Fundamental Magnetic Constants and Palaeomagnetic Recording Fidelity of Greigite (Fe3S4)

Lead Research Organisation: University of Edinburgh
Department Name: Sch of Geosciences


Greigite (Fe3S4) is a strongly magnetic mineral that is being increasingly recognised in the geological record. It is widely associated with anomalous magnetizations that complicate analysis of Earth's magnetic field behaviour and environmental change in sedimentary sequences. In particular, the Arctic is a frontier region where active international efforts are being made to understand past variations in climate. The presence of greigite in Arctic sediments makes it difficult to determine if palaeomagnetic observations result from unique magnetic field variations at high latitudes or from anomalous field recording associated with strongly magnetically interacting clusters of greigite grains. Despite the increasing recognition of the importance of greigite in the geological record, and in contrast with other important terrestrial magnetic minerals, key fundamental magnetic parameters for greigite remain unknown. This makes it impossible to model micro-scale magnetic characteristics to test whether authigenic growth of greigite in clusters can explain the anomalous magnetizations commonly associated with greigite. Recent work in the PI's research group has enabled identification of 2 of the 3 key parameters required to undertake such modelling. We request funds to determine the remaining key parameter and to undertake modelling that will provide the basis for assessing the palaeomagnetic recording fidelity of greigite. This work will benefit the international palaeomagnetic community who seek to understand high latitude geomagnetic field behaviour and the palaeoclimate community who widely use palaeomagnetic records to construct chronologies of climate change. Greigite growth is also associated with gas hydrate formation. The proposed work could therefore also provide parameters that would enable greigite to be used as a tracer for the former presence of methane hydrates in sedimentary sequences.


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Description We were able to accurately measure the fundamental magnetcicconstants in Greigite and establish the critical grains sizes where the magnetisation domain structure changes form uniform to more complex states. This then can tell us about the reliability of greigite as a recorder of the Earth's magnetic field.
Exploitation Route The work is being carried forward by numerous group that are investigating greigite as a significant carrier of paleoamagnetic signals.
Sectors Environment


Description the work has been used in the interpretation of magnetic recordings in Greigite, which is an important mineral both in palaeomagnetic interpretations as a environmental proxy.
First Year Of Impact 2010
Sector Education,Environment,Other
Impact Types Societal