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Paleointensity Estimates from the Pleistocene of Northern Israel: Implications for hemispheric asymmetry in the time averaged field
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  • Lisa Tauxe,
  • Hanna Asefaw,
  • Nicole Andrea Behar,
  • Anthony A.P. Koppers,
  • Ron Shaar
Lisa Tauxe
University of California, San Diego, University of California, San Diego

Corresponding Author:[email protected]

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Hanna Asefaw
Scripps Institution of Oceanography, University of California San Diego, USA, Scripps Institution of Oceanography, University of California San Diego, USA
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Nicole Andrea Behar
The Institute of Earth Sciences, Hebrew University of Jerusalem, Israel, The Institute of Earth Sciences, Hebrew University of Jerusalem, Israel
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Anthony A.P. Koppers
Oregon State University, Oregon State University
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Ron Shaar
Hebrew University of Jerusalem, Hebrew University of Jerusalem
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Abstract

Twenty-two sites, subjected to an IZZI-modified Thellier-Thellier experiment and strict selection criteria, recover a paleomagnetic axial dipole moment (PADM) of 62.24$\pm$ 30.6 ZAm$^2$ 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 $\pm$ 23 ZAm$^2$, n = 51 sites) and even higher than the Antarctica average %\cite{asefaw21} (PADM = 40.3 $\pm$ 17.3 ZAm$^2$, n = 42 sites). Also, the data from the Hawaiian drill core, HSDP2, spanning the last half million years (PADM = 76.7 $\pm$ 21.3 ZAm$^2$, 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$^{\circ}$N. The weaker intensities found at high (northern and southern) latitudes therefore, cannot be attributed to inadequate spatio-temporal 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 five million year time-averaged geomagnetic field models.