The chemical compositions and textures of matrices and chondrule rims of eight unequilibrated ordinary chondrites: A preliminary report

Abstract

The matrices and chondrule rims of eight unequilibrated ordinary chondrites, Semarkona (LL3), Krymka (L3), Sharps (H3), Chainpur (LL3), Tieschitz (H3), Mezo-Madaras (L3), ALH-77214 (L3) and ALH-77216 (L3), have been investigated in detail with the scanning electron microscope. The analyses were made by the SEM-EDS technique, using a Link System Model 860 energy dispersive spectrometer equipped to a JEOL-T200. Although chondrule rims have similarities in texture and composition to matrices, chondrule rims show wider variabilities in chemical composition in comparison with matrices and often have significantly different compositions from the matrices. From compositional relationships between matrix and rim materials and chondrules in Semarkona, it is shown that the most non-refractory, FeO-rich chondrule rims might have been one of the non-refractory components of precursor materials of the Semarkona chondrules, suggesting that chondrules and and matrix and rim materials have one common component in Semarkona.