Archaeomagnetism for resolving chronological problems: Status and future potential
Program Unit: Israel Geological Society (IGS) Annual Meeting 2011, Mitzpe Ramon, Israel
Shaar, R., Ben-Yosef, E., Ron, H., Tauxe, L., Agnon, A., Kessel, R., and Finkelstein, I.

The direction and intensity of the Earth magnetic field are changing over timescales ranging from decades (or even less) to millions of years. A main aim of paleomagnetic research is to document these variations in order to understand their mechanism. Paleomagnetic research is possible because magnetized rocks and archaeological artifacts can act as recording media of the field at the time of their formation. Paleomagnetic study of archaeological artifacts is referred to as archaeomagnetism. This paper demonstrates the application of archeomagnetism using three types of archaeological recording materials: 1) copper slag from the Timna Valley, 2) potsherds from Tel-Megiddo, and 3) in-situ ovens and kilns. Each of these recorders has its advantage. The copper slag and potsherds usually allow only the determination of the absolute intensity of the past magnetic field (i.e. paleointensity), while the ovens and kilns allow also the measurements of the direction of the past magnetic field - inclination and declination. The combination of these three types of recorders, collected from different late Bronze-Age to Iron-Age archaeological contexts, is used to generate a unique full-vector description of the geomagnetic field. Our results reveal that dramatic variations in the field may occur over timescales of hundreds of years to less than decades. One important implication of our findings is that the archaeomagnetic record is a promising means for chronological correlation, especially when the 14C-based chronology is limited. We demonstrate the application of this approach by resolving a high-resolution chronology of copper production in Timna. Using the paleomagnetic measurements we correlate two 14C dated slag mounds from Israel and Jordan, and achieve combined well-constrained dates. Preliminary Iron-Age data from Tel-Megiddo remarkably agree with the data obtained from the slag, thus realizing the potential of our working methodology.