Earth’s mantle tagged posts

New research lends credence to an unorthodox retelling of the story of early Earth first proposed by a geophysicist at Scripps Institution of Oceanography at UC San Diego.

In a study appearing March 15 in the journal Earth and Planetary Science Letters, Scripps Oceanography researchers Dave Stegman, Leah Ziegler, and Nicolas Blanc provide new estimates for the thermodynamics of magnetic field generation within the liquid portion of the early Earth’s mantle and show how long that field was available.

The paper provides a “door-opening opportunity” to resolve inconsistencies in the narrative of the planet’s early days...

Cutaway of the Earth’s surface, down to the liquid core. A numerical convection experiment shows blobs in green, surrounding mantle rock in blue, and former oceanic crust from the surface that has subducted into the interior in yellow. Credit: Dr. Mingming Li/University of Colorado

2 massive blob-like structures lie deep within Earth, roughly on opposite sides of the planet. Each the size of a continent and 100 times taller than Mount Everest, sit on the core, 1,800 miles deep, and about halfway to the center of Earth. Arizona State University scientists suggest these blobs are made of something different from the rest of Earth’s mantle.

“While the origin and composition of the blobs are yet unknown,” said Garnero, “we suspect they hold important clues as to how Earth was formed and how ...

A specimen of a Witwatersrand diamond. Credit: Wits University

The 3 diamonds extracted from 3B-yr-old Witwatersrand Supergroup – the rock formation that is host to the famous Johannesburg gold mines to study when modern-style plate tectonics began to operate on planet Earth. “Because diamonds are some of the the hardest, most robust material on Earth, they are perfect little time capsules and have the capacity to tell us what processes were occurring extremely early in Earth’s history,” says Dr Katie Smart.

A cluster of the Witwatersrand diamonds. Credit: Wits University

The Earth is ~4...