Allan Hills A76004 meteorite, Allan Hills, Victoria Land, Eastern Antarctica, Antarcticai
| Regional Level Types | |
|---|---|
| Allan Hills A76004 meteorite | Meteorite Fall Location |
| Allan Hills | Group of Hills |
| Victoria Land | Region |
| Eastern Antarctica | Region |
| Antarctica | Continent |
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Latitude & Longitude (WGS84):
76° 43' South , 159° 40' East
Latitude & Longitude (decimal):
Locality type:
Meteorite Class:
Meteoritical Society Class:
KΓΆppen climate type:
Other/historical names associated with this locality:
ALHA76004; ALH 76004
Unequilibrated ordinary chondrite, breccia (LL3,br; S2; W1)
Found, 1976-1977; 305 g, several pieces
Allan Hills A76004 was discovered during the austral summer of 1977-78. Although the meteorite is quite small it turned out to be one of the more petrographically and mineralogically diverse of the Antarctic meteorites recovered during the first meteorite hunting expeditions of the late 1970's. Under a somewhat weather-rounded fusion crust was a very dark gray matrix which contained a plethora of chondrules, fragments, glass, and irregular clasts β plus some diverse inclusions several cm in diameter. Chondrules [usually < 2 mm in diameter] are mainly porphyritic olivine [PO] and porphyritic olivine-pyroxene [POP], but several other types are also present. A large proportion of compound and elongated, plastically deformed chondrules are present. The range in olivine (Fa 0-34) and Ca-poor pyroxene (Fs0-53) composition is unusually large. Variable anorthic plagioclase and several varieties of silicate glass are present as well. In reflected light Fe-Ni metal and sulfides are also visible (~5 vol%). The metallic grains are often found in assemblages rimmed by troilite. Preliminary investigations revealed a number of additional phases in the chondrules, matrix, and/or inclusions (opaques, phyllosilicates, other silicatesβ¦). Shock indicators (shock level S2) include undulose extinction in olivine as well as the deformed chondrules. Weathering is relatively light (W1) with some limonite stains and small veins.
A cosmic ray exposure age of ~25 Ma is reported.
Names and abbreviations of Antarctic Meteorites: In the early 1980's a convention was fixed of using 3 letter abbreviations for Antarctic meteorites instead of the 4 letters used here. This convention did not alter the names and official abbreviations for the meteorites recognized before this time. However, one also sees β for example β 'Allan Hills 76004' and 'ALH 76004' in some of the formal scientific literature.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsMineral List
8 valid minerals.
Meteorite/Rock Types Recorded
Note: data is currently VERY limited. Please bear with us while we work towards adding this information!
Select Rock List Type
Alphabetical List Tree DiagramDetailed Mineral List:
| β Augite Formula: (CaxMgyFez)(Mgy1Fez1)Si2O6 Reference: Olsen, E. et al. (1978). Eleven new meteorites from Antarctica, 1976-1977, Meteoritics 3( 2): 209-225. |
| β Augite var. Fassaite Formula: (Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6] Reference: Olsen, E. et al. (1978). Eleven new meteorites from Antarctica, 1976-1977, Meteoritics 3( 2): 209-225. |
| β Chromite Formula: Fe2+Cr3+2O4 Reference: Olsen, E. et al. (1978). Eleven new meteorites from Antarctica, 1976-1977, Meteoritics 3( 2): 209-225.; Brearley, A.J. & Jones, R.H. (1998) Chondritic Meteorites. In: Planetary Materials (Papike, JJ - Ed.), Chapter 3: 1-398: Mineralogical Society of America, Washington, DC, USA. |
| β Diopside Formula: CaMgSi2O6 Reference: Steele. I.M. (1995) Oscillatory zoning in meteoritic Forsterite: American Mineralogist 80 (7&8): 823-832. (Jul/Aug1995). |
| β 'Fayalite-Forsterite Series' Description: Olivine compositionβ Fayalite 0-34 (mol%). Reference: Graham, A.L. (1979). Meteoritical Bulletin, No. 56. Meteoritics 14 (1): 161-175. (March 1979).; Olsen, E. et al. (1978). Eleven new meteorites from Antarctica, 1976-1977, Meteoritics 3( 2): 209-225.; Graham, A.L., Bevan, A. W. R. & Hutchison, B. (1985) Catalogue of Meteorites (4/e). University of Arizona Press: Tucson.; Grady, M.M., Pratesi, G. & Moggi-Cecchi, V. (2015) Atlas of Meteorites. Cambridge University Press: Cambridge, United Kingdom. 373 pages. |
| β Ferrosilite Formula: FeSiO3 Description: Ferrosiliteβ Pyroxenes include a small component of grains with Fe#>Mg#. Reference: Graham, A.L. (1979). Meteoritical Bulletin, No. 56. Meteoritics 14 (1): 161-175. (March 1979). |
| β Forsterite Formula: Mg2SiO4 Description: Forsterite, sensu strictu [Olivine, Fa0-9] includes Fa 0.2 grain w. oscillatory zoning. Reference: Graham, A.L., Bevan, A. W. R. & Hutchison, B. (1985) Catalogue of Meteorites (4/e). University of Arizona Press: Tucson.; Brearley, A.J. & Jones, R.H. (1998) Chondritic Meteorites. In: Planetary Materials (Papike, JJ - Ed.), Chapter 3: 1-398: Mineralogical Society of America, Washington, DC, USA. ; Steele. I.M. (1995) Oscillatory zoning in meteoritic Forsterite: American Mineralogist 80 (7&8): 823-832. (Jul/Aug1995). |
| β 'Glass' Description: Glass is quite variable with Si-rich, K-rich, and ultramafic varieties. Reference: Olsen, E. et al. (1978). Eleven new meteorites from Antarctica, 1976-1977, Meteoritics 3( 2): 209-225.; Steele. I.M. (1995) Oscillatory zoning in meteoritic Forsterite: American Mineralogist 80 (7&8): 823-832. (Jul/Aug1995). |
| β 'Limonite' Reference: Grady, M.M., Pratesi, G. & Moggi-Cecchi, V. (2015) Atlas of Meteorites. Cambridge University Press: Cambridge, United Kingdom. 373 pages. |
| β 'Meteoritic Iron' Reference: Grady, M.M., Pratesi, G. & Moggi-Cecchi, V. (2015) Atlas of Meteorites. Cambridge University Press: Cambridge, United Kingdom. 373 pages. |
| β Nepheline Formula: Na3K(Al4Si4O16) Reference: Olsen, E. et al. (1978). Eleven new meteorites from Antarctica, 1976-1977, Meteoritics 3( 2): 209-225. |
| β 'Plagioclase' Formula: (Na,Ca)[(Si,Al)AlSi2]O8 Description: Variable Anorthitic Plagioclase (An65-82). Reference: Olsen, E. et al. (1978). Eleven new meteorites from Antarctica, 1976-1977, Meteoritics 3( 2): 209-225.; Brearley, A.J. & Jones, R.H. (1998) Chondritic Meteorites. In: Planetary Materials (Papike, JJ - Ed.), Chapter 3: 1-398: Mineralogical Society of America, Washington, DC, USA. |
| β 'Pyroxene Group' Formula: ADSi2O6 Description: Ca-poor Pyroxene : Fs (0-53) βVery small, mineralogically uncharacterized pyroxene grains include a likely clinoenstatite (sensu strictu: En>90) component. Reference: Graham, A.L. (1979). Meteoritical Bulletin, No. 56. Meteoritics 14 (1): 161-175. (March 1979).; Graham, A.L., Bevan, A. W. R. & Hutchison, B. (1985) Catalogue of Meteorites (4/e). University of Arizona Press: Tucson.; Grady, M.M., Pratesi, G. & Moggi-Cecchi, V. (2015) Atlas of Meteorites. Cambridge University Press: Cambridge, United Kingdom. 373 pages. |
| β Spinel Formula: MgAl2O4 Reference: Brearley, A.J. & Jones, R.H. (1998) Chondritic Meteorites. In: Planetary Materials (Papike, JJ - Ed.), Chapter 3: 1-398: Mineralogical Society of America, Washington, DC, USA. |
| β Troilite Formula: FeS Reference: Grady, M.M., Pratesi, G. & Moggi-Cecchi, V. (2015) Atlas of Meteorites. Cambridge University Press: Cambridge, United Kingdom. 373 pages. |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 2 - Sulphides and Sulfosalts | |||
|---|---|---|---|
| β | Troilite | 2.CC.10 | FeS |
| Group 4 - Oxides and Hydroxides | |||
| β | Chromite | 4.BB.05 | Fe2+Cr3+2O4 |
| β | Spinel | 4.BB.05 | MgAl2O4 |
| Group 9 - Silicates | |||
| β | Augite | 9.DA.15 | (CaxMgyFez)(Mgy1Fez1)Si2O6 |
| β | var. Fassaite | 9.DA.15 | (Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6] |
| β | Diopside | 9.DA.15 | CaMgSi2O6 |
| β | Ferrosilite | 9.DA.05 | FeSiO3 |
| β | Forsterite | 9.AC.05 | Mg2SiO4 |
| β | Nepheline | 9.FA.05 | Na3K(Al4Si4O16) |
| Unclassified Minerals, Rocks, etc. | |||
| β | 'Fayalite-Forsterite Series' | - | |
| β | 'Glass' | - | |
| β | 'Limonite' | - | |
| β | 'Meteoritic Iron' | - | |
| β | 'Plagioclase' | - | (Na,Ca)[(Si,Al)AlSi2]O8 |
| β | 'Pyroxene Group' | - | ADSi2O6 |
List of minerals for each chemical element
| O | Oxygen | |
|---|---|---|
| O | β Ferrosilite | FeSiO3 |
| O | β Pyroxene Group | ADSi2O6 |
| O | β Chromite | Fe2+Cr23+O4 |
| O | β Augite var. Fassaite | (Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6] |
| O | β Plagioclase | (Na,Ca)[(Si,Al)AlSi2]O8 |
| O | β Nepheline | Na3K(Al4Si4O16) |
| O | β Forsterite | Mg2SiO4 |
| O | β Spinel | MgAl2O4 |
| O | β Diopside | CaMgSi2O6 |
| O | β Augite | (CaxMgyFez)(Mgy1Fez1)Si2O6 |
| Na | Sodium | |
| Na | β Augite var. Fassaite | (Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6] |
| Na | β Plagioclase | (Na,Ca)[(Si,Al)AlSi2]O8 |
| Na | β Nepheline | Na3K(Al4Si4O16) |
| Mg | Magnesium | |
| Mg | β Augite var. Fassaite | (Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6] |
| Mg | β Forsterite | Mg2SiO4 |
| Mg | β Spinel | MgAl2O4 |
| Mg | β Diopside | CaMgSi2O6 |
| Mg | β Augite | (CaxMgyFez)(Mgy1Fez1)Si2O6 |
| Al | Aluminium | |
| Al | β Augite var. Fassaite | (Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6] |
| Al | β Plagioclase | (Na,Ca)[(Si,Al)AlSi2]O8 |
| Al | β Nepheline | Na3K(Al4Si4O16) |
| Al | β Spinel | MgAl2O4 |
| Si | Silicon | |
| Si | β Ferrosilite | FeSiO3 |
| Si | β Pyroxene Group | ADSi2O6 |
| Si | β Augite var. Fassaite | (Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6] |
| Si | β Plagioclase | (Na,Ca)[(Si,Al)AlSi2]O8 |
| Si | β Nepheline | Na3K(Al4Si4O16) |
| Si | β Forsterite | Mg2SiO4 |
| Si | β Diopside | CaMgSi2O6 |
| Si | β Augite | (CaxMgyFez)(Mgy1Fez1)Si2O6 |
| S | Sulfur | |
| S | β Troilite | FeS |
| K | Potassium | |
| K | β Nepheline | Na3K(Al4Si4O16) |
| Ca | Calcium | |
| Ca | β Augite var. Fassaite | (Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6] |
| Ca | β Plagioclase | (Na,Ca)[(Si,Al)AlSi2]O8 |
| Ca | β Diopside | CaMgSi2O6 |
| Ca | β Augite | (CaxMgyFez)(Mgy1Fez1)Si2O6 |
| Ti | Titanium | |
| Ti | β Augite var. Fassaite | (Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6] |
| Cr | Chromium | |
| Cr | β Chromite | Fe2+Cr23+O4 |
| Fe | Iron | |
| Fe | β Ferrosilite | FeSiO3 |
| Fe | β Chromite | Fe2+Cr23+O4 |
| Fe | β Augite var. Fassaite | (Ca,Na)(Mg,Fe2+,Al,Fe3+,Ti)[(Si,Al)2O6] |
| Fe | β Troilite | FeS |
| Fe | β Augite | (CaxMgyFez)(Mgy1Fez1)Si2O6 |
References
Sort by
Year (asc) Year (desc) Author (A-Z) Author (Z-A)Olsen, E. et al. (1978). Eleven new meteorites from Antarctica, 1976-1977: Meteoritics 3( 2): 209-225.
Meteorite Working Group (1978) Antarctic Meteorite Newsletter 1(3). Johnson Space Center, Houston. (Nov 1978).
Graham, A.L. (1979). Meteoritical Bulletin, No. 56. Meteoritics 14 (1): 161-175. (March 1979).
Graham, A.L., Bevan, A. W. R. & Hutchison, B. (1985) Catalogue of Meteorites (4/e). University of Arizona Press: Tucson.
Grossman, J.N. (1994). The Meteoritical Bulletin, No. 76: Meteoritics 29 (1): 100-143. (Jan 1994).
Graf, T. & Marti, K. (1994) Collisional records in LL-chondrites. Meteoritics 29(5): 643β648. (Sept 1994).
Steele. I.M. (1995) Oscillatory zoning in meteoritic Forsterite: American Mineralogist 80 (7&8): 823-832. (Jul/Aug1995).
Brearley, A.J. & Jones, R.H. (1998) Chondritic Meteorites. In: Planetary Materials (Papike, JJ - Ed.), Chapter 3: 1-398: Mineralogical Society of America, Washington, DC, USA.
Grady, M.M. (2000). Catalogue of Meteorites (5/e). Cambridge University Press: Cambridge; New York; Oakleigh; Madrid; Cape Town. 689 pages.
Menzies, O.N., Bland, P. A., Berry, F.J. & Cressey, G. (2005) MΓΆssbauer spectroscopy and X-ray diffraction study of ordinary chondrites: Quantification of modal mineralogy and implications for redox conditions during metamorphism. Meteoritics & Planetary Science 40 (7): 1023-1042. (July 2005).
Grady, M.M., Pratesi, G. & Moggi-Cecchi, V. (2015) Atlas of Meteorites. Cambridge University Press: Cambridge, United Kingdom. 373 pages.
External Links
http://www.lpi.usra.edu/meteor/metbull.php - MeteoriticalBulletinDatabase
http://www.lpi.usra.edu/meteor/metbull.php?code=1311 -ALHA76004 @MetBullDatabase
http://www.lpi.usra.edu/meteor/metbull.php?code=1311 -ALHA76004 @MetBullDatabase
Other Regions, Features and Areas containing this locality
Antarctic MeteoritesGroup of Meteorite Fall Locations
Antarctic PlateTectonic Plate
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