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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The Permian Dongfanghong island-arc gabbro of the Wandashan Orogen, NE China: Implications for Paleo-Pacific subduction
TL;DR: The Dongfanghong hornblende gabbro is located in the western part of the Wandashan Orogen and to the east of the Jiamusi Block in NE China.
Journal ArticleDOI
Granulite xenoliths from Cenozoic Basalts in SE China provide geochemical fingerprints to distinguish lower crust terranes from the North and South China tectonic blocks
Jinhai Yu,Jinhai Yu,Xisheng Xu,Xisheng Xu,Suzanne Y. O'Reilly,William L. Griffin,William L. Griffin,Ming Zhang +7 more
TL;DR: A large suite of lower crustal xenoliths from Cenozoic basaltic rocks from three widely spaced localities in the eastern part of the South China Block (SCB; Xilong, Qilin and Leizhou) and two localities (Nushan and Guizishan) close to the suture between the North and South China Blocks in Southeast China has been studied in detail as mentioned in this paper.
Journal ArticleDOI
238U-230Th-226Ra-210Pb-210Po, 232Th-228Ra, and 235U-231Pa constraints on the ages and petrogenesis of Vailulu'u and Malumalu Lavas, Samoa
Kenneth W.W. Sims,Stanley R. Hart,Mark K. Reagan,Jerzy S. Blusztajn,Hubert Staudigel,Robert A. Sohn,Graham D. Layne,Graham D. Layne,Lary Ball,Lary Ball,J. E. Andrews +10 more
TL;DR: In this article, a suite of 14 basaltic samples from the Samoan volcanoes Vailulu'u, Malumalu, and Savai'i were analyzed and the authors reported 238U-230Th-226Ra-210Pb-210Po, 232Th-228Ra and 235U-231Pa measurements.
Journal ArticleDOI
Drastic shift in lava geochemistry in the volcanic-front to rear-arc region of the Southern Kamchatkan subduction zone: Evidence for the transition from slab surface dehydration to sediment melting
Svend Duggen,Maxim Portnyagin,Maxim Portnyagin,Joel A. Baker,David Ulfbeck,Kaj Hoernle,Dieter Garbe-Schönberg,Nathalie Grassineau +7 more
TL;DR: In this paper, the authors focus on the geochemical composition of two adjacent volcanic centres from the volcanic front to rear-arc (RA) transition of the Southern Kamchatkan subduction zone, with the aim to examine whether the shift in lava geochemistry is associated with processes in the mantle wedge or in the subducted oceanic lithosphere or both.
Journal ArticleDOI
Mapping the geometry and geographic distribution of a very low velocity province at the base of the Earth's mantle
Yi Wang,Lianxing Wen +1 more
TL;DR: In this article, the geometry and geographic distribution of a very low velocity province (VLVP) at the base of the Earth's mantle beneath the South Atlantic and Indian Oceans, based on waveform modeling and travel time analysis of seismic data recorded in Africa, are determined.
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.
Journal ArticleDOI
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.
Journal ArticleDOI
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.
Journal ArticleDOI
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.