A thin mantle transition zone beneath the equatorial Mid-Atlantic Ridge

Matthew R. Agius (), Catherine A. Rychert, Nicholas Harmon, Saikiran Tharimena and J.-Michael Kendall
Additional contact information
Matthew R. Agius: University of Southampton
Catherine A. Rychert: University of Southampton
Nicholas Harmon: University of Southampton
Saikiran Tharimena: University of Southampton
J.-Michael Kendall: University of Oxford

Nature, 2021, vol. 589, issue 7843, 562-566

Abstract: Abstract The location and degree of material transfer between the upper and lower mantle are key to the Earth’s thermal and chemical evolution. Sinking slabs and rising plumes are generally accepted as locations of transfer1,2, whereas mid-ocean ridges are not typically assumed to have a role3. However, tight constraints from in situ measurements at ridges have proved to be challenging. Here we use receiver functions that reveal the conversion of primary to secondary seismic waves to image the discontinuities that bound the mantle transition zone, using ocean bottom seismic data from the equatorial Mid-Atlantic Ridge. Our images show that the seismic discontinuity at depths of about 660 kilometres is broadly uplifted by 10 ± 4 kilometres over a swath about 600 kilometres wide and that the 410-kilometre discontinuity is depressed by 5 ± 4 kilometres. This thinning of the mantle transition zone is coincident with slow shear-wave velocities in the mantle, from global seismic tomography4–7. In addition, seismic velocities in the mantle transition zone beneath the Mid-Atlantic Ridge are on average slower than those beneath older Atlantic Ocean seafloor. The observations imply material transfer from the lower to the upper mantle—either continuous or punctuated—that is linked to the Mid-Atlantic Ridge. Given the length and longevity of the mid-ocean ridge system, this implies that whole-mantle convection may be more prevalent than previously thought, with ridge upwellings having a role in counterbalancing slab downwellings.

Date: 2021
References: Add references at CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.nature.com/articles/s41586-020-03139-x Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:nature:v:589:y:2021:i:7843:d:10.1038_s41586-020-03139-x

Ordering information: This journal article can be ordered from
https://www.nature.com/

DOI: 10.1038/s41586-020-03139-x

Access Statistics for this article

Nature is currently edited by Magdalena Skipper

More articles in Nature from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().