Journal ArticleDOI
A large-scale isotope anomaly in the Southern Hemisphere mantle
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The authors showed that the isotopic mantle anomaly is globe-encircling in extent, centred on latitude 30° S. They also showed that this mantle anomaly has been in existence for billions of years and placed severe constraints on mantle convection models.Abstract:
Basalts from many Southern Hemisphere regions have anomalous Sr and Pb isotopic characteristics. This article shows that the isotopic mantle anomaly is globe-encircling in extent, centred on latitude 30° S. Arguments suggesting that this mantle anomaly has been in existence for billions of years place severe constraints on mantle convection models.read more
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A Cenozoic diffuse alkaline magmatic province (DAMP) in the Southwest Pacific without rift or plume origin
TL;DR: In this paper, the authors suggest that sudden detachment and sinking of subducted slabs in the late Cretaceous induced Rayleigh-Taylor instabilities along the former Gondwana margin that in turn triggered lateral and vertical flow of warm Pacific mantle.
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Crustal control in the genesis of Plio-Quaternary bimodal magmatism of the Main Ethiopian Rift (MER): geochemical and isotopic (Sr, Nd, Pb) evidence
TL;DR: In this article, the Asela-Ziway mafic and Chilalo intermediate lavas have been analyzed and shown to have a similar range of Nd and Pb isotopic ratios: 0.70392-0.70510.
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The age and distribution of mantle heterogeneity along the Mid-Atlantic Ridge (31–41°N)
TL;DR: In this article, trace element and isotope data for basalts from the mid-Atlantic ridge between 31 and 41oN allow a better description of the geochemical gradient south of the Azores triple junction, and the systematics of mantle source heterogeneity.
Journal ArticleDOI
Evolution of helium isotopes in the Earth's mantle
TL;DR: A new global data compilation of ocean island basalts, representing upwelling ‘plumes’ from the deep mantle, is presented, and it is inferred that differences between plumes and the upper-mantle source of ocean-ridge basalts reflect isolation of plume sources from the convecting mantle for ∼1–2 Gyr.
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The volcanism of southern Italy: Role of subduction and the relationship between potassic and sodic alkaline magmatism
TL;DR: In this paper, it was shown that midplate tholeiitic to Na-alkalic magmatism and continental margin calc-alkaline to ultrapotassic magmas were derived from mantle sources which, prior to subduction, had similar isotopic signatures.
References
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Journal ArticleDOI
Mantle plumes from ancient oceanic crust
TL;DR: In this article, the authors propose a model for the origin of hot-spot volcanism, where oceanic crust is returned to the mantle during subduction and sinks into the deeper mantle and accumulates at some level of density compensation, possibly the core-mantle boundary.
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Lead isotopic study of young volcanic rocks from mid-ocean ridges, ocean islands and island arcs
TL;DR: Lead isotopic compositions of young volcanic rocks from different tectonic environments have distinctive characteristics their differences are evaluated within the framework of global tectonics and mantle differentiation Ocean island leads are in general more radiogenic than mid-ocean ridge basalt (morb) leads as discussed by the authors.
Journal ArticleDOI
Ore lead isotope ratios in a continuously changing earth
G.L. Cumming,J.R. Richards +1 more
TL;DR: In this paper, a critical re-assessment of the construction of simple ore lead isotopic development curves is followed by three fresh approximations, all designed to involve the minimum possible number of assumptions.
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Sr and Nd isotope geochemistry of oceanic basalts and mantle evolution
TL;DR: Sr and Nd isotope ratios for 17 mid-ocean ridge basalts and for 11 oceanic islands and island groups are reported in this article, and the results are not explained by binary mixing of depleted and undepleted mantle reservoirs or variable magmatic depletion of a planetary reservoir, but support mantle evolution models involving re-injection of crust material into the mantle.
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Pb–Sr isotope variation in Indian Ocean basalts and mixing phenomena
Bernard Dupré,Claude J. Allègre +1 more
TL;DR: Pb and Sr isotopic compositions from the Indian Ocean (active ridges, old ocean floor and aseismic ridge samples) confirm the characteristic nature of the mantle record in this region as mentioned in this paper.