New Late Neolithic (c. 7000–5000 BC) archeointensity data from Syria. Reconstructing 9000years of archeomagnetic field intensity variations in the Middle East

Abstract

International audienceWe present new archeomagnetic intensity data from two Late Neolithic archeological sites (Tell Halula and Tell Masaïkh) in Syria. These data, from 24 groups of potsherds encompassing 15 different time levels, are obtained using the Triaxe experimental protocol, which takes into account both the thermoremanent magnetization anisotropy and cooling rate effects on intensity determinations. They allow us to recover the geomagnetic intensity variations in the Middle East, between ∼7000 BC and ∼5000 BC, i.e. during the so-called pre-Halaf, proto-Halaf, Halaf and Halaf-Ubaid Transitional cultural phases. The data are compared with previous archeointensity results of similar ages from Northern Iraq (Yarim Tepe II and Tell Sotto) and Bulgaria. We find that previous dating of the Iraqi material was in error. When corrected, all northern Mesopotamian data show a relatively good consistency and also reasonably match with the Bulgarian archeointensity dataset. Using a compilation of available data, we construct 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. We further use this compilation to constrain variations in dipole field moment over most of the Holocene. In particular, we discuss the possibility that a significant dipole moment maximum occurred during the third millennium BC, which cannot easily be identified in available time-varying global geomagnetic field reconstructions

A 17,000 yr paleomagnetic secular variation record from the southeast Alaskan margin: Regional and global correlations

“…NEPSIAS -DI anomalies are associated with eastward NNA declination and NEPSIAS + DI anomalies are associated with NNA westward declinations (Figures 9 and 10). The directional records can be compared to regional geomagnetic intensity, over the past ~3000 years in the North America and back nearly 9000 years in the Euro/Mediterranean region (e.g., Genevey et al, 2008;Gallet et al, 2015); these observations suggest oscillations between the 'North American' and 'European' modes of PSV organization that may be driven by variability in the relative strength of the North American flux lobe and Euro/Mediterranean extension of the Siberian flux lobe (Gallet et al, 2009;Stoner et al, 2013). If so, the persistence of these features implicates a long-lived organizing structure imposed on the geomagnetic field, perhaps by the lower mantle (Bloxham and Gubbins, 1987;Bloxham, 2002;Gubbins et al, 2007) and/or inner core heterogeneities (Aubert et al, 2013) that profoundly influences the spatial and temporal patterns of PSV.…”

“…In the northern North Atlantic (NNA) these deviations are primarily expressed as large eastward shifts in declination associated with highs in European/Mediterranean archeomagnetic intensity over the last ~ 9000 cal ybp (e.g., Genevey et al, 2008;Gallet et al, 2015).…”

Archaeointensity results spanning the past 6 kiloyears from eastern China and implications for extreme behaviors of the geomagnetic field

“…Taking together, we establish an archaeointensity reference curve for Eastern Asia, which can be used for archaeomagnetic dating in this region. Virtual axial dipole moments (VADMs) of the data range from a Holocene-wide low of ∼27 to "spike" values of ∼166 ZAm 2 (Z: 10 21 ). The results, in conjunction with our recently published data, confirm the existence of a decrease in paleointensity (DIP) in China around ∼2200 BCE.…”

Recent Advances in Chinese Archeomagnetism

“…Only those data with age sigma less than 500 yr and standard deviation of the intensity less than 4 µT or 10% (the same requirement for sample mean as in CCRIT) were included. The reference curve was calculated with a parametric bootstrap and running average technique, following Cai et al (2017) and Gallet et al (2015). The procedure is: resample 1,000 times at each data point considering uncertainties of both age and virtual axial dipole moment (VADM) and then calculate the running average of the new dataset with a time window of 200 y shifted by 10 y (only time intervals including more than three data points were calculated).…”

“…Recent archeomagnetic studies are mostly concentrated in Europe Gómez-Paccard et al, 2012;Tema et al, 2012;Genevey et al, 2013;Hervé et al, 2013a,b;Kovacheva et al, 2014) and the Middle East (Ertepinar et al, 2012(Ertepinar et al, , 2016Gallet et al, 2015;Shaar et al, 2016;, with a few publications from other areas such as Mexico (Guerrero et al, 2016), Africa (Mitra et al, 2013;Tarduno et al, 2015;Kapper et al, 2017) and Asia (Yu et al, 2010;Hong et al, 2013;Venkatachalapathy et al, 2013). China constitutes a huge part of Eastern Asia and has a civilization that spans thousands of years leaving abundant archeological artifacts.…”