Franchi, I.A.

Hofmann, B.

Jull, A.J.T.

Koblitz, J.

McHargue, L.R.

Shahab, A.

English

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Open Research OnlineThe Open University’s repository of research publicationsand other research outputsTerrestrial ages of some meteorites from OmanConference or Workshop ItemHow to cite:Jull, A.J.T.; Koblitz, J.; Hofmann, B.; Franchi, I.A.; McHargue, L.R. and Shahab, A. (2002). Terrestrial agesof some meteorites from Oman. In: 65th Annual Meteoritical Society Meeting, 21-26 Jul 2002, Los Angeles,California, 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/metsoc2002/pdf/5044.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.ukTERRESTRIAL AGES OF SOME METEORITES FROMOMAN.  A. J. T. Jull1, J. Koblitz2, B. Hofmann3, I. A. Franchi4, L.R. McHargue1 and A. Shahab1, 1NSF Arizona AMS Laboratory,Univ. of Arizona, Tucson, AZ 85721, USA, 2Im Neuen Felde 16, D-28870 Fischerhude, Germany, 3Natural History Museum Bern, Ber-nastr. 15, CH-3012 Bern, Switzerland, 4.Planetary Sciences ResearchInstitute, Open University, Milton Keynes MK7 6AA England.Introduction: Franchi et al [1] discussed the potential of theOmani and Saudi desert regions for recovery of meteorites.  Until1999, only 7 meteorites had been recovered from the Jiddat al Hara-sis region of Oman.  About 29 meteorites (of which 20 are stones)are known from Saudi Arabia, many of which were found in theRub al-Khali [1].  In the last few years, things have changed dra-matically.  During the period 1999-2001, at least 262 meteoriteswere recovered from Oman alone [2] by European and Russian fieldparties.Franchi et al [1] reported on 6 terrestrial ages of meteorites fromOman and Saudi Arabia which were in the Natural History Museumcollections.  The terrestrial age of SaU 005, a shergottite, has beenmeasured to have a 14C-10Be terrestrial age of ~13ka [3].  Recently,Nishiizumi et al [4] have reported terrestrial ages of 360∀30 forDhofar 019 (a lunar meteorite) and an age approaching 500ka forDhofar 025 (a shergottite), based on several radionuclides.  Thesevery long terrestrial residence times would be remarkable even inthe cold and arid regions of Antarctica.Here, we report new terrestrial ages for stony meteorites fromthis region based on 14C and 10Be measurements.  All samples wereprepared using published procedures [5] using the Arizona accel-erator mass spectrometry laboratory.Results:  The age distribution of Oman meteorites we havemeasured so far is different from the exponential drop-off with agewe observe in Algerian [6] and Western Australian meteorites [7].Instead, there is a large peak at the 15-20ka range, and less than 25%of the meteorites have a terrestrial age of <5ka.  This distribution isreminiscent of the Roosevelt County meteorites.  The reason for theapparent lack of Holocene meteorite falls in the Omani collection isunclear. We hope to resolve this problem with measurements ofterrestrial age from a wider area than the restricted area sampled sofar.  The terrestrial ages for most of the meteorites we measuredfrom Oman are not noticeably older than Roosevelt County, so themechanism of survival of the 2 achondrites discussed by [4] mustalso involve burial for a long period in protective sediments or someother effects.References:  [1] Franchi I. A. et al. (1995)  LPI Tech. Rep. 95-02, pp. 29-31.  [2] Grossman J. N. and Zipfel J. (2001)  MAPS, 36,A293-A322.  [3] Nishiizumi K. et al. (2001)  LPS 32, CD-ROM(#2117).  [4]  Nishiizumi K et al. (2002)  LPS 33, CD-ROM(#1366).  [5]  Kring D. A. et al (2001), MAPS, 36, 1057-1066. [6]Wlotzka F. et al. (1995) LPI Tech. Rep. 95-02, pp. 72-73. [7] BlandP.A. et al. (2001), Quarter. Res., 53, 131-142.  [8]  Jull A. J. T. et al(1991), LPS 22, 665-666.65th Annual Meteoritical Society Meeting (2002) 5044.pdf

Terrestrial ages of some meteorites from Oman

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Terrestrial ages of some meteorites from Oman

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