Sample Petrographic Description
Sample Number | DRP 78008 |
Newsletter | 2,1 |
Location | Derrick Peak |
Field Number | 336 |
Dimensions (cm) | 37.0 x 25.0 x 21.0 |
Weight (g) | 59400.00 |
Original Classification | Iron |
Updated Classification | Iron-IIAB |
Pairing | DRP 78001; DRP 00200; DRP 00201; DRP 78002; DRP 78003; DRP 78004; DRP 78005; DRP 78006; DRP 78007; DRP 78008; DRP 78009; |
Macroscopic Description - | |
This sample was very clean and fresh when recovered in Antarctica, but on its arrival in Houston, the sample contained large quantities of rust. The B surface was touching the ground when the iron was discovered. Half of the B surface is covered with a thin coat of soil as is part of the T surface, an area ~8 cm in diameter. The overall color of the meteorite was metallic brownish-black while in the field, but now it is mostly reddish-brown due to oxidation. The meteorite is irregular but blocky. The surface is rough and has many regmaglypts. The deepest regmaglypts are ~2 cm deep and are on the B surface. The remaining surfaces have regmaglypts, however, they are not as deep as the ones on the B surface but they are wider. Silvery platy inclusions (schreibersite (?), cohenite (?), daubreelite (?) are randomly scattered over the entire meteorite. The meteorite is approximately 37 x 25 x 21 cm. | |
Thin Section Description - Roy S. Clarke, Jr. | |
This is the first of the Derrick Peak irons to be examined. The highly unusual and strikingly similar external appearances of the nine specimens seen here, DRP 78001 to 78009, suggests that they are all of the same type. An area of approximately 360 cm2 of macro-etched surface was examined. The dominant structural units distributed over perhaps 60% of the surface are 11 broad and irregular areas of swathing kamacite enclosing large hieroglyphic schreibersites, three of these schreibersites bordering centimeter-size troilites. Between these swathing kamacite areas are areas of coarsest octahedrite structure. Grain boundary schreibersite is common throughout the surface and lamellar schreibersites are present in many areas of kamacite. Neumann bands are abundant in the kamacite, and deformation zones are a common feature. Taenite and plessite are present in areas of coarsest octahedrite structure. Weathering has penetrated the section, particularly along grain boundaries bordering swathing kamacite areas. What appear to be cleavage cracks are present in some areas of kamacite. The specimen is a coarsest octahedrite, a Group IIB meteorite similar to Santa Luzia. |
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Reclassification Notes (AMN OUTSIDE) | |
The Derrick Peak irons were re-classified to IIAB Iron based on information presented by Wasson, J. T., Huber, H., Malvin, D. J., 2007, Formation of IIAB iron meteorites. Geochimica et Cosmochimica Acta, 71, 760-781. |
Antarctic Meteorite Images for Sample DRP 78008 | ||||
Lab Photo(s) : | ||||
References for Sample DRP78008 | |
Benoit, P. H., Sears, D. W. G., Akridge, J. M. C., Bland, P. A., Berry, F. J., Pillinger, C. T., 2000, The non-trivial problem of meteorite pairing. Meteoritics & Planetary Science, 35, 393-417. | |
Kirkbride, M. P., Bradshaw, M. A., Harmsen, F. J., 1991, Further finds of the Derrick Peak meteorite, Transantarctic Mountains, and implications for terrestrial age. Meteoritics, 26, 213-216. | |
Gao, X., Thiemens, M. H., 1991, Systematic study of sulfur isotopic composition in iron meteorites and the occurrence of excess 33S and 36S. Geochimica et Cosmochimica Acta, 55 Issue 9, Sep-91, 2671-2679, ISSN 0016-7037, http://dx.doi.org/10.1016/0016-7037(91)90381-E. | |
Jarosewich, E., 1990, Chemical analyses of meteorites: A compilation of stony and iron meteorite analyses. Meteoritics, 25, 323-337. | |
Marvin, U. B., Mason, B., 1984, Field and laboratory investigations of meteorites from Victoria Land, Antarctica. Smithsonian Contributions to the Earth Sciences Number, 26, 134. | |
Scott, E. R. D., 1984, Pairing of meteorites found in Victoria Land, Antarctica. Memoirs of National Institute of Polar Research., Special issue 35, 102-125, http://ci.nii.ac.jp/naid/110000009967/en/. | |
Clarke, R. S., 1982, THE DERRICK PEAK, ANTARCTICA, IRON METEORITES. Meteoritics, 17, 129-134. | |
Marvin, U. B., Mason, B., 1982, Catalog of Meteorites from Victoria Land, Antarctica 1978-1980. Smithsonian Contributions to the Earth Sciences, 24, 97. |