Ash Creek – Texas Fall 2009

I was interviewed by News 8 as we scrambled to find this stone.

News 8 Coverage of Ash Creek 1-2
News 8 Coverage of Ash Creek 2-2

I showed up the day after Mike Farmer found the first fragments. It was one of the very first falls where Doppler radar was used to isolate and identify the precise location of a meteorite strewn field.

I spend many many days walking fields and found about 10 fragments, none larger than 45 grams.  I also was able to acquire a 225 g stone.

Official Meteorite Bulletin Posting:

Ash Creek 31°48.3′N, 97°00.6′W

McLennan County, Texas, United States

Fall: 15 February 2009; 11:00 AM CST (UT-6)

Ordinary chondrite (L6)

History: On Sunday February 15, 2009 (11:00 A.M. CST), News 8 cameraman Eddie Garcia recorded a fireball 180 km south of downtown Austin, Texas. From SE of Austin to Ft. Worth, many people observed the bolide. Using National Weather Service Doppler reflectivity radar measurements (NWS Ft. Worth and Granger stations) the bolide location was recorded at 11:03 A.M. D. Dawn led a team, which interviewed witnesses in the strewn field within 48 hours following the fall. In southern Hill County, straddling the northern corner of McLennan County, sonic booms were widely heard for a duration of 20–30 s in the area from Hubbard to Aquilla. The fireball was bright and the meteoroid fragmented overhead near Birome, where the sonic booms were reported loudest. In Aquilla, the rumblings were likened to “a jet taking off,” and the event was described at 30–40 degrees altitude in the eastern sky, with some horizontal movement. Strong sonic booms were widely reported from Hubbard and Penelope. J. Trussell heard a rumbling, which initially vibrated a window at about 11:00 A.M. CST. He looked north along Ash Creek and saw two segments of a smoke trail separated by a thick cloud. Shortly afterwards, a blackened stone rolled near his foot and a second impacted a shed behind him. Meteorites were found on February 17 by D. Sadilenko and D. Dawn on the banks Ash Creek, northern corner of McLennan County.

Physical Characteristics: Three large masses were found: a 1.7 kg specimen recovered by L.B. Etter on a farm in Menlow; a 1.673 kg stone purchased by meteorite dealer S. Arnold; and a 1.5 kg specimen purchased by M. Farmer from an anonymous landowner who suggested it was found in the vicinity of Aquilla. All other masses reported were less than 300 g each. According to reports, over 300 stones were found in McLennan and Hill Counties with an estimated total of over 11.7 kg. Approximately 75% of the finds were completely covered with thick black fusion crust, often with dark rust colored spots, even on specimens recovered within two days of the fall. Drizzle and heavy dew wet specimens in the strewn field for the first two nights following the fall, and heavy rain on March 13 soaked the area, oxidizing many specimens. Broken and cut surfaces reveal a dark/light gray breccia.

Petrography (A. Rubin, UCLA): Many plagioclase grains exceed 50 μm in size. Some metal grains contain irregular troilite inclusions. Metallic Cu is present in some metal. Metal- and sulfide-bearing shock veins are present and the meteorite exhibits silicate darkening.

Mineral Compositions (A. Rubin, UCLA): Olivine (Fa24.2 ± 0.2; n = 12), low-Ca pyroxene (Fs20.5 ± 0.7, Wo1.6 ± 0.2; n = 12). Taenite is more abundant than kamacite; average compositions: kamacite (Fe = 93.1%, Ni = 5.8%, Co = 0.83%; n = 4) and taenite (Fe = 69.6%, Ni = 30.3%, Co = 0.30%; n = 9).

Classification: Ordinary chondrite (L6) breccia; S3, W0.
Type Specimen: 30.91 g is at UCLA including a crusted 17.8 g piece, a 10.02 g end cut and a 3.09 g slice. M. Farmer holds 1.5 kg, D. Stimpson purchased Etter’s 1.7 kg mass; and the 1.673 kg mass was sliced and sold. 

Support for my expedition was provided by Out of a Blue Sky who offers meteorites for sale.

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