![]() |
||
|
Allan Hills A77015 | |||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Basic information | Name: Allan Hills A77015 This is an OFFICIAL meteorite name. Abbreviation: ALHA77015 This meteorite may also be called Allan Hills 77015 (ALH 77015) in publications. Observed fall: No Year found: 1977 Country: Antarctica [Collected jointly by ANSMET (US) and NIPR (Japan)] Mass: ![]() | ||||||||||||||||||||||||
Classification history: |
This is 1 of 95 approved meteorites classified as L3.5. [show all] Search for other: L chondrites, L chondrites (type 3), Ordinary chondrites, and Ordinary chondrites (type 3) | ||||||||||||||||||||||||
Writeup![]() |
Writeup from AMN 2(1):
This text was reprinted from AMN 2(1) in AMN 4(1). In some cases, it may be an updated version from the original. Sample No.: ALHA77015 Location: Allan Hills Field No.: 77122945 Weight (gms): 411.1 Meteorite Type: L3 Chondrite
Physical Description: The specimen is angular, 9.0x5.5x5.0 cm. Dark charcoal-brown fusion crust with vitreous luster covers approximately 50% of the sample. The fusion crust is preserved on the S surface, and is partially preserved on the B surface. The remainder of the sample is devoid of fusion crust, however, it is nearly the same color. Many fractures are present in the sample. Both angular lithic fragments and chondrules were observed on the B surface. They range in color from light brown to dark gray. The largest of these clasts is approximately 0.5 cm in length. When the meteorite was cleaved in half, one chip showed a surface with dark matrix and non-weathered metallic flakes, but the remainder of the meteorites' surfaces were very weathered.
Petrographic Description: Brian Mason The section shows a close-packed aggregate of chondrules, 0.2-1.8 mm in diameter, with only a minor amount of fine-grained matrix. Chondrules are mostly olivine and olivine plus polysynthetically-twinned clinopyroxene; transparent pale brown glass is interstitial to olivine and pyroxene grains in some chondrules. Minor subequal amounts of nickel-iron and troilite are present, concentrated in the matrix and at chondrule margins; the nickel-iron grains are extensively corroded and altered to limonite, and thin veins of limonite occur throughout the section Microprobe analyses show a wide range in the composition of olivine (Fa1-Fa21) and pyroxene (Fs4- Fs24); the pyroxene is a low-calcium clinopyroxene (CaO = 0.2-0.5%). This range of composition, together with the presence of glass and twin clinopyroxene, indicates type 3, and the small amount of nickel-iron suggests L group; the meteorite is therefore tentatively classed as an L3 chondrite. | ||||||||||||||||||||||||
Data from: MB76 Table 2 Line 23: |
|
||||||||||||||||||||||||
Catalogs: |
| ||||||||||||||||||||||||
References: | Published in Antarctic Meteorite Newsletter 2(1) (1979), JSC, Houston Published in Meteoritical Bulletin, no. 76, Meteoritics 29, 100-143 (1994)
| ||||||||||||||||||||||||
Geography:![]() |
Statistics: This is 1 of 43700 approved meteorites from Antarctica (plus 3802 unapproved names) | ||||||||||||||||||||||||
Proximity search: |