Synthesis of refractory metal nuggets and constraints on the thermal histories of nugget-bearing ca, al-rich inclusions

D. Schwander, S. Buhre, G. Schönhense, U. Ott

Research output: Article

10 Citations (Scopus)

Abstract

Tiny refractory metal nuggets are mainly observed inside Ca, Al-rich inclusions (CAIs) from chondritic meteorites and are commonly assumed to be condensates from a solar composition gas. However, recent detailed studies of metal nugget compositions and their comparison with predictions from condensation show that the observed abundance patterns are extremely difficult to achieve in this way. As a test for the proposed alternative, precipitation from a silicate liquid, we conducted melting experiments, in which nine different refractory metals (nugget components) were equilibrated with each other along with a CAI-like liquid at reducing conditions. When quenched, minerals similar to those in CAIs formed from such liquids including refractory metal nuggets exhibiting compositions and appearances similar to those of the meteoritic nuggets. The run products and their comparison with a meteoritic nugget-bearing CAI is evidence for formation of refractory metal nuggets during cooling of Ca, Al-rich liquids at rates about 1000°/40 s (in the interval from 1900 to 900 °C). To achieve the formation of refractory metal nuggets and the textures observed in the host inclusions, during cooling the rate probably changed. Refractory metal nuggets apparently formed during quenching before spinel crystallized.

Original languageEnglish
Pages (from-to)893-903
Number of pages11
JournalMeteoritics and Planetary Science
Volume50
Issue number5
DOIs
Publication statusPublished - máj. 1 2015

ASJC Scopus subject areas

  • Geophysics
  • Space and Planetary Science

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