Sayh al Uhaymir 085 is similar to CV3 carbona-ceous chondrites of the oxidized subgroup, and it has some peculiarities and characteristics of CK chondrites. We report on the petrography, mineral chemistry, and oxygen isotopic compositions of Sayh al Uhaymir 085, and discuss its peculiarities and origin. Petrography and mineral chemistry. Sayh al Uhaymir (SaU) 085, a 112 g carbonaceous chondrite...

Introduction: High-Ca pyroxene and plagioclase are typically present as minor phases in diogenites [1]. However, although the trace element content of diogenite orthopyroxene has been measured in a number of studies e.g., [2, 3]; almost no trace element data is available for the high-Ca pyroxene and plagioclase with which it routinely coexists in these meteorites. These data could provide insig...

Introduction: Lunar meteorite Dhofar 026 was previously interpreted as an impact melt [1, 2]. Detailed studies of the rock and comparison to Apollo lunar samples 15418 and 60017 indicate that the rock instead is a shocked, partly melted, granulitic breccia. These studies, presented by [3], are summarized herein. Petrology of Dhofar 026: Most of the rock consists of blocky patches of monomineral...

Introduction: In each chondrite group, the bulk composition of all group members is the same, whereas the few bulk compositions of chondrules known so far show large variations [e.g. 1,2]. As these variations are observed even in primitive type 3 meteorites, they must be related to the formation event of chondrules or their precursors in the solar nebular, for example, the formation of the prec...

Introduction: Dhofar 1428 is a lunar feldspathic breccia found in 2006. Bunch et al. [1] briefly described mineral chemistry of Dhofar 1428. Korotev and Zeigler [2] analyzed its bulk FeO and Sm compositions. Here, we report such detailed data for Dhofar 1428. Results and Discussion: Dhofar 1428 has a distinct breccia texture with numerous fragments of rock, mineral, and glass all welded by a gl...

We report evidence of interchondrule matrix heterogeneity on a scale of 50 lm in the well-preserved CR2 chondrite LAP 02342. Despite minor effects resulting from asteroidal aqueous alteration, the matrix in this CR chondrite seems to preserve much of the compositional record of nebular fines. We carried out electron-microprobe studies using a 3-lm-diameter beam; we analyzed 10 elements in 36or ...

Introduction: The volatile component of apatite [Ca5(PO4)3(F,Cl,OH)] makes it a popular choice for studying the abundance and distribution of indigenous lunar volatiles [e.g. 1-5]. The thermodynamic behavior of volatile partitioning into apatite is, however, poorly constrained. Limited experimental studies of apatite/melt partitioning have focused on terrestrial systems [6], chlorine-brine syst...

Introduction: We have developed a model to calculate the cooling rate (or burial depth) by using the Fe-Mg chemical zoning profile of olivine, considering diffusional modification of zoning profiles as crystals grow by fractional crystallization from a melt [e.g., 1]. We applied the model to calculating cooling rates of olivines in the Semarkona (LL3.00) chondrite [2]. In this abstract, we appl...

Introduction: The metal-rich CH and CB chondrites are among the most primitive (unmetamorphosed, unaltered), but controversial meteorites: both nebular and asteroidal models have been proposed to explain the origins of their components [1-14]. In addition to porphyritic chondrules and rare refractory inclusions, the CHs contain a high abunbance (~20 vol%) of metal and dominant cryptocrystalline...

Introduction: Remotely sensed geochemical data provide extremely valuable information concerning the global distribution of elements on a planetary surface, and are valuable in the identification of major crustal terranes. Planetary geochemical maps of the Moon and Mars for several elements such as Th, rare earth elements (REE), K, and Fe have been or are currently being prepared and have yield...