9000 years of archeomagnetic field intensity variations in the Middle East

English Abstract:

Thanks to its rich archeological and historical heritage, the Middle East offers the possibility to travel back through the geomagnetic field history over most of the Holocene. Archeomagnetic studies conducted up to now were mainly focused on the Bronze and Iron Age archeological periods, allowing a better characterization of the regional geomagnetic field intensity behavior for the last 3 millennia BC. These studies have revealed significant field intensity variations, and in particular a series of intensity maxima between c. 2600 and 2500 BC, between c. 2300-2000 BC, around 1500 BC and at the very beginning of the first millennium BC. These studies have further shown that the beginning of the first millennium BC was most probably marked by the highest geomagnetic field intensity detected so far during the Holocene. Archeointensity data available for the pre-Bronze Age period remain scarce. However, several possibilities exist to sample archeological sites older than 3000 BC. This is particularly true for the 6th and 7^th millennia BC, which saw the development of the Hassuna and Halaf cultures throughout the northern Mesopotamian region. We will mainly discuss our recent acquisition of new archeointensity results dated to between c. 7000 and c. 5000 BC from two Syrian archeological sites (Tell Halula and Tell Masaikh). These results were obtained from 225 pottery fragments using the Triaxe protocol, which takes into account both the thermoremanent magnetization anisotropy and cooling rate effects on intensity determinations. We will then report on a geomagnetic field intensity variation curve for the Middle East encompassing the past 9000 years, which makes it presently the longest known regional archeomagnetic intensity record.