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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Isotope geochemistry of Pacific Mid-Ocean Ridge Basalt
TL;DR: In this article, the authors reported the isotope ratios of 51 mid-ocean ridge basalts from the Juan de Fuca Ridge, the Gorda Ridge, and the East Pacific Rise (EPR) and the Galapagos Spreading Center (GSC).
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Fluxes and excess temperatures of mantle plumes inferred from their interaction with migrating mid-ocean ridges
TL;DR: The behavior of thermal plumes in the Earth's upper mantle is strongly affected by their interaction with nearby mid-ocean ridges, and the magnitude of the buoyant topography and the length of the geochemical anomaly induced by plumes at migrating ridge axes provide a way to estimate their excess temperature and discharge rate, and thereby constrain their depth of origin this paper.
Journal ArticleDOI
Regionally distinctive sources of depleted MORB: Evidence from trace elements and H2O
TL;DR: In this article, the authors show that the order of incompatibility during the evolution of mid-ocean ridge basalts is La > H2O ≈ Ce > Nd.
Journal ArticleDOI
The timescales of subduction initiation and subsequent evolution of an oceanic island arc
Osamu Ishizuka,Osamu Ishizuka,Kenichiro Tani,Mark K. Reagan,Kyoko Kanayama,Susumu Umino,Yumiko Harigane,Yumiko Harigane,Izumi Sakamoto,Yuki Miyajima,Makoto Yuasa,Daniel J. Dunkley +11 more
TL;DR: The Bonin Ridge and trench slope preserves the geological record of subduction initiation and subsequent evolution of the Izu-Bonin-Mariana (IBM) arc.
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Setouchi high-Mg andesites revisited: geochemical evidence for melting of subducting sediments
TL;DR: In this paper, Pb-Nd-Sr isotopic compositions were determined for high-Mg andesite (HMA) magmas and basalts from the Miocene Setouchi volcanic belt in the SW Japan arc.
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.
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.
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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.