Journal ArticleDOI
Melting of Peridotite to 140 Gigapascals
Guillaume Fiquet,Anne-Line Auzende,Julien Siebert,Alexandre Corgne,Alexandre Corgne,Hélène Bureau,Haruka Ozawa,Haruka Ozawa,Gaston Garbarino +8 more
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TLDR
Melting phase relations and element partitioning data show that these liquids could host many incompatible elements at the base of the mantle, such that seismically anomalous zones near the boundary between the core and the mantle may result from isolated pockets of melt.Abstract:
Interrogating physical processes that occur within the lowermost mantle is a key to understanding Earth's evolution and present-day inner composition. Among such processes, partial melting has been proposed to explain mantle regions with ultralow seismic velocities near the core-mantle boundary, but experimental validation at the appropriate temperature and pressure regimes remains challenging. Using laser-heated diamond anvil cells, we constructed the solidus curve of a natural fertile peridotite between 36 and 140 gigapascals. Melting at core-mantle boundary pressures occurs at 4180 ± 150 kelvin, which is a value that matches estimated mantle geotherms. Molten regions may therefore exist at the base of the present-day mantle. Melting phase relations and element partitioning data also show that these liquids could host many incompatible elements at the base of the mantle.read more
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Book ChapterDOI
Cosmochemical Estimates of Mantle Composition
TL;DR: The composition of the primitive mantle derived by as mentioned in this paper shows that Earth was assembled from material that shows many of the same chemical fractionation processes as chondritic meteorites. But the stable isotope record excludes chondrite meteorites as the ‘building blocks’ of Earth.
Journal ArticleDOI
Melting of Iron at Earth’s Inner Core Boundary Based on Fast X-ray Diffraction
TL;DR: In this article, the melting temperature of iron at the inner core boundary is estimated to be 6230 ± 500 kelvin with a possible partial melting of the mantle at the core-mantle boundary.
Journal ArticleDOI
Accretion and differentiation of the terrestrial planets with implications for the compositions of early-formed Solar System bodies and accretion of water
David C. Rubie,Seth A. Jacobson,Seth A. Jacobson,Alessandro Morbidelli,David P. O'Brien,Edward D. Young,J. de Vries,Francis Nimmo,Herbert Palme,Daniel J. Frost +9 more
TL;DR: In this article, a multistage core-mantle differentiation model with N-body accretion simulations is proposed to test accretion simulation as well as planetary differentiation scenarios, and the model is refined by least squares minimization with up to five fitting parameters that consist of the metal-silicate equilibration pressure and 1-4 parameters that define the starting compositions of primitive bodies.
Journal ArticleDOI
The high conductivity of iron and thermal evolution of the Earth’s core
Hitoshi Gomi,Kenji Ohta,Kei Hirose,Kei Hirose,Stéphane Labrosse,Stéphane Labrosse,Razvan Caracas,Matthieu J. Verstraete,John Hernlund,John Hernlund +9 more
TL;DR: In this paper, the electrical resistivity of iron and iron-silicon alloy was measured to 100 GPa, which is significantly higher than conventional estimates, implying rapid secular core cooling, an inner core younger than 1 Ga, and ubiquitous melting of the lowermost mantle during the early Earth.
Journal ArticleDOI
Composition and State of the Core
TL;DR: The composition and state of Earth's core, located deeper than 2,900 km from the surface, remain largely uncertain this article, although some static experiments on iron and alloys performed up to inner core pressure and temperature conditions have revealed phase relations and properties of core materials.
References
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Journal ArticleDOI
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TL;DR: A boundary between compositionally distinct regions at a depth of about 1600 kilometers may explain the seismological observations pertaining to Earth's lower mantle, produce the isotopic signatures of mid-ocean ridge basalts and oceanic island basalts, and reconcile the discrepancy between the observed heat flux and the heat production of the mid-Ocean ridge basalt source region.
Journal ArticleDOI
A crystallizing dense magma ocean at the base of the Earth’s mantle
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Journal ArticleDOI
142Nd Evidence for Early (>4.53 Ga) Global Differentiation of the Silicate Earth
Maud Boyet,Richard W. Carlson +1 more
TL;DR: New high-precision samarium-neodymium isotopic data for chondritic meteorites show that their 142Nd/144Nd ratio is 20 parts per million lower than that of most terrestrial rocks, indicating that most (70 to 95%) of Earth's mantle is compositionally similar to the incompatible element–depleted source of mid-ocean ridge basalts.
Journal ArticleDOI
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J. M. Brown,Thomas J. Shankland +1 more
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