FRACTIONATION OF MODERATELY VOLATILE ELEMENTS IN ORDINARY CHONDRITES

Abstract

Observed differences in the abundance ratios of moderately volatile elements found in ordinary chondrites relative to CI chondrites may have resulted from a continuous loss of nebular gas from the ordinary‐chondrite formation region during condensation. If this occurred, the nebular volatility of these elements should be inversely correlated with their abundance ratios. Such a nebular gas loss can occur as a result of momentum exchange between solids and gases, as a result of interactions between the nebular gas and solar photons or particles at the surface of the nebula, or as a result of the settling of previously condensed solids to the median plane of the nebula.