The American Geophysical Union GeoSpace has detailed the findings of subterranean continents deep in the bowels of the earth. The continents may have formed when an ocean of ancient magma froze on the surface of the early planet Earth some 4.5 billion years ago.
Scientists have known about this underground, hot lump of compressed rock since the 1970s. Earthquakes reverberate through the rest of the mantle at a steady pace.
This strange pattern of seismic activity is helping scientists locate continents at the boundary of Earth’s mantle and molten outer core, but they still don’t know when or how those structures appeared.
Some scientists theorize that bits of the planet’s crust dipped into the mantle, broke off and clumped together over time. Geospace.
Now, a new analysis of volcanic rock paints a different picture: the underground continents may be as old as the Earth itself, and likely survived the impact of the planetary shock that first formed the Moon.
The study authors report in the online journal Geochemistry, Geophysics, Geosystems.
Study co-author Curtis Williams, a geologist at the University of California, Davis, said it was amazing that these areas survived most of Earth’s volcanic history relatively untouched.
Williams and his colleagues collected new and existing data on geological samples from Hawaii, Iceland, the Balleny Islands in Antarctica and other areas where hot rock bubbles up from the planet’s core to the surface.
The samples penetrated the crust as lava, and cooled to become igneous rock, according to the GeoSpace report.
2023-05-31 15:34:58
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