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Have wet and dry Precambrian crust largely governed Cenozoic intraplate magmatism from Arabia to East Africa?
Author(s) -
Bonavia Franco F.,
Chorowicz Jean,
Collet Bernard
Publication year - 1995
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/95gl02061
Subject(s) - geology , crust , flood basalt , craton , mantle plume , geochemistry , plume , precambrian , earth science , volcanism , intraplate earthquake , oceanic crust , magmatism , continental crust , east african rift , lithosphere , tectonics , paleontology , rift , subduction , physics , thermodynamics
To explain Cenozoic continental volcanism between Arabia and East Africa, the existing model infers that a plume impinged beneath Ethiopia, between 30 Ma and 20 Ma, and volcanism extruded within a 1000 km radius. Because relative motion of the Afro‐Arabian plate was about northeast in the last 120 Ma, we infer that at 84 Ma a plume, originated from the core‐mantle boundary, impinged beneath Nubia‐Arabia and is now under the Tanzania craton. This plume caused uplift (Afro‐Arabian swell) and magma under‐plating. After Fyfe's idea (1992), the conceptual model proposed herein suggests that, following plume impact, there was in Nubia‐Arabia only intrusion of mafic dykes because the crust was largely unprocessed (wet). At about 50 Ma the plume was under Ethiopia, and coeval volcanism extruded because the crust was highly recycled (dry). In Zaire‐Burundi and Tanzania, volcanism is explained to be coeval with the arrival of the plume because there also the crust is recycled. In Arabia and Yemen‐Ethiopia continental‐flood basalts younger than 30 Ma formed because lithospheric extension along the Red Sea‐Gulf of Aden was the cause of (or the result of) plume(s), probably originated from the upper mantle.