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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The Anatomy of an Andesite Volcano: a Time–Stratigraphic Study of Andesite Petrogenesis and Crustal Evolution at Ruapehu Volcano, New Zealand
Richard C. Price,John A. Gamble,Ian E. M. Smith,Roland Maas,Tod E. Waight,Robert B. Stewart,Jon Woodhead +6 more
TL;DR: Mortimer et al. as discussed by the authors presented an ILMAT-based worksheet for ilmenite geothermometry and geobarometry, which can be found in the Appendix of this paper.
Journal ArticleDOI
Tectonics, magmatism and geodynamics of Italy: What we know and what we imagine
TL;DR: Brando et al. as discussed by the authors proposed a geodynamic evolutionary model of the Italian area based on thermo-tectonic, magmatological, and plate-kinematics constraints, and suggested that three subduction zones have been active and have consumed oceanic and, partially, continental lithosphere: the Alpine subduction zone, with the European plate under-thrusting the Adriatic microplate; the Apenninic subduction Zone, with ancient (Mesozoic?) Ionian/Mesogean oceanic lithosphere and the Ad
Journal ArticleDOI
Ra-Th disequilibria systematics: Timescale of carbonatite magma formation at Oldoinyo Lengai volcano, Tanzania
TL;DR: In this paper, the authors measured the U and Th series nuclides in carbonatite lava and ash from the Oldoinyo Lengai volcano, Tanzania, and determined the age of the carbonatites.
Journal ArticleDOI
Petrogenesis of Basanitic to Tholeiitic Volcanic Rocks from the Miocene Vogelsberg, Central Germany
P. J. F. Bogaard,Gerhard Wörner +1 more
TL;DR: The Miocene Vogelsberg volcano in Central Germany produced mafic magmas ranging in composition from basanite to quartz tholeiite and limited amounts of evolved magmas as discussed by the authors, which reveal the presence of three distinct mantle sources: (1) a trace element enriched, asthenospheric plume-type source, similar to the European Asthenosphere Reservoir composition inferred for many other Tertiary volcanic provinces in Central Europe; (2) a depleted mantle source, located in the lithospheric mantle or uppermost asthenosphere; (3) a ve
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.