Twenty-two sites, subjected to an IZZI-modified Thellier-Thellier experiment and strict selection criteria, recover a paleomagnetic axial dipole moment (PADM) of 62.2 ± 30.6 ZAm2 in Northern Israel over the Pleistocene (0.012–2.58 Ma). Pleistocene data from comparable studies from Antarctica, Iceland, and Hawaii, re-analyzed using the same criteria and age range, show that the Northern Israeli data are on average slightly higher than those from Iceland (PADM = 53.8 ± 23 ZAm2, n = 51 sites) and even higher than the Antarctica average (PADM = 40.3 ± 17.3 ZAm2, n = 42 sites). Also, the data from the Hawaiian drill core, HSDP2, spanning the last half million years (PADM = 76.7 ± 21.3 ZAm2, n = 59 sites) are higher than those from Northern Israel. These results, when compared to Pleistocene results filtered from the PINT database (www.pintdb.org) suggest that data from the Northern hemisphere mid-latitudes are on average higher than those from the southern hemisphere and than those from latitudes higher than 60°N. The weaker intensities found at high (northern and southern) latitudes therefore, cannot be attributed to inadequate spatiotemporal sampling of a time-varying dipole moment or low quality data. The high fields in mid-latitude northern hemisphere could result from long-lived non-axial dipole terms in the geomagnetic field with episodes of high field intensities occurring at different times in different longitudes. This hypothesis is supported by an asymmetry predicted from the Holocene, 100 kyr, and 5 million year time-averaged geomagnetic field models.
Bibliographical noteFunding Information:
This study was funded by the National Science Foundation. H. Asefaw acknowledges support from the National Science Foundation Graduate Research Fellowship Grant No. DGE‐1650112 and L. Tauxe acknowledges funding from the National Science Foundation Grants EAR1345003 and EAR1827263. The authors thank Christeanne Santos and Malana Tabak for their assistance in the lab. The authors thank Huapei Wang and an anonymous reviewer for their thorough and insightful reviews which greatly improved the manuscript. The authors also thank Yael Ebert for her hard work in the field and Shuhui Cai for her helpful discussions and guidance. The authors thank Jeff Gee for his helpful comments on the manuscript. The authors also thank Huapei Wang and Roman Leonhardt for sharing their measurement level data, which have now been made available in the MagIC database. The authors thank Brendan Cych for advice on the use of the Bias‐Corrected Estimation of Paleointensity code. Thanks to Rupert Minnett for assistance with Binder.
© 2022. The Authors.
- paleointensity methods
- spatial variations