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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Chemical and isotopic systematics of oceanic basalt : implications for mantle composition and processes
TL;DR: In this article, trace-element data for mid-ocean ridge basalts and ocean island basalts are used to formulate chemical systematics for oceanic basalts, interpreted in terms of partial-melting conditions, variations in residual mineralogy, involvement of subducted sediment, recycling of oceanic lithosphere and processes within the low velocity zone.
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Chemical and isotopic systematics of oceanic basalts. Implications for Mantle Composition and Processes
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Mantle geochemistry: the message from oceanic volcanism
TL;DR: Basaltic volcanism'samples' the Earth's mantle to great depths, because solid-state convection transports deep material into the (shallow) melting region as mentioned in this paper.
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Crustal contributions to arc magmatism in the Andes of Central Chile
Wes Hildreth,Stephen Moorbath +1 more
TL;DR: In this article, 15 andesite-dacite stratovolcanoes on the volcanic front of a single segment of the Andean arc show along-arc changes in isotopic and elemental ratios that demonstrate large crustal contributions to magma genesis.
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Composition of the depleted mantle
TL;DR: In this article, a combination of approaches is required to estimate the major and trace element abundances in the depleted mantle (DM), the source for mid-ocean ridge basalts (MORBs).
References
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Journal ArticleDOI
Quadrupole convection in the lower mantle
TL;DR: In this paper, global gravity data and seismic inferences of lateral inhomogeneities in the density distribution of the Earth's mantle provide information on convection in the lower mantle and the data are interpreted in terms of a model of mantle convection with two layers separated by the interface corresponding to the 670 km seismic discontinuity.
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Nd and Sr isotopic studies on cenozoic mafic lavas from West Antarctica: Another source for continental alkali basalts
Kiyoto Futa,W. E. Le Masurier +1 more
TL;DR: The Nd and Sr isotopic ratios on a suite of continental alkali basalts from Marie Byrd Land, West Antarctica, define a change in the source over the range of K/Ar dates between 1 and 28 my ago.
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Lead concentration and isotopic composition in five peridotite inclusions of probable mantle origin
Robert E. Zartman,Fouad Tera +1 more
TL;DR: The lead content of five whole-rock peridotite inclusions (four lherzolites and one harzburgite) in alkali basalt ranges from 82 to 570 ppb (parts per billion) as mentioned in this paper.
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Lead isotope measurements on lherzolite inclusions and host basanites from Western Victoria, Australia
J.A. Cooper,David H. Green +1 more
TL;DR: In this paper, lead samples extracted from a group of lherzolite inclusions and from their host basanites have been isotopically analyzed, showing varying degrees of 206 Pb and 208 Pb deficiency.
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Strontium isotopic geochemistry of the volcanic rocks and associated megacrysts and inclusions from Ross Island and vicinity, Antarctica
TL;DR: In this paper, the authors show that a 30% variation in the 87Rb/86Sr ratio in the source region if the average ratio is less than 0057 and if the source regions has existed as a closed system for 15 by Megacrysts of titaniferous augite, kaersutite, and anorthoclase.