HR: 1340h
AN: GP53C-1376    [Abstracts]
TI: Evaluation of the Multispecimen Parallel Differential pTRM Method: A Test on Historical Lavas From Iceland and Mexico
AU: * Michalk, D M
EM: michalk@gfz-potsdam.de
AF: GeoForschungsZentrum Potsdam, Telegrafenberg, Section 3.3, Potsdam, D-14473, Germany
AU: Muxworthy, A R
EM: adrian.muxworthy@imperial.ac.uk
AF: Imperial College, Department of Earth Science and Engineering, South Kensington Campus, London, SW7 2AZ, United Kingdom
AU: Boehnel, H
EM: hboehnel@geociencias.unam.mx
AF: Centro de Geociencias, UNAM-Campus Juriquilla, Queretaro, 76230, Mexico
AU: Nowaczyk, N
EM: nowa@gfz-potsdam.de
AF: GeoForschungsZentrum Potsdam, Telegrafenberg, Section 3.3, Potsdam, D-14473, Germany
AU: Maclennan, J
EM: jmac05@esc.cam.ac.uk
AF: University of Cambridge, Department of Earth Science, Downing Street, Cambridge, CB23EQ, United Kingdom
AB: Studies of the palaeointensity are of crucial importance as they provide information about the origin of the earth's magnetic field and the geodynamic processes within the earth's core, and are a central paleomagnetic research topic. The most commonly accepted technique for determining the palaeointensity is based on several modifications of the method of Thellier and Thellier (Thellier and Thellier, 1959), where the natural remanent magnetisation of a rock is being incrementally replaced with a replicated remanence in the laboratory through multiple heating cycles. However, this technique suffers from numerous drawbacks, both theoretically and experimentally, which has ultimately lead to high failure rates and thus, hampered the acquisition of larger bodies of palaeointensity data in the past. Dekkers and Boehnel (2006) proposed a new multispecimen approach (multispecimen parallel differential pTRM method), based on their study of historical samples from the Trans Mexcian Volcanic Belt. This new method appears to be more reliable and accurate than the Thellier-Thellier methods, because it is less dependent on magnetic domain state, requires no high-temperature, alteration-inducing heating steps and also is significantly faster to measure. They propose that their parallel differential pTRM method has the potential to supersede standard Thellier-Thellier- type techniques. So far this assumption is based on a limited number of samples from Mexico. In our presentation we will report the results from a more comprehensive and robust test of their multispecimen method on 12 historical lavas with well-defined rock magnetic characteristics and ages from 1729 to 2001, from both Mexico and Iceland.
DE: 1521 Paleointensity
DE: 1560 Time variations: secular and longer
DE: 1594 Instruments and techniques
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Fall Meeting