JMDMT #1968 Microfossils of Cyanobacteria in Carbonaceous Meteorites

The James M. DuPont Meteorite Collection - 791198 chondrite, which they infer to entirely consist of "primary accretionary rock," dark matrix almost devoid of light-colored mineral fragments is mainly found adjacent to chondrules, and materials well separated from chondrules has large contents of small clasts. We are studying highly unequilibrated ordinary chondrites (OC) and have preliminary results on Bishunpur, Chainpur, Krymka, and Semarkona. Because matrixlike rims are much thinner in OC than in CM chondrites, the study is appreciably more difficult. We find that well-preserved matrixlike rims are around the high-FeO chondrules, especially around radial-pyroxene and cryptocrystalline chondrules. Only a small fraction of low-FeO porphyritic chondrules have nearby