THE IRRADIATION-INDUCED OLIVINE TO AMORPHOUS PYROXENE TRANSFORMATION PRESERVED IN AN INTERPLANETARY DUST PARTICLE
- Department of Earth and Planetary Sciences, MSC 03-2040, 1-University of New Mexico, Albuquerque, NM 87131-0001 (United States)
Amorphization of crystalline olivine to glass with a pyroxene composition is well known from high-energy irradiation experiments. This report is on the first natural occurrence of this process preserved in a chondritic aggregate interplanetary dust particle. The Fe-rich olivine grain textures and compositions and the glass grain compositions delineate this transformation that yielded glass with Fe-rich pyroxene compositions. The average glass composition, (Mg, Fe){sub 3}Si{sub 2}O{sub 7}, is a serpentine-dehydroxylate with O/Si = 3.56 +- 0.25, (Mg+Fe)/Si = 1.53 +- 0.24, and Mg/(Mg+Fe) = 0.74 +- 0.1. These measured atomic ratios match the ratios that have been proposed for amorphous interstellar silicate grains very well, albeit the measured Mg/(Mg+Fe) ratio is lower than was proposed for amorphous interstellar silicate grains, Mg/(Mg+Fe) > 0.9.
- OSTI ID:
- 21378345
- Journal Information:
- Astrophysical Journal, Vol. 705, Issue 1; Other Information: DOI: 10.1088/0004-637X/705/1/791; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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