Nepheline formation in chondrite parent bodies: Verification through experiments

From our results, we propose that the nepheline in refractory inclusions and chondrules in meteorites formed by a two-stage alteration process: (1) formation of the Na zeolites from melilite, plagioclase, and glass by hydrothermal alteration at low temperature (probably <300 °C) in the presence of small amounts of Na-rich and alkaline aqueous solutions, and (2) transformation of the Na zeolites to nepheline due to heating at higher temperature (300-700 °C) for very long durations after the solutions were lost.