34 Paleomagnetism, Rock Magnetism, Environmental Magnetism, Instrumentation, Archaeomagnetism, Planetary Magnetism, and Petrofabrics

Thursday, 17 March 2022
8:00 AM - 12:00 PM
CBC-A 110

ON THE RELATIONSHIP BETWEEN EXCURSIONS AND NORMAL SECULAR VARIATION

Paper number: 34-1
Program: Theme Sessions
Time: 8:00 AM – 8:20 AM

Authors

  • Steven Lund Presenting Author
    University of Southern California, Los Angeles, CA

Abstract

Recently, the pattern of paleomagnetic secular variation (PSV) surrounding paleomagnetic field excursions has been determined for seven excursions over the last 380 ky of the Brunhes Normal Polarity Chron. Good quality excursion records always appear to be associated with a broad decrease in paleointensity. In all cases, the PSV angular dispersion increases abruptly by a factor of two at the start of the lower paleointensity interval and decreases abruptly at the end. The doubling of PSV angular dispersion occurs with only modest (<10%) decrease or increase in paleointensity. These abrupt changes indicate some significant non-linear change in dynamo conditions. In some cases, anomalous PSV precedes excursions by up to 20 ky and displays a waveform pattern that seems to continue into the excursion waveforms themselves.

Geological Society of America Abstracts with Programs. Vol. 54, No. 2

doi: 10.1130/abs/2022CD-374015

© Copyright 2022 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.