Morro Do Rocio: An Unequilibrated H5 Chondrite*

Morro do Rocio (MdR) initially appeared to be a perfectly normal, ordinary H5 chondrite. Fortuitously, however, during the course of our study free silica and a few olivine grains with higher iron content than the majority Fa 17.8 ± 0.3 were observed. MdR has normal texture and is normal in chemical, modal and, generally, mineral composition. Further detailed studies revealed more “anomalies,” additional indications that MdR is not equilibrated. Because most, if not all, ordinary chondrites are breccias, it seems likely that they may have similar “anomalies” which then are normal and must be considered in attempts to understand the origin of chondrites.