EarthRef.org Reference Database (ERR) -- Tsunakawa & Shaw 1994

EarthRef.org Reference Database (ERR)
Development and Maintenance by the EarthRef.org Database Team

Detailed Reference Information

Tsunakawa & Shaw 1994

Tsunakawa, H. and Shaw, J. (1994). The Shaw Method of Paleointensity Determinations and Its Application to Recent Volcanic-Rocks. Geophysical Journal International 118(3): 781-787.

Our new version together with previous versions of the Shaw method has been compared by applying them to recent volcanic samples for which we have well-determined palaeointensity values. Although the earlier modifications to the Shaw method give a linear portion to the NRM-TRM diagram of all the specimens, about half of the calculated palaeointensities deviate by more than 20 per cent from the expected values. This may be caused by alteration of the magnetic minerals during the laboratory heating or by chemical alteration prior to the laboratory experiments. The new modification uses a double heating of samples above the Curie temperature in the laboratory. After heating the specimen twice in the same held, the measured intensity from the second heating is compared with the laboratory field intensity. If the difference is larger than the experimental error, then we assume that the anhysteretic remanent magnetization (ARM) correction is not applicable and the sample is therefore rejected. This technique provides a powerful criterion with which to select samples. Using this selection technique palaeointensities are generally within +/-10 per cent difference of the expected values with a success rate of about 40 per cent.

BACKGROUND DATA FILES

	Samples & Experimental Procedure

Keywords
anhysteretic remanent magnetizations (arm), double heating, paleointensity, shaw method, thermoremanent magnetization (trm), paleointensity, reliability, hawaii, field

Journal
Geophysical Journal International
http://www.blackwell-synergy.com/servlet/useragent?func=showIssues&code=gji&journal=gji

Publisher
Blackwell Science Ltd.
Osney Mead
Oxford OX2 0EL
U.K.
+44-1865-206206
+44-1865-721205
journals.cs@blacksci.co.uk