covered by thick sedimentary coverage, making it unclear precisely how old the crust is and whether it is even oceanic at all," Dr. Granot says. With the new geophysical data, we could make a big step forward in our geological understanding of the area."