Classification of two new chondritic meteorites from the Sahara desert, Libya. P.P. Sipiera, Schmitt Meteorite Research Group, Harper College, Palatine, IL 60067, USA, G. Jerman, Material Processing Laboratory and R.B. Hoover, Space Science Laboratory, NASA Marshall Space Flight Center, Huntsville, AL 35812, USA.
Introduction: Two chondritic meteorites were recovered in 1998 from the Dar al Gani and Hammadah al Hamra regions in Libya. Representative specimens were sent to the authors for classification purposes. Each was analyzed for their fayalite and ferrosilicate compositions by standard electron microprobe techniques at the Marshall Space Flight Center.
Results: A 44kg stone, consisting of a weathered main mass along with numerous smaller nearby fragments, was found near a topographical feature called Qararat al Mandil. Microprobe analyses gave a fayalite composition of Fa 17.8 (n=26) and a pyroxene composition of Fs 16.1, Wo 1.1 (n=12). The presence of some plagioclase was noted. Petrographically, the meteorite displayed a variety of whole and partial chondrules of various sizes that were well integrated into the matrix. Metal is readily apparent throughout the specimen. The second meteorite from the Hammadah al Hamra region, is a 5,055g mass with a distinct black fusion crust. Like the first meteorite, it too had numerous smaller fragments scattered around it. Microprobe analyses gave a fayalite composition of Fa 17.2 (n=25) and a pyroxene composition of Fs 15.4, Wo 1.5 (n=14). Plagioclase was also in evidence. Petrographically, partial chondrules are readily apparent as well as a few whole ones lacking clearly delineated edges. Lithic fragments are very abundant, along with occasional large dark clasts. Based on these results it is suggested that the Qararat al Mandil stone be classified as an H4 chondrite, and the Hammadah al Hamra stone as an H5.
Summary: In light of the over 1,000 meteorites that have been recovered from the Libyan and Algerian regions of the Sahara Desert it is quite possible that these two could be paired with one or more of those finds (l). Time and resources limit one's ability to pursue that particular avenue of research. Hopefully these two new finds will contribute to the data base for a better understanding of the Saharan meteorite population. Certainly more will follow.
Reference: (l) Weber, D. and Bischoff, A., Meteoritics &Planetary Science, 33, A164.