Introduction: The nakhlites are Martian igneous cumulate rocks [1]. Two nakhlites have been investigated in this study: Nakhla and MIL 03346. Texturally, these meteorites are dominated by elongate subhedral to euhedral augite with minor olivine and intercumulus mesostasis. A simple model for nakhlite petrogenesis involves a protracted, subsurface cooling history at oxidizing conditions followed...

Introduction: Enstatite chondrites have a particular minera-logical composition which consists of silicates, sulfide, metal as major phases. But, were the chondrules of EH and EL chondrites originated from the genetic context? In order to answer to this question we have started to investigate on mesostasis chemical composition of chondrules in three thin sections: one from EET90299-EL3 chondrit...

Introduction: Type 3 ordinary chondrites display a wide variety of metamorphic grades, ranging from little metamorphosed type-3.0 chondrites up to nearly equilibrated type 3.9's. Researchers commonly assume that pristine-looking chondrules found in the lowest petrological subtypes have been unaffected by metamorphic processes, and can be used to constrain pre-accretionary processes. Last year, ...

Glasses, in the Kaba CV3 chondrite, occur as mesostasis in chondrules and aggregates and as inclusions in olivines, both confined or open and connected to the mesostasis. The inclusions in olivine and the glassy mesostasis of aggregates seem to have formed contemporaneously. The confined glass inclusions and open inclusions in olivine were formed during olivine growth and the mesostasis glass d...

MIL 03346 is a newly discovered meteorite from Miller Range in Antarctica, which belongs to the nakhlite group of Martian meteorites [1]. It is an unbrecciated, mediumgrained olivinebearing clinopyroxenite with a cumulate texture, similar to the 6 other previously known nakhlites. This is only the 2 nakhlite in Antarctic collections, the other being Yamato 000593 and its pairs. The Meteorite Wo...

Introduction: Nakhlites are martian clinopyrox-enites with minor amounts of olivine and mesostasis. All the known nakhlites show similar mineralogy to each other as well as common crystallization and ejection ages and are believed to have formed in the same igneous body on Mars. The discovery of new nakhlites could offer substantial information to better understand the formation condition and g...

Introduction: Knowledge of martian igneous and mantle composition is crucial for understanding mantle evolution including early differentiation, mantle convection and the chemical alteration of the surface. Primitive magmas provide critical information on their mantle source regions but most Martian meteorites crystallized from fractionated melts [1]. The new martian meteorite NWA 5789, discove...

Introduction: Chondrules are believed to have formed by a brief but intense heating and melting event in the early solar system. Melting erased most mineralogical information about chondrules’ precursors. A sub-group of chondrules is rich in alkali elements and was classified as Naand Al-rich chondrules [1]. We describe two Na-rich chondrules and discuss their phase relations in order to disent...

Introduction: We have carried out detailed petrographical-mineralogical description of three Yamato nakhlites (Y000593, Y000749 and Y000802). These three are paired. We clarified chemical compositional differences between the Yamato nakhlites and other nakhlites, and subclassified the Yamato nakhlites as an intermediate type between NWA817 and others (Nakhla, Governador Valadares and Lafayette)...

New mineralogical studies of Lafayette reveal that it contains a notably variable abundance martian carbonate. Four percent was identified in mesostasis (3.2%) and olivine-hosted (0.8%) fractures one polished section, but only 0.2% both textural types another. The carbonates are Mg0.0-2.0Cc13.2-38.6Sd17.7-81.9Rh3.1-42.9. They have undergone extensive amounts dissolution replacement as the nakhl...