Palaeosecular Variation from a Vancouver Island Stalagmite and Comparison with Contemporary North American Records

Abstract

A record of palaeosecular variation has been obtained from a stalagmite from Vancouver Island, Canada, spanning the period 16.9 ± 6.0 to 13.3 ± 2.3 ka. Dating control was provided using the uranium-thorium disequilibrium method. The main magnetic remanence carrier in the speleothem is a fine-grained magnetite which is thought to be of detrital, rather than chemical, origin. The record is apparently free from any depositional inclination errors and compares well with a contemporaneous speleothem record obtained from the same cave (Latham et al., 1987). Good correlation also exists with several North American lacustrine records. The record provides evidence of clockwise looping of the position of the virtual geomagnetic pole over western Canada from about 14.9 to 13.6 ka, and in the interval from 16.9 to 15.2 ka the data can be modelled by a stationary, oscillating, inward-pointing source to the north-west of the sampling site. © 1995, Society of Geomagnetism and Earth, Planetary and Space Sciences. All rights reserved.