[meteorite-list] Earliest Meteorites Provide New Piece in Planetary Formation Puzzle

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue Sep 20 11:50:43 2005
Message-ID: <200509201549.j8KFnGZ05490_at_zagami.jpl.nasa.gov>

Imperial College London
London, U.K.

For further information please contact:

Laura Gallagher, Press Officer
Communications Division
Tel: +44 (0)20 7594 6702

Under embargo for 1700 EST / 2200 BST, Monday 19 September 2005

Earliest meteorites provide new piece in planetary formation puzzle

Researchers trying to understand how the planets formed have uncovered a
new clue by analysing meteorites that are older than the earth.

The research shows that the process which depleted planets and meteorites
of so-called volatile elements such as zinc, lead and sodium, must have
been one of the first things to happen in our nebula.

The implication of this clue is that 'volatile depletion' may be an
inevitable part of planet formation -- a feature not just of our Solar
System, but of many other planetary systems too.

The researchers at Imperial College London reached their conclusions after
analysing the composition of primitive meteorites, coal-like rocks that
are older than the earth and which have barely changed since the Solar
System was made up of fine dust and gas.

Their analysis, published today in the Proceedings of the National Academy
of Sciences, shows that all the components that make up these rocks are
depleted of volatile elements. This means that volatile element depletion
must have occurred before the earliest solids had formed.

Dr Phil Bland Opens in new window, from Imperial's Department of Earth
Science and Engineering, who led the research, explains: "Studying
meteorites helps us to understand the initial evolution of the early Solar
System, its environment, and what the material between stars is made of.
Our results answer one of a huge number of questions we have about the
processes that converted a nebula of fine dust and gas into planets."

For planetary scientists, the most valuable meteorites are those that are
found immediately after falling to earth, and so are only minimally
contaminated by the terrestrial environment. The researchers analysed
around half of the approximately 45 primitive meteorite falls in existence
around the world.

All of the terrestrial planets in the Solar System as far out as Jupiter,
including Earth, are depleted of volatile elements. Researchers have long
known that this depletion must have been an early process, but it was
unknown whether it occurred at the beginning of the formation of the Solar
System, or a few million years later.

Dr Phil Bland is a member of the Impacts and Astromaterials Research
Centre (IARC), which combines planetary science researchers from Imperial
College London and the Natural History Museum. The research is funded by
the Particle Physics and Astronomy Research Council.

-ends-

Notes to editors:

1. Proceedings of the National Academy of Sciences, USA, Vol. 102, no. 39
"Volatile fractionation in the early solar system and chondrule/matrix
complementarity".

2. Consistently rated in the top three UK university institutions,
Imperial College London is a world leading science-based university whose
reputation for excellence in teaching and research attracts students
(11,000) and staff (6,000) of the highest international quality.

Innovative research at the College explores the interface between science,
medicine, engineering and management and delivers practical solutions that
enhance the quality of life and the environment -- underpinned by a
dynamic enterprise culture.

Website: www.imperial.ac.uk
Received on Tue 20 Sep 2005 11:49:16 AM PDT