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Northwest Africa 4657 | |||||||||||||
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Basic information | Name: Northwest Africa 4657 This is an OFFICIAL meteorite name. Abbreviation: NWA 4657 Observed fall: No Year found: 2006 Country: Algeria Mass: ![]() | ||||||||||||
Classification history: |
This is 1 of 119 approved meteorites classified as CK4. [show all] Search for other: Carbonaceous chondrites, Carbonaceous chondrites (equilibrated), CK chondrites, CK chondrites (type 4-6), and CV-CK clan chondrites | ||||||||||||
Comments: |
Approved 1 Jan 2008 Revised 4 Aug 2008: final writeup | ||||||||||||
Writeup![]() |
Writeup from MB 93:
Northwest Africa 4657 Algeria Find: 2006 Carbonaceous chondrite (CK4) History and Physical characteristics: Purchased by B. Reed from a dealer in Erfoud, Morocco, in 2006. The single stone is a light greenish gray, 417 g stone that is partially crusted on ~70% of the surface and moderately to heavily desert-etched on the remaining surface. Petrography: (J. Wittke and T. Bunch, NAU) Contains ~18 vol% well-defined chondrules, some of which are up to 2 mm in diameter. The matrix is partially recrystallized with tiny plagioclase grains intermingled with amorphous plagioclase aggregates. Chondrule glass is mostly devitrified. Mineral compositions and Geochemistry: Olivine shows a narrow spread in FeO, although at lower values (Fa27.3-28.2) compared with typical CK chondrites; FeO/MnO = 95-123. Orthopyroxene (Fs23.8Wo2.2), magnetite (Cr2O3 = 3.79 wt%; Al2O3 = 1.56 wt%; NiO = 0.90 wt%), plagioclase (An27.9-49). Classification: Carbonaceous chondrite (CK4); moderate weathering and minimal shock. Type specimens: A 23 g sample is on deposit at NAU. Reed holds the main mass. Submitted by: T. Bunch, NAU. | ||||||||||||
Data from: MB93 Table 2 Line 88: |
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Institutions and collections |
NAU: Geology, Bldg 12
Knoles Dr
Northern Arizona University, Flagstaff, AZ 86011, United States; Website (institutional address; updated 12 Apr 2012) Reed: Blaine Reed, P.O. Box 1141, Delta, CO 81416, United States; Website (private 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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Geography:![]() |
Statistics: This is 1 of 1250 approved meteorites from Algeria (plus 29 unapproved names) (plus 4 impact craters) |