Abstract-Asteroid 2008 TC 3 impacted Earth in northern Sudan on October 7, 2008. The meteorite named Almahata Sitta was classified as a polymict ureilite. In this study, 40 small pieces from different fragments collected in the Almahata Sitta strewn field were investigated and a large number of different lithologies were found. Some of these fragments are ureilitic in origin, whereas others are clearly chondritic. As all are relatively fresh (W0-W0 ⁄ 1) and as short-lived cosmogenic radioisotopes were detected within two of the chondritic fragments, there is strong evidence that most, if not all belong to the Almahata Sitta meteorite fall. The fragments can roughly be subdivided into achondritic (ureilitic; 23 samples) and chondritic lithologies (17 samples). Among the ureilitic rocks are at least 10 different lithologies. A similar number of different chondritic lithologies also exist. Most chondritic fragments belong to at least seven different E-chondrite rock types (EH3, EL3 ⁄ 4, EL6, EL breccias, several different types of EL and EH impact melt rocks and impact melt breccias; some of the latter are shock-darkened). In addition, two H-group ordinary chondrite lithologies were identified, and one sample of a chondrite type that is so far unique. The latter has some affinities to R chondrites. Oxygen isotope compositions of 14 fragments provide further fundamental information on the lithological heterogeneity of the Almahata Sitta meteorite. Based on the findings presented in this study, the reflectance spectrum of asteroid 2008 TC 3 has to be evaluated in a new light.

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Volcanism is a substantial process during crustal growth on planetary bodies and well documented to have occurred in the early Solar System from the recognition of numerous basaltic meteorites. Considering the ureilite parent body (UPB), the compositions of magmas that formed a potential UPB crust and were complementary to the ultramafic ureilite mantle rocks are poorly constrained. Among the Almahata Sitta meteorites, a unique trachyandesite lava (with an oxygen isotope composition identical to that of common ureilites) documents the presence of volatile-and SiO 2 -rich magmas on the UPB. The magma was extracted at low degrees of disequilibrium partial melting of the UPB mantle. This trachyandesite extends the range of known ancient volcanic, crust-forming rocks and documents that volcanic rocks, similar in composition to trachyandesites on Earth, also formed on small planetary bodies ∼4.56 billion years ago. It also extends the volcanic activity on the UPB by ∼1 million years (Ma) and thus constrains the time of disruption of the body to later than 6.5 Ma after the formation of Ca-Al-rich inclusions.A large number of planetary embryos, tens to hundreds of kilometers in size, accreted within the early Solar System. In some of these embryos, internal heating triggered melting and differentiation, giving rise to a varied suite of lithologies as documented by the achondritic meteorites. Planetary crustal growth occurs via both volcanic eruptions and plutonic intrusions. Constraining these processes and the diversity of crustal materials that formed the outermost solid shell of planetary bodies is crucial for understanding Solar System planetary processes and evolution.Ureilites are among the most common achondrites and represent remnants of the mantle from a planetary body from which magmas have been extensively extracted (1−4). Several details of ureilite petrogenesis (e.g., the mode of melt extraction) remain controversial (e.g., refs. 1 and 2) because crustal rocks from the ureilite parent body (UPB) have not yet been discovered. Although tiny remnants of feldspathic and felsic melts from ureilitic breccias have been interpreted as UPB basalts or products of partial melting of plagioclase-bearing cumulates (e.g., refs. 5 and 6), it is generally assumed that the complementary melts were lost to space during explosive eruptions (e.g., refs. 7-9).A unique opportunity to gain new insights into ureilite petrogenesis was provided by the polymict asteroid 2008 TC 3 that impacted our planet October 7, 2008, in the Nubian Desert, Sudan, containing various ureilitic and ureilite-related fragments (10, 11). Among its remnant fragments collected in the strewn field, collectively named the "Almahata Sitta" meteorites, the sample ALM-A (Almahata Sitta trachyandesitic meteorite) was recovered (12). ALM-A weights 24.2 g and is covered with a greenish and shiny fusion crust (Fig. 1).The ALM-A sample described here is the only SiO 2 -rich, rapidly cooled volcanic rock among the meteorites in our collections. This rock is textura...

Abstract-Maribo is a new Danish CM chondrite, which fell on January 17, 2009, at 19:08:28 CET. The fall was observed by many eye witnesses and recorded by a surveillance camera, an all sky camera, a few seismic stations, and by meteor radar observatories in Germany. A single fragment of Maribo with a dry weight of 25.8 g was found on March 4, 2009. The coarse-grained components in Maribo include chondrules, fine-grained olivine aggregates, large isolated lithic clasts, metals, and mineral fragments (often olivine), and rare Ca,Al-rich inclusions. The components are typically rimmed by fine-grained dust mantles. The matrix includes abundant dust rimmed fragments of tochilinite with a layered, fishbone-like texture, tochilinite-cronstedtite intergrowths, sulfides, metals, and carbonates often intergrown with tochilinite. The oxygen isotopic composition: (d O and the presence of unaltered components suggest that Maribo is among the least altered CM chondrites. The bulk chemistry of Maribo is typical of CM chondrites. Trapped noble gases are similar in abundance and isotopic composition to other CM chondrites, stepwise heating data indicating the presence of gas components hosted by presolar diamond and silicon carbide. The organics in Maribo include components also seen in Murchison as well as nitrogen-rich components unique to Maribo.

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