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  • He, Y. M., Wen, L. X. and Capdeville, Y. (2021). Morphology and possible origins of the Perm anomaly in the lowermost mantle of Earth. Earth Planet. Phys., 5(1), 105–116. DOI: 10.26464/epp2021009
    Citation: He, Y. M., Wen, L. X. and Capdeville, Y. (2021). Morphology and possible origins of the Perm anomaly in the lowermost mantle of Earth. Earth Planet. Phys., 5(1), 105–116. DOI: 10.26464/epp2021009
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Morphology and possible origins of the Perm anomaly in the lowermost mantle of Earth

  • We have constrained a small-scale, dome-shaped low-velocity structure near the core-mantle boundary (CMB) of Earth beneath Perm (the Perm anomaly) using travel-time analysis and three-dimensional (3-D) forward waveform modeling of seismic data sampling of the mantle. The best-fitting dome-shaped model centers at 60.0°E, 50.5°N, and has a height of 400 km and a radius that increases from 200 km at the top to 450 km at the CMB. Its velocity reduction varies from 0% at the top to –3.0% at 240km above the CMB to –3.5% at the CMB. A surrounding 240-km-thick high-velocity D'' structure has also been detected. The Perm anomaly may represent a stable small-scale chemical pile in the lowermost mantle, although the hypothesis of a developing mantle plume cannot be ruled out.
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