The depths of the structure of the globe…” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/8/4/f/84ff7edce5_123534_earth-apollo8.jpg” data-url = ” https://news.google.com/planete/definitions/structure-earth-earth-4725/” data-more=”Read more”>still hold many secrets. The difficulty of imaging the innermost layers of our planet means that many questions remain unanswered to this day, particularly about its composition, but also about what animates the Earth’s deep mantle. For some time, however, certain enigmatic structures have attracted the particular attention of scientists.
At the interface between the outer core and the claddingindeed show the presence of large structures characterized by very low seismic velocities. These areas contrast with the rest of the deep mantle, which in turn is associated with high wave velocities that are tremendous that reigns in these depths. The hypotheses to explain this ULVZ (e.g Extremely low speed zones, areas with very low speeds) are running well. However, their study encounters the difficulty of obtaining high-quality data that allow for accurate characterization.
More accurate imaging of ULVZs
Thanks to the analysis of certain They occur when a starting impulse sets particles in motion, which in turn cause matter in contact with them to move before …” data-image=”https://cdn.futura-sciences. com /buildsv6/images/midioriginal/6/f/b/6fb435d98c_45125_sismometer-heroesbed-flickr.jpg” data-url=”https://news.google.com/planete/definitions/structure-terre-onde -seismic-13869 / ” data-more=”Read more”>diffracted at the core-mantle interface, researchers from the Universities of Cambridge and Oxford have managed to obtain new ‘images’ of these structures, which lie some 2,800 kilometers below our feet. Images much more accurate than those obtained so far, allowing to emit new assumptions about their composition and operation.
The studied area is at the base of the Hawaiian mantle cloud, well below the island of the same name. This cloud is a column of hot mantle that rises from the base of the mantle to the surface, producing intense volcanism. However, it appears that this cloud has its origins at the level of an ULVZ, which comes in the form of a 1988 sci-fi film, The Blob, depicting the invasion of Earth by an alien creature with such a morphology (bigger and bigger ) describes sour).” data-url=”https://news.google.com/planete/definitions/zoologie-blob-5469/” data-more=”Read the definition”> about twenty kilometers high. Until now, this type of “small” structure (compared to Earth’s scale) was almost invisible because it was underground Boundary of tomographic models that define .
The methoddeveloped by the researchers in the article published in the journal enabled the analysis of a high-frequency seismic signal. A means of mapping, with an accuracy of the order of a kilometer, the low-velocity area with one direction and one intensity is represented by a vector, the velocity vector. Relative velocity is the velocity of one body relative to another or relative to a frame.” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/3/1/9/319daf63f4_77541_leibniz-dp . jpg” data-url=”https://news.google.com/sciences/definitions/physics-velocity-324/” data-more=”Read definition”> at the base of the Hawaiian Plume.
Their results suggest that the internal architecture of these ULVZ is very complex, with certainly a heterogeneous composition. High-frequency signal analysis and numerical modeling
Numerical modeling consists of building a set of functions…” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/a/0/8/a0817e96b9_50037926_soleil-simulation-vibrations- sismology . jpg” data-url=”https://news.google.com/sciences/definitions/matiere-modelisation-11321/” data-more=”Read more”> of the internal structure indicate in particular that the ULVZ would be enriched an element normally characteristic of the Earth’s core, which is divided into two layers
Liquid in nature, the outer core (density 10) is…” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/7/4/6/7466fb8049_50004180_terre-270907. jpg” data-url=”https://news.google.com/planet/definitions/structure-earth-earth-core-13836/” data-more=”Read more”> underlying. The amount of iron would also be variable, since the base of the ULVZ would be richer in it than its top. This compositional anomaly, with the presence of a certain proportion of Magma, would explain the nearly 40% reduction in seismic wave speeds compared to the rest of the deep mantle.
This iron accumulation could be explained by several hypotheses. It has already been suggested that ULVZs represent, which preceded the formation of the continental crust, as the name suggests, forms the continents. It’s essentially a…” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/7/d/1/7d1ca441ac_44707_def-epaisseur-croute-terrestre-usgs.jpg” data-url=”https://news.google.com/planete/definitions/structure-terre-terrestrial-crust-2491/” data-more=”Read more”> at the very beginning of the earth’s history. In this case observed in the distribution of iron would be an index of the fractionation of iron during the various stages of crystallization of this “ocean” of molten rock.
Another hypothesis is that this composition is related to the meteorite impacts that Earth has experienced throughout its history. The iron it containshitting Earth would have mixed with the silicates of the mantle and accumulated at the interface with the core.
A final hypothesis is that the iron comes directly from the outer core. While this would have the ability to dissolve certain copper (Cu) and the copper ion, for example…” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/7 /4/d /74d6f5bda2_92001_element-chimie.jpg” data-url=”https://news.google.com/sciences/definitions/chimie-element-chimie-15852/” data-more=”Read more”>, .
Leaving aside these hypotheses yet to be tested, it appears that these particularly hot zones contribute to significant variations in heat flux. Physicists classify heat as thermal energy. In the international system, it is therefore measured in joules (J). Heat more closely corresponds to a transfer…” data-image=”https://cdn.futura-sciences.com/buildsv6/images/midioriginal/7/3/5/735709801b_92578_chaleur.jpg” data-url=” https :/ /news.google.com/sciences/definitions/physics-heat-15898/” data-more=”Read more”>recorded at the core-mantle interface. In this sense, ULVZ could play an important role in the of the mantle and thus involved in the formation of hotspots, but also of the geodynamo.
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