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A Geodynamic Investigation of Plume-Lithosphere Interactions Beneath the East African Rift

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dc.contributor.authorRajaonarison, Tahiry A.en
dc.contributor.authorStamps, D. Sarahen
dc.contributor.authorNaliboff, Johnen
dc.contributor.authorNyblade, Andrewen
dc.contributor.authorNjinju, Emmanuel A.en
dc.date.accessioned2023-06-15T12:33:24Zen
dc.date.available2023-06-15T12:33:24Zen
dc.date.issued2023-04en
dc.description.abstractThe force balance that drives and maintains continental rifting to breakup is poorly understood. The East African Rift (EAR) provides an ideal natural laboratory to elucidate the relative role of plate driving forces as only lithospheric buoyancy forces and horizontal mantle tractions act on the system. Here, we employ high-resolution 3D thermomechanical models to test whether: (a) the anomalous, rift-parallel surface deformation observed by Global Navigation Satellite System (GNSS) data in the EAR are driven by viscous coupling to northward mantle flow associated with the African Superplume, and (b) the African Superplume is the dominant source mechanism of anomalous rift-parallel seismic anisotropy beneath the EAR. We calculate Lattice Preferred Orientations (LPO) and surface deformation from two types of mantle flow: (a) a scenario with multiple plumes constrained by shear wave tomography and (b) a single superplume model with northward boundary condition to simulate large-scale flow. Comparison of calculated LPO with observed seismic anisotropy, and surface velocities with GNSS and plate kinematics reveal that there is a better fit with the superplume mantle flow model, rather than the tomography-based (multiple plumes) model. We also find a relatively better fit spatially between observed seismic anisotropy and calculated LPO with the superplume model beneath northern and central EAR, where the superplume is proposed to be shallowest. Our results suggest that the viscous coupling of the lithosphere to northward mantle flow associated with the African Superplume drives most of the rift-parallel deformation and is the dominant source of the first-order pattern of the observed seismic anisotropy in the EAR.en
dc.description.sponsorshipThis work was funded by the National Science Foundation (NSF) GeoPRISMS Grants EAR-1551864 and EAR-1551767. The authors thank the Computational Infrastructure for Geodynamics (CIG) for supporting the development of ASPECT, which is funded by NSF Awards EAR-0949446 and EAR-1550901.en
dc.description.versionAccepted versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.doihttps://doi.org/10.1029/2022JB025800en
dc.identifier.issue4en
dc.identifier.urihttp://hdl.handle.net/10919/115435en
dc.identifier.volume128en
dc.language.isoenen
dc.publisherAmerican Geophysical Unionen
dc.subjectEast African Riften
dc.subjectAfrican Superplumeen
dc.titleA Geodynamic Investigation of Plume-Lithosphere Interactions Beneath the East African Riften
dc.title.serialJGR Solid Earthen
dc.typeArticle - Refereeden
dc.type.dcmitypeTexten

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