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.