Geochemistry of the Neoproterozoic metabasic rocks from the Negele area, southern Ethiopia: Tectonomagmatic implications

Yihunie, Tadesse; Adachi, Mamoru; Yamamoto, Koshi

doi:10.1016/j.jafrearsci.2005.12.004

Cited by 11 publications

(6 citation statements)

References 34 publications

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“…(Rooney et al, 2014b). This xenolith evidence of a pervasive Pan-African aged influence in the regional lithospheric mantle is consistent with mapped crustal domains, which reveal a wide distribution of Pan-African derived subduction related volcanic rocks that comprise the current crust in this region (e.g., Stern 2002;Yihunie et al, 2006). Subsequent to the Pan-African events that formed the regional crust, some authors have suggested that a mantle plume event sometime during the Mesozoic may have impacted the lithospheric mantle and resulted in metasomatism (Baker et al, 2002).…”

Section: Accepted Manuscriptsupporting

confidence: 81%

“…Large degrees of shallow melting associated with Pan-African subduction beneath Ethiopia during the Neoproterozoic, generated mafic lavas with similarly flat HREE profiles and Sr-Nd isotopic values that overlap the Dedessa xenolith (Yihunie et al, 2006). Equally, LowTitanium (LT) flood basalts exhibit similar REE and Nd-Sr isotopic characteristics .…”

Section: Accepted Manuscriptmentioning

confidence: 99%

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The making of an underplate: Pyroxenites from the Ethiopian lithosphere

et al. 2017

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Section: Accepted Manuscriptsupporting

confidence: 81%

Section: Accepted Manuscriptmentioning

confidence: 99%

The making of an underplate: Pyroxenites from the Ethiopian lithosphere

et al. 2017

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“…Crustal contamination indicators, Ce/Pb and La/Nb, are plotted for Ethiopian samples. (a) Crustal rocks from Ethiopia [ Kebede et al , 1999; Sifeta et al , 2005; Tadesse and Allen , 2005; Yihunie et al , 2006] and 30 Ma flood basalts that exhibit a lower crustal contamination [ Pik et al , 1999; Kieffer et al , 2004]. The WFB and SDFZ lavas lie predominantly within the mantle field but extend to lower values of Ce/Pb, which may indicate crustal contamination.…”

Section: Resultsmentioning

confidence: 99%

“…Ce/Pb and La/Nb values (Figure 8) can be used to evaluate potential contamination by both upper crustal (basement rocks from Ethiopia [ Kebede et al , 1999; Sifeta et al , 2005; Tadesse and Allen , 2005; Yihunie et al , 2006]) and lower crustal lithologies (LT basalts [ Pik et al , 1999; Kieffer et al , 2004]). The majority of the WFB and SDFZ samples have La/Nb and Ce/Pb values that plot within the range observed in mantle‐derived basalts [ Hofmann et al , 1986].…”

Section: Discussionmentioning

confidence: 99%

Lithospheric modification during crustal extension in the Main Ethiopian Rift

Rooney¹,

Furman²,

Bastow³

et al. 2007

J. Geophys. Res.

119

123

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[1] Quaternary lavas erupted in zones of tectonomagmatic extension within the Main Ethiopian Rift (MER) preserve details of lithospheric structure in the East African Rift System. Despite observed source heterogeneity, basalts, trachybasalts, and basaltic trachyandesites erupted in the Wonjii Fault Belt (WFB) and the Silti-Debre Zeyit Fault Zone (SDFZ) form coherent fractionation paths dominated by variable removal of observed phenocryst phases. Crustal assimilation is not widespread, though it is observed at the southern end of the WFB where both fault belts merge; farther north, assimilation of cumulate phases related to fractional crystallization of previous magmas is identified. Shallow fractionation conditions ($1 kbar) within the WFB do not change from north to south. In contrast, lavas erupted within the contemporaneous SDFZ fractionate at various crustal depths. These results indicate a better developed magmatic system beneath the WFB where magmas rose quickly before undergoing more significant fractionation at near surface levels and a less developed system beneath the SDFZ. The distribution of magmatism and extant geophysical data indicate thinned crust and a single rift-centered zone of magmatic activity northeast of 8°30 0 N, consistent with a transitional lithosphere between continental and oceanic settings. Southwest of 8°30 0 N, thicker crust and riftmarginal axes of extension suggest lithosphere with continental affinities. The WFB is propagating southward in response to extension within the Red Sea Rift; the northward propagating SDFZ is related to rifting within the East African Rift System. This region records the unification of two rift systems, requiring care in interpreting the MER as simply transitional between continental and oceanic environments.

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“…Most are decorated by linear belts of mafic and ultramafic rocks with ophiolitic affinity. The sutures are flanked by partly migmatic gneiss terranes (given different names in different places) where rocks show higher grades of metamorphism ( Tsige and Abdelsalam, 2005 , Yihunie et al, 2006 , Yihunie and Hailu, 2007 , Stern et al, 2010b , Woldemichael et al, 2010 ). The nature of these orthogneiss terranes is debated.…”

Section: Accretion and Thickening In The Arabian–nubian Shieldmentioning

confidence: 99%

Orogen styles in the East African Orogen: A review of the Neoproterozoic to Cambrian tectonic evolution

Fritz

Abdelsalam

Ali

et al. 2013

Journal of African Earth Sciences

633

348

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GraphicalabstractCondensed timetable of major geologic events in the East African Orogen. Opening of the Mozambique Ocean and formation of rift basins in Zambia, Malawi, Mozambique and SW Madagascar was accompanied by emplacement of anorthosite melt in extending crust. A first phase of ocean closure and accretion of terranes defines the East African Orogeny. The second orogen phase, Kuungan Orogeny, mainly affected the southern parts of east Africa and Madagascar. Both shortening events were followed by extension phases that were accompanied by emplacement of late- to post-tectonic granitoids. EGCD: Eastern Granulite–Cabo Delgado Nappe Complex; Madag: Madagascar; Ub–Us: Usagaran/Ubendian Belts; WG: Western Granulite Belt; IB (Z–M): Irumide Belt of Zambia and Malawi; IB (M): Irumide Belt of Mozambique.

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Geochemistry of the Neoproterozoic metabasic rocks from the Negele area, southern Ethiopia: Tectonomagmatic implications

Cited by 11 publications

References 34 publications

The making of an underplate: Pyroxenites from the Ethiopian lithosphere

The making of an underplate: Pyroxenites from the Ethiopian lithosphere

Lithospheric modification during crustal extension in the Main Ethiopian Rift

Orogen styles in the East African Orogen: A review of the Neoproterozoic to Cambrian tectonic evolution

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