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We examined oxygen three-isotope ratios of 48 extraterrestrial chromite (EC) grains extracted from mid-Ordovician sediments from two different locations in Sweden, and one location in south-central China. The ages of the sediments (∼470Ma) coincide with the breakup event of the L chondrite parent asteroid. Elemental compositions of the chromite grains are generally consistent with their origin from L or LL chondrite parent bodies. The average Δ¹⁷O (‰-deviation from the terrestrial mass-fractionation line, measured in situ from 15μm spots by secondary ion mass spectrometry; SIMS) of EC grains extracted from fossil meteorites from Thorsberg and Brunflo are 1.17±0.09‰ (2σ) and 1.25±0.16‰, respectively, and those of fossil micrometeorites from Thorsberg and Puxi River are 1.10±0.09‰, and 1.11±0.12‰, respectively. Within uncertainty these values are all the same and consistent with the L chondrite group …