Exploring the geomagnetic field anomaly during the first millennium CE: Evidence from new archaeointensity data from China
Abstract
The paleointensity variations of the geomagnetic field during the Holocene are increasingly constrained owing to the abundance of archaeological artifacts and their favorable properties for paleointensity experiment. Establishment and improvement of the local variation curves of various areas has significant implications for global comparison, geomagnetic modeling and archaeomagnetic dating. The archaeomagnetic study in China were mainly carried out in the 1980s by Wei et al. (e.g., Wei et al., 1982, 1986, 1987) and resumed recently by Cai et al. (e.g., Cai et al., 2014, 2015). Large fluctuations of the field intensity during the past few millennia have been revealed by the published data in China. A notable feature is those high intensity values between 0-800 CE published by Wei et al. (1982, 1986). Quite a few of them are approximate to or over the level of a geomagnetic field "spike" (with virtual axial dipole moment in excess of 160 ZAm2 suggested by Cai et al. (2014)). This geomagnetic anomaly is significant to the Chinese or even the Eastern Asian local variation model of the geomagnetic field and also important for the related geodynamic processes. However, these data were obtained by previous techniques without enough quality control and the reevaluation of their reliability is not available. Besides, this anomaly has not been captured by either recently published data at adjacent ages or the global models. All these together make the reliability of this anomaly questionable. In order to clarify this issue, we conducted paleointensity experiments on a large quantity of archaeological samples from similar time period and part of them even from the same or nearby locations. The results of our study will provide strong constraints on the improvement of both the local model of Eastern Asia and the global models of the geomagnetic field.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMGP23A1315C
- Keywords:
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- 1503 Archeomagnetism;
- GEOMAGNETISM AND PALEOMAGNETISMDE: 1521 Paleointensity;
- GEOMAGNETISM AND PALEOMAGNETISMDE: 1522 Paleomagnetic secular variation;
- GEOMAGNETISM AND PALEOMAGNETISMDE: 1532 Reference fields: regional;
- global;
- GEOMAGNETISM AND PALEOMAGNETISM