All articles tagged with #mantle
Scientists modeling Earth’s interior propose a long-lived, hot, low-density mantle upwelling originating beneath Africa drifts east beneath the Indian Ocean, reducing local mass and producing the observed geoid low. The idea, supported by 100-million-year simulations and the Indian plate’s motion, explains why satellite data show a persistent dip in the sea surface, though the interpretation is still debated.
Scientists report a vast, bound water reservoir about 700 km below the surface, stored in the mineral ringwoodite in the mantle's transition zone. Using seismic data from roughly 2,000 stations and 500 earthquakes, they estimate this deep ocean could contain about three times as much water as all surface oceans, suggesting Earth's water partly originates from within and that the deep cycle helps keep surface oceans stable over geological time.
Geologists studying the Kafue Rift in Zambia found mantle-derived helium signatures in hot springs, suggesting an active fault boundary and early signs that sub-Saharan Africa may be splitting; while this raises the possibility of geothermal energy opportunities, the researchers caution that data from other segments are needed to confirm a new plate boundary.
Scientists pulled a 1,268‑meter section from the Earth’s mantle during JOIDES Resolution Expedition 399, a milestone in Earth science. The mantle rocks show less pyroxene and more magnesium than expected, suggesting more melting in the mantle than previously thought and offering new clues about how magma forms and powers seabed volcanism. The findings also hint that olivine reacting with seawater could produce hydrogen, a potential piece of life’s origin puzzle. The team, led by Professor Johan Lissenberg, will continue analyses, with the study published in Science.
A new study finds Mount Etna's lava originates from a melt in the mantle's low-velocity zone and rises through a tectonically complex zone at the Africa-Eurasia boundary, producing early silica-rich lava and later alkali-rich lava, suggesting Etna represents a previously unclassified form of volcanism that could be more widespread than scientists previously thought.
A Science Advances study links rare earth element formation to fertilized mantle regions created by fluids released at ancient subduction zones; alkaline and carbonatite magmas hosting these elements cluster above these fertilized mantle zones, and a majority of known deposits lie there, offering a targeted strategy for locating large reserves.
A new 3D model of Yellowstone and the Eastern Snake River Plain suggests tectonic forces within the lithosphere drive magma generation and migration from the shallow mantle (upper asthenosphere) into a complex plumbing system, rather than a deep mantle plume powering a single giant chamber. This tectonically controlled magma movement could improve eruption forecasting and hazard assessment for the park’s massive caldera, whose last major eruption occurred about 630,000 years ago and is not expected imminently.
Scientists studying olivine in the upper mantle found that about 17% of crystals exhibit 'b' dislocations, a deformation mode once thought rare. This suggests this mechanism is more widespread and could refine models of mantle flow and plate tectonics, revealed through EBSD and TEM imaging.
A Utrecht University study using full-planet normal-mode seismology reveals two Large Low Shear Velocity Provinces beneath Africa and the central Pacific, rising about 1,000 kilometers from the core–mantle boundary. These thermochemical structures, billions of years old, appear to anchor mantle flow and influence surface tectonics; they are not surface mountains, but if placed at the surface they would extend high into the atmosphere, effectively redefining what counts as Earth's tallest feature.
Scientists report a vast water reservoir stored in the mineral ringwoodite about 700 kilometers beneath Earth's surface, forming a deep 'ocean' three times larger than all surface oceans. The finding, supported by seismic data from thousands of sensors and high-pressure lab experiments, challenges the idea that Earth's water came mainly from comets and suggests interior sources could help regulate surface oceans and geologic activity.
Two continent-sized regions deep in Earth’s mantle, called Large Low Seismic Velocity Provinces (LLSVPs), lie about 1,200 miles below the surface and rise roughly 620 miles, making them far larger than any surface mountain. They’re hotter and ancient, likely stable for hundreds of millions of years, and their existence suggests the mantle is not as well-mixed as previously thought. Seismic analyses show they dampen waves less than surrounding slabs, a property linked to unusually large mineral grains, reshaping ideas about mantle convection and the origin of mantle plumes.
NASA/DLR GRACE data showed a deep mantle gravity anomaly from 2006–2008 stretching across the eastern Atlantic. Scientists traced the signal to a phase transition in bridgmanite near the core–mantle boundary, where mineral structure changes redistribute mass and alter density. This deep-seated gravitational anomaly, not fully explained by surface water, helps explain previous geomagnetic-field–related gravity fluctuations and will guide models of core–mantle dynamics and mantle convection.
Seismologists using high-resolution full-waveform inversion on earthquake data detected large, anomalous pockets in the lower mantle beneath the Pacific, visible as regions where seismic waves move unusually fast or slow. These “sunken worlds” may be remnants of ancient plates or other mantle materials, challenging traditional ideas about subduction and plate evolution. A ETH Zurich–Caltech team notes the exact composition is unclear and more data and methods (including EM signals and mineral physics) are needed, but the findings could require updates to models of mantle convection and heat transfer. The study appears in Scientific Reports.
Two remote locations reveal mantle rocks at the surface: Macquarie Island, where ongoing plate motion brings oceanic mantle-derived rock to the surface at an active boundary, and Gros Morne National Park’s Tablelands, where an ancient ophiolite block places upper-mantle rocks atop continental crust—each site representing different tectonic settings and timescales, with Macquarie remaining remote and heavily bio-secured and Gros Morne playing a historic, foundational role in plate tectonics research.
A team aboard the JOIDES Resolution drilled 1,268 meters near the Lost City hydrothermal field, retrieving abyssal peridotite and harzburgite—the deepest mantle-like rock ever recovered—without crossing the crust–mantle Moho boundary. The findings advance understanding of the upper mantle and serpentinization, but the mission ended not from rock failure or depth limits; it was due to the operations window ending, and funding has since been cut for further mantle sampling, potentially slowing progress in deep-mantle research.