Journal ArticleDOI
A large-scale isotope anomaly in the Southern Hemisphere mantle
Reads0
Chats0
TLDR
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
Citations
More filters
Journal ArticleDOI
Petrology, geochemistry and Sr–Nd isotopes of the Trindade and Martin Vaz volcanic rocks (Southern Atlantic Ocean)
TL;DR: Geochemical, mineralogical and Sr-Nd isotopic analyses were performed on strongly undersaturated volcanic rocks of the Trindade and Martin Vaz islands, located in the South Atlantic Ocean (Brazil).
Journal ArticleDOI
Volcanic arcs as archives of plate tectonic change
TL;DR: In this paper, the authors address the question whether compositional links are sufficiently strong to allow for tracing the composition of the sedimentary and igneous oceanic crust through the chemistry of arcs, and demonstrate that elements Sr, Pb, Nd and Hf that are associated with radiogenic isotopes may preserve chemical characteristics of the subducted slab in arc magmas.
Journal ArticleDOI
D/H ratios in basalt glasses from the Salas y Gomez mantle plume interacting with the East Pacific Rise: Water from old D‐rich recycled crust or primordial water from the lower mantle?
Richard Kingsley,Richard Kingsley,Jean-Guy Schilling,Jacqueline Eaby Dixon,Peter K. Swart,Robert J. Poreda,Kyla Simons +6 more
TL;DR: In this article, deuterium/hydrogen isotope ratios were measured in 22 fresh basalt glasses dredged from young seamounts along the Easter-Salas y Gomez seamount chain (ESC) and from the spreading centers of the Easter Microplate (EMP).
Journal ArticleDOI
Petrology and Geochemistry of Eclogite Xenoliths from the Colorado Plateau: Implications for the Evolution of Subducted Oceanic Crust
TL;DR: In this article, eclogite xenoliths from the Colorado Plateau, interpreted as fragments of the subducted Farallon plate, are used to constrain the trace element and Nd-Pb isotopic compositions of oceanic crust subducting into the upper mantle.
Journal ArticleDOI
Trindade and Martı́n Vaz Islands, South Atlantic: Isotopic (Sr, Nd, Pb) and trace element constraints on plume related magmatism
Wolfgang Siebel,Raúl Becchio,Raúl Becchio,F. Volker,Marco Antonio Fontoura Hansen,José Viramonte,Robert B. Trumbull,G. Haase,M. Zimmer +8 more
TL;DR: The Trindade and Martin Vaz lavas have moderate radiogenic 206Pb/204Pb ratios of 19.00−19.33, 207Pb/(204PB) ratios of 15.56−15.60, and 208Pb(Pb) ratios 38.89−39.9 wt as mentioned in this paper.
References
More filters
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.