This paper reports 14C measurements in meteorites using an extraction method which employs RF melting of samples as small as 0.1 g. A study of extraction of cosmic-ray-produced 14C in samples of Bruderheim gave 14C levels between 38 and 60 dpm/kg for samples which had been preheated in air between 250 and 700°C, with a mean value of 46.8 ± 1.4 dpm/kg. A range of values between 35 and 59 dpm/kg was found for other falls of saturated meteorites preheated to 500°C. The preheating step is shown to be effective in removing terrestrial carbon contamination. A series of samples previously dated by 81Kr as having ages of 120-310 kyrgave 14C levels of between <0.16 and 0.37 ± 0.10 dpm/kg. These levels are consistent with levels of in situ production by cosmic rays at the Earth's surface.
ASJC Scopus subject areas
- Geochemistry and Petrology