Research could revolutionize understanding of the Earth's surface
Scientists at the University of Toronto have made a significant breakthrough in plate tectonics, discovering that the Pacific plate is not as rigid as previously thought, but instead torn apart by large underwater faults. This challenges traditional views and suggests more complex interactions between oceanic plates and the Earth's mantle.
Research shows that the Pacific Plate is being torn apart on undersea plateaus due to the weight of the oceanic plate sinking along the Western Pacific Ring of Fire.
Canadian scientists say oceanic plates are inflexible as they slide through the Earth's mantle. Instead, the researchers found that the Pacific Plate is cut by large underwater faults that split it into pieces that extend thousands of meters deep and hundreds of kilometers long, the result of enormous forces within the plate pulling it westward.
The researchers describe their findings in a paper published in the journal Geophysical Research Letters.
“We knew that geological deformation, like faults, occurs within continental plates, away from plate boundaries,— explains Erkan Gün. — But we didn’t know that the same thing was happening with ocean plates.” Russell Pisklywiec adds: “What we do, — this is clarifying plate tectonics — theory that describes how our planet works, — and show that these plates are actually not as pristine as we previously thought.»
For millions of years, the Pacific plate, which makes up most of the ocean floor, drifted west to sink into the Earth's mantle along undersea trenches or subduction zones that extend from Japan to New Zealand and Australia. When the western edge drops, it pulls the rest of the slab with it, a phenomenon compared to a tablecloth being removed from a table.
“It was believed that since suboceanic plateaus are thicker, they should be stronger, — Gun says. — But our models and seismic data show that the opposite is true: the plateaus are weaker.»
The researchers studied four plateaus in the western Pacific Ocean over a wide area roughly bounded by Hawaii, Japan, New Zealand and Australia. They made their discovery using supercomputer models and existing data, some of which was collected through research conducted in the 1970s and 1980s.
“There is evidence that volcanism occurred at these sites in the past as a result of this type of plate damage— perhaps episodically or continuously, — but it is unclear whether this is happening now, — Gün emphasizes. —However we can't be sure because the plateaus are thousands of meters below the ocean's surface, and sending research ships to collect data requires significant effort. So, really, we hope that our paper will bring some attention to the plateau and more data will be collected.»
The theory of plate tectonics has been refined over many decades by many Earth scientists, but the theory is not set in stone. and scientists are still finding new things.
«A new discovery like this overturns what we have understood and taught about the active Earth,— says Russell Pisklyvec. — And this shows that even in the grandiose functioning of our evolving planet, mysteries still remain.