Multivectorial paleointensity determination by the Thellier method

• Published in: Journal of Geophysical Research - Solid Earth Vol. 111; no. B12; pp. B12S32 - n/a
• Main Authors: Shcherbakov, V. P., Zhidkov, G. V.
• Format: Journal Article
• Language: English
• Published: American Geophysical Union 01-12-2006; Blackwell Publishing Ltd
• Subjects: Arai-Nagata diagrams; Geomagnetism and Paleomagnetism; multivectorial NRM; Paleointensity; Remagnetization; Rock and mineral magnetism; Arai-Nagata diagrams; multivectorial NRM
• ISSN: 0148-0227; 2156-2202
• DOI: 10.1029/2006JB004504

Theoretical and experimental study of shape of the Arai‐Nagata diagrams for the natural remanent magnetization (NRM) consisting of two low‐ and high‐temperature partial thermal remanent magnetization vectors directed at angle θ to each other is considered. Assuming that the NRM is carried by single‐domain and/or small pseudosingle‐domain grains, that is, the Thellier laws of additivity and independence are valid, a theoretical consideration showed that the low‐temperature portion of the diagram has a hyperbolic shape. A striking feature of the diagram is that at obtuse angle θ and strong enough low‐temperature component it exhibits a minimum. The theoretical conclusions were examined experimentally; the results of the experiments are in a good agreement with the theoretical predictions. The shape of the low‐temperature portion is predetermined by the angle θ, the relative intensity of low‐temperature component, and the field h in which this component was imparted. These three parameters can be found from the results of Thellier experiments by the least squares method. It opens a way to determine the paleofield h and the angle θ which are characteristics of the low‐temperature (presumably secondary) remanent magnetization. A few examples of such the determinations on samples from Proterozoic collections are reported.