Grimsby        43°12’N, 79°37’W

Niagara region, southern Ontario, Canada

Fell: 01:03 UT 26 September 2009 [21:03 EDST September 25]

Classification: Ordinary chondrite (H5)

History: A brilliant fireball showing three major bursts was observed during the early evening of September 25, 2009 over southwestern Ontario. Automated cameras, radar, and infrasound sensors operated by UWO recorded the event, providing an orbit for the object and an accurate estimate of its fall location. Meteorites from the event fell in a 4 km by 8 km strewn field to the west and south of Grimsby, Ontario. One 46 g individual meteorite hit a parked vehicle and was recovered on the morning after the fall by A. Garchinsky. As of December 2009, 13 fragments had been found, totaling 215 g.

Physical characteristics: (P. McCausland and R. Flemming, UWO): In situ micro-XRD of a fresh broken surface indicates the ubiquitous presence of low shock, about Fo₉₀ olivine and enstatite, kamacite, and troilite as well as polycrystalline magnesioferrite spinel in the fusion crust. Polished thin sections show abundant chondrules and chondrule fragments ranging in size from 0.03 to 0.70 mm in apparent diameter. Matrix is variably recrystallized and chondrule rims are poorly defined, but feldspar is not well developed. Coarse olivines and pyroxenes show sharp optical extinction, implying a low shock state. Minor Fe-oxide has developed adjacent to some metal and troilite.

Geochemistry: EPMA: olivine (Fa_{17.8 ± 0.4}, n = 8) and low Ca pyroxene (Fs_{15.8 ± 1.0}, n = 5).

Classification: Ordinary chondrite (H5), S2, W0-1.

Specimens: A 22 g sample and two polished thin sections are on deposit at UWO. Main mass held by MFarmer.