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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Structure and geochemistry of an Alaskan-type ultramafic–mafic complex in the Eastern Pontides, NE Turkey
Yener Eyuboglu,Yener Eyuboglu,Yildirim Dilek,Erdin Bozkurt,Osman Bektaş,Bora Rojay,Cüneyt Şen +6 more
TL;DR: The Karayasmak ultramafic-mafic association (KUMA) in NE Turkey represents an Alaskan-type, pre-Liassic intrusion in the Pulur metamorphic massif and is one of many such intrusive complexes that were emplaced into the continental basement of the Eastern Pontides belt during the pre-Lithassic as mentioned in this paper.
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Seismic Modelling of the Earth's Large-Scale Three-Dimensional Structure
TL;DR: Several methods of seismic inversion and intercom pare the resulting models as mentioned in this paper, leading to a coherent picture of the Earth's internal heterogeneity, which can be used to explain some aspects of observed plate motion in terms of thermal convection in the mantle.
Journal ArticleDOI
The Cobb‐Eickelberg Seamount Chain: Hotspot volcanism with mid‐ocean ridge basalt affinity
Dana L. Desonie,Robert A. Duncan +1 more
TL;DR: Cobbs hotspot is a stationary, upper mantle melting anomaly whose volcanic products show strong mid-ocean ridge basalt (MORE) affinity as discussed by the authors, which is consistent with movement of the Pacific plate over a fixed Cobb hotspot and eventual encroachment by the westwardly migrating Juan de Fuca ridge.
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The Geochemistry of the Arabian Lithospheric Mantle—a Source for Intraplate Volcanism?
TL;DR: DANISH LITHOSPHERE CENTRE, STER VOLDGADE 10, COPENHAGEN, 1350K, DENMARK DEPARTMENT OF GEOLOGY, ROYAL HOLLOWAY UNIVERSITY OF LONDON, EGHAM TW20 0EX, UK SCHOOL OF EARTH SCIENCES, VICTORIA UNIVERSITY of WELLINGTON, PO BOX 600, WELLTONS, New ZEALAND, New Zealand, DePARTMENT of Earth and Environment Sciences, OREGON STATE UNIVERSITY, CORV
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Plume versus lithospheric sources for melts at Ua Pou, Marquesas Islands
TL;DR: In this paper, the authors report isotopic (Sr, Nd and Pb) and K-Ar age measurements for tholeiites, alkali basalts and differentiated rocks from the island of Ua Pou.
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.