School of Chemical and Physical Sciences

Geomagnetism and Palaeomagnetism

Magnetic field around Earth

Artist's impression of Earth's magnetic field from space. By Alan and Dennis Poole, South Pacific Press, reproduced with permission.

Dr Gillian Turner

Palaeomagnetism is the study of the very weak magnetizations carried by rocks, sediments and archaeological artefacts. These materials become magnetized at the time they are formed and so carry a record of the direction and strength of the geomagnetic field at that particular time.

Earth has a strong, largely dipolar magnetic field that protects us from the onslaught of the solar wind, guides birds and fish on their migrations and directs our compasses. Its source lies in the outer part of the planet's core where a seething cauldron of iron-rich fluid is stirred into complex patterns of motion by escaping heat and Earth’s rotation.


The Geodynamo

Geodynamo

The motion of the conducting fluid in an original magnetic field creates electric currents and the magnetic fields of these currents reinforce the original one. The Earth’s core is therefore a self-sustaining hydromagnetic dynamo:  the Geodynamo. 


Importance of palaeomagnetic studies

Palaeomagnetic studies have made key contributions to our understanding of the Earth and its workings. The discovery that the polarity of the geomagnetic field has reversed numerous times led to the development of the geomagnetic polarity timescale which is now an essential tool in dating geological materials. Palaeomagnetism also played a central role in confirming continental drift and developing the theory of plate tectonics.

Palaeomagnetic studies of the geomagnetic secular variation and polarity reversals have been crucial in setting the parameters that must be satisfied by viable simulations of the geodynamo.


Collaborators

We carry out research on a range of topics in palaeomagnetism. We collaborate closely with other research groups, both in New Zealand and overseas.Key collaborators include: Prof Andrew Roberts, (Australian National University), Dr Mimi Hill (Liverpool University) and Prof Peter Sheppard (Auckland University).


Enquiries

Enquiries from prospective PhD students are welcome at any time. Please email Gillian Turner  in the first instance. Victoria University awards a limited number of scholarships on a competitive basis. In addition, funding is sometimes available through specific projects.

See our research projects.

Read more about PhD degrees.