Heterogeneous distribution of 60Fe in the early solar nebula: Achondrite evidence
© The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences. 2006
Received: 2 December 2005
Accepted: 20 April 2006
Published: 16 September 2006
60Fe-60Ni systematics in quenched angrites and two old eucrites were investigated by secondary ion mass spectrometry. The 60Ni/62Ni isotopic compositions were normal within 2σ errors. The inferred initial 60Fe/56Fe ratios for quenched angrites was (6±9)× 10−9, and similar upper limit values were also obtained from eucrites. Using the age difference of approximately 5 Ma between the quenched angrites and Ca−Al-rich inclusions, the initial 60Fe/56Fe ratio at the start of the solar system was calculated to be approximately (6±9)× 10−8. This initial ratio is significantly smaller than previously published values obtained from chondritic materials, suggesting the heterogeneous distribution of 60Fe in the solar nebula.