Nongeocentric axial dipole field behavior during the Mono Lake excursion

Authors

Robert M. Negrini, California State University - BakersfieldFollow
Daniel T. McCuan, California State University - Bakersfield
Robert A. Horton, California State University - Bakersfield
James D. Lopez, California State University - Bakersfield
William S. Cassata, Lawrence Livermore National Laboratory
James E.T. Channell, University of Florida
Kenneth L. Verosub, University of California - Davis
Jeffrey R. Knott, California State University - Fullerton
Robert S. Coe, University of California - Santa Cruz
Joseph C. Liddicoat, Barnard College
Steven P. Lund, University of Southern CaliforniaFollow
Larry V. Benson, University of Colorado at BoulderFollow
Andrei M. Sarna-Wojcicki, USGS

Document Type

Article

Date of this Version

3-2014

Citation

Journal of Geophysical Research: Solid Earth (March 10, 2014)

Abstract

A new record of the Mono Lake excursion (MLE) is reported from the Summer Lake basin of Oregon, USA. Sediment magnetic properties indicate magnetite as the magnetization carrier and imply suitability of the sediments as accurate recorders of the magnetic field including relative paleointensity (RPI) variations. The magnitudes and phases of the declination, inclination, and RPI components of the new record correlate well with other coeval but lower resolution records from western North America including records from the Wilson Creek Formation exposed around Mono Lake. The virtual geomagnetic pole (VGP) path of the new record is similar to that from another high-resolution record of the MLE from ODP Site 919 in the Irminger basin between Iceland and Greenland, but different from the VGP path for the Laschamp excursion (LE), including that found lower in the ODP-919 core. Thus the prominent excursion recorded at Mono Lake, CA is not the LE but rather one that is several thousands of years younger. The MLE VGP path contains clusters, the locations of which coincide with nonaxial dipole features found in the Holocene geomagnetic field. The clusters are occupied in the same time progression by VGPs from Summer Lake and the Irminger basin, but the phase of occupation is offset, a behavior that suggests time-transgressive decay and return of the principal field components at the beginning and end of the MLE, respectively, leaving the nonaxial dipole features associated with the clusters dominant during the excursion.