Phase transition of pyrope garnet under lower mantle conditions

1998 ◽  
pp. 419-427 ◽  
Author(s):  
Tadashi Kondo ◽  
Takehiko Yagi
Keyword(s):  
Phase Transition ◽  
Lower Mantle

scholarly journals Velocity and density characteristics of subducted oceanic crust and the origin of lower-mantle heterogeneities

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Wenzhong Wang ◽  
Yinhan Xu ◽  
Daoyuan Sun ◽  
Sidao Ni ◽  
Renata Wentzcovitch ◽  
...  
Keyword(s):  
Phase Transition ◽  
Oceanic Crust ◽  
Seismic Tomography ◽  
Lower Mantle ◽  
Shear Velocity ◽  
Calcium Ferrite ◽  
Velocity Anomaly ◽  
Mantle Heterogeneities ◽  
Subducted Oceanic Crust ◽  
Low Shear

AbstractSeismic heterogeneities detected in the lower mantle were proposed to be related to subducted oceanic crust. However, the velocity and density of subducted oceanic crust at lower-mantle conditions remain unknown. Here, we report ab initio results for the elastic properties of calcium ferrite‐type phases and determine the velocities and density of oceanic crust along different mantle geotherms. We find that the subducted oceanic crust shows a large negative shear velocity anomaly at the phase boundary between stishovite and CaCl2-type silica, which is highly consistent with the feature of mid-mantle scatterers. After this phase transition in silica, subducted oceanic crust will be visible as high-velocity heterogeneities as imaged by seismic tomography. This study suggests that the presence of subducted oceanic crust could provide good explanations for some lower-mantle seismic heterogeneities with different length scales except large low shear velocity provinces (LLSVPs).

Perovskite in Earth’s deep interior

Science ◽  
2017 ◽  
Vol 358 (6364) ◽  
pp. 734-738 ◽  
Author(s):  
Kei Hirose ◽  
Ryosuke Sinmyo ◽  
John Hernlund
Keyword(s):  
Phase Transition ◽  
Trace Elements ◽  
Transport Properties ◽  
Lower Mantle ◽  
Dynamic Evolution ◽  
Deep Interior ◽  
Rocky Planets ◽  
The Universe ◽  
Perovskite Type ◽  
Important Constituent

Silicate perovskite-type phases are the most abundant constituent inside our planet and are the predominant minerals in Earth’s lower mantle more than 660 kilometers below the surface. Magnesium-rich perovskite is a major lower mantle phase and undergoes a phase transition to post-perovskite near the bottom of the mantle. Calcium-rich perovskite is proportionally minor but may host numerous trace elements that record chemical differentiation events. The properties of mantle perovskites are the key to understanding the dynamic evolution of Earth, as they strongly influence the transport properties of lower mantle rocks. Perovskites are expected to be an important constituent of rocky planets larger than Mars and thus play a major role in modulating the evolution of terrestrial planets throughout the universe.

scholarly journals The post-stishovite phase transition in hydrous alumina-bearing SiO2 in the lower mantle of the earth

2007 ◽  
Vol 104 (34) ◽  
pp. 13588-13590 ◽  
Author(s):  
D. L. Lakshtanov ◽  
S. V. Sinogeikin ◽  
K. D. Litasov ◽  
V. B. Prakapenka ◽  
H. Hellwig ◽  
...  
Keyword(s):  
Phase Transition ◽  
Lower Mantle ◽  
The Earth

Phase transition of Ca-perovskite and stability of Al-bearing Mg-perovskite in the lower mantle

2004 ◽  
Vol 89 (10) ◽  
pp. 1480-1485 ◽  
Author(s):  
Shigeaki Ono ◽  
Yasuo Ohishi ◽  
Kenji Mibe
Keyword(s):  
Phase Transition ◽  
Lower Mantle

Phase transition in MgSiO3 perovskite in the earth's lower mantle

2004 ◽  
Vol 224 (3-4) ◽  
pp. 241-248 ◽  
Author(s):  
Taku Tsuchiya ◽  
Jun Tsuchiya ◽  
Koichiro Umemoto ◽  
Renata M. Wentzcovitch
Keyword(s):  
Phase Transition ◽  
Lower Mantle ◽  
Mgsio3 Perovskite

Detecting a magnesiowüstite phase transition in the lower mantle by inversion of geomagnetic data

2014 ◽  
Vol 55 (9) ◽  
pp. 1138-1145 ◽  
Author(s):  
V.V. Plotkin ◽  
P.G. Dyad’kov ◽  
S.G. Ovchinnikov
Keyword(s):  
Phase Transition ◽  
Lower Mantle ◽  
Geomagnetic Data
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