Paleomagnetism and Paleosecular Variations From the Plio-Pleistocene Golan Heights Volcanic Plateau, Israel

Nicole Behar*, Ron Shaar, Lisa Tauxe, Hanna Asefaw, Yael Ebert, Ariel Heimann, Anthony A.P. Koppers, Hagai Ron

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

Statistical analysis of geomagnetic paleosecular variation (PSV) and time-averaged field has been largely based on global compilations of paleomagnetic data from lava flows. These show different trends in the averaged inclination anomaly (ΔI) between the two hemispheres, with small positive (<2°) anomalies in midsouthern latitudes and large negative (> −5°) anomalies in midnorthern latitudes. To inspect the large ΔI between 20°N and 40°N we augment the global data with a new paleomagnetic data set from the Golan-Heights (GH), a Plio-Pleistocene volcanic plateau in northeast Israel, located at 32–33°N. The GH data set consists of 91 lava flows sites: 40 sites obtained in the 1990s and 51 obtained in this study. The chronology of the flows is constrained by 57 40Ar/39Ar ages: 39 from previous studies and 18 from this study, which together cover most of the GH plateau. We show that the 1990s data set might be affected by block rotations and does not fully sample PSV. The Plio-Pleistocene pole (86.3°N, 120.8°E, N = 44, k = 25, α95 = 4.4°), calculated after applying selection criteria with Fisher precision parameter (k) ≥ 100 and number of specimens per site (n) ≥ 5 is consistent with a geocentric axial dipole field and shows smaller inclination anomaly (ΔI = −0.4°) than predicted by global compilations and PSV models. Reexamination of the inclination anomaly in the global compilation using different calculation methods and selection criteria suggests that inclination anomaly values are affected by (1) inclusion of poor quality data, (2) averaging data by latitude bins, and (3) the way the inclination anomaly is calculated.

Original languageAmerican English
Pages (from-to)4319-4335
Number of pages17
JournalGeochemistry, Geophysics, Geosystems
Volume20
Issue number9
DOIs
StatePublished - 1 Sep 2019

Bibliographical note

Publisher Copyright:
©2019. American Geophysical Union. All Rights Reserved.

Keywords

  • Ar/Ar ages
  • Golan Heights
  • inclination anomaly
  • paleomagnetism
  • paleosecular variations
  • time averaged field

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