The first global map of magnetic peculiarities - or anomalies - on earth has been assembled by an international team of researchers. The map shows the variation in strength of the magnetic field over the earths surface. The redder (hotter) the colours the higher the magnetic strength while the bluer (cooler) the colours the lower the values. It would seem that Africa has the greatest concentration of these magetic anomalies with central west and north west Africa being the most affected.

Magnetic anomalies are caused by differences in the magnetisation of the rocks in the Earth's crust. Many years of negotiation were required to obtain confidential data from governments and institutes.

Scientists hope to use the map to learn more about the geological composition of our planet.

The World Digital Magnetic Anomaly Map (WDMAM) is available through the Commission for the Geological Map of the World. The magnetic signature of the Earth's crust has been measured for many decades by a multitude of groups; but now, for the first time, the data has been combined to give a truly worldwide view of the phenomenon.

A British company involved in the project is GETECH, a spin-off from Leeds University.