JMDMT #2459 Microfossils of Cyanobacteria in Carbonaceous Meteorites

The James M. DuPont Meteorite Collection - rocks strongly suggest that both the melt phase and the clast populations differ somewhat among rocks. This is systematic in that the finer-grained rocks tend to have a more incompatible-element-rich bulk-rock composition, and thus are not just more rapidly cooled variants of coarse-grained melts. The lack of systematic variation of the major elements, including alumina, is suggestive that all target components were essentially basaltic or noritic in composition, lacking ferroan anorthosite, consistent with detailed analysis of plagioclase and mafic mineral fragments in these rocks [4]. The sum of the evidence suggests that these rocks are dominantly mixtures of small amounts of highly concentrated KREEP in a basaltic rock with varied noritic rocks forming the melt, plus