Arapahoe meteorite, Cheyenne County, Colorado, USAi
| Regional Level Types | |
|---|---|
| Arapahoe meteorite | Meteorite Fall Location |
| Cheyenne County | County |
| Colorado | State |
| USA | Country |
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Latitude & Longitude (WGS84):
38° 48' North , 102° 12' West
Latitude & Longitude (decimal):
Meteorite Class:
Meteoritical Society Class:
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Cheyenne Wells | 837 (2017) | 13.5km |
| Weskan | 161 (2017) | 21.7km |
| Sharon Springs | 761 (2017) | 40.3km |
| Tribune | 793 (2017) | 53.4km |
Ordinary chondrite, black (L5,br)
Find, 1940; 19.08 kg
A brecciated, black chondritic stone was recovered. Inspections reveal chondrules and chondrule fragments within a shock-darkened matrix. Compositionally, total iron (22.1 wt%), equilibrated olivine (Fa23), and low Ca-orthopyroxene ('hypersthene') are characteristic of the L-chondrite chemical group. Mineralogically, the meteorite consists primarily of olivine accompanied by orthopyroxene plus minor troilite and Fe-Ni metal. Accessory chromite, copper, ilmenite, and isocubanite are also reported. Tiny phosphate micro-spherules and phosphides blebs have been reported as well, but are not mineralogically characterized. Olivine is fractured with mosaic extinction and granulation while plagioclase has been largely replaced by maskelynite. Martensite and rounded troilite-metal boundaries indicate that, in particular, troilite and Fe-Ni metal have been mobilized by post-accretional shock events.
A K-Ar degassing age of ~900 Ma and the relatively short U-He age of ~400 Ma may be indicative of a major collision involving an important intermediate parent body (IPB) for a large number of L chondrites ~ 500 Ma ago. As with many meteorites recovered by Harvey Nininger, the largest mass is held at Arizona State University's Center for Meteorite Studies in Tempe [4.8551 kg in 2017].
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsMineral List
7 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:
| ⓘ Chromite Formula: Fe2+Cr3+2O4 |
| ⓘ 'Fayalite-Forsterite Series' Description: Olivine composition (Fa23)— Mason,1963. Pervasive brecciation noted by Lambert et al.,1981 |
| ⓘ Ilmenite Formula: Fe2+TiO3 Description: Deemed primary (preterrestrial) by Ramdohr,1963. |
| ⓘ Isocubanite Formula: CuFe2S3 |
| ⓘ 'Maskelynite' Description: Plagioclase largely replaced by maskelynite. |
| ⓘ Native Copper Formula: Cu |
| ⓘ Native Iron Formula: Fe |
| ⓘ Native Iron var. Kamacite Formula: (Fe,Ni) Description: Secondary kamacite present. |
| ⓘ Native Iron var. Martensite Formula: Fe |
| ⓘ 'Orthopyroxene Subgroup' |
| ⓘ Taenite Formula: (Fe,Ni) |
| ⓘ Troilite Formula: FeS Description: Rounded metal-troilite boundaries present. References: |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| ⓘ | Native Copper | 1.AA.05 | Cu |
| ⓘ | Native Iron | 1.AE.05 | Fe |
| ⓘ | var. Kamacite | 1.AE.05 | (Fe,Ni) |
| ⓘ | var. Martensite | 1.AE.05 | Fe |
| ⓘ | Taenite | 1.AE.10 | (Fe,Ni) |
| Group 2 - Sulphides and Sulfosalts | |||
| ⓘ | Isocubanite | 2.CB.55b | CuFe2S3 |
| ⓘ | Troilite | 2.CC.10 | FeS |
| Group 4 - Oxides and Hydroxides | |||
| ⓘ | Chromite | 4.BB.05 | Fe2+Cr3+2O4 |
| ⓘ | Ilmenite | 4.CB.05 | Fe2+TiO3 |
| Unclassified | |||
| ⓘ | 'Maskelynite' | - | |
| ⓘ | 'Fayalite-Forsterite Series' | - | |
| ⓘ | 'Orthopyroxene Subgroup' | - | |
List of minerals for each chemical element
| O | Oxygen | |
|---|---|---|
| O | ⓘ Chromite | Fe2+Cr23+O4 |
| O | ⓘ Ilmenite | Fe2+TiO3 |
| O | ⓘ Fayalite-Forsterite Series | |
| Mg | Magnesium | |
| Mg | ⓘ Fayalite-Forsterite Series | |
| Si | Silicon | |
| Si | ⓘ Fayalite-Forsterite Series | |
| S | Sulfur | |
| S | ⓘ Isocubanite | CuFe2S3 |
| S | ⓘ Troilite | FeS |
| Ti | Titanium | |
| Ti | ⓘ Ilmenite | Fe2+TiO3 |
| Cr | Chromium | |
| Cr | ⓘ Chromite | Fe2+Cr23+O4 |
| Fe | Iron | |
| Fe | ⓘ Chromite | Fe2+Cr23+O4 |
| Fe | ⓘ Ilmenite | Fe2+TiO3 |
| Fe | ⓘ Native Iron | Fe |
| Fe | ⓘ Isocubanite | CuFe2S3 |
| Fe | ⓘ Native Iron var. Kamacite | (Fe,Ni) |
| Fe | ⓘ Taenite | (Fe,Ni) |
| Fe | ⓘ Troilite | FeS |
| Fe | ⓘ Fayalite-Forsterite Series | |
| Fe | ⓘ Native Iron var. Martensite | Fe |
| Ni | Nickel | |
| Ni | ⓘ Native Iron var. Kamacite | (Fe,Ni) |
| Ni | ⓘ Taenite | (Fe,Ni) |
| Cu | Copper | |
| Cu | ⓘ Native Copper | Cu |
| Cu | ⓘ Isocubanite | CuFe2S3 |
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- Great Plains DomainDomain
- Yavapai TerraneVolcanic Arc
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References
Mason, Brian (1963) Olivine composition in chondrites. Geochimica et Cosmochimica Acta, 27 (10) 1011-1023 doi:10.1016/0016-7037(63)90062-0
Smith, B.A., Goldstein, J.I. (1977) The metallic microstructures and thermal histories of severely reheated chondrites. Geochimica et Cosmochimica Acta, 41 (8) 1061-1072 doi:10.1016/0016-7037(77)90100-4
