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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Postcollisional mafic igneous rocks record crust-mantle interaction during continental deep subduction
TL;DR: Postcollisional mafic igneous rocks above continental subduction zones are an analog to arc volcanics above oceanic subduction zone, providing an additional laboratory for the study of crust-mantle interaction at convergent plate margins.
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Assessment of the Zr/Hf fractionation in oceanic basalts and continental materials during petrogenetic processes
TL;DR: In this paper, a negative correlation observed between Sc concentrations and Zr/Hf ratios indicates that during fractional crystallisation, the latter are controlled by the precipitation of clinopyroxene.
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Oceanic plateau and island arcs of southwestern Ecuador: their place in the geodynamic evolution of northwestern South America
Cedric Reynaud,Etienne Jaillard,Henriette Lapierre,Marc Mamberti,Marc Mamberti,Georges Mascle +5 more
TL;DR: Coastal Ecuador is made up of an oceanic igneous basement overlain by Upper Cretaceous to Lower Paleocene (≈98-60 Ma) volcaniclastic and volcanic rocks of island-arc affinities as mentioned in this paper.
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MORB-type rocks from the Paleo-Tethyan Mian-Lueyang northern ophiolite in the Qinling Mountains, central China: implications for the source of the low 206Pb/204Pb and high 143Nd/144Nd mantle component in the Indian Ocean
TL;DR: In this paper, Zhang et al. showed that the unique isotopic signature of both the Paleo-Tethyan oceanic igneous crust and the modern Indian MORB may have come from a very similar, if not identical mantle reservoir.
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Pb isotopic and elemental evidence for OIB derivation from young HIMU mantle
TL;DR: In this article, the authors proposed a model for the source of negative-7/4Pb ocean island basalts and showed that these OIBs can be derived from a relatively pure young HIMU 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.
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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.
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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.