Botta, O.

Ehrenfreund, P.

Franchi, I.A

Greenwood, R.C.

Hofmann, B.A.

Martins, Z.

English

Open Research Online (The Open University)

Open Research OnlineThe Open University’s repository of research publicationsand other research outputsAmino acids composition and oxygen isotopes in theShisr 033 CR chondriteConference or Workshop ItemHow to cite:Martins, Z.; Greenwood, R.C.; Franchi, I.A; Botta, O.; Ehrenfreund, P. and Hofmann, B.A. (2005). Aminoacids composition and oxygen isotopes in the Shisr 033 CR chondrite. In: 68th Annual Meteoritical Society Meeting,12-16 Sep 2005, Gatlinburg, Tennessee, USA.For guidance on citations see FAQs.c© [not recorded]Version: [not recorded]Link(s) to article on publisher’s website:http://www.lpi.usra.edu/meetings/metsoc2005/pdf/5164.pdfCopyright and Moral Rights for the articles on this site are retained by the individual authors and/or other copyrightowners. For more information on Open Research Online’s data policy on reuse of materials please consult the policiespage.oro.open.ac.ukAMINO ACIDS COMPOSITION AND OXYGEN ISOTOPES IN THE SHISR 033 CR CHONDRITE Z. Mar-tins1, R. C. Greenwood2, I. A. Franchi2, O. Botta3, P. Ehren-freund1, B. A. Hofmann4 1Astrobiology Lab, Leiden Institute of Chemistry, P.O. Box 9502, 2300 RA Leiden, The Netherlands E-mail: z.martins@chem.leidenuniv.nl 2PSSRI, Open University, Milton Keynes, MK7 6AA, UK 3International Space Science In-stitute, Hallerstrasse 6, CH-3012 Bern, Switzerland. 4Natural His-tory Museum, Bernastrasse 15, CH-3005 Bern, Switzerland  Shisr 033 is the first CR chondrite recovered in Oman. It con-sists of 65 fragments with a total mass of 1098 g collected from an area of a few square meters. The meteorite shows medium weathering of metal (W2) with omnipresent Fe-hydroxide stain-ing. Compared with 14C-dated ordinary chondrites from Oman the degree of weathering is consistent with a terrestrial age of 5-15 kyr. Many fine-grained phyllosilicate-rich inclusions contain-ing pyrrhotite and framboidal magnetite are apparent. The second largest fragment (249.9 g) was selected and 23 g of interior mate-rial were obtained by splitting away surface material. After gentle crushing, 4.86 g of fines enriched in phyllosilicate-rich material was selected for amino acids analysis. Selected individual phyl-losilicate-rich clasts were analyzed by pyrolysis. From the coarse material individual chondrules were selected for O isotope analy-sis.  The acid hydrolyzed hot water extracts of the fines enriched in phyllosilicate-rich material were analyzed for amino acids us-ing hot water extraction, followed by acid hydrolysis, desalting and pre-column derivatization [1]. Amino acids separation was achieved by high-performance liquid chromatography (HPLC) and by gas chromatography-mass spectrometry (GC-MS). Amino acid abundances were determined by comparison of the chroma-tographic signals with those of known standards. Shisr 033 con-tains extraterrestrial amino acids, including α-aminoisobutyric acid (AIB); however, comparisons to the CM2 Murchison, the CI Orgueil, and the CR Renazzo show a distinct amino acid distribu-tion for this meteorite. The D/L ratio determined for alanine indi-cates the presence of terrestrial contamination.  Oxygen isotopic analyses were performed on a bulk sample (B), a bulk sample leached with ethanolaminthioglycollate to re-move iron hydroxides (B2), a sample of composite chondrules (H) and a hand-picked dark clast (D). Samples B, B2 and H fall onto the CR trend as defined by Clayton and Mayeda (1999) [2]. The uncleaned bulk sample is significantly heavier than the cleaned one, most likely indicating an influence by terrestrial Fe-hydroxides (calculated δ18O around +8‰ in equilibrium with Oman desert rainwater). The dark clast (D) falls onto the CV-CO trend. Stepped combustion of a dark clast revealed a low organic carbon and high carbonate contents indicative of terrestrial con-tamination.  References: [1] O. Botta and Bada J. L. 2002. Surveys in Geophysics 23: 411-467. [2] R. N. Clayton and T. K. Mayeda. 1999. Geochimica et Cosmochimica Acta 63: 2089-2104.   68th Annual Meteoritical Society Meeting (2005) 5164.pdf

Amino acids composition and oxygen isotopes in the Shisr 033 CR chondrite

http://oro.open.ac.uk/8479/1/AMINO_ACIDS_COMPOSITION_AND_OXYGEN_ISOTOPES_IN_THE_SHISR_033_CR_CHONDRITE..pdf

Amino acids composition and oxygen isotopes in the Shisr 033 CR chondrite

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