[meteorite-list] News on NWA

From: Jeff Grossman <jgrossman_at_meteoritecentral.com>
Date: Mon Mar 21 13:24:53 2005
Message-ID: <5.1.0.14.2.20050301125547.02af2e60_at_gsvaresm02.er.usgs.gov>

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
>
>? Found 2003
>? Ordinary chondrite LL3
>
>One stone weighing 19 g was bought at Erfoud market by
>an anonymous buyer. Mineralogy and classification
>(G.Pratesi, V.Moggi Cecchi, MSP)): the meteorite
>consists of chondrules 500-700 ?m in size, of
>different types (PO, POP, BO, RP) and their fragments
>embedded in a fine-grained matrix; olivine is
>Fa29.83-43.73, PMD 22%, the average is Fa35.64; mean
>low-Ca pyroxene is Fs24.87En73.57Wo1.57; minor phases
>are pigeonite, (Fs9.40En45.72Wo44.88), augite,
>kamacite, taenite and troilite; POP and PO chondrules
>are moderately zoned and contain a glassy mesostasis.
>Compositional data on olivine point to a petrological
>subtype 3.8/3.9. Weathering grade is W3; shock stage
>is S2. Specimens: one thin section and 3.7 g, MSP;
>main mass with anonymous buyer.
>
>NWA 2179
>
>? Found 2003
>? Ordinary chondrite H3
>
>Several stones weighing in total 367.2 g was bought at
>Erfoud market by an anonymous buyer. Mineralogy and
>classification (G.Pratesi, V.Moggi Cecchi, MSP)): the
>meteorite consists of chondrules 500-700 ?m in size,
>of different types (PO, POP, BO, RP) and their
>fragments embedded in a fine-grained matrix; olivine
>is Fa0.81-18.38, with an average of Fa6.68; two
>clusters of analyses, with mean values at Fa1.53 and
>Fa12.02, respectively, can be delineated for chondrule
>olivines, pointing to a classification as H chondrite.
>Low-Ca pyroxenes range from Fs6.13En93.07Wo0.80 to
>Fs21.01En78.17Wo0.83, in good agreement with olivine
>data; minor phases are pigeonite, 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 W2;
>shock stage is S1. Specimens: one thin section and
>29.4 g, MSP; main mass (88.8 g) with anonymous buyer
>
>NWA 1052
>
>? Morocco
>? Found 2001
>? Acapulcoite
>
>A stone of 22 g was bought in Erfoud (Morocco) by
>Matteo Chinellato. 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 = 5.95 mol %);
>orthopyroxene is bronzitic (Fs = 7.60, Wo = 1.44 mol
>%). High Ca-pyroxene (Fs = 3.63, En = 51.11, Wo =
>45.26, Al-px = 1.44 mol %) and plagioclase (An =
>13.73, Ab = 79.90, Or = 6.37 mol %) are also common.
>Apart from silicates, major phases are metal and
>troilite. Accessory phases include Na- and
>Ca-Merrillite and magnesiochromite (Cr/(Cr+Al) = 0.91;
>Fe:Mn:Mg ratios = 0.58:0.09:0.33). 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 1.18 to
>1.43 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
>(Matteo Chinellato); type specimen (4.7 g) and thin
>section, MSP.
>
>Take a look at 1 hour to this link
>http://it.geocities.com/mcomemeteoritecollection/nwa.html
>for the other classifications.... pieces of this
>meteorites its available, not the NWA 1807
>
>Matteo
>
>
>
>
>
>
>
>
>=====
>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/
>
>
>
>___________________________________
>Nuovo Yahoo! Messenger: E' molto pi? divertente: Audibles, Avatar, Webcam,
>Giochi, Rubrica
 Scaricalo ora!
>http://it.messenger.yahoo.it
>______________________________________________
>Meteorite-list mailing list
>Meteorite-list_at_meteoritecentral.com
>http://six.pairlist.net/mailman/listinfo/meteorite-list

Dr. Jeffrey N. Grossman phone: (703) 648-6184
US Geological Survey fax: (703) 648-6383
954 National Center
Reston, VA 20192, USA
Received on Wed 02 Mar 2005 02:41:26 PM PST