The Earth’s magnetic field in Jerusalem during the Babylonian destruction: A unique reference for field behavior and an anchor for archaeomagnetic dating

Abstract

Paleomagnetic analysis of archaeological materials is crucial for understanding the behavior of the geomagnetic field in the past. As it is often difficult to accurately date the acquisition of magnetic information recorded in archaeological materials, large age uncertainties and discrepancies are common in archaeomagnetic datasets, limiting the ability to use these data for geomagnetic modeling and archaeomagnetic dating. Here we present an accurately dated reconstruction of the intensity and direction of the field in Jerusalem in August, 586 BCE, the date of the city's destruction by fire by the Babylonian army, which marks the end of the Iron Age in the Levant. We analyzed 54 floor segments, of unprecedented construction quality, unearthed within a large monumental structure that had served as an elite or public building and collapsed during the conflagration. From the reconstructed paleomagnetic directions, we conclude that the tilted floor segments had originally been part of the floor of the second story of the building and cooled after they had collapsed. This firmly connects the time of the magnetic acquisition to the date of the destruction. The relatively high field intensity, corresponding to virtual axial dipole moment (VADM) of 148.9 ± 3.9 ZAm 2 , accompanied by a geocentric axial dipole (GAD) inclination and a positive declination of 8.3˚, suggests instability of the field during the 6 th century BCE and redefines the duration of the Levantine Iron Age Anomaly. The narrow dating of the geomagnetic reconstruction enabled us to constrain the age of other Iron Age finds and resolve a long archaeological and historical discussion regarding the role and dating of royal Judean stamped jar handles. This demonstrates how archaeomagnetic data derived from historically-dated destructions can serve as an anchor for archaeomagnetic dating and its particular potency for periods in which radiocarbon is not adequate for high resolution dating.

Searching for the fundamentals of rehydroxylation dating of archaeological ceramics via NMR and IR microscopy

“…Such data are compared to a geomagnetic secular variation curve, based on synchronization with contemporaneous radiocarbon dates and/or historical records, etc. Since the Earth's magnetic field also varies according to geographical location, a separate calibration curve is needed for different regions 15‐17 . However, detailed secular variation curves for many different regions are not yet well‐defined, and archaeomagnetic dating is often not possible.…”

“…Since the Earth's magnetic field also varies according to geographical location, a separate calibration curve is needed for different regions. [15][16][17] However, detailed secular variation curves for many different regions are not yet well-defined, and archaeomagnetic dating is often not possible.…”

Decadal Geomagnetic Secular Variations From Greigite Bearing Dead Sea Sediments

“…Vaknin et al. (2020) suggested that the LIAA extended at least until 2,536 cal yr BP based on high field intensity values from historically dated burnt structure. This raises a question regarding the timing of the termination of the LIAA.…”

“…The VGP path of Caricchi et al (2020) also identified a VGP stand at relatively low latitudes around northern Europe during the early stages of the LIAA, which may explain the high inclinations observed in the Levant before the deposition of the Ein-Feshkha sediments. (Ben-Yosef et al, 2017;Shaar et al, 2011Shaar et al, , 2016Vaknin et al, 2020), Jordan (Ben-Yosef et al, 2009, Syria (Gallet & Al-Maqdissi, 2010;Gallet et al, 2006Gallet et al, , 2008Gallet et al, , 2014Genevey et al, 2003), and Cyprus (Shaar et al, 2015). (b-c) Declination and inclination from EF and from archeomagnetism (Shaar et al, 2018;Speranza et al, 2006;Tema et al, 2018Tema et al, , 2021Vaknin et al, 2020).…”

“…(a) Paleointensity data from Israel(Ben-Yosef et al, 2017;Shaar et al, 2011Shaar et al, , 2016Vaknin et al, 2020), Jordan(Ben-Yosef et al, 2009), Syria(Gallet & Al-Maqdissi, 2010;Gallet et al, 2006Gallet et al, , 2008Gallet et al, , 2014Genevey et al, 2003), and Cyprus(Shaar et al, 2015). (b-c) Declination and inclination from EF and from archeomagnetism(Shaar et al, 2018;Speranza et al, 2006;Tema et al, 2018Tema et al, , 2021Vaknin et al, 2020). Fast change in the inclinations of EF is observed between 2,400 and 2,200 cal yr BP (d) Deviation from the geocentric axial dipole (GAD); a deviation of 20° appears in EF at ∼2,200 yr BP, suggesting a later decaying of the LIAA.…”