MetSoc Home            Publications            Contacts  
Search the Meteoritical Bulletin Database
Last update: 19 Mar 2023
Search for: Search type: Search limits: Display: Publication:
Text help
Starts with
Sounds like
Falls  Non-NWAs
What's new
  in the last:
Limit to approved meteorite names
Search text:  
Grass Flat
Basic information Name: Grass Flat
     This is an OFFICIAL meteorite name.
Abbreviation: There is no official abbreviation for this meteorite.
Observed fall: No
Year found: 1979
Country: United States
Mass:help 2.12 kg
Recommended:  Iron, IAB-MG    [explanation]

This is 1 of 120 approved meteorites classified as Iron, IAB-MG.   [show all]
Search for other: IAB complex irons, Iron meteorites, and Metal-rich meteorites
Comments: Approved 29 Jan 2023
Writeup from MB 112:

Grass Flat        39°40.715’N, 120°56.940’W

California, United States

Find: 1979

Classification: Iron meteorite (IAB-MG)

History: The single mass was found by a Plumas County/California highway construction crew in 1979, during road improvement 2 miles southeast of the town of La Porte, where French Camp Road crosses Slate Creek. Grass Flat is a neaby ghost town. The meteorite had been in the possession of Mrs. Sharon Cisneros, Mineralogical Research Company, for at least two decades prior to the meteorite being sold to Dr. Howard L. McLean in February 2020. An estimated 30 g had been previously removed for classification but that material was reportedly lost.

Physical characteristics: The single, irregularly shaped mass has deep regmaglypts and a dark brown exterior.

Petrography: (C. Herd, UAb) Optical investigation of a ~5 cm × 9 cm polished and etched slice shows a well-defined Widmanstaetten pattern with average kamacite bandwidth of 2.3±0.7 mm (n = 25), consistent with a coarse octahedrite. Two rounded troilite inclusions each at least 2 cm across and rimmed by schreibersite are present in the slice examined. Minor alteration extends along fractures into the interior.

Geochemistry: ICP-MS data, using sample of North Chile (Filomena) as standard (C. Herd and S. DuFrane UAb): Ni = 6.8, Co = 0.462 (both in wt%); Ir = 2.4, Ga = 87, Ge = 294, As = 13, Ru = 5.4, Pd = 3.6, Re = 0.22, W = 1.1, Pt = 6.4, Cu = 144, Au = 1.5 (all µg/g).

Classification: (C. Herd, UAb): IAB iron, Main Group.

Specimens: Type specimen of 69.5 g in two pieces at UAb. Main mass with Howard L. McLean.

Data from:
  Table 0
  Line 0:
Mass (g):2119
Class:Iron, IAB-MG
Shock stage:low
Weathering grade:low
Classifier:C. Herd, UAb
Type spec mass (g):69.5
Type spec location:UAb
Main mass:Howard L. McLean
Comments:Submitted by C. Herd
   and collections
UAb: 1-26 Earth Sciences Building, University of Alberta, Edmonton, AB, T6G 2E3, Canada, Canada; Website (institutional address; updated 17 Oct 2011)
References: Published in Meteoritical Bulletin, no. 112, in preparation (2023)
Find references in NASA ADS:
Find references in Google Scholar:

United States
     Recommended::   (39° 40' 43"N, 120° 56' 56"W)

     This is 1 of 269 approved meteorites from California, United States (plus 24 unapproved names)
     This is 1 of 1893 approved meteorites from United States (plus 890 unapproved names) (plus 28 impact craters)
Proximity search:
Find nearby meteorites: enter search radius (km):

Direct link to this page