Olivine grain growth in partially molten Fe–Ni–S: A proxy for the genesis of pallasite meteorites

Nickel isotope fractionation during metal-silicate differentiation of planetesimals: Experimental petrology and ab initio calculations

“…Different formation scenarios are invoked for pallasites: these meteorites either sample the mantle core boundary of a differentiated body and result from magmatic processes (e.g. Wasson and Choi, 2003;McKibbin et al, 2016 and references therein), or they formed by impacts between already differentiated planetesimals (Scott, 2007;Solferino et al, 2015;Solferino and Golabek, 2018). Nickel and Fe isotopes data can be discussed relative to these different processes.…”

Reevaluation of metal interconnectivity in a partially molten silicate matrix using 3D microtomography

“…by their initial values. The parameters of the growth laws for our experimental system (olivine + silicate melt + nickel) are taken from Guignard et al (2016 and and Guignard (2011) for solid and partially molten conditions, respectively, while those for Fe-FeS meltolivine systems representative of literature studies are taken from Solferino et al (2015) and Solferino and Golabek (2018). This figure indicates that the textural maturation J o u r n a l P r e -p r o o f of nickel grains is limited by grain growth of the rigid silicate matrix.…”

“…Yoshino et al ( 2003) used San Carlos olivine powder with a mean grain size of 10-20 µm and equilibrated the samples for 20 hours at 1573 K (Figure 8b, green curve), while Roberts et al (2007) and Watson and Roberts (2011) used a starting grain size of 45 µm, temperature in the range 1573-1623 K and run durations of 24 hours (Figure 8b, blue curve). Using grain growth laws of olivine grains in presence of an iron-sulfide melt (Solferino et al, 2015;Solferino and Golabek, 2018), the evolution of the normalized total surface area shows no decrease during the time of experiment (Figure 8b, full green and blue curves). At these conditions, the model predicts that the evolution of the normalized surface area (and associated break up of the forced network) requires thousands of hours for experiments of Yoshino et al ( 2003) (Figure 8b green dashed line) and ≈ 10 7 hours (i.e.…”

Pore Network Modeling of Core Forming Melts in Planetesimals

“…The process of textural maturation in partially molten aggregates, liquid phase sintering (German, 2013), involves simultaneous grain growth and melt redistribution, primarily driven by surface tension. The aspect of grain growth in the samples used in our study were reported in detail by Solferino et al (2015) and Solferino and Golabek (2018). In this work, we focus on the second aspect of textural maturation involving melt redistribution driven by surface tension (Hier-Majumder et al, 2006;Takei and Hier-Majumder, 2009;King et al, 2011).…”

“…In contrast, laboratory experiments where the samples were annealed for 72 h (Bagdassarov et al, 2009a,b), the connection threshold was much higher, near 16 vol%, in agreement with numerical models of Fe-FeS melt in a matrix containing irregular shaped grains (Ghanbarzadeh et al, 2017, 10-19 vol%). To address the discrepancy between these two sets of observations, we present the first results of direct pore network modeling of melt connectivity from microtomographic images of samples annealed by Solferino et al (2015) and Solferino and Golabek (2018). In these experiments, samples consisting of Fe-FeS melt in an olivine matrix were annealed between 40 and 360 h. To constrain the conditions for the establishment of the connected network of core forming minerals, it is important to consider the textural evolution of partially molten aggregates.…”