Environmental magnetism
Environmental magnetism is the study of
archeology.[1]
The main advantages of using magnetic measurements are that magnetic minerals are almost ubiquitous and magnetic measurements are quick and non-invasive.
History
Environmental magnetism was first identified as a distinct field in 1978 and was introduced to a wider audience by the book Environmental Magnetism in 1986.[2][3] Since then it has grown rapidly, finding application in and making major contributions to a range of diverse fields, especially paleoclimate, sedimentology, paleoceanography, and studies of particulate pollution.[4][5]
Fundamentals
Environmental magnetism is built on two parts of
iron oxides, including magnetite, maghemite, hematite; and iron sulfides (particularly greigite and pyrrhotite). These minerals are strongly magnetic because, at room temperature, they are magnetically ordered (magnetite, maghemite and greigite are ferrimagnets while hematite is a canted antiferromagnet
).
To relate magnetic measurements to the environment, environmental magnetists have identified a variety of processes that give rise to each magnetic mineral. These include
magnetosomes by magnetotactic bacteria
.
Applications
Paleoclimate
Magnetic measurements have been used to investigate past climate. A classic example is the study of
oxygen isotope stages. Ultimately, this work allowed environmental magnetists to map out the variations in the monsoon cycle during the Quaternary.[5] Magnetic measurements of lacustrine sediments can also be used to reconstruct the upland surface processes that were associated with past climate.[8]
See also
Notes
References
- Dekkers, M. J. (1997). "Environmental magnetism: an introduction". Geologie en Mijnbouw. 76 (1–2): 163–182. S2CID 127663569.
- Dunlop, David J.; Özdemir, Özden (1997). Rock magnetism: Fundamentals and Frontiers. ISBN 978-0-521-32514-1.
- Evans, Michael E.; Heller, Friedrich (2003). Environmental Magnetism: Principles and Applications of Enviromagnetics. ISBN 978-0-12-243851-6.
- Maher, B.A. (1988). "Magnetic properties of some synthetic sub-micron magnetites". Geophys. J. R. Astron. Soc. 94 (1): 83–96. .
- Maher, B.A.; Thompson, R. (1999). Quaternary Environments, Climates and Magnetism. ISBN 978-0-521-62417-6.
- Oldfield, F.; Dearing, J.A.; Thompson, R.; Garret-Jones, S.E. (1978). "Some magnetic properties of lake sediments and their possible links with erosion rates". Polskie Archive. Hydrobiologia. 25: 321–331.
- Thompson, R.; Oldfield, F. (1986). Environmental Magnetism. ISBN 978-0-04-538003-9.
- Verosub, Kenneth L.; Roberts, Andrew P. (1995). "Environmental magnetism: Past, present and future". J. Geophys. Res. 100 (B2): 2175–2192. .