Relationships between Mafic and Peralkaline Silicic Magmatism in Continental Rift Settings: a Petrological, Geochemical and Isotopic Study of the Gedemsa Volcano, Central Ethiopian Rift

Peccerillo, Angelo; Barberio, Marino Domenico; Yirgu, Gezahegn; Ayalew, Dereje; Barbieri, M. Adelaide; Wu, Tian

doi:10.1093/petrology/egg068

Cited by 390 publications

(284 citation statements)

References 66 publications

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“…In addition, the rhyolites have relatively lower ε Nd(t) and higher ( 206 Pb/ 204 Pb) t than HAB. Fractionation of basaltic magmas or partial melting of mafic rocks will produce small amounts of silicic magma (Knesel and Davidson, 1997;Peccerillo et al, 2003). 10 km 3 of parental basaltic equivalents are required to generate 1 km 3 of rhyolite.…”

Section: Fractional Crystallization Of Coexisted High-al Basaltmentioning

confidence: 99%

Petrogenesis and geodynamic implications of the Late Carboniferous felsic volcanics in the Bogda belt, Chinese Northern Tianshan

Xie

Luo

et al. 2016

Gondwana Research

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Section: Fractional Crystallization Of Coexisted High-al Basaltmentioning

confidence: 99%

Petrogenesis and geodynamic implications of the Late Carboniferous felsic volcanics in the Bogda belt, Chinese Northern Tianshan

Xie

Luo

et al. 2016

Gondwana Research

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“…The WFB is segmented along its length into~60-km-long, right stepping en-echelon volcanic systems (Ebinger and Casey, 2001), which consist of fault bounded lava units b 2 Ma (Morton et al, 1979;Chernet et al, 1998; and are characterised by a bimodal distribution of mafic and acidic magma types (e.g. Trua et al, 1999;Peccerillo et al, 2003).…”

Section: Study Areamentioning

confidence: 99%

Spatial relationship between earthquakes and volcanic vents in the central-northern Main Ethiopian Rift

Mazzarini

Keir

Isola

2013

Journal of Volcanology and Geothermal Research

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During the breakup of continents extension is commonly accommodated by connected networks of fluid filled fractures (dykes) and by faults. Despite the importance of these two extension mechanisms their spatial relationship in three dimensions is poorly understood primarily because it is difficult to quantify the subsurface distribution of faulting and intrusion. In order to address this problem, we conduct a quantitative analysis of the spatial distribution and clustering of earthquakes and volcanic vents in the Main Ethiopian Rift in East Africa in order to understand how extension by faulting and intrusion is distributed throughout the volcanic rift. We use fractal analysis of earthquake epicentres in order to infer the 2D characteristics of the subsurface fault network, and directly test our model results against the 3D distribution of earthquake hypocentres. Our results show that fractal analysis of these features is a reliable means to characterise the 3D properties of the fault network. In addition, the strong similarity between the properties of the fault network derived from earthquakes and properties of the magma-filled fracture network derived from fractal analysis of volcanic vents strongly suggests that these are genetically linked. We then explore their spatial link using computation of earthquake and vent density, which shows that the zone of seismicity is generally around 20-30-km-wide, while the zone of vents is narrower and centred within the zone of seismicity. This spatial relationship suggests that the faults, which form rift axial grabens, are induced above a narrower and central zone of diking. We also demonstrate significant along-rift variation in degree of magmatism and faulting with regions of increased degree of diking inferred from a higher cone density characterised by reduced degree of faulting.

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“…Fractional crystallization of basaltic magma rather than anatexis of continental crust was the major source for the silicic magmas of the Afar and rift valley margins Peccerillo et al, 2003;Peccerillo et al, 2007;Ayalew and Gibson, 2009;Rooney et al, 2012b). A lessened magma supply rate, resulting in magmatic intrusion at greater depths and slower cooling (Behn et al, 2006), fostered crystal fractionation processes together with lithospheric assimilation.…”

Section: Stage 2: Tectonic Stretchingmentioning

confidence: 99%

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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Relationships between Mafic and Peralkaline Silicic Magmatism in Continental Rift Settings: a Petrological, Geochemical and Isotopic Study of the Gedemsa Volcano, Central Ethiopian Rift

Cited by 390 publications

References 66 publications

Petrogenesis and geodynamic implications of the Late Carboniferous felsic volcanics in the Bogda belt, Chinese Northern Tianshan

Petrogenesis and geodynamic implications of the Late Carboniferous felsic volcanics in the Bogda belt, Chinese Northern Tianshan

Spatial relationship between earthquakes and volcanic vents in the central-northern Main Ethiopian Rift

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

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