Isotopic and trace element signatures of Ethiopian flood basalts: evidence for plume–lithosphere interactions

Pik, Raphaël; Deniel, Catherine; Coulon, Christian; Yirgu, Gezahegn; Marty, Bernard

doi:10.1016/s0016-7037(99)00141-6

Cited by 272 publications

(270 citation statements)

References 59 publications

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“…7; samples MER 1302, SUD 1443, 14565 in eFig. 5) comparable to the low Ti Afar flood basalts, which were considered to be crust-contaminated (Pik et al 1999). Further, the La/Nb ratios of MER 1302 and SUD 14565 are more crust-like compared with the composition of all other samples (eFig.5 i-l).…”

Section: Crustal Contamination By Juvenile Crustmentioning

confidence: 89%

“…6). Possible distinctive isotopic compositions of the Afar-plume have been extracted from the flood basalts by Baker et al (1996) and Pik et al (1999) and younger rocks occurring in the area influenced by the Afarplume (Djibouti; Vidal et al 1991;Deniel et al 1994;Barrat et al 1998). Pb isotope compositions of the plume material are less (most samples: 206 Pb/ 204 Pb<19) and Sr isotopes more radiogenic (most samples 87 Sr/ 86 Sr>0.7035) than of intra-plate magmatic rocks from NE-Africa ( Fig.…”

Section: Lithospheric Versus Convective Mantle Sources In the Intra-pmentioning

confidence: 99%

“…9). Substantial contributions of material from the Afar-plume indicating young metasomatism according to process (1) are precluded for NE-African and Arabian (discussion in Bertrand et al 2003) intra-plate magmatic rocks, because a high-µ signature of this plume has not been established (e.g., Vidal et al 1991;Schilling et al 1992;Deniel et al 1994;Baker et al 1996Baker et al , 1997Baker et al , 1998Pik et al 1999).…”

Section: Origin Of the Radiogenic Pb In The Lithospheric Mantle And Imentioning

confidence: 99%

“…Isotope compositions of the Afar-plume at ~30 Ma (e.g. Baker et al 1996;Pik et al 1999) and younger rocks ascribed to the activity of this plume (Deniel et al 1994;Barrat et al 1998 are not substantially different (Furman et al 2006 b). These isotope compositions can be explained by (1) mixing between melts from the convective MORB-type mantle and the regional lithospheric mantle sources, (2) as melts from the lithospheric mantle, and (3) as melts from a source sui generis related to the plume.…”

Section: Implications For the Composition Of The Afar Flood Basaltsmentioning

confidence: 99%

“…(3) The Ethiopian and Yemenite ('Afar') flood basalts form a third compositional group, which erupted around ca 30 Ma , before the onset of rifting in the Afar region. The variations in their isotope ratios were interpreted in terms of a slightly heterogeneous depleted sub-lithospheric mantle source without affinities to high-µ or MORB type mantle endmembers, which represents the presumable Afar plume composition, and variable contributions of lithospheric mantle and/or crust (e.g., Baker et al 1996Baker et al , 1997Pik et al 1999). The recent composition of the Afar plume was derived from young basalts of the Afar region (e.g., Deniel et al 1994;Barrat et al 1998).…”

Section: Introductionmentioning

confidence: 99%

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Nd, Pb, and Sr isotope composition of Late Mesozoic to Quaternary intra-plate magmatism in NE-Africa (Sudan, Egypt): high-μ signatures from the mantle lithosphere

Lucassen

Franz

Romer

et al. 2008

Contrib Mineral Petrol

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The isotopic composition of mafic small-volume intra-plate magmatism constrains the compositions of the sub-continental mantle sources. The Nd, Pb, and Sr isotope signatures of widespread late Mesozoic to Quaternary intra-plate magmatism in NE Africa (Sudan, South Egypt) are surprisingly uniform and indicate the presence of a high-µ (µ= 238 U/ 204 Pb) source in the mantle. The rocks are characterized by small ranges in the initial isotopic composition of Nd, Pb, and Sr and most samples fall within ε Nd ca 3 to 6, 206 Sr/ 86 Sr ca. 0.7028 to 0.7034. We interpret this reservoir as lithospheric mantle that formed beneath the Pan-African orogens and magmatic arcs from asthenospheric mantle, which was enriched in trace elements (U, Th, and light REE). Combining our new data set with published data of intra-plate magmatic rocks from the Arabian plate indicates two compositionally different domains of lithospheric mantle in NE-Africa -Arabia. The two domains are spatially related to the subdivision of the Pan-African orogen into a western section dominated by reworked cratonic basement (NEAfrica; high-µ lithospheric mantle) and an eastern section dominated by juvenile Pan-African basement (easternmost NE-Africa and Arabia; moderate µ lithospheric mantle). The compositions of the Pan-African lithospheric mantle and the MORB-type mantle of the Red Sea and Gulf of Aden spreading centers could explain the Nd-Pb-Sr isotopic compositions of the most pristine Afar flood basalts in Yemen and Ethiopia by mixtures of the isotopic composition of regional lithospheric and asthenospheric sources.

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Section: Crustal Contamination By Juvenile Crustmentioning

confidence: 89%

Section: Lithospheric Versus Convective Mantle Sources In the Intra-pmentioning

confidence: 99%

Section: Origin Of the Radiogenic Pb In The Lithospheric Mantle And Imentioning

confidence: 99%

Section: Implications For the Composition Of The Afar Flood Basaltsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Nd, Pb, and Sr isotope composition of Late Mesozoic to Quaternary intra-plate magmatism in NE-Africa (Sudan, Egypt): high-μ signatures from the mantle lithosphere

Lucassen

Franz

Romer

et al. 2008

Contrib Mineral Petrol

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Coronae formation on Venus via extension and lithospheric instability

2014

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Over 500 quasi-circular volcano-tectonic features called coronae occur on Venus. They are believed to form via small-scale mantle upwellings, lithospheric instability, or a combination thereof. Coronae and rifts commonly occur together, including many coronae that lie outside of the fracture zone. However, the genetic link between the two has remained unclear. This paper proposes a mechanism for the formation of off-rift coronae due to the rifting process. We model the interaction of a rising mantle plume associated with a rift with a hypothetical preexisting layer of dense material in the lithosphere. We show that a rift and its associated off-rift coronae could be genetically linked by the process of development of secondary ringlike dripping instabilities initiating at the plume margins. We calculate the resulting surface topographies, melt volumes, and Bouguer gravity anomalies and compare them to observations.

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Multiple mantle upwellings in the transition zone beneath the northern East‐African Rift system from relative P‐wave travel‐time tomography

Civiero

Hammond

Goes

et al. 2015

Geochem Geophys Geosyst

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Mantle plumes and consequent plate extension have been invoked as the likely cause of East African Rift volcanism. However, the nature of mantle upwelling is debated, with proposed configurations ranging from a single broad plume connected to the large low-shear-velocity province beneath Southern Africa, the so-called African Superplume, to multiple lower-mantle sources along the rift. We present a new P-wave travel-time tomography model below the northern East-African, Red Sea, and Gulf of Aden rifts and surrounding areas. Data are from stations that span an area from Madagascar to Saudi Arabia. The aperture of the integrated data set allows us to image structures of 100 km length-scale down to depths of 700-800 km beneath the study region. Our images provide evidence of two clusters of low-velocity structures consisting of features with diameter of 100-200 km that extend through the transition zone, the first beneath Afar and a second just west of the Main Ethiopian Rift, a region with off-rift volcanism. Considering seismic sensitivity to temperature, we interpret these features as upwellings with excess temperatures of 100 6 50 K. The scale of the upwellings is smaller than expected for lower mantle plume sources. This, together with the change in pattern of the low-velocity anomalies across the base of the transition zone, suggests that ponding or flow of deep-plume material below the transition zone may be spawning these upper mantle upwellings.

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Isotopic and trace element signatures of Ethiopian flood basalts: evidence for plume–lithosphere interactions

Cited by 272 publications

References 59 publications

Nd, Pb, and Sr isotope composition of Late Mesozoic to Quaternary intra-plate magmatism in NE-Africa (Sudan, Egypt): high-μ signatures from the mantle lithosphere

Nd, Pb, and Sr isotope composition of Late Mesozoic to Quaternary intra-plate magmatism in NE-Africa (Sudan, Egypt): high-μ signatures from the mantle lithosphere

Coronae formation on Venus via extension and lithospheric instability

Multiple mantle upwellings in the transition zone beneath the northern East‐African Rift system from relative P‐wave travel‐time tomography

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