Directional errors in remanent magnetization of non‐cubic soft sediment specimens measured with spinner magnetometers

Abstract

Summary. This paper assesses theoretically and experimentally the errors in palaeomagnetic directions introduced by measuring rectangular but non‐cubic blocks of soft sediments in slow speed spinner magnetometers. Plastic boxes commonly used for this purpose hold samples 21 × 21 × 15 mm. This study models the response of Schonstedt and Molspin spinners to such specimens and presents the results of experiments in which the remanent magnetization (RM) of obsidian blocks, both as cubes and after subsequent cutting to fit within the boxes, was measured to determine actual instrument behaviour. These experiments indicate that the error introduced by use of specimens of the above dimensions may be as much as 8.5° for the smallest specimen‐sensor separation in the Schonstedt spinner. For the Molspin spinner and for the next smallest specimen‐sensor separation in the Schonstedt instrument, the error is smaller but nevertheless non‐negligible. Copyright © 1989, Wiley Blackwell. All rights reserved