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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Cryptic striations in the upper mantle revealed by hafnium isotopes in southeast Indian ridge basalts.
TL;DR: It is shown that mid-ocean ridge basalts from 2,000 km along the southeast Indian ridge (SEIR) display a bimodal hafnium isotopic distribution, which reveals the presence of ancient compositional striations (streaks) in the Indian Ocean upper mantle.
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Sources of Pb for Indian Ocean ferromanganese crusts; a record of Himalayan erosion?
Martin Frank,R.K. O'Nions +1 more
TL;DR: In this paper, a high resolution Pb isotope time series for the last 26 Ma, dated by 10Be/9Be chronology, is reported for a north Indian Ocean ferromanganese crust.
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Geochemical Differences of the Hawaiian Shield Lavas: Implications for Melting Process in the Heterogeneous Hawaiian Plume
Zhong-Yuan Ren,Takeshi Hanyu,Takashi Miyazaki,Qing Chang,Hiroshi Kawabata,Toshiro Takahashi,Yuka Hirahara,Alexander R. L. Nichols,Yoshiyuki Tatsumi +8 more
TL;DR: In this article, a suite of fresh submarine lavas erupted by the Koolau, Kilauea and Loihi volcanoes were studied, and it was shown that the LoihI component is a common component, forming the matrix in the Hawaiian mantle plume, and that the isotopic differences between the various shield lavas reflect different mixing proportions of the LoIi component and recycled oceanic crust components (EM-1-like and HIMU-like).
Journal ArticleDOI
The calc-alkaline and adakitic volcanism of the Sabzevar structural zone (NE Iran): Implications for the Eocene magmatic flare-up in Central Iran
Hadi Shafaii Moghadam,Federico Rossetti,Federico Lucci,Massimo Chiaradia,Axel Gerdes,Margarita López Martínez,Ghasem Ghorbani,Mohsen Nasrabady +7 more
TL;DR: A major magmatic flare-up is documented along the Bitlis-Zagros suture zone in Eocene-Oligocene times as mentioned in this paper, where calc-alkaline and adakitic geochemical signatures were found in the Sabzevar volcanic rocks.
Journal ArticleDOI
70 Ma chemical zonation of the Tristan-Gough hotspot track
Joana Rohde,Kaj Hoernle,Folkmar Hauff,Reinhard Werner,John O'Connor,John O'Connor,John O'Connor,Cornelia Class,Dieter Garbe-Schönberg,Wilfried Jokat +9 more
TL;DR: In this paper, the authors used trace-element and Sr-Nd-Hf-Pb isotope data from the Tristan-Gough hotspot track in the South Atlantic to identify a bilateral, asymmetric zonation with two distinct mantle source components, making it the first zoned plume overlying the African superplume.
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.
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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.