Meteorites from the Sahara: Find locations, shock classification, degree of weathering and pairing

Abstract

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.

A Bayesian statistical assessment of representative samples for asteroidal or meteoritical material

“…Taking meteorite fall data as an example, we know that the fraction of total falls that are chondrites is 0.86 and the fraction of these that are carbonaceous chondrites is 0.05 (Bischoff and Geiger 1995). Therefore, we can generate the value PðLjIÞ ¼ 0:86 Â 0:05 ¼ 0:043 (C10) P(Tj S;I): The Probability of a False Positive PðTj S;IÞ appears in equations A12 and A13; it is the probability that the test procedure, given a sample that at the time the sample was created did not contain the target material, produces a positive result.…”

Weathering of meteorites from Oman: Correlation of chemical and mineralogical weathering proxies with14C terrestrial ages and the influence of soil chemistry

“…This is supported by the occurrence of barite, celestine, and anhydrite crystals in fractures and holes filled by iron oxides/hydroxides and calcite. Also barite is reported from a number of weathered meteorites from Sahara (Bischoff and Geiger 1995).…”

“…As the degree of weathering of meteorites increases with their terrestrial age, old surfaces are likely to yield more highly-weathered meteorites than younger surfaces. Due to meteorite accumulation over long periods of time, hot or cold desert environments are most suitable for weathering studies (Bischoff and Geiger 1995;Bland et al 1996;Stelzner et al 1999;Welten 1999;Lee and Bland 2004).…”

The Dar al Gani meteorite field (Libyan Sahara): Geological setting, pairing of meteorites, and recovery density

“…The main masses ofSaharan meteorites-from Algeria and the Hamadah al Hamra region- (Bischoff and Geiger, 1995) were between 100 and 150 g. The discovery of lunar and martian meteorites in the Dar al Gani region in the later years led to a more detailed search in the Dar al Gani region resulting in the find of more smaller meteorites, shifting the mean value towards a smaller mass.…”