Sample Petrographic Description
Sample Number | ALH 79001 |
Newsletter | 4,1 |
Location | Allan Hills |
Field Number | 1171 |
Dimensions (cm) | 4.0 x 3.5 x 1.5 |
Weight (g) | 32.31 |
Original Classification | L3 Chondrite |
Updated Classification | L3.5 Chondrite |
Pairing | ALH 77011; ALH 77015; ALH 77031; ALH 77033; ALH 77034; ALH 77036; ALH 77043; ALH 77047; ALH 77049; ALH 77050; ALH 77052; ALH 77115; ALH 77140; ALH 77160; ALH 77163; ALH 77164; ALH 77165; ALH 77166; ALH 77167; ALH 77170; ALH 77175; ALH 77178; ALH 77185; ALH 77211; ALH 77214; ALH 77241; ALH 77244; ALH 77249; ALH 77260; ALH 77303; ALH 78013; ALH 78015; ALH 78017; ALH 78037; ALH 78038; ALH 78041; ALH 78162; ALH 78170; ALH 78176; ALH 78180; ALH 78186; ALH 78188; ALH 78235; ALH 78236; ALH 78238; ALH 78239; ALH 78243; ALH 79001; ALH 79045; ALH 80133; ALH 81025; ALH 81030; ALH 81031; ALH 81032; ALH 81053; ALH 81060; ALH 81061; ALH 81065; ALH 81066; ALH 81069; ALH 81085; ALH 81087; ALH 81121; ALH 81145; ALH 81156; ALH 81162; ALH 81190; ALH 81191; ALH 81214; ALH 81229; ALH 81243; ALH 81259; ALH 81272; ALH 81280; ALH 81292; ALH 81299; ALH 83038; ALH 85155; |
Mineral Composition (%Fa & %Fs) | |
Fayalite (mol%): 6-39;Ferrosilite (mol%): 2-31 | |
Weathering | |
C | |
Fracturing | |
A | |
Macroscopic Description - Roberta Score | |
Five exterior surfaces have a dull reddish-brown color while the sixth surface has a iridescent reddish-brown color. Though the interior is extremely weathered, clasts are visible. ALH 79001 and ALH 79003 are probably the same meteorite. | |
Thin Section Description - Brian Mason | |
The polished thin section shows a closely packed aggregate of chondrules (0.2-2 mm in diameter) and irregular crystalline aggregates, set in a small amount of dark fine-grained matrix which includes minor subequal amounts of nickel-iron and troilite. A considerable variety of chondrules is present, the most common being granular olivine with or without polysynthetically twinned clinopyroxene, porphyritic olivine, and fine-grained pyroxene. Some chondrules have intergranular transparent pale brown glass, in others the glass is turbid and partly devitrified. Some weathering is indicated by the presence of a moderate amount of brown limonite as veins and patches. Microprobe analyses show a wide range in the composition of olivine (Fa6-39) and pyroxene (Fs2-31); the pyroxene is a low-calcium clinopyroxene (CaO = 0.2-1.8%). This range of composition, together with the presence of glass and twinned clinopyroxene, indicates type 3, and the small amount of nickel-iron suggests L group; the meteorite is therefore tentatively classed as an L3 chondrite. | |
Reclassification Notes (AMN OUTSIDE) | |
Classification updated in Meteoritical Bulletin 76. |
Antarctic Meteorite Images for Sample ALH 79001 | ||||
Lab Photo(s) : | ||||
Antarctic Meteorite Images for Sample ALH 79001 | ||||
Thin Section Photo(s) : | ||||