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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New Samoan lavas from Ofu Island reveal a hemispherically heterogeneous high 3 He/ 4 He mantle
TL;DR: In this paper, the high 3He/4He ratios in Samoan lavas from Ofu Island (19.5-33.8 times atmospheric) were used to extend the known range for 3He4He in the southern hemisphere mantle.
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Isotope and Trace Element Geochemistry of Cretaceous Damaraland Lamprophyres and Carbonatites, Northwestern Namibia: Evidence for Plume—Lithosphere Interactions
Anton P. Le Roex,Ruth Lanyon +1 more
TL;DR: The relationship between lamprophyres and carbonatites is still not fully understood as mentioned in this paper, however, a strong but variable, enrichment in incompatible trace elements (e.g., carbonatite magmas are derived via La 45-7232 ppm; Nb 89-1961 ppm; Sr 700-43 000 ppm), the direct partial melting of mantle peridotite, and the processes involved in their gendykes.
Journal ArticleDOI
Recycling plus: A new recipe for the formation of Alpine–Himalayan orogenic mantle lithosphere
TL;DR: The origin of the lithospheric mantle beneath accretionary orogens is enigmatic; although severe compression of the buoyant crust occurs, the mantle lithosphere is generally thought to be removed and returned to the convecting mantle as discussed by the authors.
Journal ArticleDOI
Pb, Nd, and Sr isotopic evidence for a multicomponent source for rocks of Cook-Austral Islands and heterogeneities of mantle plumes
TL;DR: Sr, Nd, and Pb isotopic compositions were measured in alkaline volcanic rocks from the South Cook Islands (Aitutaki, Mauke, Rarotonga, Atiu, and Mangaia) and the Austral Islands (Rimatara and Rurutu) as mentioned in this paper.
Journal ArticleDOI
Intracontinental eocene-oligocene porphyry Cu mineral systems of Yunnan, Western Yangtze Craton, China: Compositional characteristics, sources, and implications for continental collision metallogeny
Yongjun Lu,Robert Kerrich,Robert Kerrich,Anthony I.S. Kemp,T. Campbell McCuaig,Zengqian Hou,Craig J.R. Hart,Zheng-Xiang Li,Peter A. Cawood,Peter A. Cawood,Leon Bagas,Zhiming Yang,John B. Cliff,Elena Belousova,Fred Jourdan,Noreen J. Evans +15 more
TL;DR: In this paper, the authors investigated the role of lamprophyre-like potassic felsic intrusions in a postcollisional intracontinental setting in western Yunnan, China.
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.
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.
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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.