Bohn, M.

Boudouma, O.

Chennaoui-Aoudjehane, H.

Franchi, I.A.

Jambon, A.

English

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Open Research OnlineThe Open University’s repository of research publicationsand other research outputsAl Mala’ika (NWA 1669): A new Shergottite fromMorocco: mineralogy and petrologyConference or Workshop ItemHow to cite:Jambon, A.; Bohn, M.; Boudouma, O.; Chennaoui-Aoudjehane, H. and Franchi, I.A. (2003). Al Mala’ika(NWA 1669): A new Shergottite from Morocco: mineralogy and petrology. In: 66th Annual Meteoritical SocietyMeeting, 28 Jul - 1 Aug 2003, Munster, Germany.For guidance on citations see FAQs.c© [not recorded]Version: Not SetLink(s) to article on publisher’s website:http://www.lpi.usra.edu/meetings/metsoc2003/pdf/5071.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.ukAL MALA’IKA (NWA 1669):  A NEW SHERGOTTITE FROM MOROCCO/MINERALOGY AND PETROLOGY.  A. Jambon1 , M. Bohn2, O. Boudouma1, H. Chennaoui-Aoudjehane1,3, and I. Franchi4, 1Université P. et M. Curie, Paris 6, (France), 2Université de Bretagne occidentale Brest, 3Univ Casablanca, 4Open University, Milton Keynes (UK).  Introduction: Al Mala’ika (NWA1669) a meteorite of 36g, found in 2001 has been recently identified as a shergottite. The single stone is covered with desert varnish with a few remnants of fusion crust. It is a fine grained rock, with two closely intricated pyroxenes: pigeonite En 58-25 Wo 9-19 Fs 32-61 and augite En 47-19 Wo 39-24 Fs 54-18. Their FeO/MnO ratio of 34 on the average, is typical for a shergottite. Their Mg# indicate that augite crystallized first. Plagioclase transformed to maskelynite  (Ab41-53 Or1-6 An58-42) is injected between pyroxene phenocrysts.  Accessory minerals are: merrilite, Cl-apatite, pyrrhotite, ulvöspinel, ilmenite, silica and baddeleyite. Impact melt pockets contain submicrometric stishovite needles. The rock is highly fractured at all scales : the cores of pyroxenes are crosscut by wide fractures while their margins are cut only by numerous small fractures.  Maskelynite is marginally affected by few of the largest ones.  Secondary carbonate is present in some fractures. The major and trace element composition is under study. Oxygen Isotopes:  ∆17O= 0.30‰, δ17O= 2.85‰, δ18O= 4.91‰. These values are in agreement with the martian origin of this meteorite. According to the experimental works, the compositions of pyroxenes indicate that augite crystallized first followed by the syncrystallisation of augite and pigeonite. According to the experimental work, this order of crystallization indicates  a significant P(H2O), on the order of 0.2 Gpa, pointing out the significant abundance of water of the magma compared to the terrestrial basaltic equivalents. 66th Annual Meteoritical Society Meeting (2003) 5071.pdf

Al Mala'ika (NWA 1669): A new Shergottite from Morocco: mineralogy and petrology

http://oro.open.ac.uk/8632/421/AL_MALA_IKA_%5BNWA_1669%5D_-_A_NEW_SHERGOTTITE_FROM_MOROCCO.pdf

Al Mala'ika (NWA 1669): A new Shergottite from Morocco: mineralogy and petrology

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