Britain’s Largest Meteorite Impact
Geologists at Aberdeen and Oxford have reinterpreted the Stac Fada Member of the Torridonian Stoer Group, previously believed to be a volcanic mudflow deposit, as a fossilised ejecta blanket from a meteorite impact about 1.2 billion years ago near Ullapool in Northwest Scotland. The unit bears the chemical signature of extraterrestrial origin including high iridium levels.
[Image from Waters 2003]
This unit presents a superb opportunity to examine an ejecta blanket deposit from an impact into a wet substrate. I don’t know of any other terrestrial examples.
[Image from Waters 2003]
The unit is up to 20m thick, unbedded and poorly sorted with angular clasts.
[Image from Waters 2003]
The rock also contains devitrified volcanic glass.
I have no insight to offer here. As a geologist, particularly one with an interest in planetary geology I’m fascinated by it and hope to get to see it one day.
Geology article abstract
http://www.gsajournals.org/perlserv/?request=get-abstract&doi=10.1130%2FG24454A.1
Aberdeen University Press Release
http://www.abdn.ac.uk/mediareleases/release.php?id=1275
BBC News Story
http://news.bbc.co.uk/1/hi/sci/tech/7314329.stm
Waters DJ, 2003. Rocks of N.W. Scotland
http://www.earth.ox.ac.uk/~oesis/nws/nws-a98-st1.html#field
[Hat-tip Ole]
