Revised interpretation of a specific historical meteorite impact in the Adelaide Hills - Kurianda, A potential meteorite impact site

Abstract

Crawford and Flaxman impact data that have been attributed to the Eocene, and were published at the turn of the millenium, have been reinterpreted in the light of a visible crater structure in the Barossa area of the Adelaide hills. New considerations include apparent iron meteorite fragments and proposed iron melt, around the Angaston area. At the focus, 300 m north of the junction of Lambtail Corner Rd and Hutton Vale Rd Angaston, a central uplift is present, 50 m above local lows. Until this report, geological studies in this exact area had not deduced an inclusive geological history, as besides the Stockwell and Kitchener faults no other faults are present to account for these hills. In the 1960's, it was documented that immediately underlying a massive heamatite deposit at Breakneck Hill Rd West is kunkar, which not only underlays but occasionally penetrates the heamatite. Kunkar above the haematite also contains and surrounds isolated iron nodules. Haematite iron deposits do not exist within 25 km, except on these hills, as far as documented. Magnetite iron fragments found above ground nearby are smooth, magnetic, and dark, with 5 mm fusion crust, and are candidates for representing meteorite dispersal fragments. Weathered pieces of putative H chondrite occur alongside the smoothed and fusion crusted pieces. These contain 1 mm presumed Ni-Fe inclusons and 0.l mm inclusions of the same type. On the basis of these observations, it is proposed that the bolide may have been iron-rich, and that vaporisation was incomplete. Determination of the form of target rocks, and the relationship of Kurianda to Crawford and Flaxman will follow, under a model whereby the incident meteor may have been of the "rubble pile" type, breaking up upon entry to the atmosphere.