Calcium-aluminum-rich inclusions from enstatite chondrites: indigenous or foreign?
The primary mineral assemblages and initial (26)Al/(27)Al ratios of rare calcium-aluminum-rich inclusions (CAIs) from enstatite (E) chondrites are similar to those of CAIs from other chondrite classes. CAIs from all chondrite classes formed under oxidizing conditions that are much different from the reducing conditions under which the E chondrites formed. Either CAIs formed at an earlier, more oxidizing epoch in the region where E chondrites ultimately formed, or they formed at a different place in the solar nebula and were transported into the E chondrite formation region.
Guan
Y
Department of Mineral Sciences, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560-0119, USA. Lunatic Asylum, Division of Geological and Planetary Sciences 170-25, California Institute of Technology, Pasadena,
Huss
GR
MacPherson
GJ
Wasserburg
GJ