ORCID

0000-0001-8584-9190 (Ames), 0000-0002-8863-8783 (Georgen)

Document Type

Article

Publication Date

2026

DOI

10.1029/2025GC012860

Publication Title

Geochemistry, Geophysics, Geosystems

Volume

27

Issue

7

Pages

e2025GC012860

Abstract

This study investigates the nature of plume-ridge interactions near a tectonic microplate using mantle Bouguer anomaly (MBA) gravity calculations. The focus of this investigation is a comparison of the Easter and Juan Fernandez microplates, which are located in the eastern Pacific Ocean along the Pacific, Nazca, and Antarctic plate boundaries. The microplates have several similar characteristics, including general size, time of formation, and clockwise rotation within the larger bounding mid-ocean ridge systems. Unlike the Juan Fernandez microplate, however, the Easter microplate is located near a mantle plume (Easter/Salas y Gomez). Previously published geochemical data suggest that material from this plume significantly contributes to mantle melting processes along the east rift of the Easter microplate. For both microplates, average MBA is different between the west and east ridges, which is consistent with the east ridges rifting into cooler, older, denser lithosphere. Interestingly, MBA anomalies along the plume-affected portion of the Easter microplate are minimal despite other indications of robust plume strength such as significant off-axis seafloor depth anomalies. It is possible that complex plate boundary geometry at the mid-ocean ridge, and specifically microplate lithospheric structure, modifies the geophysical expression of plume-ridge interaction in this setting. Overall, these MBA results provide insights into the importance of taking plate boundary geometry into consideration when using observational data to constrain plume properties.

Rights

© 2026 The Authors.

This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Data Availability

Article states: "Bathymetry and gravity data used in this study are available from https://topex.ucsd.edu/marine_topo/ and https://topex.ucsd.edu/marine_grav/mar_grav.html. GMT (https://www.generic-mapping-tools.org/download/) was used to prepare map figures."

Original Publication Citation

Ames, K., & Georgen, J. (2026). The effects of a microplate on plume-ridge interactions: Constraints from comparing Easter and Juan Fernandez microplates in the eastern Pacific Ocean. Geochemistry, Geophysics, Geosystems, 27(7), Article e2025GC012860. https://doi.org/10.1029/2025GC012860

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