scholarly journals Confirming a pyrolitic lower mantle using self-consistent pressure scales and new constraints on CaSiO3 perovskite

2016 ◽  
Vol 121 (7) ◽  
pp. 4876-4894 ◽  
Author(s):  
Ningyu Sun ◽  
Zhu Mao ◽  
Shuai Yan ◽  
Xiang Wu ◽  
Vitali B. Prakapenka ◽  
...  
Keyword(s):  
Lower Mantle ◽  
Self Consistent ◽  
Casio3 Perovskite

scholarly journals CaSiO3 perovskite in diamond indicates the recycling of oceanic crust into the lower mantle

Nature ◽  
2018 ◽  
Vol 555 (7695) ◽  
pp. 237-241 ◽  
Author(s):  
F. Nestola ◽  
N. Korolev ◽  
M. Kopylova ◽  
N. Rotiroti ◽  
D. G. Pearson ◽  
...  
Keyword(s):  
Oceanic Crust ◽  
Lower Mantle ◽  
Casio3 Perovskite

scholarly journals Seismic velocities of CaSiO3 perovskite can explain LLSVPs in Earth’s lower mantle

Nature ◽  
2019 ◽  
Vol 572 (7771) ◽  
pp. 643-647 ◽  
Author(s):  
A. R. Thomson ◽  
W. A. Crichton ◽  
J. P. Brodholt ◽  
I. G. Wood ◽  
N. C. Siersch ◽  
...  
Keyword(s):  
Lower Mantle ◽  
Seismic Velocities ◽  
Casio3 Perovskite

Origin, properties, and structure of breyite: The second most abundant mineral inclusion in super-deep diamonds

2021 ◽  
Vol 106 (1) ◽  
pp. 38-43
Author(s):  
Frank E. Brenker ◽  
Fabrizio Nestola ◽  
Lion Brenker ◽  
Luca Peruzzo ◽  
Jeffrey W. Harris
Keyword(s):  
Crystal Structure ◽  
Transition Zone ◽  
Lower Mantle ◽  
Major Element ◽  
Mineral Inclusion ◽  
Major Element Composition ◽  
Triclinic Space Group ◽  
Casio3 Perovskite ◽  
Almost All ◽  
Original Crystal

Abstract Earth's lower mantle most likely mainly consists of ferropericlase, bridgmanite, and a CaSiO3- phase in the perovskite structure. If separately trapped in diamonds, these phases can be transported to Earth's surface without reacting with the surrounding mantle. Although all inclusions will remain chemically pristine, only ferropericlase will stay in its original crystal structure, whereas in almost all cases bridgmanite and CaSiO3-perovskite will transform to their lower-pressure polymorphs. In the case of perovskite structured CaSiO3, the new structure that is formed is closely related to that of walstromite. This mineral is now approved by the IMA commission on new minerals and named breyite. The crystal structure is triclinic (space group: P1) with lattice parameters a0 = 6.6970(4) Å, b0 = 9.2986(7) Å, c0 = 6.6501(4) Å, α = 83.458(6)°, β = 76.226(6)°, γ = 69.581(7)°, and V = 376.72(4) Å. The major element composition found for the studied breyite is Ca3.01(2)Si2.98(2)O9. Breyite is the second most abundant mineral inclusion after ferropericlase in diamonds of super-deep origin. The occurrence of breyite has been widely presumed to be a strong indication of lower mantle (=670 km depth) or at least lower transition zone (=520 km depth) origin of both the host diamond and the inclusion suite. In this work, we demonstrate through different formation scenarios that the finding of breyite alone in a diamond is not a reliable indicator of the formation depth in the transition zone or in the lower mantle and that accompanying paragenetic phases such as ferropericlase together with MgSiO3 are needed.

Phase transition in Al-bearing CaSiO3 perovskite: implications for seismic discontinuities in the lower mantle

2004 ◽  
Vol 145 (1-4) ◽  
pp. 67-74 ◽  
Author(s):  
Tsuyoshi Kurashina ◽  
Kei Hirose ◽  
Shigeaki Ono ◽  
Nagayoshi Sata ◽  
Yasuo Ohishi
Keyword(s):  
Phase Transition ◽  
Lower Mantle ◽  
Seismic Discontinuities ◽  
Casio3 Perovskite

scholarly journals Interphase REE Partitioning at the Boundary between the Earth’s Transition Zone and Lower Mantle: Evidence from Experiments and Atomistic Modeling

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 262
Author(s):  
Anastasia P. Tamarova ◽  
Ekaterina I. Marchenko ◽  
Andrey V. Bobrov ◽  
Nikolay N. Eremin ◽  
Nina G. Zinov’eva ◽  
...  
Keyword(s):  
High Pressure ◽  
Lower Mantle ◽  
Partition Coefficients ◽  
Solid Phase ◽  
Trace Element Composition ◽  
Solid State Reactions ◽  
Atomistic Modeling ◽  
Deep Earth ◽  
Casio3 Perovskite ◽  
First Time

Trace elements play a significant role in interpretation of different processes in the deep Earth. However, the systematics of interphase rare-earth element (REE) partitioning under the conditions of the uppermost lower mantle are poorly understood. We performed high-pressure experiments to study the phase relations in key solid-phase reactions CaMgSi2O6 = CaSiO3-perovskite + MgSiO3-bridgmanite and (Mg,Fe)2SiO4-ringwoodite = (Mg,Fe)SiO3-bridgmanite + (Mg,Fe)O with addition of 1 wt % of REE oxides. Atomistic modeling was used to obtain more accurate quantitative estimates of the interphase REE partitioning and displayed the ideal model for the high-pressure minerals. HREE (Er, Tm, Yb, and Lu) are mostly accumulated in bridgmanite, while LREE are predominantly redistributed into CaSiO3. On the basis of the results of experiments and atomistic modeling, REE in bridgmanite are clearly divided into two groups (from La to Gd and from Gd to Lu). Interphase REE partition coefficients in solid-state reactions were calculated at 21.5 and 24 GPa for the first time. The new data are applicable for interpretation of the trace-element composition of the lower mantle inclusions in natural diamonds from kimberlite; the experimentally determined effect of pressure on the interphase (bridgmanite/CaSiO3-perovskite) REE partition coefficients can be a potential qualitative geobarometer for mineral inclusions in super-deep diamonds.

Sound velocity of CaSiO3 perovskite suggests the presence of basaltic crust in the Earth’s lower mantle

Nature ◽  
2019 ◽  
Vol 565 (7738) ◽  
pp. 218-221 ◽  
Author(s):  
Steeve Gréaux ◽  
Tetsuo Irifune ◽  
Yuji Higo ◽  
Yoshinori Tange ◽  
Takeshi Arimoto ◽  
...  
Keyword(s):  
Sound Velocity ◽  
Lower Mantle ◽  
Casio3 Perovskite ◽  
Basaltic Crust

Ab initio calculations of uranium and thorium storage in CaSiO3-perovskite in the Earth’s lower mantle

2017 ◽  
Vol 102 (2) ◽  
pp. 321-326 ◽  
Author(s):  
Samuel N. Perry ◽  
Jeffrey S. Pigott ◽  
Wendy R. Panero
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Lower Mantle ◽  
Casio3 Perovskite

scholarly journals Bridgmanite-Predominant Lower Mantle Evidenced from Velocity and Density Profiles across the 660-km Discontinuity

2021 ◽  
Author(s):  
Suyu Fu ◽  
Yanyao Zhang ◽  
Takuo Okuchi ◽  
Jung-Fu Lin
Keyword(s):  
Lower Mantle ◽  
P Wave ◽  
S Wave ◽  
Seismic Profiles ◽  
Density Profiles ◽  
Deep Earth ◽  
Casio3 Perovskite ◽  
Diamond Anvil ◽  
Heat Capacity Measurements ◽  
Best Fit

Abstract Earth’s mantle composition is essential to our understanding of its physics and dynamics. Here we report single-crystal elasticity (Cij) of (Al,Fe)-bearing bridgmanite, Mg0.88Fe0.1Al0.14Si0.90O3 with Fe3+/∑Fe=~0.65, up to ~82 GPa measured in diamond anvil cells. Together with heat capacity measurements on bridgmanite and ferropericlase, we develop a fully internally-consistent thermoelastic model to simultaneously evaluate lower-mantle mineralogy and geotherm via comparisons of P-wave, S-wave velocities, and density (VP, VS, and ρ) with one-dimensional seismic profiles. Our best-fit model demonstrates the lower mantle consists of ~89 vol% (Al,Fe)-bearing bridgmanite, ~4 vol% ferropericlase, and ~7 vol% CaSiO3 perovskite. A chemically layered mantle with pyrolitic upper mantle and bridgmanite-predominant lower mantle would display ~3.2(±1.5)%, ~5.2(±1.5)%, and ~5.0(±1.0)% jumps in VP, VS, and ρ, respectively, across the 660-km discontinuity, which are well consistent with seismic reflection observations. The lower mantle could have become bridgmanite-predominant via accumulations of ancient silica-rich materials, which helps explain current deep-Earth seismic and geochemical signatures.

scholarly journals CaSiO3 Perovskite May Cause Electrical Conductivity Jump in the Topmost Lower Mantle

2017 ◽  
Vol 44 (20) ◽  
pp. 10,226-10,232 ◽  
Author(s):  
Hongzhan Fei ◽  
Rong Huang ◽  
Xiaozhi Yang
Keyword(s):  
Electrical Conductivity ◽  
Lower Mantle ◽  
Casio3 Perovskite ◽  
Conductivity Jump
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