[meteorite-list] Britain's Biggest Meteorite Impact Found

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 27 Mar 2008 14:58:53 -0700 (PDT)
Message-ID: <200803272158.OAA05921_at_zagami.jpl.nasa.gov>

Office of External Affairs
University of Aberdeen
King's College, Aberdeen, Scotland

Contact: Angela Ferguson
Tel: +44 (0)1224 272960
Fax: +44 (0)1224 272086

Issued on: Wednesday 26th of March 2008

Ref: 69meteorite

Britain's biggest meteorite impact found

Evidence of the biggest meteorite ever to hit the British Isles has been
found by scientists from the University of Aberdeen and the University of
Oxford.

The scientists believe that a large meteorite hit northwest Scotland about
1.2 billion years ago near the Scottish town of Ullapool.

Previously it was thought that unusual rock formations in the area had been
formed by volcanic activity. But, the team report in the journal Geology
that they found evidence buried in a layer of rock which they now believe is
the ejected material thrown out during the formation of a meteorite crater.
Ejected material from the huge meteorite strike is scattered over an area
about 50 kilometres across, roughly centred on the northern town of
Ullapool.

Ken Amor of Oxford University's Department of Earth Sciences, co-author on
the Geology paper, said: "Chemical testing of the rocks found the
characteristic signature of meteoritic material, which has high levels of
the key element iridium, normally only found in low concentrations in
surface rocks on Earth. We found more evidence when we examined the rocks
under a microscope; tell-tale microscopic parallel fractures that also imply
a meteorite strike."

The proposed volcanic origin for the rock formations has always been a
puzzle as there are no volcanic vents or other volcanic sediments nearby.
Scientists took samples from the formations during fieldwork in 2006 and
have just had their findings published.

Professor John Parnell, Head of Geology & Petroleum Geology at the
University of Aberdeen, also a co-author on the paper, said: "These rocks
are superbly displayed on the west coast of Scotland, and visited by
numerous student parties each year. We're very lucky to have them available
for study, as they can tell us much about how planetary surfaces, including
Mars, become modified by large meteorite strikes. Building up the evidence
has been painstaking, but has resulted in proof of the largest meteorite
strike known in the British Isles.

Scott Thackrey,a PhD student in Geology and Petroleum Geology at the
University of Aberdeen, and also co-author of the paper, added: "The type of
ejected deposit discovered in North West Scotland is only observed on
planets and satellites that possess a volatile rich subsurface, for example,
Venus, Mars and Earth. Due to the rare nature of these deposits, each new
discovery provides revelations in terms of the atmospheric and surface
processes that occur round craters just after impact."

"If there had been human observers in Scotland 1.2 billion years ago they
would have seen quite a show," continued Ken Amor. "The massive impact would
have melted rocks and thrown up an enormous cloud of vapour that scattered
material over a large part of the region around Ullapool. The crater was
rapidly buried by sandstone which helped to preserve the evidence."

Since the formation of the solar system leftover space material has collided
regularly with the Earth and other planets. Some of these impacts are large
enough to leave craters, and there are about 174 known craters or their
remnants on Earth.

Ken Amor added: "This is the most spectacular evidence for a meteorite
impact within the British Isles found to date, and what we have discovered
about this meteorite strike could help us to understand the ancient impacts
that shaped the surface of other planets, such as Mars."

ENDS

Notes to Editors:

For more information contact:
Ken Amor on +44 (0)1865 272000

Alternatively contact the University of Oxford Press Office on +44 (0)1865
283877

Or the University of Aberdeen Communications Office on +44 (0)1224 272960

A report of the research, 'A Precambrian proximal ejecta blanket from
Scotland' is published online in the journal Geology:

http://www.gsajournals.org/perlserv/?request=get-document&doi=10.1130%2FG24454A.1

The research has been conducted by Ken Amor, Professor Stephen Hesselbo and
Dr Don Porcelli of Oxford University's Department of Earth Sciences and
Professor John Parnell and Scott Thackrey of the Department of Geology and
Petroleum Geology at the University of Aberdeen.

Professor Parnell is currently on a field trip to the very rocks where
evidence of the meteorite impact has been found. To get in touch with
scientists from the University of Aberdeen involved in the project please
contact Angela Ferguson, Communications Office, on +44 (0)1224 272960.

This research was self-funded.
Received on Thu 27 Mar 2008 05:58:53 PM PDT