Fe-Mn systematics of type IIA chondrules in unequilibrated CO, CR, and ordinary chondrites

摘要: We have examined Fe/Mn systematics of 34 type IIA chondrules in eight highly unequilibrated CO, CR, and ordinary chondrites using new data from this study prior studies our laboratory. Olivine grains CO (UOC) significantly different ratios, with mean molar = 99 44, respectively. analyses both these chondrite groups show well-defined trends Mn versus Fe (afu) Fe/Mg diagrams. In general, CR properties intermediate between those UOC chondrites. most chondrules, the ratio olivine decreases during crystallization, whereas does not appear to change. It is difficult interpret observed terms differing moderately volatile element depletions inherited precursor materials. Instead, we suggest that significant differences abundances silicates sulfides +/- metals material, as well open-system behavior chondrule formation, were responsible for establishing trends. Using Fe-Mn-Mg systematics, are able identify relict which could be derived previous generations including other groups, possibly chondritic reservoirs been sampled previously.