The postspinel boundary in pyrolitic compositions determined in the laser‐heated diamond anvil cell

Ye, Yu; Gu, Chen; Shim, Sang‐Heon; Meng, Yue; Prakapenka, Vitali B.

doi:10.1002/2014gl060060

Cited by 33 publications

(39 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As shown in Figure a, we obtained the best match between the postspinel transition pressure and the pressure expected for the 660 km depth (23–24 GPa) when the Pt‐D07 scale is used. As reported by Ye et al [], the Au‐D07 scale predicts a 2–3 GPa higher pressure for the same phase boundary. As discussed above, due to the low melting temperature of gold, anharmonic effects could be severe for gold at the P ‐ T conditions of the experiments.…”

Section: Implications For the Mantle Phase Boundariessupporting

confidence: 78%

“…Although the gap has been reduced, later multianvil press studies with updated gold scales and MgO scales [ Litasov and Ohtani , ; Katsura et al , ; Fei et al , ] combined with energy‐dispersive XRD have reported the boundary at systematically lower pressures than that for the 660 km discontinuity. Ye et al [] have measured the postspinel boundary in different mantle‐related compositions in LHDAC with high‐resolution angle dispersive XRD, including pure Mg 2 SiO 4 and pyrolite, and reported that the P ‐ T conditions of the postspinel boundary agree well with those expected for the 660 km discontinuity if the platinum scales are used. However, they found that the gold scales systematically overestimate pressure by 3 GPa compared with the platinum scales.…”

Section: Implications For the Mantle Phase Boundariesmentioning

confidence: 88%

See 1 more Smart Citation

Intercomparison of the gold, platinum, and MgO pressure scales up to 140 GPa and 2500 K

Prakapenka

Meng

et al. 2017

JGR Solid Earth

View full text Add to dashboard Cite

In order to intercalibrate the equations of state (EOSs) of the three widely used pressure standards, gold, platinum, and MgO, we have measured their unit cell volumes together in the laser‐heated diamond anvil cell up to 140 GPa and 2500 K. At 300 K, three standards agree with each other within ±2.5 GPa to 135 GPa if the EOSs measured in quasi‐hydrostatic media are used. We further refined the EOSs at 300 K, making them consistent with each other within ±1 GPa up to 135 GPa. At high temperature (T), the three standards match the best within ±1 GPa between 40 and 140 GPa, when we use the scales by Dorogokupets and Dewaele (2007). However, a 2–3 GPa discrepancy remains at 20–40 GPa and 1500–2000 K, with gold yielding the highest pressure (P). The pressure discrepancy is likely related to steep decreases in the Grüneisen parameter, the anharmonicity, and/or the electronic effects for the standards at the P‐T conditions. Because gold melts near the temperatures expected for the mantle transition zone, severe anharmonic effects expected under premelting conditions make gold unsuitable for determining the phase boundaries in the region. The pressure scales by Dorogokupets and Dewaele (2007) provide tighter constrains on the Clapeyron slopes of the postspinel boundary to −2.0 to −2.7 MPa/K and the postperovskite boundary to 7–10 MPa/K. The data and refined EOSs presented here allow for reliable comparisons among experiments with different pressure standards for the entire P‐T conditions expected for the Earth's lower mantle.

show abstract

Section: Implications For the Mantle Phase Boundariessupporting

confidence: 78%

Section: Implications For the Mantle Phase Boundariesmentioning

confidence: 88%

Intercomparison of the gold, platinum, and MgO pressure scales up to 140 GPa and 2500 K

Prakapenka

Meng

et al. 2017

JGR Solid Earth

View full text Add to dashboard Cite

show abstract

“…Observed seismic topography is shown in grey shaded bins based on the histogram in Figure a. (a) Clapeyron slopes from experiments for the dissociations of ringwoodite to bridgmanite and periclase are shown for dry (solid blue) [ Litasov et al , ] and hydrous (dashed blue) [ Litasov et al , ] pyrolite in a multianvil press; dry (solid green) and hydrous (dashed green) ringwoodite in a multianvil press [ Ghosh et al , ]; and dry pyrolite in a diamond anvil cell (red) [ Ye et al , ]. Also shown are the results from the first principle calculations of Yu et al [] (yellow).…”

Section: Discussionmentioning

confidence: 99%

Large‐scale mantle discontinuity topography beneath Europe: Signature of akimotoite in subducting slabs

Cottaar

Deuss

2016

JGR Solid Earth

View full text Add to dashboard Cite

The mantle transition zone is delineated by seismic discontinuities around 410 and 660 km, which are generally related to mineral phase transitions. Study of the topography of the discontinuities further constrains which phase transitions play a role and, combined with their Clapeyron slopes, what temperature variations occur. Here we use P to S converted seismic waves or receiver functions to study the topography of the mantle seismic discontinuities beneath Europe and the effect of subducting and ponding slabs beneath southern Europe on these features. We combine roughly 28,000 of the highest quality receiver functions into a common conversion point stack. In the topography of the discontinuity around 660 km, we find broadscale depressions of 30 km beneath central Europe and around the Mediterranean. These depressions do not correlate with any topography on the discontinuity around 410 km. Explaining these strong depressions by purely thermal effects on the dissociation of ringwoodite to bridgmanite and periclase requires unrealistically large temperature reductions. Presence of several wt % water in ringwoodite leads to a deeper phase transition, but complementary observations, such as elevated Vp/Vs ratio, attenuation, and electrical conductivity, are not observed beneath central Europe. Our preferred hypothesis is the dissociation of ringwoodite into akimotoite and periclase in cold downwelling slabs at the bottom of the transition zone. The strongly negative Clapeyron slope predicted for the subsequent transition of akimotoite to bridgmanite explains the depression with a temperature reduction of 200–300 K and provides a mechanism to pond slabs in the first place.

show abstract

“…When running models at Ra lower than Earth-like (≈ 10 8 ; Weeraratne and Manga, 1998) the modelled Clapeyron slope must be more negative to obtain Earth-like behaviour. The probable value of the real Clapeyron slope for 660 is −2.5 ± 0.4 MPa K −1 (Ye et al, 2014).…”

Section: Modelling Methodsmentioning

confidence: 94%

Breaking supercontinents; no need to choose between passive or active

Wolstencroft

Davies

2017

Solid Earth

View full text Add to dashboard Cite

Abstract. Much debate has centred on whether continental break-up is predominantly caused by active upwelling in the mantle (e.g. plumes) or by long-range extensional stresses in the lithosphere. We propose the hypothesis that global supercontinent break-up events should always involve both. The fundamental principle involved is the conservation of mass within the spherical shell of the mantle, which requires a return flow for any major upwelling beneath a supercontinent. This shallow horizontal return flow away from the locus of upwelling produces extensional stress. We demonstrate this principle with numerical models, which simultaneously exhibit both upwellings and significant lateral flow in the upper mantle. For non-global break-up the impact of the finite geometry of the mantle will be less pronounced, weakening this process. This observation should motivate future studies of continental break-up to explicitly consider the global perspective, even when observations or models are of regional extent.

show abstract

The postspinel boundary in pyrolitic compositions determined in the laser‐heated diamond anvil cell

Cited by 33 publications

References 41 publications

Intercomparison of the gold, platinum, and MgO pressure scales up to 140 GPa and 2500 K

Intercomparison of the gold, platinum, and MgO pressure scales up to 140 GPa and 2500 K

Large‐scale mantle discontinuity topography beneath Europe: Signature of akimotoite in subducting slabs

Breaking supercontinents; no need to choose between passive or active

Contact Info

Product

Resources

About