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Brownfield (1937) meteorite, Terry Co., Texas, USA

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Latitude & Longitude (WGS84): 33° 13' 0'' North , 102° 10' 59'' West
Latitude & Longitude (decimal): 33.21667,-102.18333
Non-native locality type:Meteorite
Meteorite Class:H3.7 chondrite meteorite
Meteoritical Society Class: H3.7
Metbull:View entry in Meteoritical Bulletin Database
Köppen climate type:BSk : Cold semi-arid (steppe) climate


Ordinary chondrite, unequilibrated (H3.7; S1; W3)
Found, 1937; 40.96 kg

After two stones had been found in 1937, five additional associated stones had been recovered by 1971. Inspections reveal distinct chondrules and chondrule fragments, and xenoliths within a complex matrix. Compositionally, bulk iron contents (26 wt% Fe), the nearly equilibrated olivine (Fa18.5,ave.), and the more variable pyroxenes are characteristic of the unequilibrated H chondrites. Mineralogically, the meteorite consists primarily of dominant olivine and pyroxene with minor troilite, and Fe-Ni metal. Pyroxene in chondrules is variable and usually clinopyroxene, but is often mantled by more Ca-rich phases. In a few porphyritic [POP] and radial pyroxene [RP] chondrules, clinoenstatite (sensu strictu, En>90) is found. Accessory chromite, ilmenite, feldspar and other very minor phases are also reported in the chondrules and/or matrix. Taenite, if present, is apparently quite sparse — perhaps due to extensive weathering (weathering grade W3). Secondary goethite and magnetite are among the more prominent terrestrial weatherates reported by Ramdohr (1973). Ar, Kr, and Xe gases appear to include residues of the early solar nebula. A cosmic ray exposure (CRE) age of ~30.4 Ma and a terrestrial age of 21 ka have also been reported.

The H group of ordinary chondrites constitute roughly 35-40% of all recovered meteorites with over 20,000 recovered by early 2017. However, only 75 meteorites have been classified as exactly 'H3.7' [as of January 2017]. Brownfield (1937) is the second-most massive member of this small meteoritic subtype. Only the 200 kg Dimmitt L3.7 chondrite (another Texas stone) is more massive.

What's in a name? Harvey Nininger and his son-in-law, Glenn Huss, were instrumental in recovering several meteoritic stones from Terry County. After confusion in some instances, it became clear that the Brownfield (iron), Brownfield (1964), and Brownfield (c) meteorites [IID, H5, OC, resp.] represented an additional two or three individual falls.


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12 valid minerals.

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This page contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.

References

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Bunch, T.E., Keil, K. & Snetsinger, K.G. (1967) Chromite composition in relation to chemistry and texture of ordinary chondrites. Geochimica et Cosmochimica Acta 31(10): 1569-1582. (Oct 1967).
Snetsinger, K.G. & Keil, K. (1969) Ilmenite in ordinary chondrites. Amer. Mineral. 54 (5/6):780-786. (May-June1969).
Ramdohr, P. (1973). The Opaque Minerals in Stony Meteorites. Elsevier Publishing Company: Amsterdam; London: New York. 245 pages.
Moniot, R.K. (1980) Noble-gas-rich separates from ordinary chondrites: Geochimica et Cosmochimica Acta 44: 253-271. (Feb. 1980).
Rubin, A. (1990) Olivine & Kamacite in Ordinary Chondrites: Intergroup and Intragroup relationships. Geochimica et Cosmochimica Acta 54: 1217-1230. (May 1990).
Jull, A.J.T., Donahue, D.J., Cielaszyk, E. & Wlotzka, F. (1993) Carbon-14 terrestrial ages and weathering of 27 meteorites from the southern high plains and adjacent areas (USA): Meteoritics 28(2): 188-195. (June 1993).
Graf, T. & Marti, K. (1995) Collisional History of H Chondrites: Journal of Geophysical Research 100 (E10): 247-263. (Oct 1995).
Grady, M.M (2000). Catalogue of Meteorites (5/e). Cambridge University Press: Cambridge; New York; Oakleigh; Madrid; Cape Town. 689 pages.
Ferraris, C., Folco, L., & Mellini, M. (2002) Chondrule thermal history from unequilibrated H chondrites: A transmission and analytical electron microscopy study. Meteoritics & Planetary Science 37(10): 1299-1321. (Oct. 2002)

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