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Abstract-The Saharan meteorite Acfer 094 is a unique type of carbonaceous chondrite. Mineralogical and petrological considerations and 0 isotopes are unable to distinguish unambiguously between a C03 VS. CM2 classification. The other important light elements, C and N, have systematics that do not match any previously recognised meteorite group. Particularly important in this respect is the very low CIN ratio and ol3C of the macromolecular C. Acfer 094 has more diamond and SiC, especially X type grains, than any other specimen studied, suggesting minimal thermal or aqueous processing to decrease its very primitive status.

Abatract-F'reviously, three meteorites from Australia and Antarctica were described as a new chondritic "grouplet" ( Acfer 217 is a regolith breccia consistimg of up to cm-sized clasts (=33 ~01%) embedded in a fme-grained, well-limed clastic matrix. The most abundant mineral is olivine (a72 vol%), which has a high Facontent of 37-39 mol%. The major minerals (olivine, Iow-Ca pyroxene, Ca-pyroxene, and plagioclase) show some compositional variability indicating a slightly unequilibrated nature of the meteorite.Considering the mean olivine composition Of Fa37.8 * 5.7, a classification of M e r 217 as a R3.8 chondrite would result; however, Acfer 217 is a regolith breccia consisting of clasts of various petrologic types. Therefore, we suggest to classify Acfer 217 as a R3-5 chondrite regolith breccia. The bulk meteorite is very weakly shocked (S2).The bulk composition of Acfer 217 and other R-meteorites show that the R-meteorites are basically chondritic in composition. The pattern of moderately volatile elements is unique in R chon&, Na and Mn are essentially undepleted, similar to ordinary chondrites, while Zn and Se contents are similar to concentrations in CM chondrites. The oxygen isotopic composition in Acfer 217 is similar to that of Rumwuti, Carlisle Lakes, AL.H 85 15 1, and Y-75302. In a 6 170 vs. 61 8O-diagram, the R-meteorites form a group well resolved h m other chondrite groups.Acfer 2 17 was a meteoroid of common size with a radius between 15 -65 cm and with a single stage exposure history. Based on 21Ne, an exposure age of about 35 Ma was calculated.

Abstract— Adzhi‐Bogdo is an ordinary chondrite regolith breccia (LL3–6) which fell on 1949 October 30 in Gobi Altay, Mongolia. The rock consists of submm‐ to cm‐sized fragments embedded in a fine‐grained clastic matrix. The polymict breccia contains various types of clasts, some of which must be of foreign origin. Components of the breccia include chondrules, melt rock clasts (some of which are K‐rich), highly recrystallized rock fragments (“granulites”), breccia clasts, pyroxene‐rich fragments with achondritic textures, and alkali‐granitoids. The composition of olivine in most fragments is in the range of LL‐chondrites. However, olivine in some components has significantly lower fayalite contents, characteristic of L‐chondrites. The bulk meteorite is very weakly shocked (S2). Based on the bulk chemical composition, Adzhi‐Bogdo is an ordinary chondrite. The concentrations of Fe and Ni are somewhat intermediate between L‐ and LL‐chondrites. The contents of solar gases indicate that Adzhi‐Bogdo is a regolith breccia. Most of the solar He and probably a part of the solar Ne of Adzhi‐Bogdo has been lost. It is suggested that Adzhi‐Bogdo experienced an (impact‐induced) thermal event early in its history, because most of the radiogenic 40Ar is retained.

The Sahara is an extraordinary area for recovering meteorites. Between 1989 and 1993, 471 meteorites were collected in Algeria and Libya. Studies of 465 samples have been done. In addition to the classifications of the meteorites that were published in various "Meteoritical Bulletins" in past years, we present here the results on the determination of the shock metamorphism and the degree of weathering. Also, we have tried to solve the pairing problem by considering the find locations, the degree of shock metamorphism, the degree of weathering, and the mineral compositions of olivine and pyroxene. A comprehensive table listing all samples contains references about previous work on these meteorites.