We conducted Mössbauer spectroscopic studies on the Ghubara meteorite which had been described as at least two-generation regolith breccia on the macro scale. The isomer shift and quadrupole splitting of the Fe-Ni part are quite different from those obtained in ordinary chondrites, reflecting shock effects. We observed a large amount of magnetite that may have come from weathering of, primarily, the silicate fraction. We found very similar iron mineralogy in the Densmore meteorite.

Chondrules, silicate spheres typically 0.1 to 1 mm in diameter, are the most abundant constituents in the most common meteorites falling on Earth, the ordinary chondrites. In addition, many primitive meteorites have calcium-aluminum-rich inclusions (CAIs). The question of whether comets have chondrules or CAIs is relevant to understanding what the interior of a comet is like and what a cometary meteorite might be like. In addition, one prominent model for forming chondrules and CAIs, the X-wind model, predicts their presence in comets, while most other models do not. At present, the best way to search for chondrules and CAIs in comets is through meteor showers derived from comets, in particular, the Leonid meteor shower. Evidence potentially could be found in the overall mass distribution of the shower, in chemical analyses of meteors, or in light curves. There is no evidence for a chondrule abundance in the Leonid meteors similar to that found in chondritic meteorites. There is intriguing evidence for chondrule- or CAI-sized objects in a small fraction of the light curves, but further work is required to generate a definitive test.

Surficial suevites from the Ries impact structure have been investigated in the field and using optical and analytical scanning electron microscopy. The groundmass of these suevites comprises calcite, clay minerals, impact melt glass, crystallites (plagioclase, garnet, and pyroxene), francolite, and Ba-phillipsite. The latter zeolite is a secondary phase. Abundant textures have been observed: intricate flow textures between the various groundmass phases, globules of each phase in the other phases, spheroids of pyrrhotite in calcite, the "budding-off" of clay globules into silicate glass and/or calcite, euhedral overgrowths of francolite on apatite clasts, and quench-textured crystallites in the groundmass. Groundmass-forming calcite displays higher FeO, MnO, and SiO2 contents than limestone target material. The composition of suevite "clay minerals" is highly variable and not always consistent with montmorillonite. Three types of glasses are distinguished in the groundmass. Type 1 glasses are SiO2-rich and are clearly derived from sandstones in the sedimentary cover, while the protoliths of the other two glass types remains unclear. Analytical data and micro-textures indicate that the calcite, silicate glass, francolite, and clay minerals of the groundmass of the Ries suevites represent a series of impact-generated melts that were molten at the time of, and after, deposition. On cooling, plagioclase, pyroxene, and garnet crystallized from the groundmass. These results are at variance with the current, traditional descriptive definition of suevite. Given that Ries is the original type occurrence of "suevite," some modification to the traditional definition may be in order. As the results of this study are most consistent with the groundmass of Ries surficial suevites representing a mix of several types of impact-generated melts, we suggest that a possible origin for these suevites is as some form of impact melt flow(s) that emanated from different regions of the evolving crater.

We describe an analytical technique for measurements of Fe, Ni, Co, Mo, Ru, Rh, W, Re, Os, Ir, Pt, and Au in bulk samples of iron meteorites. The technique involves EPMA (Fe, Ni, Co) and LA-ICP-MS analyses of individual phases of iron meteorites, followed by calculation of bulk compositions based on the abundances of these phases. We report, for the first time, a consistent set of concentrations of Mo, Ru, Rh, Pd, W, Re, Os, Ir, Pt, and Au in the iron meteorites Arispe, Bennett County, Grant, Cape of Good Hope, Cape York, Carbo, Chinga, Coahuila, Duchesne, Gibeon, Henbury, Mundrabilla, Negrillos, Odessa, Sikhote-Alin, and Toluca and the Divnoe primitive achondrite. The comparison of our LA-ICP-MS data for a number of iron meteorites with high-precision isotope dilution and INAA data demonstrates the good precision and accuracy of our technique. The narrow ranges of variations of Mo and Pd concentrations within individual groups of iron meteorites suggest that these elements can provide important insights into the evolution of parent bodies of iron meteorites. Under certain assumptions, the Mo concentrations can be used to estimate mass fractions of the metal-sulfide cores in the parent bodies of iron meteorites. It appears that a range of Pd variations within a group of iron meteorites can serve as a useful indicator of S content in the core of its parent body.

A large meteorite fall in southern Germany on April 6, 2002 was captured by camera stations of the European Fireball Network (EN) which routinely monitors the night sky over central Europe. From analysis of the images, a prediction on the geographic location of the meteorite strewn field could be made. Following systematic ground searches in difficult high-mountain terrain, three fragments of a rare EL6 enstatite chondrite were recovered during search campaigns in the summers of 2002 and 2003. Neuschwanstein is the fourth meteorite fall in history that has been photographed by fireball networks and the fragments of which have been found subsequently. It is the first time since the beginning of the EN operation in the early sixties that the photographic observations have made a meteorite recovery possible.

We have analyzed several types of data associated with the well-documented fall of the Neuschwanstein meteorites on April 6, 2002 (a total of three meteorites have been recovered). This includes ground-based photographic and radiometer data as well as infrasound and seismic data from this very significant bolide event (Spurn et al. 2002, 2003). We have also used these data to model the entry of Neuschwanstein, including the expected dynamics, energetics, panchromatic luminosity, and associated fragmentation effects. In addition, we have calculated the differential efficiency of acoustical waves for Neuschwanstein and used these values to compare against the efficiency calculated using available ground-based infrasound data. This new numerical technique has allowed the source height to be determined independent of ray tracing solutions. We have also carried out theoretical ray tracing for a moving point source (not strictly a cylindrical line emission) and for an infinite speed line source. In addition, we have determined the ray turning heights as a function of the source height for both initially upward and downward propagating rays, independent of the explicit ray tracing (detailed propagation path) programs. These results all agree on the origins of the acoustic emission and explicit source heights for Neuschwanstein for the strongest infrasonic signals. Calculated source energies using more than four different independent approaches agree that Neuschwanstein was certainly <500 kg in initial mass, given the initial velocity of 20.95 km/s, resulting in an initial source energy less than or equal to 0.015-0.0276 kt TNT equivalent (4.185 x 10^12 J). Local source energies at the calculated infrasonic/seismic source altitudes are up to two orders of magnitude smaller than this initial source energy.