[meteorite-list] News on NWA

From: M come Meteorite Meteorites <mcomemeteorite2004_at_meteoritecentral.com>
Date: Mon Mar 21 13:24:53 2005
Message-ID: <20050302200013.52962.qmail_at_web50103.mail.yahoo.com>

Why not exit??? My Institute have sent this to Sara
Rusell and she have say there is not problems, the
same for the Lago Valscura meteorite and Lido di
Venezia meteorite

Matteo


 --- Jeff Grossman <jgrossman_at_usgs.gov> ha scritto:
> The entries quoted below have not appeared in the
> Meteoritical Bulletin,
> nor have they been approved for the next Bulletin.
> This has happened on
> the List several times recently. Folks need to be
> careful to say
> "submitted" or "in preparation" when posting things
> like these.
>
> jeff
>
> At 11:23 AM 3/1/2005, M come Meteorite Meteorites
> wrote:
> >Hello
> >
> >I have finaly received the analysis of many of my
> NWA,
> >this is some special entry exit in the new
> >Met.Bulletin
> >
> >NWA 903
> >
> >? Found 2003
> >? Ordinary chondrite H3
> >
> >Several stones were bought at Erfoud market by an
> >anonymous buyer. Classification and mineralogy
> >(G.Pratesi, V.Moggi-Cecchi, A. Salvadori, MSP:
> >petrography and EMPA; G. Sighinolfi and S. Lugli,
> UMo:
> >EMPA): the meteorite consists of chondrules 300-600
> ?m
> >in size, of different types (PO, POP, BO, RP) and
> >their fragments embedded in a fine-grained matrix;
> >olivine is Fa1.62-35.17, with an average of
> Fa14.85;
> >olivine compositions vary continuously between
> these
> >two values. The mean value and the amount of Fe,Ni
> >alloy suggest a classification as H chondrite.
> Low-Ca
> >pyroxenes range from Fs4.26En92.95Wo1.34 to
> >Fs17.36En82.16Wo0.48. A diopsidic pyroxene (SiO2
> >50.57, Al2O3 10.49, MgO 9.99, CaO 7.98 wt. %; SiO2
> >49.80, Al2O3 1.79, MgO 20.48, CaO 1.25 wt. %) has
> been
> >found, too. Minor phases are kamacite, taenite and
> >troilite; some olivine grains in BO and PO
> chondrules
> >are markedly zoned and contain a glassy mesostasis.
> >Compositional data on olivine point to a
> petrological
> >subtype <3.5. Weathering grade is W3; shock stage
> is
> >S1. Specimens: one thin section and 28.9 g, MSP;
> main
> >mass (500 g) with anonymous buyer.
> >
> >NWA 1054
> >
> >? Morocco
> >? Found 2001
> >? Acapulcoite
> >
> >A stone of 86 g was bought in Erfoud (Morocco) by
> an
> >anonymous dealer. Classification and mineralogy
> >(G.Pratesi, V.Moggi-Cecchi, L. Mancini, MSP:
> >petrography and EMPA; G. Sighinolfi and S. Lugli,
> UMo:
> >EMPA): either thin section and type specimen sample
> >look to be composed by a fine grained aggregate. In
> >thin section it displays an granular texture with
> >grains mainly represented by olivine, pyroxene,
> Fe,Ni
> >alloy and troilite and ranging from 200 to 700 ?m
> in
> >dimensions. Olivine is homogeneous and has a
> typical
> >forsteritic composition, (Fa = 6.37 mol %);
> >orthopyroxene is bronzitic (Fs = 7.77, Wo = 1.32
> mol
> >%). High Ca-pyroxene (Fs = 3.33, En = 51.23, Wo =
> >45.44, Al-Px = 1.50 mol %) and plagioclase (An =
> >14.27, Ab = 79.47, Or = 6.25 mol %) are also
> common.
> >Apart from silicates, major phases are metal and
> >troilite. Accessory phases include Na-Merrillite
> and
> >magnesiochromite (Cr/(Cr+Al) = 0.96; Fe:Mn:Mg
> ratios =
> >0.60:0.12:0.28). Nichelphosphide grains with an
> >anomalous composition, pointing to a (Ni,Fe)4P
> formula
> >have been found, too. This meteorite shows a
> >recrystallization texture with abundant 120? triple
> >junctions and many interstices filled with metal.
> >Based on texture (fine coarsed), mineralogy and
> >chemistry (Cr content of diopside varying from 1.17
> to
> >1.35 wt. %) the meteorite is classified as an
> >acapulcoite. Terrestrial weathering grade is rather
> >low (W1); optical features (sharp extinction of
> >olivine) indicate that the sample is very weakly or
> >not shocked (S1). Specimens: main mass with buyer;
> >type specimen (17.9 g) and thin section, MSP.
> >
> >NWA 1807
> >
> >? Morocco
> >? Found 2002
> >? Carbonaceous chondrite (CV3)
> >
> >A stone of 274 g was bought in Erfoud (Morocco) by
> Mr.
> >Matteo Chinellato. The main mass, weighing 54.5 g,
> has
> >no crust. Classification and mineralogy (G.Pratesi,
> >V.Moggi Cecchi, MSP): a cut surface on the type
> >specimen displays rather large chondrules and some
> >small white spots. In thin section many chondrules
> of
> >various kinds (POP, PO, BO, RP) accounting for ~50%
> >vol. and ranging from 500 to 1200 ?m are visible,
> set
> >in a fine intergrowth of microporphyric
> >orthopyroxenes. Olivine composition ranges from
> Fa0.83
> >to Fa5.03 mol. % in the chondrules and reaches
> Fa49.72
> >out of them. Orthopyroxene is enstatitic (En98.14,
> >Wo1.06). An augitic pyroxene is also present
> >(Fs15.54-28.61, En25.12-36.97, Wo46.12-47.49).
> >Chondrules glass is anorthitic (An84.67, Ab15.3
> mol.
> >%). Fe,Ni alloy and troilite are rather uncommon
> (less
> >than 5% vol.). Rare apatite grains and CAIs are
> >present. Oxygen isotope measurements (I.Franchi,
> >R.Greenwood, Open University) d17O = -1.643?
> d18O =
> >2.524?; D17O = -2.955? plot on the end of the CV
> >range. Based on texture, mineralogy, chemistry and
> OI
> >data, the meteorite is classified as a CM2
> >carbonaceous chondrite. Terrestrial weathering
> grade
> >is rather low (W1); optical features indicate a low
> >shock stage (S1). Specimens: main mass with buyer;
> >type specimen (20.5 g) and thin section, MSP.
> >
> >NWA 1808
> >
> >? Morocco
> >? Found 2002
> >? H5, impact melt breccia
> >
> >A dark brown stone of 684 g was bought in Erfoud
> >(Morocco) by an anonymous buyer. Classification and
> >mineralogy (G.Pratesi, V.Moggi Cecchi, MSP): the
> main
> >mass has no crust and a large metal vein on its
> >surface. A cut surface on the type specimen
> displays
> >areas with a marked difference in the amount of
> metal
> >and seems to be composed by two different portions:
> a
> >fine grained one and a coarse grained one. In thin
> >section the fine grained part shows a
> >re-crystallization texture with few grains of
> residual
> >metal and olivine in a matrix of feldspatic glass
> (An
> >= 17.62, Ab = 77.49, Or = 4.88 mol. %) containing
> very
> >fine grained olivine and pyroxenes crystals; metal
> >pools and droplets shows fringes substituting the
> >outstanding glass. The coarse grained portion
> presents
> >a typical chondritic texture: major phases are
> olivine
> >and low-Ca pyroxene (Fa = 18,96 mol. %; Fs = 16,31,
> En
> >= 82,03, Wo = 1.67 mol %), metal and troilite.
> Based
> >on texture, mineralogy and chemistry of the coarse
> >grained portion, the meteorite is classified as an
> H
> >chondrite impact melt breccia. Terrestrial
> weathering
> >grade is absent (W0); optical features (undulatory
> >extinction of olivine) indicate that the sample is
> >rather distinctly shocked (S3). Specimens: main
> mass
> >with buyer; type specimen (20.1 g) and thin
> section,
> >MSP.
> >
> >NWA 2045
> >
>
=== message truncated ===

=====
M come Meteorite - Matteo Chinellato
Via Triestina 126/A - 30030 - TESSERA, VENEZIA, ITALY
Email: mcomemeteorite2004_at_yahoo.it
Sale Site: http://www.mcomemeteorite.it
Collection Site: http://www.mcomemeteorite.info
International Meteorite Collectors Association #2140
MSN Messanger: spacerocks at hotmail.com
EBAY.COM:http://members.ebay.com/aboutme/mcomemeteorite/


                
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Received on Wed 02 Mar 2005 03:00:13 PM PST


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