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Updated: Jul 16, 2026
06:55
Kinematic History of a Salient-recess Junction Explored through a Combined Approach of Field Data and Analog Sandbox Modeling
Published on: August 5, 2016
Subducted sediments hidden in the upper-mantle X-discontinuities.
Baoyun Wang1,2, Jin Liu3, Yanyao Zhang4
1School of Geography and Environmental Sciences, Guizhou Normal University, Guiyang, China. baoyunwang@gznu.edu.cn.
Nature Communications
|July 14, 2026
Summary
Subducted sediments create seismic anomalies in the upper mantle, detectable at X-discontinuities. These findings explain mantle chemical variations and enriched volcanism in ocean island basalts.
Area of Science:
- Geophysics
- Mineral Physics
- Geochemistry
Background:
- Sediments subducted into the mantle are a key source of chemical heterogeneity.
- The deep-mantle detection and geophysical interpretation of these sediments remain challenging.
- Enriched volcanism in ocean island basalts suggests deep mantle sources.
Purpose of the Study:
- To investigate the geophysical signatures of subducted sediments in the upper mantle.
- To link sediment composition to seismic velocity anomalies.
- To explain the origin of upper-mantle X-discontinuities and their role in mantle heterogeneity.
Main Methods:
- Seismic velocity modeling of various sediment compositions.
- Comparison with mid-ocean ridge basalts and pyrolite.
- Analysis of seismological observations and mineral physics data.
Main Results:
- Sediment-derived minerals, like liebermannite and stishovite, form at 250-350 km depths.
- These minerals cause significant seismic velocity increases (4.0-19.4% shear, 3.2-15.3% compressional).
- Seismic anomalies are minimally sensitive to variations in sediment composition.
Conclusions:
- Upper-mantle X-discontinuities may represent transient windows for subducted sediment migration.
- Seismically detectable sediments can be entrained by mantle plumes.
- This process contributes to the enriched geochemical signatures observed in ocean island basalts.
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