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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Constraining subduction-collision processes of the Paleo-Tethys along the Changning–Menglian Suture: New zircon U-Pb ages and Sr–Nd–Pb–Hf–O isotopes of the Lincang Batholith
TL;DR: In this article, a geochronology study on granitoids of the Lincang Batholith, a prominent magmatic feature along the Changning-Menglian suture, yields crystallization age of 261-±-1/4 Ma, 252-± 1/4Ma, and 203-±1/1/3 Ma, confirming a multi-stage emplacement of the batholith.
Journal ArticleDOI
Sr–Nd–Pb isotopic constraints on the nature of the mantle sources involved in the genesis of the high-Ti tholeiites from northern Paraná Continental Flood Basalts (Brazil)
Eduardo R.V. Rocha-Júnior,Eduardo R.V. Rocha-Júnior,Leila Soares Marques,Marly Babinski,Antonio José Ranalli Nardy,Ana Maria Graciano Figueiredo,Fábio Braz Machado +6 more
TL;DR: In this article, the authors examined the mantle sources involved in the high-Ti (Pitanga and Paranapanema) basalt genesis, and studied Sr, Nd and Pb isotopic systematics, and major, minor and incompatible trace element abundances.
Journal ArticleDOI
Diverse magmatic effects of subducting a hot slab in SW Japan: Results from forward modeling
Jun-Ichi Kimura,James B. Gill,Tomoyuki Kunikiyo,Isaku Osaka,Yusuke Shimoshioiri,Maiko Katakuse,Susumu Kakubuchi,Takashi Nagao,Katsuhiko Furuyama,Atsushi Kamei,Hiroshi Kawabata,Junichi Nakajima,Peter E. van Keken,Robert J. Stern +13 more
TL;DR: In this article, the authors investigated the genetic conditions of the arc basalt suites using a geochemical mass balance model, Arc Basalt Simulator version 4 (ABS4), that uses these data to solve for the parameters such as pressure/temperature of slab dehydration/melting and slab flux fraction, pressure, and temperature of mantle melting.
Journal ArticleDOI
Cenozoic Volcanism on the Hangai Dome, Central Mongolia: Geochemical Evidence for Changing Melt Sources and Implications for Mechanisms of Melting
TL;DR: A mechanism for melting beneath the Hangai dome has, however, thus far remained enigmatic as discussed by the authors, and the lack of a viable mechanism to generate small-scale upwelling lends support to a model involving delamination of the lithospheric mantle beneath the Hwangai dome.
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Lead isotope study of orogenic lherzolite massifs
Bruno Hamelin,Claude J. Allègre +1 more
TL;DR: Orogenic lherzolites allow for almost "in-situ" observation of mantle isotopic heterogeneities on a restricted geographical scale, in contrast to basalts for which melting processes have averaged original mantle compositions over uncertain scales 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.
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.
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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.