Palaeomagnetism and Rock Magnetism

Research Group

The Palaeomagnetism and Rock Magnetism Group at the University of Oxford using the magnetism of natural samples to explore a broad spectrum of problems in Earth and Planetary Sciences. These involve topics in sedimentology, volcanology, ancient Earth, lunar evolution, and the formation and evolution of other planetary bodies (Moon, Mars, asteroids). The group’s work is conducted primarily in the Oxford Magnetism Laboratory, which includes a 2G-enterprises Superconducting Rock Magnetometer, a state-of-the-art Quantum Diamond Microscope, several paleomagnetic ovens (including one with atmosphere control), and a kappabridge. We also employ a range of thermal evolution models of planetary cores to simulate the generation of natural magnetic fields, and compare these to our measured data to recover the deepest level of insight possible from our data. Please see the links on the left for details of the people in the group, current projects, our world-leading facilities, and recent publications.

Facilities

The Paleomagnetism and Rock Magnetism Laboratory includes:

Photograph of a 2G-enterprises super conducting rock magnetometer

A 2G-enterprises super conducting rock magnetometer

This instrument measures the bulk magnetism carried by natural samples, including samples collected during coring programs, material that dates to the Archean, and meteorites. The magnetisation of these rocks is typically measured as a function of temperature (using one of our paleomagnetic ovens) or alternating magnetic field (using our in-line degausser).

 

Photograph of a quantum diamond microscope (QDM)

A quantum diamond microscope (QDM)

This cutting-edge instrument is one of two geo-QDMs in Europe, and is capable of imaging the stray magnetic fields emanating from samples with micrometre-scale resolution. As such, this instrument opens a new length-scale of material to rock and paleomagnetic investigation. For instance, this instrument is capable of measuring the magnetic romances carried by the individual grains in sedimentary rocks, so unlocks a suite of new material to reliable paleomagnetic studies.

 

Paleomagnetic ovens

Paleomagnetic ovens

The lab currently houses two high-precision ovens that are capable of demagnetising and remagnetising samples to high precisions. The lab will soon be receiving a new, state-of-the-art oven that will include atmospheric control, allowing samples to be heated in environments that minimise their alteration so that their remanences can be unlocked reliably for the first time. The aim is to apply this technique to lunar rocks, meteorites, and samples from the early Earth.

 

Photograph of a kappabridge

A kappabridge

This instrument is capable of measuring magnetic susceptibility as a function of both low and high temperatures, as well as room temperature.

Projects

The Paleomagnetism and Rock Magnetism group is involved in a wide range of projects. These span from focussed projects that involve PhD students targeting specific questions, to larger projects funded by external bodies, to nationwide consortia.

Larger projects include:

The Winchcombe Meteorite Consortium

The Winchcombe meteorite fell in the Cotswolds on 28 February 2021. Within a week, this consortium was set-up to characterise this incredibly fresh carbonaceous chondrite, with the aim of using it to recover a particular clear and reliable picture of the early evolution of our solar system. The Oxford Magnetism Group was chosen to conduct and oversee the magnetic measurements performed on this fascinating sample.

International Space Science Institute Science Team: Atmospheric Escape

A long standing question in studying planetary atmospheres and their connection to their host star is what are the processes that control atmospheric retention or loss, and how these are controlled by the radiation and stellar wind from the host star,  geological processes, and planetary magnetism.

The multi-disciplinary team includes experts from space sciences and planetary sciences, palaeomagnetism (including Claire Nichols from the Oxford Magnetism Group), and Earth and atmospheric sciences, in order to tackle this problem from all angles presently afforded by the scientific community.

Publications