|Basic information||Name: Sutter's Mill|
This is an OFFICIAL meteorite name.
Abbreviation: There is no official abbreviation for this meteorite.
Observed fall: Yes
Year fell: 2012
Country: United States
Mass: 993 g
This is 1 of 8 approved meteorites classified as C. [show all]
Search for other: Carbonaceous chondrites
Approved 22 May 2012|
Revised 28 Nov 2012: Updated mass and number of pieces
Writeup from MB 100:
Sutter’s Mill 38°48’14"N, 120°54’29"W
California, United States
Fell: 22 Apr 2012
Classification: Carbonaceous chondrite (C)
History: (P. Jenniskens, SETI): A bright daytime east-to-west moving fireball was seen on April 22, 2012, from locations over California and Nevada between 7:51:10 and 7:51:30 am local daylight time (UT-7). The meteoroid fragmented towards the end of its trajectory. A loud sonic boom was heard in a wide region around Lake Tahoe. Wind gusts were felt and houses shook. At least a kiloton of kinetic energy was released, based on the infrasound signal detected at two stations. Eye witnesses in the townships of Coloma and Lotus, El Dorado County, reported hearing whistling sounds and some smelled a "welding" odor. U.S. National Climatic Data Center’s "NEXRAD" Doppler weather radar sweeps detected the falling meteorites. In data analyzed by Marc Fries, PSI, and Robert Matson, SAIC, the radar-defined strewn field is centered on the Sutter’s Mill historic site. On April 24, Robert Ward searched under the radar footprint and collected the first 5.5 g meteorite in Henningsen-Lotus Park. Later that day, Peter Jenniskens recovered a crushed 4 g fragment in the parking lot of that same park. A third find was made by Brien Cook, before heavy rain descended on the area in the following two days. After the rains more fragments were found including at the Sutter’s Mill site in the James W. Marshall Gold Discovery State Historic Park.
Physical characteristics: As of November 27th, 2012, 90 fragments have been recovered with a total mass of 992.5 g. A tally is maintained at the Sutter’s Mill Meteorite Consortium website: http://asima.seti.org/sm/.
Petrography: (M. Zolensky, JSC): A small piece was examined for petrography, taken from the stone found by Jenniskens on the parking lot surface, which had been crushed by an automobile tire and had some adhering terrestrial soil. The meteorite is unusually hard compared to CM2 chondrites, and microprobe totals for the matrix are also high for CM2, suggesting possibly incomplete aqueous alteration or, alternatively, mild thermal metamorphism. Various coarse-grained components are embedded within an opaque fine-grained matrix including chondrules, fine-grained porous olivine aggregates, fine-grained porous low-Ca pyroxene aggregates, large isolated lithic and mineral fragments (both olivine, low-Ca pyroxene), abundant CAIs, and grains of pyrrhotite and pentlandite. The components are often rimmed by fine-grained dust mantles. Chondrule diameters are generally less than 0.4 mm with a few exceeding 1 mm. Some chondrule contents are partially altered to tochilinite and cronstedtite and/or serpentine. Fe-Ni metal occurs (as a minor constituent) in chondrules and aggregate olivine crystals. The porous aggregates are irregular in shape and measure up to a couple of hundred microns across. The CAI are typical layered CM variety, with spinel cores, diopside rims and cronstedtite or Fe-rich serpentine between. The matrix includes abundant tochilinite intergrown with serpentine with a layered structure. Veins are present consisting of pyrrhotite, pentlandite, and Fe-Ni-Cr phosphides. One small, embayed grain of oldhamite was observed in matrix. Several grains of a refractory carbon phase were observed in the matrix, measuring up to 10 µm. No carbonates were observed.
Geochemistry: Most olivines in the chondrules and coarse-grained components are forsterite (below Fa3), but some Fe-rich olivine is present (Fa23). Coarse-grained olivine grains in the matrix are similar, although the iron-rich ones are up to Fa37. Olivine, from 22 analyses, averaged Fa4, with a range Fa1-29. Low-Ca pyroxene, from 19 analyses averaged Fs4Wo2, with a range Fs2Wo1 - Fs7Wo4.
Classification: Carbonaceous chondrite.
Specimens: Current institutional holdings include ASU - 24.9 g, FMNH - 10.1 g, UAz - 15.9, and UNM - 11.0 g. 3 g of the crushed 4 g specimen and a 17 g specimen are located at ARC.
ASU: Center for Meteorite Studies, Arizona State University, Tempe, Arizona 85287-1404, United States; Website (institutional address; updated 14 Jan 2012)
FMNH: Department of Geology The Field Museum of Natural History 1400 South Lake Shore Drive Chicago, IL 60605-2496, USA, United States; Website (institutional address; updated 16 Nov 2011)
JSC: Mailcode KT, 2101 NASA Parkway, NASA Johnson Space Center, Houston, TX 77058, United States; Website (institutional address; updated 3 Sep 2013)
UAz: Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd., Tucson, AZ 85721, United States (institutional address; updated 14 Jan 2012)
UNM: Institute of Meteoritics MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 USA, United States; Website (institutional address; updated 26 Dec 2011)
ARC: NASA-Ames Research Center, Moffett Field, California 94035-1000, United States (institutional address; updated 22 May 2012)
PSI: Planetary Science Institute, 1700 East Fort Lowell, Suite 106, Tucson, AZ 85719-2395, United States (institutional address; updated 22 May 2012)
SAIC: Science Applications International Corp., 3030 Old Ranch Pkwy., Ste. 200, Seal Beach, CA 90740, United States (institutional address; updated 22 May 2012)
SETI: SETI Institute, Carl Sagan Center, 189 Bernardo Avenue, Mountain View, California 94043, United States (institutional address; updated 22 May 2012)
Ward: No contact information provided. (private address)
|References:||Published in Meteoritical Bulletin, no. 100, MAPS 46, in preparation (2013)|
This is 1 of 242 approved meteorites from California, United States (plus 24 unapproved names)
This is 1 of 1735 approved meteorites from United States (plus 263 unapproved names) (plus 28 impact craters)
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