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
Multiple enrichment of the Carpathian‐Pannonian mantle: Pb‐Sr‐Nd isotope and trace element constraints
TL;DR: In this article, the authors used principal component analysis of Pb-Sr-Nd isotope and rare earth element compositions of pyroxenes to identify the geochemical characteristics of the original lithospheric mantle protolith and a spectrum of infiltrating metasomatic agents including subduction-related aqueous fluids and silicate melts derived from a subduction modified mantle wedge which contains a St Helena-type (HIMU) plume component.
Journal ArticleDOI
Origin of Indian Ocean Seamount Province by shallow recycling of continental lithosphere
Kaj Hoernle,Folkmar Hauff,Reinhard Werner,P. van den Bogaard,Ana D. Gibbons,S. Conrad,Ralph Müller +6 more
TL;DR: The origin of the Christmas Island Seamount Province in the northeast Indian Ocean is enigmatic. as discussed by the authors combine 40Ar/39Ar age, Sr, Nd, Hf and high-precision Pb isotope analyses of volcanic rocks from the province with plate tectonic reconstructions and find that the seamounts are 47-136 million years old, decrease in age from east to west and are consistently 0-25 million years younger than the underlying oceanic crust.
Journal ArticleDOI
Permian high Ti/Y basalts from the eastern part of the Emeishan Large Igneous Province, southwestern China: Petrogenesis and tectonic implications
TL;DR: Guo et al. as mentioned in this paper investigated the geochemical and isotopic signature of basalts from the Guangxi and Guizhou regions in the eastern margin of the Emeishan LIP and reported the occurrence of high Ti/Y basalts in Guangxi.
Journal ArticleDOI
Mantle heterogeneities beneath the South Atlantic: a NdSrPb isotope study along the Mid-Atlantic Ridge (3°S–46°S)
TL;DR: In this paper, Hanan et al. reported on 55 Nd and Sr isotope analyses of MAR basalt glasses from 3°S to 46°S, using the same samples on which Pb and He isotope ratios were reported earlier.
Journal ArticleDOI
Local and regional heterogeneity in MORB from the Mid-Atlantic Ridge between 54.5°S and 51°S: Evidence for geochemical enrichment☆
TL;DR: Basaltic lavas from the southern Mid-Atlantic Ridge between the Bouvet triple junction at 54.5°S 1°W and 51°S, show a range in texture from aphyric to highly olivine or plagioclase porphyritic 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.