Continental Flood Basalts and Mantle Plumes: a Case Study of the Northern Ethiopian Plateau

Beccaluva, Luigi; Bianchini, Gianluca; Natali, Claudio; Siena, Franca

doi:10.1093/petrology/egp024

Cited by 152 publications

(172 citation statements)

References 63 publications

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“…In contrast, Group 4b dikes yield ages clustered around 24 Ma and are restricted to the Desse-Combolcha sector. These dikes are (Pik et al, 1999;Kieffer et al, 2004;Beccaluva et al, 2009). Group 1 samples plot within the range of other western plateau samples and exhibit a similar trace element pattern.…”

Section: Group 4 Dikes ($25-12 Ma)mentioning

confidence: 62%

“…On the basis of geochemistry, the Ethiopian (or Western) plateau has been divided into separate high-and low-titanium (HT and LT) domains (Pik et al, 1998). While this study lies well within the HT domain, Group 1 dikes have a geochemical signature that broadly resembles that of the earliest, low-titanium (LT) Ethiopian Plateau flood basalts (Kieffer et al, 2004;Beccaluva et al, 2009). Major element variation diagrams for Group 1 dolerites and LT basalts typically overlap, though Al 2 O 3 is significantly lower and TiO 2 slightly elevated in the dolerites (Fig.…”

Section: Groups 1 and 2 Dikes ($31-27 Ma)mentioning

confidence: 97%

“…Group 1 samples plot within the range of other western plateau samples and exhibit a similar trace element pattern. (b) High-Ti type 1 (HT-1) basalts from Group 2 are plotted with HT-1 samples from the western Ethiopian plateau (Pik et al, 1999;Beccaluva et al, 2009). Patterns between both series broadly correlate though Group 2 samples extend to depleted values of the more compatible elements, and higher values of Nb-Ta in comparison to other HT-1 basalts.…”

Section: Group 4 Dikes ($25-12 Ma)mentioning

confidence: 99%

“…These variations may reflect lithospheric assimilation evident in the radiogenic isotope properties of these rocks. (Pik et al, 1999;Kieffer et al, 2004;Beccaluva et al, 2009) and Yemen (Baker et al, 1996b). (a) MgO-X diagrams illustrating the variance between our Group 3 and the 10 MaRecent activity in MER of Ethiopia (Rooney et al, 2005;Furman et al, 2006;Rooney et al, 2007;Rooney, 2010), Pliocene-Quaternary Djibouti, Quaternary Asal Rift, and 4-9 Ma Dahla series (Deniel et al, 1994).…”

Section: Group 4 Dikes ($25-12 Ma)mentioning

confidence: 99%

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Geochemical evidence of mantle reservoir evolution during progressive rifting along the western Afar margin

Rooney

Mohr

Dosso

et al. 2013

Geochimica et Cosmochimica Acta

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evidence of mantle reservoir evolution during progressive rifting along the western Afar margin. Geochimica et Cosmochimica Acta, Elsevier, 2013Elsevier, , 102, pp.65-88. 10.1016Elsevier, /j.gca.2012 Geochemical evidence of mantle reservoir evolution during progressive rifting along the western Afar margin AbstractThe Afar triple junction, where the Red Sea, Gulf of Aden and African Rift System extension zones converge, is a pivotal domain for the study of continental-to-oceanic rift evolution. The western margin of Afar forms the southernmost sector of the western margin of the Red Sea rift where that margin enters the Ethiopian flood basalt province. Tectonism and volcanism at the triple junction had commenced by $31 Ma with crustal fissuring, diking and voluminous eruption of the EthiopianYemen flood basalt pile. The dikes which fed the Oligocene-Quaternary lava sequence covering the western Afar rift margin provide an opportunity to probe the geochemical reservoirs associated with the evolution of a still active continental margin. 40 Ar/ 39 Ar geochronology reveals that the western Afar margin dikes span the entire history of rift evolution from the initial Oligocene flood basalt event to the development of focused zones of intrusion in rift marginal basins. Major element, trace element and isotopic (Sr-Nd-Pb-Hf) data demonstrate temporal geochemical heterogeneities resulting from variable contributions from the Afar plume, depleted asthenospheric mantle, and African lithosphere. The various dikes erupted between 31 Ma and 22 Ma all share isotopic signatures attesting to a contribution from the Afar plume, indicating this initial period in the evolution of the Afar margin was one of magma-assisted weakening of the lithosphere. From 22 Ma to 12 Ma, however, diffuse diking during continued evolution of the rift margin facilitated ascent of magmas in which depleted mantle and lithospheric sources predominated, though contributions from the Afar plume persisted. After 10 Ma, magmatic intrusion migrated eastwards towards the Afar rift floor, with an increasing fraction of the magmas derived from depleted mantle with less of a lithospheric signature. The dikes of the western Afar margin reveal that magma generation processes during the evolution of this continental rift margin are increasingly dominated by shallow decompressional melting of the ambient asthenosphere, the composition of which may in part be controlled by preferential channeling of plume material along the developing neo-oceanic axes of extension.

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Section: Group 4 Dikes ($25-12 Ma)mentioning

confidence: 62%

Section: Groups 1 and 2 Dikes ($31-27 Ma)mentioning

confidence: 97%

Section: Group 4 Dikes ($25-12 Ma)mentioning

confidence: 99%

Section: Group 4 Dikes ($25-12 Ma)mentioning

confidence: 99%

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Geochemical evidence of mantle reservoir evolution during progressive rifting along the western Afar margin

Rooney

Mohr

Dosso

et al. 2013

Geochimica et Cosmochimica Acta

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“…Physical state of the Ethiopian mantle: evidence from the geological record The~2 km thick sequences of flood basalts and rhyolites that erupted onto the Ethiopian plateau (e.g., Baker et al, 1996;Hofmann et al, 1997) prior to or concomitant with the 29-31 Ma onset of extension in the Red Sea and Gulf of Aden rift systems (e.g., Wolfenden et al, 2004), have frequently been cited as evidence for one or more traditional mantle plumes beneath the region. The location and number of plumes or upper mantle convective cells are debated, however (e.g., Beccaluva et al, 2009;Burke, 1996;Courtillot et al, 1999;Ebinger and Sleep, 1998;Furman et al, 2006;George et al, 1998;Kieffer et al, 2004;Rogers, 2006;Rogers et al, 2000;Rooney et al, 2012a,b;Schilling et al, 1992). Ebinger and Sleep (1998), for example, suggested that one large plume spread beneath the African Plate near Turkana at~45 Ma, with melt production minimal until lithospheric thinning commenced in the Red Sea and Gulf of Aden.…”

Section: The Ethiopian Mantlementioning

confidence: 99%

The development of extension and magmatism in the Red Sea rift of Afar

et al. 2013

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Despite the importance of continental breakup in plate tectonics, precisely how extensional processes such as brittle faulting, ductile plate stretching, and magma intrusion evolve in space and time during the development of new ocean basins remains poorly understood. The rifting of Arabia from Africa in the Afar depression is an ideal natural laboratory to address this problem since the region exposes subaerially the tectonically active transition from continental rifting to incipient seafloor spreading. We review recent constraints on along-axis variations in rift morphology, crustal and mantle structure, the distribution and style of ongoing faulting, subsurface magmatism and surface volcanism in the Red Sea rift of Afar to understand processes ultimately responsible for the formation of magmatic rifted continental margins. Our synthesis shows that there is a fundamental change in rift morphology from central Afar northward into the Danakil depression, spatially coincident with marked thinning of the crust, an increase in the volume of young basalt flows, and subsidence of the land towards and below sea-level. The variations can be attributed to a northward increase in proportion of extension by ductile plate stretching at the expense of magma intrusion. This is likely in response to a longer history of localised heating and weakening in a narrower rift. Thus, although magma intrusion accommodates strain for a protracted period during rift development, the final stages of breakup are dominated by a phase of plate stretching with a shift from intrusive to extrusive magmatism. This late-stage pulse of decompression melting due to plate thinning may be responsible for the formation of seaward dipping reflector sequences of basalts and sediments, which are ubiquitous at magmatic rifted margins worldwide.

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Non-plume flood basalt volcanism before the emplacement of the Afar mantle plume head

Yoshimura

Ishizuka

Yamazaki

et al. 2022

Preprint

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The Ethiopia-Yemen flood basalts are spatially zoned with progressively lower TiO2 lavas from near the Afar depression toward the margins. The timing and rate of emplacement of low TiO2 (LT) lavas are poorly known compared with the ultra-high TiO2 (HT2) lavas. We measured two high-precision 40Ar/39Ar ages of 29.63 ± 0.14 and 30.02 ± 0.22 Ma (2σ) from basalts of the 2-km-thick LT lava sequence at the Afar plume head margin. Using our eruption age model constructed from our and previous 40Ar/39Ar ages with the paleomagnetic directions, we estimate that the LT lava eruption continued over Chrons C12r-C12n-C11r. The eruption of the plume head margin started earlier than the plume head axis emplacement in C12n. Also, the eruption rate was low at the margin, high at the axis. We estimate that the LT lavas are induced by the edge-driven convection, the result of a plume-lithosphere interaction, not a plume head.

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Continental Flood Basalts and Mantle Plumes: a Case Study of the Northern Ethiopian Plateau

Cited by 152 publications

References 63 publications

Geochemical evidence of mantle reservoir evolution during progressive rifting along the western Afar margin

Geochemical evidence of mantle reservoir evolution during progressive rifting along the western Afar margin

The development of extension and magmatism in the Red Sea rift of Afar

Non-plume flood basalt volcanism before the emplacement of the Afar mantle plume head

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