Scholarlink

<p>Sequestered sediments drive mantle chemical heterogeneity and enriched volcanism, yet their deep-mantle detection and geophysical interpretation remain enigmatic. Here, we identify sediment-related processes as a viable contributor to the upper-mantle X-discontinuities, through seismic velocity modeling of various sediment compositions coupled with mid-ocean ridge basalts and pyrolite in comparison to seismological observations. The sediment-derived formation of liebermannite (KAlSi<sub>3</sub>O<sub>8</sub>) and stishovite (SiO<sub>2</sub>) at 250–350 km depths can generate substantial seismic anomalies (4.0–19.4% and 3.2–15.3% increases in shear and compressional wave velocities, respectively), with minimal sensitivity to sediment compositional variations. These results suggest that the upper-mantle X-discontinuities may represent transient phase-transition windows through which subducted sediments migrate and become seismically detectable. Once these sediments are entrained by upwelling mantle plumes, they may yield distinct enriched geochemical signatures observed in ocean island basalts originating from hotspots associated with the X-discontinuities.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Subducted sediments hidden in the upper-mantle X-discontinuities

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年7月14日

查看全文
  • Baoyun Wang,
  • Jin Liu,
  • Yanyao Zhang,
  • Lulu Liu,
  • Zhongfa Zhou,
  • Yongjun Tian

摘要

Sequestered sediments drive mantle chemical heterogeneity and enriched volcanism, yet their deep-mantle detection and geophysical interpretation remain enigmatic. Here, we identify sediment-related processes as a viable contributor to the upper-mantle X-discontinuities, through seismic velocity modeling of various sediment compositions coupled with mid-ocean ridge basalts and pyrolite in comparison to seismological observations. The sediment-derived formation of liebermannite (KAlSi3O8) and stishovite (SiO2) at 250–350 km depths can generate substantial seismic anomalies (4.0–19.4% and 3.2–15.3% increases in shear and compressional wave velocities, respectively), with minimal sensitivity to sediment compositional variations. These results suggest that the upper-mantle X-discontinuities may represent transient phase-transition windows through which subducted sediments migrate and become seismically detectable. Once these sediments are entrained by upwelling mantle plumes, they may yield distinct enriched geochemical signatures observed in ocean island basalts originating from hotspots associated with the X-discontinuities.