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Northwest Africa 4425 | |||||||||
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Basic information | Name: Northwest Africa 4425 This is an OFFICIAL meteorite name. Abbreviation: NWA 4425 Observed fall: No Year found: 2006 Country: Algeria Mass: ![]() | ||||||||
Classification history: |
This is 1 of 79 approved meteorites classified as CK3. [show all] Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 3), CK chondrites, CK3 chondrites, and CV-CK clan chondrites | ||||||||
Comments: |
Approved 17 Apr 2008 Revised 4 Aug 2008: final writeup | ||||||||
Writeup![]() |
Writeup from MB 93:
Northwest Africa 4425 Algeria Find: May 2006 Carbonaceous chondrite (CK3) History: A stone was purchased by P. Thomas in May 2006. Physical characteristics: A complete, ventifacted stone weighing 579 g, without fusion crust. It has a brownish color indicating significant terrestrial alteration. Petrography: (M. Bourot-Denise, MNHN) Chondrules are mm-sized. Most CAIs are also visible to the naked eye. The type specimen contains a CAI 1.5 cm in diameter rimmed with spinel and diopside. Chondrules are generally porphyritic with wide rims, and contain magnetite beads. Large opaque nodules of magnetite and sulfide are present in the matrix. Matrix is either crystallized or fine, with abundant small magnetite crystals. BSE images indicate that this chondrite is not completely equilibrated; olivines and pyroxene in porphyritic chondrules are zoned. In the type specimen, there is an angular clast, 2 cm in diameter, containing small, porphyritic pyroxene chondrules (100- 500 µm); chondrules and well-crystallized matrix are completely equilibrated; magnetite is finely scattered through the clast and does not make up nodules as in the host; the interface between the clast and the host is highlighted by small, euhedral magnetites. Geochemistry: Olivine (Fa13.6±12.6; range Fa0.54-34.1), low-Ca pyroxene (Fs16.8±11.0; range Fs2.8-30.7), magnetite (Cr2O3 = 2.6-3.7, MgO = 0.87-1.15 [both wt%]) all in the CK3 domain. Pyroxene in the angular clast: Fs23.35±0.86. Magnetic susceptibility (J. Gattacceca, CEREGE) log χ = 4.6 10-9 m3/kg. Classification: Carbonaceous chondrite (CK3, estimated subtype 3.8); minimal shock and moderate weathering. Type specimens: A total of 32.8 g of sample (1 sawn fragment) and two polished mounts are on deposit at MNHN. Thomas holds the main mass. Submitted by: M. Bourot-Denise, MNHN. | ||||||||
Data from: MB93 Table 2 Line 46: |
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Institutions and collections |
CEREGE: CEREGE
BP 80
Avenue Philibert, Technopole de l'Arbois
13545 Aix-en-Provence Cedex 4
France, France (institutional address; updated 10 Jun 2023) MNHN: Museum National d'Histoire Naturelle, IMPMC-CP52, 57 rue Cuvier, 75005 Paris, France, France; Website (institutional address) |
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Catalogs: |
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References: | Published in Meteoritical Bulletin, no. 93, MAPS 43, 571-632 (2008)
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Photos: |
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Geography:![]() |
Statistics: This is 1 of 1315 approved meteorites from Algeria (plus 30 unapproved names) (plus 4 impact craters) |