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The effect of temperature and pressure on the distribution of iron group elements between metal and olivine phases in the process of differentiation of protoplanetary materialThe distribution patterns of Ni, Co, Mn, and Cr were studied in olivines of various origins: from meteorites (chondrites, achondrites, pallasites), which are likely analogs of the protoplanetary material, to peridotite inclusions in kimberlite pipes, which are analogs of mantle material. According to X-ray microanalysis data, nickel is concentrated in peridotite olivines, while manganese is concentrated in meteoritic olivines. The maximum chromium content was found in ureilites, which were formed under reducing conditions. Experiments at pressures of 20 to 70 kbar and temperatures of 1100 to 2000 C have shown that in a mixture of olivine and Ni metal or NiO, nickel enters the silicate phase, displacing Fe into the metallic phase. Equilibrium temperatures were estimated from the Fe, Ni distribution coefficients between the metal and olivine: 1500 K for pallasites, 1600 K for olivine-bronzite H6 chondrites, 1200 K for olivine-hypersthene L6, 900 K for LL6, and 1900 K for ureilites (at P = 1 atm). The equilibrium conditions of peridotites are close to T = 1800 K and P over 100 kbar. It is concluded that there is a sharp difference between the conditions of differentiation of the protoplanetary material at the time meteorites were formed and the conditions of differentiation of the planets into concentric layers.
Document ID
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Vinogradov, A. P.
(Academy of Sciences (USSR) Moscow, Ussr)
Ilyin, N. P.
(Academy of Sciences (USSR) Moscow, Ussr)
Kolomeytsava, L. N.
(Academy of Sciences (USSR) Moscow, Ussr)
Date Acquired
August 9, 2013
Publication Date
January 1, 1977
Publication Information
Publication: NASA, Washington The Soviet-Am. Conf. on Cosmochem. of the Moon and Planets, pt. 1
Subject Category
Accession Number
Distribution Limits
Work of the US Gov. Public Use Permitted.
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