A Rock Dragged 90 Km Into Earth Came Back With a Temperature Story That Breaks The Models
Geologists have discovered a rock from Papua New Guinea that displays anomalous thermal patterns, challenging existing models of subduction zone temperatures. The rock, which traveled 90 kilometers deep into the Earth, suggests that internal temperature gradients are more complex than previously understood.
Why it matters
Understanding the thermal history of Earth's interior is crucial for refining geological models of plate tectonics and planetary evolution.
Scientists have discovered a mysterious rock in eastern Papua New Guinea that traveled to the underworld roughly 4.4 million years ago.
The story it has to tell is strange indeed.
As the rock journeyed deeper into our planet's interior, pushed by the forces of a subduction zone, its temperature did not do what scientists expected.
At 45 kilometers below the surface, researchers estimate the rock became unusually warm, experiencing temperatures of about 700 °C (1,292 °F).
That's hotter than models predict subduction zones should be at that depth.
But that's not all. When the rock reached more than 90 kilometers (56 miles) deep, its temperature only rose by a further 100 °C.
"What makes this rock so interesting is that it records two very different thermal conditions at different stages of its time deep inside Earth," says geologist Axel Schmitt from Curtin University in Australia.
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