Archaeointensity of Historically Dated Burnt Structures in the Southern Levant: Anchors for the Evolution of the Levantine Iron Age Anomaly and the Timing of Geomagnetic Spikes

Abstract:

In the ongoing effort to accurately reconstruct the secular variations of Earth’s ancient magnetic field, archaeomagnetism plays an important role, supplying relatively well dated materials. The Southern Levant can contribute considerably to this effort, since it has undergone intensive archaeological research. Here we present paleointensity (PI) results from 22 destruction layers from 15 archaeological sites in this region, spanning the Late Bronze and Iron Ages (ca. 1300 BCE to 586 BCE). From each destruction layer we present between 7 to 29 specimens that met the strict criteria common in PI experiments.

The destruction layers represent events which are often very well dated with an error range of less than several decades. In several cases they are dated to the year based on their association with specific historical events, a type of evidence which is particularly important for the period after ~800 BCE, when a plateau in the radiocarbon calibration curve does not enable high resolution dating. In this study, we focused on building materials, mainly sun dried mud bricks, that were first fired during destruction events. In addition to intensity, we also reconstructed paleomagnetic directional data when the materials were sampled in the original position in which they had cooled down. In turn, these data were used to corroborate archaeological observations of a destruction by fire.

As the acquisition of the magnetic information in the sampled materials occurred at a discrete point in time, the new archaeomagnetic data help chronologically constrain the evolution of the Levantine Iron Age Anomaly, which spanned the period from the 10th century BCE until at least the 6th century BCE in the Near East. The new data further confirm the existence of intensity spikes during this period and help to chronologically pinpoint them.