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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He, Sr and Nd isotopic variations in lavas from the Juan Fernandez Archipelago, SE Pacific
TL;DR: A suite of lavas from the intra-plate volcanos of the Juan Fernandez Archipelago, Chile have been measured and helium, Sr, and Nd isotopic ratios and major and trace element compositions were measured as mentioned in this paper.
Journal ArticleDOI
South Atlantic DUPAL anomaly — Dynamic and compositional evidence against a recent shallow origin
Cornelia Class,Anton P. le Roex +1 more
TL;DR: In this article, the authors identify the Namaqua-Natal Belt of southern Africa as the most likely origin of any subcontinental lithospheric mantle (SCLM) or lower continental crust (LCC) recently introduced into the source of DUPAL oceanic basalts by processes of plume erosion of the SCLM, general erosion of SCLMs by the mantle flow field, or tectonic detachment of SMLM and LCC related to continental breakup.
Journal ArticleDOI
Onset of the Indian Ocean isotopic signature in the Philippine Sea Plate: Hf and Pb isotope evidence from Early Cretaceous terranes
TL;DR: In this paper, the authors examined the isotopic composition of rocks from Early Cretaceous terranes within the Philippine Sea Plate, in order to understand the onset and origin of the Indian Ocean mid-ocean ridge basalts (MORB).
Journal ArticleDOI
Origin of geochemical mantle components: Role of subduction filter
TL;DR: In this article, the role of the subduction zone filter in the Earth's geochemical cycle is explored using numerical mass balance models, and it is shown that the residual igneous oceanic crust from hot subduction zones can evolve isotopically to the HIMU mantle component, the residual base of the mantle wedge to EMI, and the residual sediment becomes an essential part of EMII.
Journal ArticleDOI
The Incompatible Element Characteristics of an Ancient Subducted Sedimentary Component in Ocean Island Basalts from French Polynesia
TL;DR: In this article, the isotopic char-acteristics of the end-member mantle components are derived by ancient subduction of oceanic crust, delamination and subsequent sinking of subcontinental lithosphere deep into the mantle.
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.
Journal ArticleDOI
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.
Journal ArticleDOI
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.
Journal ArticleDOI
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.