Journal ArticleDOI
A large-scale isotope anomaly in the Southern Hemisphere mantle
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TLDR
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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Seismic evidence for a thermo-chemical boundary at the base of the Earth’s mantle
TL;DR: In this article, seismic evidence for a unique 300 km thick layer at the base of the mantle beneath the south Atlantic ocean, with a steeply dipping edge, anomalously low shear wave velocities linearly decreasing from 2% (top) to 10-12% (bottom), and a maximum P velocity decrease of 3% relative to the preliminary reference Earth model (PREM).
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Isotopic data from the Amba Dongar Carbonatite Complex, west-central India: Evidence for an enriched mantle source
TL;DR: In this paper, the authors proposed that the Reunion hot spot responsible for the Deccan flood basalts may have had some bearing on producing the parental melt that generated the Amba Dongar carbonatite.
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Geochemistry of Early Cretaceous calc-alkaline lamprophyres in the Jiaodong Peninsula: Implication for lithospheric evolution of the eastern North China Craton
Liang Ma,Shao-Yong Jiang,Shao-Yong Jiang,Ming-Lan Hou,Bao-Zhang Dai,Yao-Hui Jiang,Tao Yang,Kui-Dong Zhao,Kui-Dong Zhao,Wei Pu,Zhiyong Zhu,Bin Xu +11 more
TL;DR: In this paper, the authors analyzed major and trace elements and isotopic compositions of lamprophyres from the Linglong and Penglai Au-ore districts in the Jiaodong Peninsula, in an attempt to better understand Mesozoic lithospheric evolution beneath the eastern North China Craton.
Journal ArticleDOI
A MORB source for low-Ti magmatism in the Semail ophiolite
TL;DR: In this article, a trace element and Nd, Sr and Pb isotope study of a tholeiitic volcanic section in the Salahi massif was carried out in order to characterize the evolution from MOR-type (Geotimes) to the earliest stages of low-Ti arc-like (Lasail) magmatism in the Semail ophiolite.
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SrNdPb geochemical morphology between 10° and 17°N on the Mid-Atlantic Ridge: A new MORB isotope signature
Laure Dosso,Barry B. Hanan,Barry B. Hanan,Henri Bougault,Jean-Guy Schilling,Jean-Louis Joron +5 more
TL;DR: In this article, the 14°N mantle source is shown to be a mixture of Walvis-like and HIMU-like materials and the geochimical observations support the model of an incipient ridge-centered plume.
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.