The petrogenesis of L-6 chondrites: insights from the chemistry of minerals

Rare earth element abundances in the CK chondrites including the Kobe meteorite.

“…If this is the case, Eu may have been in equilibrium among minerals during the period of 10 6 years of thermal metamorphism, as demonstrated by Curtis and Schmitt (1979) for the L-6 chondrites. However, a considerable fraction of the CK Eu may have existed in the trivalent state, in which case there is no correlation with Sr or clear trend in the Eu/Sm-Sm diagram (Fig.…”

“…The heterogeneous distribution of Na in plagioclase grains suggests that other alkali elements such as K and Rb may also have non-equilibrium distributions. Curtis and Schmitt (1979) reported that alkalis (Na, K and Rb) are exclusively associated with feldspar in L6 chondrites and thus a close relationship between K and Rb is expected. However, this is not the case for these samples as seen in Fig.…”

“…The main hosts of Eu +2 and Sm +3 are plagioclase and phosphates, respectively (Curtis and Schmitt, 1979;Ebihara and Honda, 1984). It is suggested that plagioclase grains developed from the chondrule mesostasis had captured divalent Eu more efficiently in the more reducing conditions prevalent during the early thermal metamorphism and become more homogeneously distributed in bulk chondrites.…”

The Leedey, Oklahoma, chondrite: Fall, petrology, chemistry and an unusual Fe, Ni‐FeS inclusion

“…Brief descriptions of the shower and recovery were given by Nininger and Nininger (1950) and Moore (1971). Leedey has been briefly studied petrologically for classification purposes (Mason, 1963;Van Schmus and Wood, 1967;Rubin, 1990) and major and trace element mineral compositions and modal abundances were given by Curtis and Schmitt (1979). The chemical composition of Leedey has been examined by a number of workers (e.g., Konig, 1964;Jarosewich, 1967;Masuda et al, 1973), who participated in a long-term study of an interlaboratory comparison organized by C. B. Moore and using Leedey as a standard.…”

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“…Ca-phosphate is also the host mineral for the rare earth elements (REE) in the ordinary chondrites (Mason and Graham, 1970;Allen and Mason, 1973;Curtis and Schmitt, 1979;Ebihara and Honda, 1983). Based on the REE abundances Ebihara and Honda ( 1983) suggested that chemical fractionation had taken place among the actinoid and lanthanoid elements during the formation of some ordinary chondrites.…”