64th Annual Meeting (2001) 5036.pdf

SIX NEW FINDS FROM DAR AL GANI AND HAMADA AL HAMRA, LIBYA. P.P. Sipiera, Schmitt Research Group, Harper College, Palatine, Il 60067, USA, G.A. Jerman, Material Processing Laboratory, NASA Marshall Space Flight Center, Huntsville, AL 35812, Richard Pelisson and Roland Pelisson, SaharaMet, La Terrasse, France.

Introduction: Six new have been recovered by Richard and Roland Pelisson during a 1998 systematic search for in the Dar al Gani and Hamada al Hamra regions. Over the past several years their efforts have resulted in the recovery and documentation of over 200 meteorites, most of which are still in various stages of research. Significant among these six finds are an LL4 (DaG 860) and an H3 (DaG 862). In addition an accurate location map has been constructed which positions all of the reported finds from Dar al Gani.

Results: The classification data for the six new chondrites DaG 859 – 862 and HaH 289 and 290 is reported in Table 1. Each was photographed in situ and its location was documented with precise GPS coordinates. In appearance DaG 859 exhibits a dark black fusion crust exterior. On a cut and polished surface it appears highly fractured and gives the appearance of two different lithologies. Most of the meteorite has a typical chondritic appearance in contrast to a second lithology that has a more distinct brecciated texture. An apparent contact plane defines the two lithologies. In probe section lithic fragments and partial dominate. Mineralogically, olivine compositions fall within a range of Fa19.89 to 24.87, and pyroxenes range from Fs17.72 to 20.33. Among the accessory minerals noted were plagioclase and apatite. DaG 860, an LL4 chondrite, also displays a black fusion crust. A cut surface reveals a greenish-gray interior along with numerous chondrules, many with metallic rims. In probe section whole porphyritic, barred olivine, and radiating pyroxene chondrules are common. Mineralogically, olivine compositions ranged from Fa27.06 to 32.17 with pyroxenes ranging from Fs22.2 to 26.7. DaG 861, an H5 chondrite, exhibits a black exterior in contrast to a deep chocolate-brown colored interior. Petrographically, partial chondrules and lithic fragements are common but whole chondrules nearly absent. Olivine compositions range from Fa17.46 to 22.41, with pyroxenes ranging from Fs16.02 to 17.65. In appearance DaG 862 resembles the L3.5 chondrite Ragland, New Mexico especially in the number of chondrules seen in a cut section. Mineralogically, olivine compositions have a wide range from Fa0.33 to 32.29, as do the pyroxenes that range from Fs1.09 to 32.21. In contrast, HaH 289 and 290 are not nearly as interesting. In probe section partial chondrules and lithic fragments dominate the petrography of HaH 289. Some metal is still present. Compositionally, olivines range from Fa22.75 to 31.07 and pyroxenes from Fs18.5 to 25.23. A classification of L5 is appropriate for HaH 289. In many respects HaH 290 is similar to HaH 289. A black exterior, highly weathered and fractured interior, and general lack of chondrules. Analyses of its principal silicates phases gave a different picture. Olivine compositions range from Fa15.25 to 23.97 and its pyroxenes range from Fs13.73 to 18.80. HaH 290 is best classified as an H6. Given the large number of meteorites recovered from Dar al Gani and Hamada al Hamra it is very likely that these meteorites may be paired with many others.

Table 1. Location and classification data for six chondrites recovered in Dar al Gani and Hamada al Hamra, Libya.

Name Mass(g) Type Latitude Longitude Fa Fs Shock WG

DaG 859 2517 L6 26 deg. 58.84’N 16 deg. 20.78’E 22.7 19.1 S3 W2 DaG 860 149 LL4 26 deg. 52.36’N 16 deg. 42.22’E 28.7 23.4 S2 W2 DaG 861 495 H5 26 deg. 52.29’N 16 deg. 38.05’E 18.8 16.5 S2 W3 DaG 862 294 H3 27 deg. 09.12’N 16 deg. 18.96’E 14.4 13.1 S2 W2

HaH 289 3030 L5 29 deg. 05.71’N 12 deg. 33.93’E 24.7 20.5 S2 W3 HaH 290 5205 H6 29 deg. 00.89’N 12 deg. 37.65’E 18.9 16.9 S3 W3

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