946 Okahandja - Okano Okahandja is related to Coahuila, North Chile and DESCRIPTION Keen Mountain, and it is a member of group IIA. Okahan­ The mass is roughly lenticular in shape with the overall dja apparently has had a complicated cosmic history dimensions 18 x I2 x 7 em. One surface is rather smooth involving slow cooling for the primary structure, followed and convex, while the other shows numerous angular by plastic deformation and Neumann band-producing shock regmaglypts, 2-3 em in diameter, and a small beak. The events. Some of the internal cubic cleavage fissures and the fusion crust covers most of the surface as a thick crust cracks along phosphides must have been open microcavities measuring up to I mm. On the specimen in Washington it is for countless millions of years in space. very thin, however, about 25 J.l., and consists of fused oxides only. Under the fusion crust is a 2-3 mm wide heat-affected zone of cx 2 • In the outer 50%, where the rhabdites are Okano, Hyogo Province, Honshu, Japan melted and phosphorus has become partly dissolved in the 35°5'N, I35°12'E metal, the microhardness is 180±5; in the inner part the cx 2 hardness is only 155±5, indicating that phosphorus in solid Hexahedrite, H. Single crystal larger than 10 em. Neumann bands. solution contributes significantly to the hardness of the HV 170±10. cx 2 phase (Buchwald 1966: I8). Group IIA. 5.40% Ni, 0.42% Co , 0.23% P, 60 ppm Ga, 180 ppm Ge, 11 ppm Ir. Okano is a normal hexahedrite, a single ferrite crystal larger than IO em. Neumann bands are well developed and reach from cx 2 to cx 2 zone, more or less uninterrupted. The HISTORY microhardness of the matrix is 170±5. Sub boundaries are A mass of 4.74 kg was observed to fall on April 7, present and are best seen near the troilite inclusions where 1904, at 6:35 a.m. near the village of Okano. This is near they are decorated by 1-2 J.1 phosphides. No taenite is Sasayama and 40 km north of Kobe. A noise resembling a present. distant cannon was heard there. A teacher who observed Schreibersite occurs as 50-200 J.1 thick precipitates on the fall from a point 30 km north of the impact reported: the troilite. Rhabdites are very common. They range from "On the northwestern sky, at an altitude of about 70°, 0.5 to 25 J.1 in size. Where they are finest, around the there suddenly appeared a white-glowing mass. From its troilite-schreibersite inclusons, the matrix appears matte to tail I saw fused drops fall off. The light phenomenon the naked eye, and the Neumann bands are narrow -about lasted 1-2 seconds and then disappeared on the south­ eastern sky, but the white trail of smoke could be I J.l.. The microhardness increases in these areas to I80±5. distinguished for another eight minutes. Some minutes Where they are coarsest, their mutual distance is larger, the after the disappearance (of the light) a loud noise like a matrix appears bright, and the Neumann bands are broad. It thunderclap was heard, and this continued for about a is this variation in morphology that is responsible for the minute." subdivision of an etched surface in irregular patches The iron was located in a small forest by a farmer who conspicuous to the naked eye. In addition to the rhabdite saw it fall. It was recovered immediately from an 80 em rods mentioned above a number of plate shaped rhabdites deep hole in clay. The mass was acquired by the Metallur­ occur. They are typically I-2 mm in two dimensions and as gical Institute of Kyoto University where it was described little as 5-I5 J.1 in the third dimension. They are frequently by Jimb6 (1906) who gave a map, and by Chikashige & offset by the Neumann bands. Hiki (1912) and Hiki (1912) who reproduced figures of the Troilite is common as I-10 mm nodules with about exterior shape and discussed the metallography - some­ I5% daubreelite. The troilite is monocrystalline but shows what biased, however, by their erroneous finding of only numerous lenticular-acicular twins from plastic deforma­ 4.4% Ni. tion. The daubreelite forms parallel lamellae ranging from IO J.1 to 1 mm in width. COLLECTIONS Okano is a normal hexahedrite which is structurally Kyoto (3.5 kg), Harvard (383 g), London (302 g), New and chemically closely related to Braunau, which fell in York (205 g), Washington (17 g). 1847. OKANO - SELECTED CHEMICAL ANALYSES percentage ppm References Ni Co p c s Cr Cu Zn Ga Ge Ir Pt Moss in Hey I966 5.4 Cobb 1967 5.25 0.42 I38 59 10 Wasson 1969 5.55 59.9 I80 II Chikashige & Hiki (1912) reported 0.23% P. Okano - Orange River 947 Specimen in the U.S. National Museum in Washington: four pieces of 7.8, 5.8, 1.0 and 0.1 kg were found in 1925, 80 em 17.5 g part slice (no. 1363, 3.5 x 3 x 0.2 em) below the surface in a loess deposit on the Kylesovsky Hill. The material has been described as a hexahedrite by Drahny (1926) and Rost (1955) with 5.6% Ni. The main masses are in Praha Polytechnic, Dejvice; 611 g is in Prague National Museum (Hey Oktibbeha County, Mississippi, U.S.A. 1966: 359). About 33~ 0 N, 89°W Orange River, South Africa A mass of 156 g was found about 1854 in an Indian tumulus. It was described and analyzed by Taylor (1857) and Cohen (1892) who 29° 40'S, 22° 45'E found 59.7 and 62.0% Ni, respectively. This high nickel content has made the material suspect in the eyes of many authors. Wiilfing (1897: 265), Cohen (1905: 135), Farrington (1915: 9) and Medium octahedrite, Om. Bandwidth 1.20±0.15 mm. E-structure. Buddhue (1938) thus assumed that the small mass was a pseudo­ HV 310±20. meteorite. To make things still worse, half of the original 156 g mass Group lllAB. 8.54% Ni , 0.50% Co, 0.26% P, 21 ppm Ga, 44 ppm was cut off and forged and is now lost (Taylor 1857). It may be Ge, 0.12 ppm Jr. feared that the unforged half was also artificially reheated and thereby more or less altered. HISTORY Perry (1944: plate 34) showed four photomicrographs which Little is known of the origin of this 150 kg meteorite. indicated the presence of meteoritic minerals; a reexamination by Shepard {1856) described it and presented two good Reed (1972a) also strongly suggests that Oktibbeha County is a meteorite, albeit a very extraordinary one which has no relatives at sketches of the exterior. He stated that he had purchased all. With about 60% nickel, it is about twice as nickel-rich as the the mass in 1855 after it had been brought to London by nearest irons, such as Santa Catharina (36% Ni), Tishomingo (32.5% Ni), Twin City (30.0% Ni) and Lime Creek (28% Ni). See, however, the master of a Scottish ship. The meteorite had evidently the new find, Dermbach, with about 42% Ni. been discovered shortly before that time by a farmer of the Unfortunately, it is not known from where the Indians got the Orange River district. No further information was pub­ material. Was it an entire individual monolith, or a fragment lished, except for uncommented notes by Brezina detached from a larger mass? If it were an entire monolith, heat-affected rim zones from the atmospheric flight might perhaps {1886: 264) and Ward {1904a: 19) that the meteorite had still be identified. Or perhaps the artificial reheating altered the been found at Garib or Gariep. This is the old name for structure too much for any conclusions to be drawn. Orange River, but it was also the name of a mission station located near the junction of Orange River and Brak River, COLLECTIONS near the present Prieska; see, e.g., Colton's General Atlas, Philadelphia {25 g), New York {14.8 g), Harvard {6 g), 1866: 116. Furthermore, Gariep Station is at the border of London {less than a gram). The 1.9 g Washington sample is the old Griqualand district, a name which has been used as apparently lost. a synonym for the meteorite in some publications. The coordinates given above are those of Prieska, since it is felt Ollague. See Imilac in the Supplement. that there is a certain probability that this was the place of find; at this late date, however, it is difficult to reach a definitive conclusion. Opava, Silesia, Czechoslovakia COLLECTIONS 49°58'N, 17°54'E Amherst {146 kg), London {828 g), Tempe (567 g), Chicago (283 g), Washington (110 g), New York {91 g), ~-- --...-- Calcutta {66 g), Leningrad {49 g), Vienna (47 g), Budapest j ,;;> (43 g), Harvard (32 g), Gottingen {30 g), Berlin (28 g), Vatican (26 g), Paris {22 g), Yale {18 g). Figure 1327. Opava (Prague no. 322 of 68 g). A little known hexahedrite. The white zones along the rim and around troilite Figure 1328. Orange River (Amherst). The 146 kg main mass. To the inclusions are artificial and represent metal that was protected by right, a significant portion of the ·Ruff's Mountain meteorite. Ruler wax during deep-etching. Scale bar 2 em. is 10 em. 948 Orange River Reeds (1937: 607), and Hey (1966: 359) state in Narraburra and certain other high phosphorus group IIIB "Repository of main mass unknown." However, for over meteorites.