Host: The Japanese Association of Mineralogists, Petrologists and Economic Geologists
Abundant refractory inclusions were found in the Sahara 97159 EH3 chondrite. All of the inclusions are intensely altered, mainly producing feldspathoids and albite, CaO depletion and minor Ti-rich compounds, such as Ti-sulfides. The alteration assemblages and FeO-poor spinel suggest that the reactions took place under reducing and SiO2-rich conditions. This is consistent with the redox state of the host enstatite chondrite. The presence of Ti sulfides and low FeO alteration phases distinguishes alteration of E chondrite refractory inclusions from that of carbonaceous and ordinary chondrites. On the other hand, some ordinary chondrites contain high amount of the inclusions, and the characteristic features are close to those in enstatite chondrites. However, the secondary minerals in ordinary chondrites are nepheline, sodalite, ilmenite and hedenbergite, different from those in enstatite chondrites.The bulk compositions, O isotopic compositions and REE patterns, of the enstatite and ordinary chondrites also resemble those in carbonaceous chondrites, indicative of a common reservoir of refractory inclusions in enstatite, ordinary and carbonaceous chondrites.
