H chondrite
| H chondrite | |
|---|---|
| — Group — | |
 |
|
| Weston meteorite, H4 | |
| Type | Chondrite |
| Structural classification | ? |
| Class | Ordinary chondrite |
| Subgroups |
|
| Parent body | Possibly 6 Hebe, less likely 3 Juno & 7 Iris |
| Composition | Iron ~25-31%, bronzite (an orthopyroxene), olivine (with characteristic fayalite (Fa) content 16 to 20 mol%), nickel-iron 15-19%, troilite 5% |
| Petrologic type | 3 (~2.5%), 5 (40%), 4 & 6 (57.5%) |
| Alternative names | Bronzite chondrites, Olivine bronzite chondrites |
 |
|
| Nuevo Mercurio, H5 | |
The H type ordinary chondrites are the most common type of meteorite, accounting for approximately 40% of all those catalogued, 46% of the ordinary chondrites, and 44% of the chondrites.[1]
Contents |
Name [edit]
The name comes from their High iron abundance, with respect to other ordinary chondrites.
Historically, the H chondrites have been named bronzite chondrites or olivine bronzite chondrites for the dominant minerals, but these terms are now obsolete.
Parent body [edit]
A probable parent body for this group is the S-type asteroid 6 Hebe, with less likely candidates being 3 Juno and 7 Iris.[2] It is supposed that these meteorites arise from impacts onto small near-earth asteroids broken off from 6 Hebe in the past, rather than originating from 6 Hebe directly.
The H chondrites have very similar trace element abundances and Oxygen isotope ratios to the IIE iron meteorites, making it likely that they both originate from the same parent body.
Iron [edit]
Their high iron abundance is about 25-31% by weight. Over half of this is present in metallic form, making these meteorites strongly magnetic despite the stony chondritic appearance.
Mineralogy [edit]
The most abundant minerals are bronzite (an orthopyroxene), and olivine. Characteristic is the fayalite (Fa) content of the olivine of 16 to 20 mol%. They contain also 15-19% of nickel-iron metal and about 5% of troilite. The majority of these meteorites have been significantly metamorphosed, with over 40% being in petrologic class 5, most of the rest in classes 4 and 6. Only a few (about 2.5%) are of the largely unaltered petrologic class 3.
Gallery [edit]
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Gao-Guenie, H5
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H5 Dar Bou Nali South Morocco
See also [edit]
References [edit]
External links [edit]
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