The Wood Lake, Ontario H4 ordinary chondrite, a new Canadian meteorite

The 350g Wood Lake meteorite was found by a jogger in July, 2003 as a single fusion-encrusted fragment beside a road in the Muskoka region of Ontario, 20-30 km east of Bracebridge. Mineralogical examination of the Wood Lake meteorite reveals abundant metal and sulphide, numerous sharply defined chondrules with occasional mesostasis chondrule glass, a lack of coarse feldspar but little variation in silicate compositions, indicating Wood Lake to be an H4 ordinary chondrite. Chondrules have barred, radiating, and granular/polycrystalline textures. The bulk of the stone has undergone a moderate level of shock (S3) as indicated in thin section by uneven optical extinction and the presence of planar dislocations in silicate grains, as well as by moderate distortion of silicate crystal structures observed using in situ microXRD. Mineral chemistry for Wood Lake olivine (Fa18.3+/-0.9, n=28), and orthopyroxene (Fs17.5+/-2.6, n=16) agrees well with H chondrite averages for these minerals. The grain density for Wood Lake (3.64+/-0.01 g/cm3) and its magnetic susceptibility (log X = 5.17) are typical of fresh H chondrite falls, consistent with its observed low weathering state (W1). A comparison with known Canadian H chondrites indicates Wood Lake to be a new meteorite, which, given its low weathering grade and high magnetic susceptibility, is likely to have fallen not long before its discovery in 2003.