| Summary: | Stable isotope ratios in C, H, N, O and S are powerful indicators of a wide variety of planetary geophysical processes that can identify origin, transport, temperature history, radiation exposure, atmospheric escape, environmental habitability and biology [1]. For the Allan Hills 84001 meteorite, for example, the ¹³C/¹²C ratio identifies it as a Mars (SNC) mete- orite; the ⁴⁰K/⁴⁰Ar ratio tells us the last time the rock cooled to solid, namely 4 Gya; isotope ratios in ³He, ²¹Ne and ³⁸Ar show it was in space (cosmic ray expo- sure) for 10-20 million years; ¹⁴C dating that it sat in Antarctica for 13,000 years before discovery; and clumped isotope analysis of ¹⁸O¹³C¹⁶O in its carbonate that it was formed at 18±4 ⁰C in a near-surface aqueous environment [2]. Solar System Formation NASA/JPL
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