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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Pb-Nd isotopic constraints on sedimentary input into the Lesser Antilles arc system
TL;DR: In this paper, the authors presented new Nd, Sm, Th, U and Pb concentrations and Nd-Pb isotopic data for over 60 sediments from three sites located in the fore arc region of the Lesser Antilles arc.
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The Somuncura Large Igneous Province in Patagonia: Interaction of a Transient Mantle Thermal Anomaly with a Subducting Slab
TL;DR: The Oligo-Miocene Somuncura province is the largest back-arc mafic volcanic field in Patagonia, and one of Earth's largest with no clear link to a hotspot or major extension.
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Re — Os isotopic constraints on the origin of volcanic rocks, Gorgona Island, Colombia: Os isotopic evidence for ancient heterogeneities in the mantle
TL;DR: The Re-Os isotopic systematics of komatiites and spatially associated basalts from Gorgona Island, Colombia, indicate that they were produced at 155±43 Ma as discussed by the authors.
Journal ArticleDOI
The Transition to Potassic Alkaline Volcanism in Island Arcs: The Ringgit—Beser Complex, East Java, Indonesia
Caroline M. H. Edwards,Caroline M. H. Edwards,Martin Menzies,Matthew F. Thirlwall,Julie Morris,William P. Leeman,Russell S. Harmon +6 more
TL;DR: The origin of potassic lavas with within-plate characteristics in island arc settings is unclear as mentioned in this paper, and the origin of these primitive lavas gives an unusual insight into the source characteristics of the potassic Lavas.
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Tracing Crustal Evolution in the Southern Central Andes from Late Precambrian to Permian with Geochemical and Nd and Pb Isotope Data
TL;DR: In this article, major and trace element abundances and Nd and Pb isotopes of sedimentary and igneous rocks of Late Proterozoic to Permian age from northwest Argentina and northern Chile (northern Puna) have been analyzed to evaluate paleogeographic reconstructions and the crustal evolution of the Pacific margin of Gondwana during the Paleozoic.
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.