Lithospheric Control of Melt Generation Beneath the Rungwe Volcanic Province, East Africa: Implications for a Plume Source

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dc.contributor.authorNjinju, Emmanuel A.en
dc.contributor.authorStamps, D. Sarahen
dc.contributor.authorNeumiller, Kodien
dc.contributor.authorGallager, Jamesen
dc.contributor.departmentGeosciencesen
dc.date.accessioned2021-07-29T12:47:02Zen
dc.date.available2021-07-29T12:47:02Zen
dc.date.issued2021-05en
dc.description.abstractThe Rungwe Volcanic Province (RVP) is a volcanic center in an anomalous region of magma-assisted rifting positioned within the magma-poor Western Branch of the East African Rift (EAR). The source of sublithospheric melt for the RVP is enigmatic, particularly since the volcanism is highly localized, unlike the Eastern Branch of the EAR. Some studies suggest the source of sublithospheric melt beneath the RVP arises from thermal perturbations in the upper mantle associated with an offshoot of the African superplume flowing from the SW, while others propose a similar mechanism, but from the Kenyan plume diverted around the Tanzania Craton from the NE. Another possibility is decompression melting from upwelling sublithospheric mantle due to lithospheric modulated convection (LMC) where the lithosphere is thin. The authors test the hypothesis that sublithospheric melt feeding the RVP can be generated from LMC. We develop a 3D thermomechanical model of LMC beneath the RVP and the Malawi Rift and constrain parameters for sublithospheric melt generation due to LMC. We assume a rigid lithosphere and use non-Newtonian, temperature-, pressure-, and porosity-dependent creep laws of anhydrous peridotite for the sublithospheric mantle. We find a pattern of upwelling from LMC beneath the RVP. The upwelling generates melt only for elevated mantle potential temperatures (T-p), which suggests a heat source possibly from plume material. At elevated T-p, LMC associated decompression melts occurs at a maximum depth of similar to 150 km beneath the RVP. We suggest upwelling due to LMC entrains plume materials resulting in melt generation beneath the RVP.en
dc.description.notesThis project is supported by the NSF EarthCube Integration grant #1740704 and #1740627. Most of the figures in this paper were generated with Generic Mapping Tools V5.4.2 (Wessel et al., 2013). We also created some of the figures with VISIT v2.9 developed by the Lawrence Livermore National Laboratory. We thank the Computational Infrastructure for Geodynamics for supporting the development of ASPECT, which is funded by National Science Foundation Awards EAR0949446 and EAR-1550901. We thank Editor Michael Bostock and Associate Editor Mark D. Behn for handling the manuscript and two reviewers: Dr. P. Barry and Dr. H. Schmeling for detailed and constructive comments.en
dc.description.sponsorshipNSF EarthCube Integration grant [1740704, 1740627]; National Science FoundationNational Science Foundation (NSF) [EAR-0949446, EAR-1550901]en
dc.description.versionPublished versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.doihttps://doi.org/10.1029/2020JB020728en
dc.identifier.eissn2169-9356en
dc.identifier.issn2169-9313en
dc.identifier.issue5en
dc.identifier.othere2020JB020728en
dc.identifier.urihttp://hdl.handle.net/10919/104434en
dc.identifier.volume126en
dc.language.isoenen
dc.rightsCreative Commons Attribution 4.0 Internationalen
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/en
dc.subjectEast African Riften
dc.subjectlithospheric modulated convectionen
dc.subjectMalawi Rift Zoneen
dc.subjectmelt generationen
dc.subjectRungwe Volcanic Provinceen
dc.subjectplume sourceen
dc.titleLithospheric Control of Melt Generation Beneath the Rungwe Volcanic Province, East Africa: Implications for a Plume Sourceen
dc.title.serialJournal of Geophysical Research-Solid Earthen
dc.typeArticle - Refereeden
dc.type.dcmitypeTexten
dc.type.dcmitypeStillImageen

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