The H6 Aarhus meteorite breccia: A new look at an old rock.

On 2 October 1951, a 750 g meteorite fell as two pieces over the Danish city of Aarhus. A sample of Aarhus is examined here using modern in situ analytical methods to reassess the meteorite’s history, which was previously investigated in 1963 using petrography, wet chemistry and X-ray diffraction. It is here confirmed to be an H6 ordinary chondrite based on the textural characteristics and the homogenous olivine (olivine (#Fa19.9±0.5) and orthorhombic low-Ca pyroxene (enstatite, Fs17.6±0.7) compositions. The meteorite’s pyroxene Mn/Fe ratios align with the trend of those for non-differentiated planetary bodies and thus support the assumption that the parent body largely retained a chondritic composition. Aarhus preserves textural evidence for a phase of brecciation pre-dating the major metamorphic recrystallisation phase and so occurred early on in the parent body history, possibly during the asteroid’s construction. The main metamorphic textures are then overprinted by shock fracturing of olivine and pyroxene and the formation of maskelynite after plagioclase, which may relate to the catastrophic disruption of the parent body. Aarhus is similar to the Danish meteorites Ejby (H5/6), which landed on Copenhagen in 2016, and Dueodde (H5), which was recovered from a roof on Bornholm in 2017.