Deformation of a crystalline aggregate with a small percentage of high-dihedral-angle liquid: Implications for core–mantle differentiation during planetary formation

Walte, Nicolas P.; Rubie, D. C.; Bons, Paul D.; Frost, Daniel J.

doi:10.1016/j.epsl.2011.02.049

Cited by 31 publications

(51 citation statements)

References 42 publications

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“…The D-DIA is not restricted solely to use with synchrotron X-rays. For example, Walte et al 43 looked at the distribution of melts in deformed polycrystalline olivine in recovered samples and Howell et al 10 investigated the textures developed during plastic deformation of diamond.…”

Section: Introductionmentioning

confidence: 99%

Deformation T-Cup: A new multi-anvil apparatus for controlled strain-rate deformation experiments at pressures above 18 GPa

Hunt

Weidner

McCormack

et al. 2014

Review of Scientific Instruments

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A new multi-anvil deformation apparatus, based on the widely used 6-8 split-cylinder, geometry, has been developed which is capable of deformation experiments at pressures in excess of 18 GPa at room temperature. In 6-8 (Kawai-type) devices eight cubic anvils are used to compress the sample assembly. In our new apparatus two of the eight cubes which sit along the split-cylinder axis have been replaced by hexagonal cross section anvils. Combining these anvils hexagonal-anvils with secondary differential actuators incorporated into the load frame, for the first time, enables the 6-8 multi-anvil apparatus to be used for controlled strain-rate deformation experiments to high strains. Testing of the design, both with and without synchrotron-X-rays, has demonstrated the Deformation T-Cup (DT-Cup) is capable of deforming 1–2 mm long samples to over 55% strain at high temperatures and pressures. To date the apparatus has been calibrated to, and deformed at, 18.8 GPa and deformation experiments performed in conjunction with synchrotron X-rays at confining pressures up to 10 GPa at 800 °C .

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Section: Introductionmentioning

confidence: 99%

Deformation T-Cup: A new multi-anvil apparatus for controlled strain-rate deformation experiments at pressures above 18 GPa

Hunt

Weidner

McCormack

et al. 2014

Review of Scientific Instruments

View full text Add to dashboard Cite

show abstract

“…The experimental run M175 was executed without the presence of basaltic melt; however, the FeS content was kept at 5 wt.%. The decision to keep 5 wt.% of FeS in all experiments was twofold: (i) to obtain results compatible with those of a previous experimental study on olivine-FeS liquid deformation (Walte et al, 2011); (ii) this value is below the critical connectivity threshold for static systems of 5 vol.% according to Yoshino et al (2003); hence, any connection and segregation of FeS liquid observed in the experiments can be assumed to be due to deformation.…”

Section: Methodsmentioning

confidence: 87%

“…The greyscale SEM-BSE images were transformed into binary images highlighting the FeS liquid pockets and analyzed statistically. In this way the average sulphide liquid fraction, and the distribution and size of liquid pockets were determined in the quenched samples after deformation as described in Walte et al (2011). Due to the often irregular shape of liquid pockets, the liquid pocket area is expressed in radii of equivalent circles, and the 2-D results are plotted in bar diagrams with a bin-size of 1 μm, which allows the sulphide liquid distribution of different experiments to be compared e.g.…”

Section: Methodsmentioning

confidence: 99%

“…All studies have agreed that deformation has the potential to mobilize Fe-S liquids and lower the percentage of stranded liquid with estimations ranging from 1 vol.% (Groebner and Kohlstedt, 2006) to 2-3 vol.% (Walte et al, 2011) as long as the differential stress or strain rate is sufficient to overcome the capillary forces of the liquid (Groebner and Kohlstedt, 2006;Walte et al, 2011).…”

Section: Differentiation After Crossing the Sulphide Solidusmentioning

confidence: 96%

“…Deformation-induced interconnection in olivine/peridotite-metallic liquid aggregates has been investigated in several experimental studies as a candidate for lowering this percentage of stranded liquid (Bruhn et al, 2000;Hustoft and Kohlstedt, 2006;Groebner and Kohlstedt, 2006;Rushmer et al, 2005;Walte et al, 2011). All studies have agreed that deformation has the potential to mobilize Fe-S liquids and lower the percentage of stranded liquid with estimations ranging from 1 vol.% (Groebner and Kohlstedt, 2006) to 2-3 vol.% (Walte et al, 2011) as long as the differential stress or strain rate is sufficient to overcome the capillary forces of the liquid (Groebner and Kohlstedt, 2006;Walte et al, 2011).…”

Section: Differentiation After Crossing the Sulphide Solidusmentioning

confidence: 99%

See 2 more Smart Citations

Deformation of a crystalline olivine aggregate containing two immiscible liquids: Implications for early core–mantle differentiation

Cerantola

Walte

Rubie

2015

Earth and Planetary Science Letters

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Deformation-assisted segregation of metallic and sulphidic liquid from a solid peridotitic matrix is a process that may contribute to the early differentiation of small planetesimals into a metallic core and a silicate mantle. Here we present results of an experimental study using a simplified system consisting of a polycrystalline Fo 90 -olivine matrix containing a small percentage of iron sulphide and a synthetic primitive MORB melt, in order to investigate whether the silicate melt enhances the interconnection and segregation of FeS liquid under deformation conditions at varying strain rates. The experiments have been performed at 2 GPa, 1450 • C and strain rates between 1 × 10 −3 s −1 to 1 × 10 −5 s −1 . Our resultsshow that the presence of silicate melt actually hinders the migration and segregation of sulphide liquid by reducing its interconnectivity. At low to moderate strain rates the sulphide liquid pockets preserved a roundish shape, showing the liquid behavior is governed mainly by surface tension rather than by differential stress. Even at the highest strain rates, insignificant FeS segregation and interconnection were observed. On the other hand the basaltic melt was very mobile during deformation, accommodating part of the strain, which led to its segregation from the matrix at high bulk strains leaving the sulphide liquid stranded in the olivine matrix. Hence, we conclude that deformation-induced percolation of sulphide liquid does not contribute to the formation of planetary cores after the silicate solidus is overstepped. A possible early deformation enhanced core-mantle differentiation after overstepping the Fe-S solidus is not possible between the initial formation of silicate melt and the formation of a widespread magma ocean.

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Consequences of giant impacts in early Mars: Core merging and Martian dynamo evolution

Monteux

Arkani‐Hamed

2014

JGR Planets

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A giant impact is an increasingly popular explanation for the formation of the northern lowland on Mars. It is plausible that at the impact time both Mars and the impactor were differentiated with solid silicate mantles and liquid iron cores. Such a large impact likely resulted in merging of the cores of both bodies, a process which will have implications on the thermal state of the planet. We model the evolution of the Martian mantle following a giant impact and characterize the thermochemical consequences of the sinking of an impactor's core as a single diapir. The impact heating and the viscous heating induced during the core merging may affect the early thermal state of Mars during several tens of million years. Our results show that large viscosity contrasts between the impactor's core and the surrounding mantle silicates can reduce the duration of the merging down to 1 kyr but do not modify the merging temperature. When the viscosity contrast between the diapir and the surrounding silicates is larger than a factor of 1000, the descent of the diapir can lead to some entrainment of the relatively shallow silicates to deepest regions close to the core-mantle boundary. Finally, the direct impact heating of Martian core leads to thermal stratification of the core and kills the core dynamo. It takes on the order of 150-200 Myr to reinitiate a strong dynamo anew. The merging of the impactor's core with the Martian core only delays the reinitiation of the dynamo for a very short time.

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Deformation of a crystalline aggregate with a small percentage of high-dihedral-angle liquid: Implications for core–mantle differentiation during planetary formation

Cited by 31 publications

References 42 publications

Deformation T-Cup: A new multi-anvil apparatus for controlled strain-rate deformation experiments at pressures above 18 GPa

Deformation T-Cup: A new multi-anvil apparatus for controlled strain-rate deformation experiments at pressures above 18 GPa

Deformation of a crystalline olivine aggregate containing two immiscible liquids: Implications for early core–mantle differentiation

Consequences of giant impacts in early Mars: Core merging and Martian dynamo evolution

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