Sample Petrographic Description
Sample Number | ALH 79045 |
Newsletter | 4,1 |
Location | Allan Hills |
Field Number | 1177 |
Dimensions (cm) | 5.5 x 4.5 x 3.0 |
Weight (g) | 115.40 |
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%): 2-38;Ferrosilite (mol%): 2-29 | |
Weathering | |
C | |
Fracturing | |
B | |
Macroscopic Description - Roberta Score | |
A small patch of weathered fusion crust is visible on one surface. What may be remnant fusion crust on two surfaces is iridescent reddish-brown. The remaining three surfaces have weathered to a dull reddish-brown in color but the clastic nature of this meteorite is highly visible. One particular inclusion is 4 mm in diameter and yellow in color. The interior of the stone revealed through chipping is totally weathered. | |
Thin Section Description - Brian Mason | |
The meteorite consists of a close-packed aggregate of chondrules (0.3-2.1 mm across) and irregular clasts (some of them chondrule fragments), with a relatively small amount of matrix material. Chondrule types include porphyritic and granular olivine and olivine-pyroxene, barred olivine, and fine-grained pyroxene. Some chondrules have black troilite-rich rims. Intergranular glass in chondrules may be transparent and pale brown, but is usually turbid and partly devitrified. Only a small amount of nickel-iron is present. Most of the pyroxene shows polysynthetic twinning. Brown limonitic staining pervades the section. Microprobe analyses show variable composition for both olivine and pyroxene: olivine, Fa2-38, average Fa23; pyroxene Fs2-29, average Fs8. The variability of olivine and pyroxene compositions indicates type 3, and the low metal content suggests L group, so the meteorite is tentatively classified as an L3 chondrite. | |
Reclassification Notes (AMN OUTSIDE) | |
Classification updated in Meteoritical Bulletin 76. |
Antarctic Meteorite Images for Sample ALH 79045 | ||||
Lab Photo(s) : | ||||
Antarctic Meteorite Images for Sample ALH 79045 | ||||
Thin Section Photo(s) : | ||||