Aqueous alteration of meteorite parent bodies: Possible role of unfrozen water and the Antarctic meteorite analogy

Based on oxygen isotrophy the alteration of CM2 chondrites could occur at or near O C (273 K). Such a scenario can be understood if C chondrite parent bodies evolved as rock/ice mixtures that contained unfrozen (mobile or quasi-liquid below 273K) pure water, a well known phenomenon in cold soils on Earth. The importance of unfrozen water diagenesis in C chondrite history can be tested by a combined program of experimental simulations and petrologic study of analogous features developed by weathering of meteorites in or an Antarctic ice.