![]() This photo originally published in “ The Larsen C Ice Shelf Collapse Is Just the Beginning-Antarctica Is Melting.” Photograph by Camille Seaman The continent’s coastal ice is crumbling as the sea and air around it warm. Silica, a major chemical compound in volcanic rocks, also wasn’t as common as it should be, indicating that it was pushed out by a high proportion of carbon dioxide.Ī startling sunset reddens the Lemaire Channel, off the west coast of the Antarctic Peninsula. The water content of minerals like pyroxene, known to be incredibly dry, were oddly wet in Bermuda’s core samples. Sure enough, the core sample contained signs of these tell-tale geological fingerprints. ![]() Diamonds that sneak up from the mantle’s transition zone reveal that it contains multiple oceans’ worth of water, as well as plenty of compounds like carbon dioxide. These slabs were likely stored in the mantle’s so-called transition zone, a physically unusual region between 250 and 400 miles underground. If tapped into, these doomed slabs could be the source of young material the team was looking for. ![]() Either during the formation or destruction of this supercontinent, slithers of tectonic plates were shoved down into the mantle below what would one day be the Atlantic Ocean. The Atlantic Ocean, though, is a special place: It only exists because of the breakup of the supercontinent Pangaea hundreds of millions of years ago, Mazza says. This could only be explained if the source within the mantle was geologically young, but the mantle under Bermuda should be extremely old. For one, it has unusual proportions of different lead compounds, formed by the decay of two types of uranium. That’s where the rock core comes into play, which chronicled the volcanic underworld hiding beneath Bermuda’s pink beaches. There is no Hawaiian-like island chain to speak of, and if there was a plume, there should also be volcanism at a spot far southeast of Bermuda where it is predicted to be today, and there isn’t. But the evidence for it being a Hawaii-like plume isn’t exactly strong. Geophysical research does suggest there is an upward-moving warm structure beneath Bermuda. The volcanic underbelly of Bermuda has traditionally been explained by a mantle plume, which is how the Hawaiian archipelago formed: a stationary plume created numerous volcanic islands that grew, erupted then died out as the tectonic plate above it kept moving. ![]() These processes can all create magma patches in Earth’s crust that can then give rise to eruptive peaks at the surface. Until now, the known methods for building volcanoes included plumes rising within the hot and plasticky mantle, two tectonic plates diverging from each other at a mid-ocean ridge, or one plate diving beneath another in a subduction zone. “We just haven’t found them yet,” she says.Īnd Aurélie Germa, a volcanologist and geochemist at the University of South Florida, says that the team’s model for building Bermuda “will probably help solve some geochemical inconsistencies” at other volcanoes in similar tectonic settings “that nobody could have really explained before.” Tectonic lead balloons With a new model for volcano-making in hand, Bermuda may not be alone: Other volcanoes could exist in the Atlantic Ocean that formed by the same or similar processes, says study coauthor Sarah Mazza, a geochemist at the University of Münster. “Sometimes, by luck, you just find something new and different.” “After 50 years of people doing geochemical research on oceanic lavas, no one has found the signature we’ve found in Bermuda,” says study coauthor Esteban Gazel, a geochemist at Cornell University. Find out the origins of our home planet and some of the key ingredients that help make this blue speck in space a unique global ecosystem. Earth is the only planet known to maintain life. ![]()
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