Peridotite melting and mineral–melt partitioning of major and minor elements at 22–24.5 GPa

Trønnes, Reidar G.; Frost, Daniel J.

doi:10.1016/s0012-821x(02)00466-1

Cited by 140 publications

(92 citation statements)

References 43 publications

(67 reference statements)

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“…Diffraction patterns were recorded in transmission geometry at each step. The diffraction pattern images were corrected for diffuse scattering from the glass slide of the thin section using Fit2D (32). The patterns were then corrected for geometric distortion from detector tilt using GSE-ADA (33) and integrated using Fit2D (32).…”

Section: Methodsmentioning

confidence: 99%

Discovery of bridgmanite, the most abundant mineral in Earth, in a shocked meteorite

Tschauner

Beckett

et al. 2014

Science

252

179

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Meteorites exposed to high pressures and temperatures during impact-induced shock often contain minerals whose occurrence and stability normally confine them to the deeper portions of Earth’s mantle. One exception has been MgSiO3 in the perovskite structure, which is the most abundant solid phase in Earth. Here we report the discovery of this important phase as a mineral in the Tenham L6 chondrite and approved by the International Mineralogical Association (specimen IMA 2014-017). MgSiO3-perovskite is now called bridgmanite. The associated phase assemblage constrains peak shock conditions to ~ 24 gigapascals and 2300 kelvin. The discovery concludes a half century of efforts to find, identify, and characterize a natural specimen of this important mineral.

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Section: Methodsmentioning

confidence: 99%

Discovery of bridgmanite, the most abundant mineral in Earth, in a shocked meteorite

Tschauner

Beckett

et al. 2014

Science

252

179

View full text Add to dashboard Cite

show abstract

“…This P interval is so wide as to broadly encompass that of ''pyrolite" liquidus (i.e. Corgne et al, 2005) at lower mantle pressures, inferred from the melting experiments of Trønnes and Frost (2002) and Ito et al (2004). At P > 24 GPa, the sub-solidus post-spinel transition is completed even in the presence of 2 wt.% H 2 O (Ghosh et al, 2013); setting an upper P-limit of 80 GPa ($2000 km depth) allows the D" region to be excluded, where the developed mineral partitioning model cannot be used.…”

Section: Computingmentioning

confidence: 97%

Lower mantle hydrogen partitioning between periclase and perovskite: A quantum chemical modelling

Merli

Bonadiman

Diella

et al. 2016

Geochimica et Cosmochimica Acta

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“…Although the partitioning of iron (K D ) between solid and melts remains controversial at lower mantle pressures (9,25), it is agreed that iron is an incompatible element. Therefore, iron is enriched in the melt phase with a K D value as low as ∼0.4-0.3 at 25 GPa (26,27) and most likely even lower at higher pressures. Given that even in the absence of iron, MgSiO 3 melt is already nearly as dense as its crystalline counterpart at CMB conditions (Fig.…”

mentioning

confidence: 99%

Fate of MgSiO ₃ melts at core–mantle boundary conditions

Petitgirard

Malfait

Sinmyo

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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One key for understanding the stratification in the deep mantle lies in the determination of the density and structure of matter at high pressures, as well as the density contrast between solid and liquid silicate phases. Indeed, the density contrast is the main control on the entrainment or settlement of matter and is of fundamental importance for understanding the past and present dynamic behavior of the deepest part of the Earth's mantle. Here, we adapted the X-ray absorption method to the small dimensions of the diamond anvil cell, enabling density measurements of amorphous materials to unprecedented conditions of pressure. Our density data for MgSiO 3 glass up to 127 GPa are considerably higher than those previously derived from Brillouin spectroscopy but validate recent ab initio molecular dynamics simulations. A fourth-order Birch-Murnaghan equation of state reproduces our experimental data over the entire pressure regime of the mantle. At the core-mantle boundary (CMB) pressure, the density of MgSiO 3 glass is 5.48 ± 0.18 g/cm 3 , which is only 1.6% lower than that of MgSiO 3 bridgmanite at 5.57 g/cm 3 , i.e., they are the same within the uncertainty. Taking into account the partitioning of iron into the melt, we conclude that melts are denser than the surrounding solid phases in the lowermost mantle and that melts will be trapped above the CMB.silicate glass density | X-ray absorption | basal magma ocean V ariations in seismic velocities observed in the deep mantle could be attributed to melting phenomena (1), accumulation of dense matter (2), core-mantle interactions (3), or even a deep hidden geochemical reservoir that dates from the early differentiation of the Earth (4). Indeed, melting phenomena play a critical role in the formation and evolution of terrestrial planets. In the early Earth's history, large-scale melting events and magma oceans facilitated the segregation of the iron-rich core and the partitioning of elements between the different layers of the Earth (5). Catastrophic events like the moon-forming giant impact may have melted the entire Earth and modified the thermal and chemical state of the planet's interior (6). It has long been thought that the mantle crystallized from the bottom to the top, with crystals being denser than melts (7). However, the formation of a dense basal magma ocean (BMO) at the bottom of the mantle concomitant to the final accretion of the Earth was proposed as a consequence of partial melting (2). The formation of a BMO requires the accumulation of dense iron-rich silicate melts at the core-mantle boundary (CMB). In this scenario, the mantle starts to crystallize at an intermediate depth, and a raft of crystals continues to grow toward both the bottom and top of the mantle. In the modern mantle, seismic observations highlight ultralow velocity zones (ULVZs) near the CMB (8) that may be caused by melting of deep mantle material (9), potentially feeding sources of hot spots. Alternatively, the ULVZs may be dense remnants from an initial BMO (10, 11). Both scenar...

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Peridotite melting and mineral–melt partitioning of major and minor elements at 22–24.5 GPa

Cited by 140 publications

References 43 publications

Discovery of bridgmanite, the most abundant mineral in Earth, in a shocked meteorite

Discovery of bridgmanite, the most abundant mineral in Earth, in a shocked meteorite

Lower mantle hydrogen partitioning between periclase and perovskite: A quantum chemical modelling

Fate of MgSiO ₃ melts at core–mantle boundary conditions

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Peridotite melting and mineral–melt partitioning of major and minor elements at 22–24.5 GPa

Cited by 140 publications

References 43 publications

Discovery of bridgmanite, the most abundant mineral in Earth, in a shocked meteorite

Discovery of bridgmanite, the most abundant mineral in Earth, in a shocked meteorite

Lower mantle hydrogen partitioning between periclase and perovskite: A quantum chemical modelling

Fate of MgSiO 3 melts at core–mantle boundary conditions

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Fate of MgSiO ₃ melts at core–mantle boundary conditions