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Updated: Nov 19, 2025
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
8.4K
A thin mantle transition zone beneath the equatorial Mid-Atlantic Ridge
Matthew R Agius1,2, Catherine A Rychert3, Nicholas Harmon3
1Ocean and Earth Science, University of Southampton, Southampton, UK. matthew.agius@soton.ac.uk.
Nature
|January 28, 2021
Summary
Mid-ocean ridges facilitate material transfer between Earth's upper and lower mantle, challenging previous assumptions. This discovery suggests whole-mantle convection is more significant than previously understood, with ridges playing a key role.
Area of Science:
- Geophysics
- Seismology
- Earth Science
Background:
- Material transfer between Earth's mantle layers is crucial for its evolution.
- Slab subduction and mantle plumes are known transfer sites, but mid-ocean ridges were not considered significant.
- Direct measurements at mid-ocean ridges are difficult.
Purpose of the Study:
- To investigate the role of mid-ocean ridges in mantle material transfer.
- To image seismic discontinuities bounding the mantle transition zone beneath the Mid-Atlantic Ridge.
- To assess the implications for whole-mantle convection.
Main Methods:
- Utilized receiver functions to convert seismic waves.
- Analyzed ocean bottom seismic data from the equatorial Mid-Atlantic Ridge.
- Interpreted seismic discontinuities at 410 km and 660 km depths.
Main Results:
- Observed uplift of the 660 km discontinuity and depression of the 410 km discontinuity, indicating thinning of the mantle transition zone.
- Coincident slow shear-wave velocities suggest upwelling material.
- Slower seismic velocities beneath the Mid-Atlantic Ridge compared to older seafloor.
Conclusions:
- Mid-ocean ridges are sites of lower-to-upper mantle material transfer.
- This transfer may occur continuously or intermittently.
- Ridge upwelling contributes to whole-mantle convection, potentially balancing slab downwelling.
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