Radionuclides in Chassigny and Nakhla meteorites of Mars origin: Implications for their pre-atmospheric sizes and cosmic-ray exposure ages
P.P. Povinec, I. Sýkora, R.J. Macke, J. Tóth, L. Kornoš, V. Porubčan
Planetary and Space Science
In Press, Journal Pre-proof, Available online 26 March 2020
“Highlights
• Two Martian meteorites, Chassigny and Nakhla, were analyzed by non-destructive gamma-ray spectrometry to determine concentrations of cosmogenic 26Al.
• Pre-atmospheric radii of the Chassigny and Nakhla meteorites were estimated to be 17 ± 4 and 30 ± 5 cm, respectively.
• Cosmic-ray exposure ages of the Chassigny and Nakhla meteorites were estimated to be 12.8 ± 2.5 and 11.6 ± 1.8 Myr, respectively.
• The obtained results are in agreement with published ages of chassignites and nakhlites.”
“Two Martian meteorites, Chassigny and Nakhla, were analyzed by non-destructive gamma-ray spectrometry to determine concentrations of cosmogenic (26Al) and primordial (40K, 238U, 232Th) radionuclides, and to estimate their pre-atmospheric sizes and cosmic-ray exposure ages. The pre-atmospheric radii of the Chassigny and Nakhla meteorites were estimated using the cosmogenic 26Al to be 17 ± 4 and 30 ± 5 cm, which would result in their total masses of 30–130 and 210–580 kg, respectively. This is comparable to the size and mass estimated for other chassignites and nakhlites. The cosmic-ray exposure ages of the Chassigny and Nakhla meteorites estimated using the 26Al – 21Ne isotope pair were 12.8 ± 2.5 and 11.6 ± 1.8 Myr, respectively, in agreement with published ages of chassignites and nakhlites averaged from several isotope methods, i.e. 11.6 ± 0.8 and 12.2 ± 0.8 Myr, respectively.”
