TY  - JOUR
AU  - Montagner, J-P
AU  - Marty, B.
AU  - Stutzmann, E.
AU  - Sicilia, D.
AU  - Cara, M.
AU  - Pik, R.
AU  - Lévêque, J-J
AU  - Roult, G.
AU  - Beucler, E.
AU  - Debayle, E.
PY  - 2007//
TI  - Mantle upwellings and convective instabilities revealed by seismic tomography and helium isotope geochemistry beneath eastern Africa
JO  - Geophysical research letters
VL  - 34
PB  - American Geophysical Union
KW  - anisotropy tomography
KW  - helium isotope data
KW  - Africa
KW  - 8121 Tectonophysics: Dynamics: convection currents
KW  - and mantle plumes
KW  - 7270 Seismology: Tomography
KW  - 1040 Geochemistry: Radiogenic isotope geochemistry
KW  - 7208 Seismology: Mantle
KW  - 9305 Geographic Location: Africa
N2  - The relationship between intraplate volcanism and continental tectonics has been investigated for North and East Africa using a high resolution three-dimensional anisotropic tomographic model derived from seismic data of a French experiment “Horn of Africa” and existing broadband data. The joint inversion for seismic velocity and anisotropy of the upper 400 km of the mantle, and geochemical data reveals a complex interaction between mantle upwellings, and lithosphere. Two kinds of mantle upwellings can be distinguished: The first one, the Afar “plume” originates from deeper than 400 km and is characterized by enrichment in primordial 3He and 3He/4He ratios higher than those along mid-ocean ridges (MOR). The second one, associated with other Cenozoic volcanic provinces (Darfur, Tibesti, Hoggar, Cameroon), with 3He/4He ratios similar to, or lower than MOR, is a consequence of shallower upwelling. The presumed asthenospheric convective instabilities are oriented in an east-west direction, resulting from interaction between south-north asthenospheric mantle flow, main plume head and topography on the base of lithosphere.
SN  - 0094-8276
UR  - http://dx.doi.org/10.1029/2007GL031098
N1  - exported from refbase (http://publi.ipev.fr/polar_references/show.php?record=5511), last updated on Mon, 27 Apr 2009 17:50:28 +0200
ID  - Montagner_etal2007
ER  -