Jiddat al Harasis 845 (JaH 845)        19° 59.178’ N, 56° 25.279’ E

Al Wusta, Oman

Found: 2004

Classification: Mesosiderite (group C2)

History: Three rusty pieces, totaling 119.1 g were found by John Blennert in Oman in 2004.

Physical characteristics: The stone is dark and weathered with patches of caliche. A few large, green pyroxene crystals visible on the surface. Fusion crust is absent. Sawn surface shows scattered large pyroxene crystals (to 4 mm) and one 10 mm × 4 mm shard of olivine. Metal (before weathering) and troilite ~20% of rock.

Petrography: Thin section shows cataclastic texture with silicates dominated by pyroxene (~90%) and ~10% Ca-plagioclase. Poikilitic minerals and textures absent. Moderate recrystallization at pyroxene grain margins. Section contains the same olivine shard as the polished hand specimen, which is enclosed by a reaction rim dominated by pyroxene. Metal is heavily weathered (80 to 100%) and troilite less so.

Geochemistry: (Y. Osawa, D. Dunlap, J. Connell, and L. Garvie, ASU) EMPA. Low Ca-pyroxene Fs_29.5±1.3Wo_2.8±0.6, FeO/MnO = 30.61, n=11; diopside, Fs_13.9Wo_43.7, FeO/MnO = 21.67, n=1; olivine shard Fa_35.6±0.25, FeO/MnO = 54.31, n=2; and plagioclase Or_0.36±0.19Ab_9.0±2.9, An_91±3.0, n= 5. Oxygen isotope replicate analyses (R. Tanaka, OkaU) of acid washed, bulk sample by laser fluorination gave δ¹⁷O = 1.938 and 1.929, δ¹⁸O = 4.077 and 4.045, and Δ¹⁷O = -0.208 and -0.201.

Classification: Textures and mineralogy suggest C mesosiderite (dominated by low-Ca pyroxene) of textural type 2. Likely paired with JaH 203.

Specimens: 43.2 g and one polished thin section at ASU.