Unusual seismic data in the Pacific reveals a massive mysterious structure that has been penetrating the Earth since the age of dinosaurs.
According to SciTech Daily, a research team led by geologist Jingchuan Wang from the University of Maryland (USA) has identified the remnants of a prehistoric ocean floor that the Earth swallowed approximately 250 million years ago.
“Our discovery opens up new questions about how the deep Earth influences what we see on the surface over vast distances and time scales,” said Dr. Wang.
A mysterious structure moving beneath the Nazca Plate may be a piece of Earth’s crust that sank deep 250 million years ago – (Photo: NATURE ADVANCE).
By transmitting seismic waves deep into the Earth to create seismic maps, Dr. Wang and his colleagues discovered something unusual slowly moving beneath the Nazca tectonic plate in the Pacific.
The tectonic plates can be understood as massive pieces of Earth’s crust that “carry” parts of continents or oceans. The Earth’s surface is composed of over 20 such plates.
Over time, Earth’s tectonic plates continuously rearrange, sliding over one another, causing the continents and oceans to change shape.
Plates that are subducted into the Earth’s interior will gradually melt, with materials from them blending with mantle materials and potentially being recycled into the materials of other plates that rise to the surface in the future.
In this area, the Nazca Plate is currently sinking beneath the South American Plate. However, there are some strange details.
First, on the western side of this sinking plate, there is a gigantic ocean ridge that is rapidly developing.
Additionally, in this area, material is sinking at only half the rate that scientists expected, indicating that something is obstructing material from above from sinking deep into the mantle.
Further analyses revealed a structure that is denser and colder than the surrounding material, which is stuck at the upper part of the mantle.
Publishing their findings in the scientific journal Science Advances, the authors suggest that this dense area is an ancient “fossilized” oceanic crust.
It has fortunately not melted completely into the surrounding mantle material and appears to be trapped, suspended.
Its impact has contributed to the development of the aforementioned gigantic ocean ridge.
This discovery is incredibly interesting because the trapped state of this ancient oceanic crust provides a wonderful opportunity to study what happens deep within the Earth and further clarify the still-mysterious theory of plate tectonics.
Looking ahead, the research team plans to expand their studies to other areas of the Pacific and beyond.
This will include creating a more comprehensive map of ancient regions that have sunk and risen, or more ambitiously, full models of how tectonic plates have moved throughout Earth’s history.
