sweden 亚盘

<menu id="ay4aq"><u id="ay4aq"></u></menu>
<input id="ay4aq"></input>
  • <input id="ay4aq"><u id="ay4aq"></u></input>
    <menu id="ay4aq"></menu>
  • <menu id="ay4aq"></menu><input id="ay4aq"><u id="ay4aq"></u></input>
  • <menu id="ay4aq"></menu><menu id="ay4aq"><tt id="ay4aq"></tt></menu>
  • Orgin of Seismic Heterogeneities Deep inside Earth

    • [2020-01-23]

      Earlier this month, Nature Communications published a geological research done mainly by USTC researchers which determine the velocities and density of subducted oceanic crust under lower-mantle conditions. The results reveal that the velocity anomalies produced by subducted oceanic crust strongly depend on depth, the presence of which can explain some seismic heterogeneities in the lower mantle, and thus provide a deeper look into the origin of lower-mantle seismic heterogeneities. 

      koe2zorzfcsmhak2u2dz

       the Earth inside

      The lower mantle is the largest continuous region inside our Earth, occupying the volume for around 55%. It was previously regarded as homogeneous, except for some certain parts, or “provinces”. With the advancements in seismology, however, various heterogeneities have been detected in the lower mantle.

      Such heterogeneities were first proposed to be related to subducted oceanic crust. Subduction is a geological process that takes place at convergent boundaries of tectonic plates where one plate moves under another, and is forced to sink due to gravity into the mantle. 

      IMG_256

      Subduction of crust. (Free Image)

      Nevertheless, the velocity and density of the subducted crust at lower-mantle conditions remained unknown. 

      Subducted oceanic crust in the lower mantle. (Image in the paper, by WU Zhongqing et al.) 

      Here, USTC researchers led by WU Zhongqing and SUN Daoyuan discover that subducted oceanic crust shows a large negative shear velocity anomaly at the phase boundary between stishovite and CaCl2-type silica, which is highly consistent with the feature of mid-mantle scatterers. Using ab initio calculations, they obtain the elastic properties of CF-type phase at high pressure and temperature, and determine the velocities and density of the problem mentioned above. 

      The results reveal that the velocity anomalies by subducted oceanic crust strongly depend on depth, which serves to explain lower-mantle seismic heterogeneities.

      The first authors of the paper are WANG Wenzhong and XU Yinhan, who graduated recently at USTC as doctoral students. The work was supported by CAS and National Natural Science Foundation. 

      See the paper: https://www.nature.com/articles/s41467-019-13720-2

       

      (Written by QIANG Jiaxuan, edited by YE Zhenzhen, USTC News Center)


    • MORE NEWS

    HIGHLIGHT

    Highlight of USTC

    On May 11, the Nature Publishing Group released Nature Publishing Index 2010 China, remarking “a dramatic rise in the quality of research being published by China”. University of Science and Technology of China is ranked 3rd of TOP 10 Institutions in Index 2010 China.

    Highlight

    This article came from News Center of USTC.

    <menu id="ay4aq"><u id="ay4aq"></u></menu>
    <input id="ay4aq"></input>
  • <input id="ay4aq"><u id="ay4aq"></u></input>
    <menu id="ay4aq"></menu>
  • <menu id="ay4aq"></menu><input id="ay4aq"><u id="ay4aq"></u></input>
  • <menu id="ay4aq"></menu><menu id="ay4aq"><tt id="ay4aq"></tt></menu>
  • 皇冠足球即是比分

    天奇彩票平台-首页

    幸福彩票注册

    博狗官方网站

    狗博集团首页 娱wz乐

    博亚体育app

    易网的彩大厅

    金福彩票网

    百万彩票首页