The Iron Age Geomagnetic Field

考古学和对地球古代磁场的研究之间的相互作用可以追溯到19世纪末，当时物理学家意识到陶瓷和其他考古材料可以保留古代磁场的记录。陶瓷材料是现代实验方法确定古代磁场强度的第一批目标之一，被称为“考古磁学”的磁场今天仍然充满活力。考古学家开始利用对物质年龄的强大限制，在具有准确参考模型的地区，完全磁矢量是可能的，地磁学家正在利用不断增长的古地磁数据库，它正在产生更多具有更好年龄限制的高质量数据。然而，部分由于从地质和考古材料中恢复古代磁场强度的实验困难，部分由于缺乏可供研究的准确年代的材料，考古磁学数据库仍然严重偏向于过去数千年的欧洲数据。这笔赠款将支持扩大过去四千年全球数据集的努力，包括新的放射性碳年龄控制和来自目前采样不足地区的新的古地磁和考古地磁数据。这项研究将对地磁场的数值模拟产生影响，并为考古学研究提供更高分辨率的年龄约束。准确地描绘全球尺度上的古强度变化(该项目对此作出贡献但不能自行解决的目标)对于了解放射性碳生产的变化和对放射性碳时间尺度的校准至关重要。最后，这项提议将有助于支持继续开发古地磁学在线教材，其形式是国际地磁学联合会的古地磁学要点在线教科书项目(见http://magician.ucsd.edu/Essentials))，并促进向世界各地的研究生提供古地磁学在线课程。

The interplay between archaeology and the study of the Earth's ancient magnetic field goes back to the late 19th century when physicists realized that ceramics and other archeological materials could retain a record of the ancient magnetic field. Ceramic materials were among the very first targets of modern experimental methods to determine the ancient field strength and the field known as "archaeomagnetism" remains vibrant today. Archaeologists are beginning to take advantage of the powerful constraints on ages of material for which full magnetic vectors are possible in regions with an accurate reference model and geomagnetists are taking advantage of the growing archeomagnetic data base which is producing more high quality data with better age constraints. However, partly owing to the experimental difficulties in recovering ancient magnetic field strength from geological and archaeological materials and partly because of a lack of well-dated materials for study, the archaeomagnetic data base remains heavily biased towards European data from the last millennia. This grant will support efforts to expand the global data set over the last four millennia, including new radiocarbon age control and new paleomagnetic and archaeomagnetic data from places that are currently under-sampled. The research supported here will have implications for numerical simulations of the geomagnetic field, and provide higher resolution age constraints for archaeological research. An accurate picture of paleointensity changes on a global scale (a goal to which this project contributes but does not solve by itself) is essential for understanding variations in the production of radiocarbon and the calibration of the radiocarbon time scale. Finally, this proposal will help support the continued development of online paleomagnetic teaching materials in the form of the Essentials of Paleomagnetism online textbook project of the PI (see http://magician.ucsd.edu/Essentials) and facilitate offering of online classes in paleomagnetism offered to graduate students the world over.