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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Geochemical fingerprints of Late Triassic calc-alkaline lamprophyres from the Eastern Pontides, NE Turkey: A key to understanding lamprophyre formation in a subduction-related environment
Orhan Karsli,Abdurrahman Dokuz,Melanie Kaliwoda,Ibrahim Uysal,Faruk Aydin,Raif Kandemir,Karl-Thomas Fehr +6 more
TL;DR: The lamprophyres are widely scattered and intrude Late Carboniferous granitoid rocks in NE Turkey and exhibit fine-grained textures and are mineralogically uniform.
Journal ArticleDOI
Mantle sources and magma evolution beneath the Cameroon Volcanic Line: Geochemistry of mafic rocks from the Bamenda Mountains (NW Cameroon)
Pierre Kamgang,Gilles Chazot,Gilles Chazot,Emmanuel Njonfang,Nicaise Blaise Tchuimegnie Ngongang,Félix M. Tchoua +5 more
TL;DR: In this article, the mineralogy, geochemistry and geochronology of the mafic rocks from the Bamenda Mountains, part of the Cameroon Volcanic Line (CVL), are discussed.
Journal ArticleDOI
Water in Hawaiian garnet pyroxenites: Implications for water heterogeneity in the mantle
Michael Bizimis,Anne H. Peslier +1 more
TL;DR: In this paper, the authors report water concentrations by FTIR on garnet pyroxenite xenoliths from Salt Lake Crater vent, Oahu, Hawaii, in order to constrain the role of lithological variability in the distribution of water in the upper oceanic mantle.
Journal ArticleDOI
Isotope Geochemistry of the Oceanic Mantle Near the Bouvet Triple Junction
TL;DR: This article measured the isotopes of helium and lead in three suites of basalt basalt basalts from the Southwest Indian Ridge, the America-Antarctic Ridge, and the Mid-Atlantic Ridge near the Bouvet triple junction.
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NdSrPb isotopic, and major- and trace-element geochemistry of Cenozoic lavas from the Khorat Plateau, Thailand: sources and petrogenesis
Pinbo Zhou,Samuel B. Mukasa +1 more
TL;DR: Basaltic rocks from Khorat Plateau, Thailand, dated at 0.9 Ma, coincide in time with the lithospheric extension of continental southeast Asia that began in the mid-Cenozoic as mentioned in this paper.
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.