Jiddat al Harasis 1101 (JaH 1101)        19°44.58’N, 56°41.22’E

Al Wusta, Oman

Find: 15 Feb 2015

Classification: Ureilite

Physical characteristics: A 460 g sample supplied by the Sultan Qaboos University, which has a millimeter thick, dark brown-gray fusion crust present on all faces except one cut face. This fusion crust lacks remaglypts instead has a mainly rough surface. There are no contraction cracks present on this sample. This rock has already been cut and there is a clean face already present. Rounded grey laths can be identified on the cut face, with most less than 0.5 cm wide. The sample is also magnetic.

Petrography (P. Hill, UWO) The sample is a composed of elongated grains of olivine and pyroxene that are ~1-2 mm wide. Olivine is much more prevalent than pyroxene (60 vol % vs. 30 vol %). The olivine grains show mocaicized texture with some grains of olivine exhibiting undulatory extinction suggesting high levels of shock. Pyroxene grains are fractured but still have clear and distinct extinction. The grain boundaries are defined by oxides and graphite. Pyroxene is often associated with small porous inclusions throughout the grains. Though distinct exsolution lamellae are not present, small blebs of a more Ca-rich pyroxene are present throughout the pyroxene grains. In particular, a single grain of pyroxene (100 µm wide) is surrounded by olivine and completely rimmed by iron oxide that in some places is 50 µm thick. The olivine contains reduction rims ~50 μm thick with significant amounts of graphite remaining. Based on the classification put forward by Wittke et al. (2007), this sample fits in the R2 grade. Though the grain boundaries are defined by iron oxides, kamacite and taenite are present as inclusions within grains where fractures have not exposed the metal to terrestrial weathering. In one occurrence an iron oxide rim surrounds a Fe-Ni core. Overall there is little evidence of the silicate phases weathering; however, several sulfate veins were observed. This sample has been moderately weathered based on the presence of sulfates, oxidization of most Fe-Ni metal, but the absence of any silicate weathering phase. The olivine within these samples does show undulose extinction and the mosaic texture of the olivines suggest higher levels of shock metamorphism.

Geochemistry: Mineral composition and geochemistry (M. Beauchamp, P. Hill, UWO) Olivine (Fa_23.8±3.0), low-Ca pyroxene (Fs_15.8±2.0Wo_7.5±1.7)

Classification: Classificaiton: Ureilite, S5, W3.

Specimens: 460 g type specimen, including polished thin section, are on deposit at SQU.