@article {3458,
	title = {Paleomagnetic field intensity derived from non-SD: Testing the Thellier IZZI technique on MD slag and a new bootstrap procedure},
	journal = {Earth and Planetary Science Letters},
	volume = {310},
	year = {2011},
	note = {864XJ Times Cited:7 Cited References Count:44},
	pages = {213-224},
	type = {Journal Article},
	abstract = {Experimental techniques to determine paleomagnetic field intensity are based on a theoretical framework that is valid only for single-domain (SD) ferromagnetic particles. Yet, most of the available materials exhibit distinctly non-SD properties. Designing the optimal paleointensity methodology for non-SD is, therefore, a fundamental challenge in paleomagnetism. The objective of this study is to experimentally test the IZZI Thellier absolute paleointensity method on small MD recorders. The test has two purposes: 1) to describe the characteristic non-SD patterns occurring in Arai plots, and 2) to identify the optimal approach in interpreting non-SD behavior. We carried out paleointensity experiments on 40 specimens from 4 synthetic re-melted slag samples with identical magnetic properties (mineralogy, texture, and non-SD state) produced under different field intensities. We ran three batches of IZZI experiments using different conditions that allow for a detailed characterization of the non-SD behavior. We find that the curvature of the Arai plot is systematically dependent on the angle and the proportion between the field used in the paleointensity experiment (B-TRM) and the field in which the NRM was acquired (B-NRM). Straight-line Arai plot occur when the two fields are parallel and equal, and seems to always give the {\textquoteright}true{\textquoteright} slope. Convex curves occur when B-TRM is parallel and significantly stronger than B-NRM. Concave curves occur in all the other cases and yield two end-case slopes that are always different than the {\textquoteright}true{\textquoteright} slope. In addition, zigzagged patterns increase with the angle the proportion between B-TRM and B-NRM. We test the accuracy of the {\textquoteright}best fitting{\textquoteright} line approach and conclude that {\textquoteright}best fitting{\textquoteright} line in curved plots cannot provide robust paleointensity estimates. Yet, the two {\textquoteright}end-case{\textquoteright} slopes in concave curves provide adequate constraints for the true value. We introduce a new procedure to calculate a 95\% confidence interval of the paleointensity from curved plots using bootstrap statistics. We substantiate the new procedure by conducting two independent tests. The first uses synthetic re-melted slag produced under known field intensities - 3 SD samples and 4 non-SD samples. The second compares paleointensity determinations from archeological slag samples of the same age - 34 SD samples and 10 non-SD samples. The two tests demonstrate that the bootstrap technique may be the optimal approach for non-ideal dataset. (C) 2011 Elsevier BM. All rights reserved.},
	keywords = {paleointensity archeomagnetism thellier slag trm multi-domain paleointensity experiments geomagnetic-field single-domain partial thermoremanence ferromagnetic grains multidomain behavior 1st-order symmetry pseudo-single copper slag lava flows},
	issn = {0012-821X},
	doi = {Doi 10.1016/J.Epsl.2011.08.024},
	url = {<Go to ISI>://WOS:000298273500005},
	author = {Shaar, R. and Ron, N. and Tauxe, L. and Kessel, R. and Agnon, A.}
}
