People at Fort Hoofddijk

Lennart de Groot
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L.V. de Groot, MSc
Paleomagnetic Laboratory
Fort Hoofddijk
Department of Earth Sciences
Utrecht University 
Budapestlaan 17, 3584 CD Utrecht 
The Netherlands 

Phone +31 30 253 5418


Research of Lennart de Groot

A new approach for determining the absolute paleointensity of the Earth's magnetic field
Lennart drilling on the Etna

In recent years, significant advances have been made in paleointensity studies, best illustrated by the introduction of a new PI method. The Multi-Specimen method (MSP), introduced by Mark Dekkers and Harald Boehnel heats specimens to the same set-temperature while applying different fields per specimen. Plotting the fraction of the NRM that is left after the heating step as a function of the applied field and fitting a line through the data, gives the field for which the pTRM is the same as the NRM and thus -in theory- the strength of the paleofield.

Lennart drilling in Etna volcanics

At the summit of Mount Etna
Lennarts project focusses on assessing and gaining experience with the MSP method and comparing it to other PI methods, such as microwave experiments or the more classical Thellier-Thellier-style experiments. In the fall of 2008 a data set was drilled on different recent lava flows on the flanks of Mt. Etna, Sicily. The results of all applied PI methods are puzzling at least...In the spring of 2010 a fieldwork will be carried out in the state of Hawaii, at the Big Island and Maui, to further assess the MSP method. Besides that, more theoretical and fundamental work will be done to test and hopefully further establish this new PI method.

Lennarts project is supervised by Mark Dekkers with valuable support from Tom Mullender

publications Publications of Lennart de Groot
  • De Groot, L.V., Biggin, A.J., Dekkers, M.J., Langereis, C.G., Herrero-Bervera, E. (2013). Rapid regional perturbations to the recent global geomagnetic decay revealed by a new Hawaiian record, Nature Communications, 4, doi: 10.1038/ncomms3727.  
  • De Groot, L.V., Mullender, T.A.T. and Dekkers, M.J. (2013). An evaluation of the influence of the experimental cooling rate along with other thermomagnetic effects to explain anomalously low paleointensities obtained for historic lavas of Mt. Etna  (Italy), Geophys. J. Int., 193, 1198-1215, doi: 10.1093/gji/ggt065. 
  • De Groot, L.V., Dekkers, M.J., Mullender, T.A.T. (2012). Exploring the potential of acquisition curves of the anhysteretic remanent magnetization as a tool to detect subtle magnetic alteration induced by heating, Phys. Earth Planet. Inter., 194-195, 71-84.