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sources. This suggests that the oldest group of meteorites is more closely related to one another than they are to the younger meteorites that are derived from less incompatible-element-depleted sources. Closed-system fractional crystallization of this suite of meteorites is modeled with the MELTS algorithm using the bulk composition of Yamato 980459 as a parent. These models reproduce many of the major element and mineralogical variations observed in the suite. In 2 addition, the rare-earth element systematics of these meteorites are reproduced by fractional crystallization using the proportions of phases and extents of crystallization that are calculated by MELTS. The combined effects of source composition and fractional crystallization are therefore likely to account for the major element, trace element, and isotopic diversity of all shergottites.Thus, assimilation of a martian crustal component is not required to explain the geochemical diversity of the shergottites.

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