World's oldest ocean crust discovered

The oldest oceanic crust on Earth is located in the eastern Mediterranean and is about 340 million years old.

The world's oldest oceanic crust in the eastern Mediterranean. Photo: Jason Thomson.

According to Science Daily, Roi Granot, PhD in the Department of Environmental Geology at Ben-Gurion University of the Negev (BGU), Israel, determined that the eastern Mediterranean Sea contains the world's oldest oceanic crust. The research results were published in the journal Nature Geoscience on August 15.

Many basic tectonic features in the eastern Mediterranean remain a mystery due to the relatively thick sedimentary layer (10-15 km) and the lack of magnetic anomaly data. The team used sensors to survey the marine magnetic field for 7,000 km across the Herodotus and Levant basins in the eastern Mediterranean. They wanted to understand the nature and age of the Earth's crust underneath.

The data shows that rocks in the Herodotus Basin are characterized by the presence of a “magnetic streak,” a sign that oceanic crust forms at mid-ocean ridges. As magma at mid-ocean ridges cools, the magnetization and orientation of minerals in the rocks are guided by the Earth’s magnetic field.

"Changes in magnetic field orientation over time recorded at the ocean floor provide insight into the formation of the Earth's crust, shedding light on tectonic plate structures and geodynamic processes in the region," said Granot.

By measuring the deflection of the magnetic track, Granot showed that the oceanic crust in the Herodotus Basin was about 340 million years old. Oceanic crust typically reenters the Earth's mantle relatively quickly at subduction zones due to its high density. Therefore, most of the oceanic crust is less than 200 million years old.

"With the new geophysical data, we make great strides in understanding the geology of the study area," said Granot.

According to Granot, the oceanic crust in the Herodotus Basin is most likely the remains of the ancient Tethys Ocean that lay between the supercontinents Gondwana and Laurasia during the Mesozoic Era, before the formation of the Atlantic and Indian Oceans.

According to VNE