Results 241 to 250 of about 220,882 (295)

Spin Transition Zone in Earth's Lower Mantle

Science, 2007
Mineral properties in Earth's lower mantle are affected by iron electronic states, but representative pressures and temperatures have not yet been probed. Spin states of iron in lower-mantle ferropericlase have been measured up to 95 gigapascals and 2000 kelvin with x-ray emission in a laser-heated diamond cell. A gradual spin transition of iron occurs
Jung-Fu, Lin, György, Vankó, Steven D, Jacobsen, Valentin, Iota, Viktor V, Struzhkin, Vitali B, Prakapenka, Alexei, Kuznetsov, Choong-Shik, Yoo   +7 more
openaire   +2 more sources

Properties of the mantle transition zone in northern Eurasia

Journal of Geophysical Research: Solid Earth, 1998
Short‐period, three‐component recordings of peaceful nuclear explosions (PNEs) in northern Eurasia are used to constrain the P wave velocity structure of the mantle transition zone. The properties of the upper mantle discontinuities play an important role in understanding the nature of mantle processes.
Ryberg, Trond, Wenzel, Friedemann, Egorkin, Alexei V., Solodilov, Leonid   +3 more
openaire   +2 more sources

Palaeoslab and plume signatures in the mantle transition zone beneath Eastern Himalaya and adjoining regions

, 2020
A comprehensive data set of 73 876 high quality receiver functions computed using waveforms recorded by 327 broad-band seismic stations is used to investigate the mantle transition zone (MTZ) structure beneath the eastern Himalaya, southern Tibet ...
D. Saikia, M. Kumar, Ashutosh Kumar Singh   +2 more
semanticscholar   +1 more source

Mantle plumes pinched in the transition zone

Earth and Planetary Science Letters, 2000
Abstract We have employed an axisymmetric, spherical shell model with the two major phase transitions and variable viscosity to study the dynamical processes associated with both regular mantle plumes and superplumes, which can develop spontaneously in strongly time-dependent situations.
David Brunet, David A. Yuen
openaire   +1 more source

Water in Transition Zone and Lower Mantle Minerals

2013
Wadsleyite and ringwoodite have the potential to contain up to 3.2 weight percent of water as structurally bound hydroxyl (OH). However, at transition zone pressures the solubility of water in these phases decreases with increasing temperature to ∼2 wt% H 2 O at 1460°C for wadsleyite and to ∼1 wt% H 2 O at 1600°C for ringwoodite, the approximate ...
Bolfan-Casanova, Nathalie, Mccammon, Catherine, Mackwell, Stephen   +2 more
openaire   +2 more sources

The Upper Mantle and Transition Zone

Elements, 2008
The upper mantle is the source of almost all magmas. It contains major transitions in rheological and thermal behaviour that control the character of plate tectonics and the style of mantle dynamics. Essential parameters in any model to describe these phenomena are the mantle's compositional and thermal structure.
openaire   +1 more source

Decarbonation of Stagnant Slab in the Mantle Transition Zone

Journal of Geophysical Research: Solid Earth, 2020
AbstractPhase relations of carbonated basalts have been investigated at 13–20 GPa and 1200–1600°C, to model the decarbonation process of stagnant slab in the mantle transition zone (MTZ). Two synthetic mixes with CO2 contents of 2.5 wt% (PC‐a) and 5.0 wt% (PC‐b) were used as the starting materials.
Yanfei Zhang, Chao Wang, Zhenmin Jin
openaire   +1 more source

Magnetism in cold subducting slabs at mantle transition zone depths

Nature, 2019
The Earth's crust-mantle boundary, the Mohorovičić discontinuity, has been traditionally considered to be the interface between the magnetic crust and the non-magnetic mantle1. However, this assumption has been questioned by geophysical observations2,3 and by the identification of magnetic remanence in mantle xenoliths4, which suggest mantle magnetic ...
I. Kupenko, G. Aprilis, D. Vasiukov, C. McCammon, S. Chariton, V. Cerantola, Innokenty Kantor, A. Chumakov, R. Rüffer, L. Dubrovinsky, C. Sanchez-Valle   +10 more
semanticscholar   +3 more sources

Subducting slab morphology and mantle transition zone upwelling in double-slab subduction models with inward-dipping directions

Geophysical Journal International, 2019
Lithospheric plates on the Earth's surface interact with each other, producing distinctive structures comprising two descending slabs. Double-slab subduction with inward-dipping directions represents an important multiplate system that is not yet well ...
Tianyang Lyu, Zhiyuan Zhu, Benjun Wu
semanticscholar   +1 more source

Whole-mantle convection and the transition-zone water filter

Nature, 2003
Because of their distinct chemical signatures, ocean-island and mid-ocean-ridge basalts are traditionally inferred to arise from separate, isolated reservoirs in the Earth's mantle. Such mantle reservoir models, however, typically satisfy geochemical constraints, but not geophysical observations.
David, Bercovici, Shun-Ichiro, Karato
openaire   +2 more sources