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Northwest Africa 12430 | |||||||||||||||||||||||||||||
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Basic information | Name: Northwest Africa 12430 This is an OFFICIAL meteorite name. Abbreviation: NWA 12430 Observed fall: No Year found: 2006 Country: (Northwest Africa) Mass: 485 g | ||||||||||||||||||||||||||||
Classification history: |
This is 1 of 93 approved meteorites classified as LL4-6. [show all] Search for other: LL chondrites, LL chondrites (type 4-7), Ordinary chondrites, and Ordinary chondrites (type 4-7) | ||||||||||||||||||||||||||||
Comments: | Approved 23 Jan 2019 | ||||||||||||||||||||||||||||
Writeup |
Writeup from MB 108:
Northwest Africa 12430 (NWA 12430) (Northwest Africa) Purchased: Sept 2006 Classification: Ordinary chondrite (LL4-6) History: Found in northwest Africa, donated to Cascadia July 2012. Physical characteristics: In cut slices, exterior is black with brown patches, interior is gray with well-defined chondrules and dark- and light-colored angular clasts. Petrography: (M. Hutson, A. Ruzicka, Cascadia) Thin section shows a host lithology composed of a mix of well-defined chondrules and chondrule fragments. Both plagioclase feldspar (less than 40 μm across) and feldspathic glass are present. The host lithology surrounds a dozen angular coarser-grained chondritic clasts, the largest of which (Clast 5) is approximately 4 × 5 mm in size. Clast 5 and Clast 4 (approximately 2 × 4 mm in size) were analyzed. Clast 5 is coarse-grained, with plagioclase feldspar grains up to 110 μm in length, and contains three barely discernable chondrules. Clast 4 contains two chondrules with indistinct edges and plagioclase feldspar grains between 40 and 60 μm in length. Geochemistry: Mineral compositions and geochemistry: (M. Hutson and J. Graham-Davis, Cascadia) Olivine (host Fa31.9±0.5, N=22; Clast 4 Fa32.0±0.7, N=10; Clast 5 Fa32.2±0.2, N=7), low-Ca pyroxene (host Fs19.2±5.2Wo1.1±0.1, N=15; Clast 4 Fs26.0±0.5Wo2.0±0.2, N=7; Fs26.2±0.6Wo2.0±0.3, N=5), plagioclase feldspar (Clast 4 Ab85.1±0.9Or3.3±0.7, N=6; Clast 5 Ab85.2±1.2Or3.7±0.3, N=3). Classification: LL4-6 genomict breccia, based on iron contents in olivine and pyroxene and plagioclase feldspar grain size. Specimens: Cascadia holds 22.6 g in two pieces, in addition to a polished thin section and a mounted butt. | ||||||||||||||||||||||||||||
Data from: MB108 Table 0 Line 0: |
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Institutions and collections |
Cascadia: Cascadia Meteorite Laboratory, Portland State University, Department of Geology, Room 17 Cramer Hall, 1721 SW Broadway, Portland, OR 97201, United States; Website (institutional address; updated 28 Oct 2011) |
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Catalogs: |
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References: | Published in Meteoritical Bulletin, no. 108 (2020) Meteorit. Planet. Sci. 55, 1146-1150
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Geography: |
Statistics: This is 1 of 9933 approved meteorites from (Northwest Africa) (plus 1837 unapproved names) |