Geophysics

The fast expansion of technological knowledge which came after the Second World War has allowed great advances in geophysics, the study ofphisical properties of the world. This is not a new science, it goes back to the early seventeenth century, prospectors from Sweden were using magnetized iron bars to locate magnetic bodies of iron ore. But it developed very quickly during the post-war boom. And computerization has meant the amount of data we can process and acquire on site has increased in a dramatical form.

In all of the geophysical surveys, what is being looked for is an anomaly – an exception to the norm. A geophysical anomaly is an area where the earth has unusual physical properties.

In a typical geophysical survey, a physical property like the magnetic or gravitational field is measured on a grid of locations over the survey area. The value found at each and every grid position is plotted on a plan view of the property. Lines are afterwards drawn through points which have equal value, in exactly the same way as isobars are drawn on a weather map or elevation contours on a relief map.this geophysical data map allows the prospector to select areas with the geophysical characteristics that suggest where there can be mineralization.

Another approach is to compile the data as profiles, giving a section view of the anomaly. Both geophysicists and geologists use these commonly used methods, they use them as guides in choosing the most appropriate means of further investigating the anomaly.