header
  MetSoc Home            Publications            Contacts  
Search the Meteoritical Bulletin Database
Last update: 11 Oct 2019
Search for: Search type: Search limits: Display: Publication:
Names
Text help
Places
Classes
Years
Contains
Starts with
Exact
Sounds like
NonAntarctic
Falls  Non-NWAs
What's new
  in the last:
Limit to approved meteorite names
Search text:  
Allan Hills A77304
Basic information Name: Allan Hills A77304
     This is an OFFICIAL meteorite name.
Abbreviation: ALHA77304
This meteorite may also be called Allan Hills 77304 (ALH 77304) in publications.

Observed fall: No
Year found: 1977
Country: Antarctica [Collected jointly by ANSMET (US) and NIPR (Japan)]
Mass:help 650 g
Classification
  history:
Antarctic Meteorite Newsletter:  AMN 2(1)  (1979)  LL3
AMN 7(1)  (1984)  L4
Meteoritical Bulletin:  MB 76  (1994)  L4
NHM Catalogue:  5th Edition  (2000)  L4
MetBase:  v. 7.1  (2006)  LL3.7
Antarctic Meteorite Newsletter:  AMN 33(1)  (2010)  LL3.7
Recommended:  LL3.7    [explanation]

This is 1 of 29 approved meteorites classified as LL3.7.   [show all]
Search for other: LL chondrites, LL chondrites (type 3), Ordinary chondrites, and Ordinary chondrites (type 3)
Writeuphelp
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.: ALHA77304

Location: Allan Hills

Field No.: B77123114

Weight (gms): 650.4

Meteorite Type: LL3 Chondrite

 

Physical Description:

Dull, brownish-black fusion crust, approximately 0.5 to 1 mm thick, covers all but the W surface of this angular, 9.5x8.0x6.5 cm, sample. On the W surface and areas where the fusion crust has been plucked away, greenish matrix material with numerous chondrules and irregular lithic clasts ranging from light to dark gray and as much as 1 cm in diameter, is exposed. A fracture on the B surface appears to penetrate the entire stone. When the meteorite was cleaved in half, haloing effects were observed around some of the inclusions in the interior of the stone. There is no obvious weathering rind.

 

Petrographic Description: Brian Mason

The section shows a closely-packed aggregate of chondrules, with a minimum amount of fine-grained matrix; a little troilite and nickel-iron is present in the matrix. Some of the chondrules are unusually large, ranging up to 3 mm in diameter. The commonest types are barred and porphyritic olivine chondrules with interstitial glass; some of the glass is isotropic and transparent, but most is turbid and partly denitrified. Polysynthetically twinned clinopyroxene occurs with the olivine in some chondrules. A 6x3 mm enclave, consisting of closely-packed idiomorphic olivine crystals with interstitial turbid brown glass, is present at one edge of the section. Brown limonitic staining pervades the section. Microprobe analyses show olivine (Fa18-27, average Fa24) and pyroxene (Fs13-19, average Fs15) of variable composition; the olivine in the enclave has uniform composition, Fa25. A few grains of calcic plagioclase, averaging An77, were noted. The low content of nickel-iron and troilite suggest LL group, and the wide range of olivine and pyroxene compositions type 3, so the meteorite is tentatively classified LL3; however, certain assignment of group may require additional investigation.

Data from:
  MB76
  Table 2
  Line 253:
Origin or pseudonym:Main icefield
Mass (g):650.4
Class:L4
Weathering grade:B
Fayalite (mol%):18-27
Ferrosilite (mol%):13-19
Comments:26Al=50±3
Catalogs:
Search for specimens in the Smithsonian Institution collection (U.S.):   
    Require SI photo
Search for this meteorite in the NIPR database (Japan):   
Search for this meteorite in the NASA/JSC database (U.S.):   
References: Published in Antarctic Meteorite Newsletter 2(1) (1979), JSC, Houston
Published in Meteoritical Bulletin, no. 76, Meteoritics 29, 100-143 (1994)
Find references in NASA ADS:
Find references in Google Scholar:
Geography:

Antarctica
Coordinates:
     Catalogue of Meteorites:   (76° 43'S, 159° 40'E)
     Recommended::   (76° 43'S, 159° 40'E)

Statistics:
     This is 1 of 39173 approved meteorites from Antarctica (plus 5051 unapproved names)
Proximity search:
Find nearby meteorites: enter search radius (km):

Direct link to this page