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| Ramlat as Sahmah 309 | |||||||||||||||||||||||||||||||||||
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| Basic information | Name: Ramlat as Sahmah 309 This is an OFFICIAL meteorite name. Abbreviation: RaS 309 Observed fall: No Year found: 2009 Country: Oman Mass:  1435 g | ||||||||||||||||||||||||||||||||||
| Classification history: |
This is 1 of 62 approved meteorites classified as Brachinite. [show all] Search for other: Brachinites, Primitive achondrites | ||||||||||||||||||||||||||||||||||
| Comments: | Approved 21 Sep 2012 | ||||||||||||||||||||||||||||||||||
| Writeup |
Writeup from MB 101:
Ramlat as Sahmah 309 (RaS 309) 20°45.948’N, 55°26.152’E Al Wusta, Oman Found: 17 Feb 2009 Classification: Primitive achondrite (Brachinite) History: Three stones (1218.4, 181.9, 28.1 g) were found during a search for meteorites by U. Eggenberger, E. Gnos, E. Janots and F. Zurfluh. An additional stone of 7.054 g was found nearby on 11 January 2010 by U. Eggenberger, E. Gnos, N. Greber and F. Zurfluh. Physical characteristics: The four stones have a combined mass of 1435.43 g. All stones are wind-ablated and show no fusion crust. The largest stone (16 × 7 × 4 cm) of dominantly brown color has one particularly flat surface (10 × 6 cm) showing an enrichment of green Ca-rich pyroxenes. Additional similar layers are present parallel to the exposed one in the interior of the stone, as seen on the side of the stone and in X-ray tomographic sections. Petrography: (B. Hofmann, NMBE, F. Zurfluh, E. Gnos, MHNGE): The rock shows an equigranular texture (mean grain size approx. 0.5 mm) and consists of ~94 vol% olivine, 4 vol% Ca-rich pyroxene (Fs9.1Wo47.4) and 1 vol% of chromite. Accessory phases are Ca-poor pyroxene, metal, troilite (both occurring as grains a few mm in size in silicates) and graphite (occurring as inclusions in olivine and chromite). The rock is weakly shocked (S2). Strong weathering, metal is replaced by hydroxides where not completely enclosed in silicates. Geochemistry: Olivine composition Fa33.1, pyroxene composition Fs9.1Wo47.4, accessory metal has 30-55 wt% Ni A bulk analysis showed Fe/Mn (wt%) = 74.3, Ni = 510 ppm. Oxygen isotopes (I.A. Franchi and R.C. Greenwood, OU): Analyses of a bulk sample (Fe-hydroxides removed with ethanolamine thioglycollate) yielded δ17O = 2.09, δ18O = 4.37, and Δ17O = -0.19 per mil (mean of two replicates). Classification: Based on texture, mineralogy and oxygen isotopic composition this is a brachinite. Specimens: All at NMBE. | ||||||||||||||||||||||||||||||||||
| Data from: MB101 Table 0 Line 0: |
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| Plots: | O isotopes: | ||||||||||||||||||||||||||||||||||
| Institutions and collections |
NMBE: Natural History Museum Bern
Bernastrasse 15
CH-3005 Bern
Switzerland, Switzerland; Website (institutional address; updated 2 Mar 2012) OU: Planetary and Space Sciences Department of Physical Sciences The Open University Walton Hall Milton Keynes MK7 6AA United Kingdom, United Kingdom (institutional address; updated 8 Dec 2011) MHNGE: Muséum d’histoire naturelle, Route de Malagnou 1, CH-1211 Genève 6 , Switzerland (institutional address; updated 27 Oct 2011) |
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| Catalogs: |
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| References: | Published in Meteoritical Bulletin, no. 101, MAPS 50, 1661, September 2015
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Geography:
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Statistics: This is 1 of 1780 approved meteorites from Al Wusta, Oman (plus 81 unapproved names) This is 1 of 4526 approved meteorites from Oman (plus 419 unapproved names) | ||||||||||||||||||||||||||||||||||
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