High-temperature Si isotope fractionation between iron metal and silicate

Shahar, Anat; Hillgren, V. J.; Young, Edward; Fei, Yingwei; Macris, Catherine A.; Deng, Liwei

doi:10.1016/j.gca.2011.09.038

Cited by 82 publications

(84 citation statements)

References 22 publications

(47 reference statements)

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“…Oxygen fugacity can be controlled by surrounding sample materials with buffer materials. In order to study Si isotope fractionation between metal and silicate, piston-cylinder experiments were run between 0.54 and 1 GPa pressure and in a temperature range between 1450 and 1800°C by Shahar et al (2009Shahar et al ( , 2011 and Hin et al (2014). The latter study used a rotating piston-cylinder apparatus (Schmidt et al, 2006) that enabled improved density separation of metal and silicate phases.…”

Section: High-pressure Experimental Methodsmentioning

confidence: 99%

“…7B. Metal-silicate Si isotope fractionation experiments in multi-anvil presses were previously run at pressures of 7 and 9 GPa and between 2000 and 2200°C by Shahar et al (2011) and Kempl et al (2013a). Kempl et al (2013b) used an industrial-scale blast furnace to study Si isotopic behaviour during metal-silicate segregation at low pressure.…”

Section: High-pressure Experimental Methodsmentioning

confidence: 99%

“…Georg et al, 2007;Shahar et al, 2009Shahar et al, , 2011Ziegler et al, 2010;Kempl et al, 2013a;Hin et al, 2014), driven by the different chemical bonding environment of Si in silicate rocks versus metallic liquid Georg et al, 2007). If Si isotope fractionation between metal and silicate is an equilibrium process, the heavier isotopes fractionate preferentially into the stiffer bonded phase, in this case the silicate.…”

Section: The Role Of Si Stable Isotopesmentioning

confidence: 99%

“…Experimental studies on Si isotope fractionation between metal and silicate were carried out by Shahar et al (2009Shahar et al ( , 2011 at pressures of 1 and 7 GPa, and temperatures between 1800 and 2200°C. Kempl et al (2013a) did experiments at 9 GPa and ß2150°C.…”

Section: The Role Of Hpt Experimentsmentioning

confidence: 99%

“…Shahar et al (2009Shahar et al ( , 2011 used experiments containing iron metal with 9 wt% Si and an oxide mixture simulating a BSE composition. The metal phase in their run products typically contained ß8 wt% Si (Shahar et al, 2009).…”

Section: Starting Materials and Compositionsmentioning

confidence: 99%

See 4 more Smart Citations

Silicon stable isotope fractionation between metal and silicate at high-pressure, high-temperature conditions as a tracer of planetary core formation

Kempl

Vroon

Wagt

et al. 2016

Netherlands Journal of Geosciences

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The largest differentiation event in Earth and other terrestrial planets was the high-pressure, high-temperature process of metal core segregation from a silicate mantle. The abundant element silicon (Si) can be partially sequestered into the metallic core during metal-silicate differentiation, depending on pressure, temperature and planetary oxidation state. Knowledge of the Si content of a planet's core can constrain the conditions of core formation, but in the absence of direct samples from planetary cores, quantifying core Si content is challenging. One relatively new tool to study core formation in terrestrial planets is based on combining measurements of the Si stable isotopic composition of planetary crust and mantle samples with measurements of the Si stable isotope fractionation between metal and silicate at high-temperature and high-pressure conditions. In this study we present the results of a small set of high-pressure, high-temperature (HPT) experiments and combine these with a review of literature data to investigate how the Si isotope fractionation behaviour between metal and silicate varies as a function specifically of experimental run time and temperature. We show that although there is no debate about the sign of fractionation, absolute values for Si isotope fractionation between metal and silicate are difficult to constrain because the experimental database remains incomplete, and because Si isotopic measurements of metals in particular suffer from the absence of a true inter-laboratory comparison. We conclude that in order to derive accurate quantitative estimates of the Si content of the core of the Earth or other planets a wide range of additional experiments will be required.

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Section: High-pressure Experimental Methodsmentioning

confidence: 99%

Section: High-pressure Experimental Methodsmentioning

confidence: 99%

Section: The Role Of Si Stable Isotopesmentioning

confidence: 99%

Section: The Role Of Hpt Experimentsmentioning

confidence: 99%

Section: Starting Materials and Compositionsmentioning

confidence: 99%

See 3 more Smart Citations

Silicon stable isotope fractionation between metal and silicate at high-pressure, high-temperature conditions as a tracer of planetary core formation

Kempl

Vroon

Wagt

et al. 2016

Netherlands Journal of Geosciences

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Limitations on silicon in the outer core: Ultrasonic measurements at high temperatures and high dK/dP values of Fe‐Ni‐Si liquids at high pressures

et al. 2015

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The sound velocities of four iron‐nickel‐silicon liquids (Fe‐5 wt %Ni‐6 wt %Si, Fe‐5 wt %Ni‐10 wt %Si, Fe‐5 wt %Ni‐14 wt %Si, and Fe‐5 wt %Ni‐20 wt %Si) are measured between 1460 and 1925 K at ambient pressures using ultrasonic interferometry. The results constrain both the dependence on Si content of the bulk modulus of these liquids and the temperature dependence of their elasticity. These elastic data are utilized to assess both relatively low pressure (to 12 GPa) compressional data on Fe‐Si liquids and to extrapolate to higher‐pressure and higher‐temperature conditions. If a single equation of state for Fe‐Ni‐Si liquids of a given composition applies from low pressure to near core conditions, then our results imply that the isothermal pressure derivative of the bulk modulus of these liquids is high: likely 8 and above at high temperatures. This high value of the pressure derivative of the bulk modulus at low pressures in Fe‐Si liquids causes marked stiffening at higher pressures, leading to notable incompressibility and apparent low values of the pressure derivative of the bulk modulus at core conditions. These results reinforce the conclusion that silicon is not a major alloying component of Earth's core.

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An Experimental Geochemistry Perspective on Earth's Core Formation

Siebert¹,

Shahar²

2015

The Early Earth

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High-temperature Si isotope fractionation between iron metal and silicate

Cited by 82 publications

References 22 publications

Silicon stable isotope fractionation between metal and silicate at high-pressure, high-temperature conditions as a tracer of planetary core formation

Silicon stable isotope fractionation between metal and silicate at high-pressure, high-temperature conditions as a tracer of planetary core formation

Limitations on silicon in the outer core: Ultrasonic measurements at high temperatures and high dK/dP values of Fe‐Ni‐Si liquids at high pressures

An Experimental Geochemistry Perspective on Earth's Core Formation

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